Potential detoxification of Sheboygan Harbor PCB's

[From the U.S. Government Printing Office, www.gpo.gov]

TASK I.A.1

POTENTIAL DETOXIFICATION
OF
SHEBOYGAN HARBOR PCB'S

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POTENTIAL DETOXIFICATION
OF
SHEBOYGAN HARBOR PCBS

COASTAL ZONE
INFORMATION CENTER

This study was funded in part with
financial assistance provided by
the State of Wisconsin, Division of
Energy and Intergovernmental
Relations, Coastal Management
Program through a grant under the
Coastal Zone Management Improvement
Act of 1980, as amended,
administered by the Office of Ocean
and Coastal Resource Management,
National oceanic and Atmospheric
Administration.

The development of this project was
under the supervision 'of William C.
Sonzogni, University of Wisconsin,
"k,
QQN3tP,,1fPEP V E Madison, Wisconsin.
@ARJM

US Department of Commerce
NOAA Coastal Services Ccnter Library
2234 South Hobson Avenue
Charleston, SC 29405-2413

EXECUTIVE SUMMARY

POTENTIAL DETOXIFICATION OF
SHEBOYGAN HARBOR PCBS

William C. Sonzogni
Principal Investigator

over the last two years research has been conducted on
Wisconsin's Sheboygan River, a tributary to Lake Michigan located
north of the City of Milwaukee. The Sheboygan River was studied

because it is contaminated by polychlorinated biphenyls (PCBs), so

much that it has been declared a Superfund Site by the U.S.

Environmental Protection Agency and a Great Lakes Area of Concern

by the U.S./Canadian International Joint Commission. The river is

also a source of PCBs to Lake Michigan. Further, the PCBs, at

least some of more toxic PCB compounds, are a potential health risk

to inhabitants of the river or users of the river. Thus, this

research was designed to provide important information on a major

environmental problem affecting the coastal zone of the Great

Lakes.

The focus of the research was to determine whether PCB

dechlorination is occurring in the river's sediments. High

resolution gas chromatographic analyses were made on sediment,

water, and fish collected from the river and harbor. In addition,

several sail samples from a confined disposal facility holding

dredged sediment were also analyzed. Laboratory experiments were

also conducted to try and replicate some of the processes that

occur in the natural environment. information from other

investigators and the scientific literature was used when possible

to supplement findings.

Overall, the research was successful. All of the objectives

were met. major findings of the research are summarized below.

1. Data collected on PCBs in sediments indicate the
distribution of PCB compounds (congeners) has changed relative

to the distribution of PCBs that originally polluted the

river.

2. It appears, based on all the available evidence, that the

changes in the PCB distribution are the result of

dechlorination of the PCBs by anaerobic microorganisms in the

sediment.

3. Dechlorination was observed mainly in those section of the

river with accumulation of muck (sedimentation areas) and

where total PCB concentrations were high.

4. The fact that many of the higher chlorinated PCB compounds

(congeners) are being dechlorinated indicates that some

natural detoxification is occurring, as the more highly

chlorinated PCB compounds are generally considered to be more

toxic.

5. The results suggest that it may be possible to modify

natural processes to speed up the dechlorination as a

bioremediation measure. Complete degradation of the PCBs may

even be possible.

6. PCB concentrations in the harbor (about 20 km downstream

from the source) were much lower than the source area and the

distribution of PCB compounds did not show evidence of

degradation.

7. PCB concentrations in the water were much lower than in

sediment, but concentrations increased downstream from the

source. The distribution of PCB compounds varied between the

2. One thesis was published as a result of this research, and
two research papers are written so far and will be submitted

to refereed scientific journals.
3. Several presentations have been made on the project at

scientific meetings, including an international workshop on

biological remediation of contaminated sediments sponsored by

the U.S. Environmental Protection Agency. A summary of the

presentation is to be published in the workshop proceedings.

4. The multidimensional gas chromatograph, purchased for the

Wisconsin Laboratory.of Hygiene partly through this project,

will be a continuing resource for future PCB and other complex

organic analysis. As a result of demonstrating the ability of

this machine to measure "toxic" PCB compounds in this project,

Fort Howar d Paper Company has decided to purchase one of these

machines to help them in their efforts to free the lower Fox

River and Green Bay from PCB pollution.

5. The Wisconsin Department of Natural Resources has become

increasingly concerned about the presence of certain PCB

compounds (congeners) , and methods to analyze these compounds

refined during this project will be used in the future by the

State Laboratory of Hygiene in -doing analyses for the

Department.

6. Information on PCBs developed in this project will be

useful to the Green Bay Mass Balance Study now ongoing on the

Fox River and Green Bay.

T. Results of this study will be useful to the current

Superfund investigation and remedial action plan. In fact,

dissolved and particulate PCBS.
8. The types of PCBs found in fish from the Sheboygan River

were different from the PCB pattern found in contaminated

sediments.

9. While experiments to induce anaerobic dechlorination of

PCBs using bacteria extracted from Sheboygan River sediments

were negative, further experiments would likely produce

positive results.- Based on recent laboratory work by others
(with different river sediments), it is clear dechlorination

can be demonstrated in the laboratory although results are

highly variable. Key factors controlling dechlorination are

not fully understood.

10. The multidimensional (heart cutting) gas chro*matogr aph is

an effective tool for resolving PCB compounds (congeners) that

otherwise can not be measured.

11. Some of the "toxic" PCBs (having dioxin-like effects),

that can't be resolved by conventional high resolution

techniques, were quantified using the multidimensional gas

chromatograph. Concentrations were always very low and there

were indications that dechlorination of several of these

compounds was occurring.

This research has led to a number of benefits and products

other than the research findings. The most important of these are

listed below.

1. Training was provided to students and technicians. A

Master of Science degree in Water Chemistry was received by

one student working on the project.

this -study probably had an influence or helped stimulate

current ef f orts to bioremediate dredged Sheboygan sediment

through microbial processes.
8. The results of this study will be Ugeftl to other coastal

sites with in-place pollution due to PCBs. Natural

dechlorination may be a useful remedial strategy in some

situations.

9. The Assessment and Remediation of Contaminated Sediments

(ARCS) Program, set up under the 1987 amendments to the U.S.

Clean Water Act, has set the Sheboygan River as one of its

pilot study areas. Data from this study will be essential for

this Program, and information has already been given to

program officials.

10. Last but not least, findings from this study will benefit

the living near or using the S heboygan River. Knowing that

some of the more highly chlorinated, and thus potentially most

toxic, can be dechlorinated provides hope that the PCB problem

can eventually be solved.

The hard work, support and cooperation of many individuals

made this study possible. co-principal investigators included

Professors David Armstrong and Anders Andren, and Dr. John Konrad

of the Wisconsin Department of Natural Resources' Bureau of

Research. ., Laura Maack Brondyk served as Assistant Researcher

throughout most of the proDect, and played a major role in

initiating the project. Margaret David served as the student

researcher for the project, and the core findings of the project

are described in her Master of Science dissertation. Robert

Lawrence served as an Assistant researcher during the second half

of the study. Many staff at the Wisconsin Laboratory of Hygiene

contributed their expertise, particularly to the analytical
chemistry part of the work. Notable contributors were David

Degenhardt, Thomas Gibson, Carol Buelow William Krick and Thomas

Dunnick. Professor Ronald Schell and Terry Kurzynski provided

bacteriological expertise.

Finally, the generous financial support of the Wisconsin

Coastal Management Program and Wisconsin Sea Grant Program are'

gratefully acknowledged. In addition to the fiscal support, the

administrative support and general encouragement given by the

staffs of these organizations was really appreciated. The

Wisconsin State Laboratory of Hygiene and the Water Chemistry

Program of the University of Wisconsin, as well as the Wisconsin

Department of Natural Resources also provided support for this

project.

ATTACHMENTS

1. PCB Congener istribution in Sheboygan River Sediment Fish and
Water (M.S. Thesis by Margaret David).

2. Concentrations of Toxic Polychlorinated Biphenyl Congeners in
Sheboygan River (USA) Sediments (paper submitted to the
Bulletin of. Environmental Contamination and Toxicology).

3. PCB Dechlorination in the Sheboygan River, Wisconsin (summary
to be published in proceedings of a workshop on biological
remediation of contaminated sediments).

4. Summary of Laboratory Experiments to Dechlorinate PCBs using
Bacteria Extracted from Sheboygan River Sediments.

5. An Evaluation of the Potential for PCB Dechlorination in
Confined Disposal Facilities.

PCB CONGENER DISTRIBUTION IN
SHEBOYGAN RIVER SEDIMENT, FISH AND WATER

Margaret Meigs David

A thesis submitted in partial fulfillment of the
requirements for the degree of

Master of Science
(Water Chemistry Program,
Department of Civil and Environmental Engineering)

March 7, 1990

Acknowledgements

I would like to thank my parents for their undying

support and encouragement. They have been great parents and

fantastic friends. Without my friend David, this project

would be an abysmal skeleton of what it now is. David's

ideas and criticisms were excellent and his drive to truly

understand science, inspiring. I am very glad that my

younger brother and I have been in graduate school at the

same time. Andrew has been a source of humor and hope, as

well as an amazingly fluid mechanics and differential

equations tutor. Insightful comments have come from Peter

who is omniscient and of course, my older brother. He

constantly piques my curiosity about the world and desire to

learn more.

I would especially like to extend my gratitude to all of

those in the State Laboratory of Hygiene who worked with me.

Carol Buelow and Tom Gibson have been extraordinarily

helpful. Carol has saved me many a time from complete and

total frustration and has been a mentor to me. Dave

Degenhardt has made my life much simpler and for him I hope

that National Dave Degenhardt day will become a state

holiday with big band music and ice cream.

I would like to thank Bill Sonzogni for even considering

me as a research assistant and then for getting involved in

the dirty work of the science--sampling oozing, cold, wet

river sediment. Laura Maack and Debbie DeLuca were great

colleagues with whom one could discuss detection limits and

decaffeinated coffee. I would also like to thank Dr.

Armstrong who inspite of hectic schedules has always made

time to discuss this project and provide very thoughtful

criticism. And lastly, I would like to thank Dr. Andren

whose spunky interesting lectures got me involved in water

chemistry in the first place.

TABLE OF CONTENTS

Chapter 1 Introduction .................................. 1

Chapter 2 Objectives .................................... 4

Chapter 3 Literature Review of Aerobic and Anaerobic
Bacteria ...................................... 6

3.1. Aerobic Degradation of PCBs .................. 6
3.1.1. Introduction ............................... 6
3.1.2. Enzyme Systems ............................. 7
3.1.3. Aerobic Microbial Degradation Studies
of PCBs .................................... 10

3.2. Anaerobic Degradation of PCBs ............... 15
3.2.1. Introduction .............................. 15
3.2.2. Anaerobic Degradation of Structurally
Similar Compounds ......................... 17
3.2.3. Anaerobic Microbial Degradation
Studies of PCBs ........................... 21

Chapter 4 Site Description and Historical
Use of PCBs .................................. 30

Chapter 5 Sample Collection,
Materials and Methods ........................ 38

5.1. Sample Collection ........................... 38
5.1.1. Sediment .................................. 38
5.1.2. Fish ...................................... 41
5.1.3. Water ..................................... 42

5.2. Materials ................................... 43
5.2.1. Solvents .................................. 43
5.2.2. Chromatographic Adsorbents ................ 43
5.2.3. Standards ................................. 43
5.2.4. Other Chemicals and Materials ............. 44
5.2.5. Equipment ................................. 45
5.2.6. Glassware ................................. 45

5.3. Extraction and Cleanup Methods .............. 45
5.3.1. Sediment .................................. 45
5.3.2. Fish ...................................... 49
5.3.3. Water ..................................... 52

5.4. Gas Chromatography .......................... 57

5.5. Grain Size Analysis of Sediment ............. 59

Chapter 6 Results ...................................... 64

6.1. Grain Size .................................. 64

6.2. Sediment Samples from the Sheboygan
River ....................................... 65
6.2.1. Total Concentrations of PCBs in Sediment..65
6.2.2. Homolog Distribution Patterns in Sediment.71
6.2.3. Most Prominent Congeners in Sediment ...... 76
6.2.4. Accuracy, Precision and Confirmatory
Analysis for Sediment Samples ............. 81

6.3. Sediment Samples from the Harbor ............ 83
6.3.1. Total PCB Concentrations
in Harbor Sediments ....................... 83
6.3.2. Homolog Distribution in Harbor Sediment ... 83
6.3.3. Most Prominent Congeners
in Harbor Sediment ........................ 86
6.3.4. Precision and Accuracy for Harbor Samples.88

6.4. Water Samples from the Sheboygan River ...... 88
6.4.1. Total PCB Concentrations in Water ......... 88
6.4.2. PCB Homolog Distribution in Water ......... 90
6.4.3. Most Prominent Congeners in Water ......... 92
6.4.4. Accuracy, Precision, and Confirmatory
Analysis for Water ........................ 93

6.5 Fish ......................................... 95
6.5.1. Total PCB Concentrations in Fish .......... 95
6.5.2. Homolog PCB Distribution in Fish .......... 95
6.5.3. Most Prominent Congeners in Fish .......... 99

Chapter 7 Discussion of Results ....................... 101

7.1. Discussion of Sediment Results .............. 101
7.1.1. Grain Size Correlations with
PCB Concentration ........................ 101
7.1.2. Total PCE Concentrations in Sediment ..... 102

7.2. Discussion of Possible Mechanisms causing
the Congener Distribution in Sediment ...... 105
7.2.1. Physical Processes Affecting the
Distribution of PcBs in Sediment ......... 106
7.2.2. Biological Processes Affecting the
Distribution of PCBs in the Sediment ..... 112

7.3. Discussion of Water Results ................. 123
7.3.1. Total PCB Concentrations in Water ........ 123
7.3.2. Homolog and Congener Distribution
in water ................................. 125

7.4. Discussion of Fish Results ................. 126
7.4.1. Total PCB Concentrations in Fish ......... 126
7.4.2. Homolog Patterns in Fish ................. 131
7.4.3. Most Prominent Congeners in Fish ......... 132

Chapter 8 Conclusions ................................ 140

8.1. Sediment ................................... 140
8.2. Water ...................................... 142
8.3. Fish ....................................... 144
8.4. Concluding Remarks ......................... 145

Bibliography .......................................... 147

Appendices
Appendix A Limits of Detection
Appendix B PCB Congener Results

List of Tables

Chapter 3

Table 3-1 Homolog Distribution for Pattern AB and B ...... 25
Table 3-2 Energy Derived from the Oxidation of
Glucose to Carbon Dioxide and Water
using various Oxidants ......................... 26

Chapter 4

Table 4-1 PCB Mixtures Used at Tecumseh Products Site .... 36

Chapter 5

Table 5-1 operating Conditions for
the Gas Chromatograph .......................... 58

Chapter 6

Table 6-1 Results of Sieved Sediment Samples ............. 66
Table 6-2 Total PCB Concentrations in River Sediment ..... 69
Table 6-3 Most Prominent congeners in sediment ........... 78
Table 6-4 Percent Recovery from Spiked Sediment .......... 81
Table 6-5 Duplicate Sediment Samples ..................... 82
Table 6-6 Total PCB Concentrations in Harbor Sediment .... 84
Table 6-7 Most Prominent Congeners
found in Harbor Samples ........................ 86
Table 6-8 Total PCB concentrations in Water .............. 89
Table 6-9 Most Prominent Congeners in Water .............. 93
Table 6-10 Total PCB Concentrations in Fish .............. 96
Table 6-11 Most Prominent Congeners in Fish .............. 99

Chapter 7
Table 7-1 PCB Concentrations in Sheboygan
River Sediment ................................ 103
Table 7-2 Changes in Sheboygan River Sediment
Relative to Aroclors (Sediment Samples
with concentrations greater than 50 ppm) ...... 119
Table 7-3 Comparison of Congeners Predicted by
Brown et al. based on Anaerobic Degradation
to Congeners Observed in Study ................ 120
Table 7-4 Total PCB Concentrations in Water ............. 124
Table 7-5 Total PCB Concentrations in Fish
from the Sheboygan River ...................... 127
Table 7-6 A Comparison of Most Prominent
congeners in Fish ............................. 133
Table 7-7 Clearance Rates for Specific Congeners ........ 136
Table 7-8 BCF Values Reported in the Literature ......... 140

List of Figures

Chapter 3

Figure 3-1 Major Aerobic Degradation Pathway for PCBs ..... 9
Figure 3-2 Anaerobic Degradation of Chlorobenzoates ...... 19

Chapter 4

Figure 4-1 The Sheboygan River and Tributaries ........... 31

Chapter 5

Figure 5-1 Map of Sample Sites ........................... 39
Figure 5-2 Analysis of PCBs in Sediment .................. 47
Figure 5-3 Analysis of PCBs in Fish ...................... 51
Figure 5-4 Analysis of PCBs in Water ..................... 53

Chapter 6

Figure 6-1 Map of Sheboygan River illustrating Average
Sediment Core ................................. 67
Figure 6-2 Homolog Distribution in Sediment
(Concentration >50 ppm Sites B, C, D, E) ..... 73
Figure 6-3 Homolog Distribution in Sediment
(Concentration >50 ppm. Site T) ............... 74
Figure 6-4 Homolog Distribution in Sediment
(Concentration <50 ppm, Sites B,C,D,E) ........ 75
Figure 6-5 Homoloa Distribution in Sediment
(Concentration <50 ppm, Site T) ............... 77
Figure 6-.6 Most Prominent Congeners in Sediment
. (Sites B,C,D,E) ............................... 79
Figure 6-7 Most Prominent Congeners in Sediment
(Site T) ...................................... 80
Figure 6-8 Homolog Distribution in Harbor Sediment ....... 85
Figure 6-9 Most Prominent Congeners in Harbor Sediment ... 87
Figure 6-10 Homolog Distribution in Water ................ 91
Figure 6-11 Most Prominent Congeners in Water ............ 94
Figure 6-12 Homolog Distribution in Fish ................. 97
Figure 6-13 Homolog Distribution in Fish and Sediments ... 98
Figure 6-14 Most Prominent Congeners in Fish ............ 100

Chapter 7

Figure 7-1 Ortho vs Meta/Para Congeners in Sediment ..... 115
Figure 7-2 Ortho vs Meta/Para Congeners in
Spiked Sediment ..................... I ......... 117
Figure 7-3 Correlation between Fish Fat
and PCB Concentration ........................ 129

Figure 7-4 Correlation between Packed
and Capillary Column Results ................. 130
Figure 7-5 Predicted BCF from Mackay
versus Calculated BCF from Field data ........ 138

Chapter I introduction

Polychlorinated biphenyls are a class of 209 compounds

comprised of two benzene rings with one to ten chlorines.

The physical and chemical properties of the 209 compounds,

referred to as congeners, vary dramatically. Some congeners

are oily liquids at room temperature, while others are white

powdery solids. Vapor pressures vary orders of magnitudes

among the congeners; boiling points span almost 200 degrees

(Erickson, 1986).

Because of their wide range of physical and chemical

properties, thermal stability, and chemical resistance to

acids and bases, PCBs have been used in many industries for

a wide variety of purposes. PCBs were commonly used in

transformer oils, dielectric fluids, hydraulic fluids,

plasticizers, and calbonless copy paper (Erickson, 1986;

National Acaedemy of Science, 1979).

PCBs were first manufactured in the late 1920s by direct

chlorination of biphenyl with chlorine gas. Monsanto Chemical

Corporation, one of the largest producers of PCBs, marketed

PCB mixtures under the tradename of Aroclor. Each Aroclor mix

was sold as a weight percent of chlorine. The last two digits

of the Aroclor name signified the weight percent. Aroclor

1242 contains 42 percent chlorine by weight and consists

predominantly of the trichlorinated congeners (Furukawa,

1982)

In the early 1930s, PCBs were found to have delitrious

health effects and workplace threshold limit values were set.

It was not until 1977, however, that PCBs were banned from

commercial use because of possible health effects (Erickson,

1986). The scientific community is uncertain about the exact

risks posed by PCBs. When humans are exposed to PCBs in

large doses, they are thought to elicit one or more of the

following responses: wasting syndrome, skin disorders such as

chloroacne, thymic and splenic atrophy, liver damage,

endocrine and reproductive dysfunction, tetratogenesis and

carcinoqenesis (hepatocarcinoma) (Parkinson and Safe, 1987).

Several congeners are thought to be more toxic than others.

These "toxic congeners" have a planar configuration similar

to 2,3,7,8-tetrachlorodibenzo-p-dioxin, one of the most toxic

environmental contaminants known to man. Like dioxin, the

toxic congeners are thought to bind to the direboxynucleic

acid (DNA) at sites which are coded for enzyme synthesis

(Chantry, 1989).

Because PCBs were used extensively in a variety of

industries before their toxicological hazards were identified

and because they are relatively inert, their presence in the

environment is ubiquitous. PCBs have been measured in air,

water, sediment, soil and biota around the world. Many sites

in the United States contain high concentrations of PCBs

(above 50 ppm). Under federal regulation, these-sites are

required to be cleaned up to background or limits set by the

Environmental Protection Agency (EPA). The cost of cleaning

up such sites is tremendous and the success of cleaning up

such sites is often marginal.

The fate of PCBs in the environment is not completely

understood, in part because it has been difficult to quantify

all the physical and chemical properties associated with the

different congeners. Aerobic microbial degradation of the

lower chlorinated PCBs has been shown to occur under certain

conditions. Recently, there has been evidence that anaerobic

degradation of PCBs occurs as well (Brown et al., 1987b; Chen

et al., 1988; Rhee et al., 1989; Quensen et al., 1988). This

finding is significant because PCBs and PCB-contaminated waste

is often stored in anaerobic environments such as landfills,

and sediments. Determining if anaerobic degradation occurs

and how it occurs has substantial implications for the

treatment and disposal of PCBs. Significant economic gains

could be achieved if sediments could be treated in situ. In

addition, the risks of exposure would be considerably

diminished if PCBs and PCB-contaminated material were treated

in place.

Chapter 2 objectives

The overall purpose of this study is to examine PCB-

contaminated sediment from the Sheboygan River to. determine

if anaerobic dechlorination is occuring. The observed

congener distribution will be compared to the predicted

distributing based on existing knowledge of partitioning

relationships, diffusion equations, Henry's Law constants, and

observed biodegradation patterns.

The study objectives are fourfold. The first objective

is to determine the distribution of PCB congeners in the

Sheboygan River sediments and to determine the variation with

depth and distance. The second objective is to determine if

there is a significant difference between the congener

distribution found in the river sediment versus the congener

distribution found in the Aroclors originally used at the

industrial site.

The third objective is to evaluate processes such as

partitioning and biodegradation that could account for the

change in the distribution of the congeners. The work of

Burkhard et al. (1985a, 1985b) will be used to evaluate the

effects of partitioning and volatilization on the congener

distribution. The work of Brown et al. (1987), Rhee et al.

(1989) and Quensen et al.(1988) will be used to evaluate the

effects of anaerobic biodegradation on the congener

distribution. The last objective was to examine the congener

distribution in other matrixes such as fish and water and to

compare these distributions to that in the sediment.

Chapter 3 Literature Review of Aerobic and Anaerobic Bacteria

one of the goals of this research was to determine whether

sediment from the Sheboygan River had PCB congener patterns

characteristic of anaerobic dechlorination as described by

Brown et al. (1984), Quensen et al. (1988), Chen et al. (1988)

and Rhee et al. (1989). This chapter presents a synopsis of

existing knowledge of aerobic microbial degradation as well

as anaerobic microbial degradation.

An understanding of aerobic processes is important since

rivers are dynamic systems that vary temporally and spatially,

scouring and depositing sediments in a somewhat random

fashion. As a result of these processes, it is likely that

sediment that was anaerobic becomes aerobic and vice versa.

Therefore, sediment samples may have been exposed to both

types of environments.

This chapter contains a brief overview of the following

subjects; aerobic microbial degradation, aerobic bacteria,

PCB-degrading enzymesand the environment necessary for PCB-

degradation. A similar overview of anaerobic degradation

follows the discussion of aerobic microbial degradation.

3.1. Aerobic Degradation of PCBs

3.1.1. Introduction

Since the first discovery that aerobic bacteria degrade

PCBs (Ahmed and Focht, 1973) , many aerobic, PCB-degrading

bacteria have been identified. These bacteria are apparently

widely distributed in the environment. For example, Chantry

(1989) cites sixteen PCB-metabolizing genera in a review of

the literature. Several of these genera have been found in

the environment, notably Pseudomonas, Vibrio, Aeromonas,

Microccus, Acinetobacter, Bacillus, and Streptomyces

(Furukawa, 1982). In sediments from the Hudson River, which

contain PCBs, twenty isolates from five PCB-degrading genera

have been identified: Acetobacter, Acinetobacter, Alcaligenes,

Klebsiella and Pseudomonas (Furukawa, 1982).

3.1.2. Enzyme Systems

Two major aerobic enzyme systems are thought to enable

bacteria to degrade PCBs. All PCB-degrading bacteria employ

a dioxygenase enzyme, in which both atoms of the oxygen

molecule are added to the product (Stryer, 1981). In

contrast, mammals use a monooxygenase system for PCB

metabolism. A monooxygenase system, also referred to as a

mixed function oxygenase system, is one in which one atom of

oxygen is added to the product and one atom goes to f orm water

(Stryer, 1981).

The most common enzyme system used by aerobic PCB-

degrading bacteria is the 2,3 dioxygenase enzyme. Serving as

an electron acceptor, molecular oxygen is attached to an

vacant 2,3 site (or 5,6 site) on the aromatic ring to produce

a cyclic peroxide intermedlate and then a cis-dihydrodriol

(see figure 3-1). The cis-dihydrodriol then forms a 2,3

dihydroxy compound which undergoes oxidative meta ring

cleavage between the first and second carbon atom to form a

benzoic acid (Safe, 1984). Although the chlorobenzoates can

be mineralized by bacteria, there are no known bacteria which

can both degrade PCBs and mineralize the chlorobenzoates.

A second pathway for the degradation of PCBs, a 3,4

dioxygenase, has been proposed by Bedard and coworkers (Bedard

et al. , 1987a; Bedard et al., 1987b) based on experiments with

the bacteria, Alcaligenes, and Aroclor 1242. Three of Bedard

and coworker's experimental results suggest an alternative

enzyme to the 2,3 dioxygenase. First, PCBs that were

sterically hindered for the 2,3 dioxygenase enzyme (i.e

chlorinated at the 2,3 sites) were readily metabolized by

Alcaligenes H850. Second, Alcaligenes was not able to

metabolize para chlorinated biphenyls; however, it easily

metabolized ortho chlorinated biphenyls. These results are

in striking contrast to the conclusions drawn from previous

experiments which indicated that ortho chlorinated congeners

are extremely resistant to degradation by bacteria using the

2,3 dioxygenase system (Furukawa, 1982; Furukawa et al.,

CIX Bi.phenyi
02 NADH2 Biphenyl. 2,3-dioxygenase

NAD +
OH OH
H H
cis-2,3-Siphenyl-dihydradial
CIX
NAD +
Biphenyl-dihydrodiol dehydrogenase
NAOH2

2,3-Dihydroxybiphenyl
CIX
0 2 2,3-Biphenyl catechol oxygenase

H 01, OH
0C
Ring fission product (yellow)
Ox
H20 Hydrase

0 0
C"0 H 0 @ C" ffH
CIX @& '@O H H2CD-K H

Figure 3-1 Major Aerobic Degradation Pathway
For PCBs

(Source: General Electric Research and Development, 1987)

1978). Lastly, there is some evidence that the expected

metabolites from a 3,4 dicxygenase pathway are formed (Bedard

et al., 1987b).

3.1.3. Aerobic Microbial Degradation Studies of PCBs

Many different bacteria have been found to oxidize PCBs.

Although they use similar enzyme systems, the extent and the

rate of degradation among bacterial strains differ depending

an the number and the position of chlorines on the biphenyl

molecule. Three experimental results are important. First,

as the chlorine content of the PCB increases, the ability of

bacteria to metabolize PCB aerobically decreases. Second,

mixed cultures of bacteria appear to increase the

biodegradation rates of PCBs. This finding is important since

natural environments often contain mixed cultures of bacteria.

Thirdly, many bacteria appear to require an additional

substrate for growth, a process referred to as cometabolism.

Tucker and coworkers (1972) examined the ability of

microorganisms in activated sewage sludge to degrade Aroclor

mixtures at concentrations of 2.5 and 5.0 ppm. Most of the

degradation of the mono and di chlorobiphenyls in Aroclor 1221

took place in less than a day. There was a 26 percent

decrease in Aroclor 1242 in two days and no degradation of the

more highly chlorinated Aroclor 1254. From these results,

Tucker and coworkers concluded that as the degree of

chlorination increased, the degree of biodegradation

decreased.

Experiments performed by Wong and Kaiser (1975) also

support this conclusion. Microorganisms (Achromobacter and

Pseudomonas) from lake water were placed in 0.05 percent

solution of Aroclor 1221, 1242, and 1254. The bacteria

metabolized Aroclor 1221 and 1242 but not Aroclor 1254.

Aroclor 1221 was completely degraded in one month. Rates for

Aroclor 1242 and 1254 were not established.

Furukawa, Tomizuka and'Kamibayashi (1983) also found that

as the degree of chlorination increased, the ability of the

microorganisms to degrade PCBs decreased. Using PCB

contaminated soil (50 ppm) and the, bacteria, Acinetobacter,

these researchers found that Kaneclor 200 (predominantly

dichlorobiphenyls) was rapidly degraded in four hours.

Kaneclor 300 (primarily trichlorobiphenyls) and Kaneclor 400

(primarily tetrachlorobiphenyls) were also susceptible to

biodegradation but to a lesser degree. Kaneclor 500

(primarily pentachlorobiphenyls) was recalcitrant. Similarly,

microbes from activated sewage sludge were unable to degrade

Kaneclor 500 at concentrations of 0.1, 5, and 10 ppb (Kaneko

et al., 1976).

Mixed bacterial cultures may be better able to degrade

PCBs than pure strains. A mixed strain was found to degrade

Aroclor 1242 in five days, a rate considerably faster than

values previously reported in the literature (Clark et al.,

1979). The increase in the rate may be because only readily

water soluble PCBs were used (a solution was saturated with

Aroclor 1242). This may have biased the experiment because

the lower chlorinated congeners are more soluble and also more

easily degraded. In addition, the PCBs may have been more

available to bacteria since they were in solution and not

adsorbed to particulates. Again the lower chlorinated
congeners were most'easily degraded.

Furukawa and coworkers (1983) extensively studied

two bacterial strains, Alcaligenes and Acinetobacter, both of

which degrade PCBs using a 2,3 dioxygenase enzyme. The

following generalizations about aerobic PCBs degradation

result from their work and summarize much of the aerobic

research to date.

1) As the number of chlorines increased on,the biphenyl

molecule, the ability of the bacteria.to degrade the compound

decreased. This decrease may be due to increased steric

hinderance as additional chlorines are added to the molecule.

Congeners with greater than four chlorines were recalcitrant.

2) PCBs containing chlorines in the ortho position of the

ring were also resistant to degradation. These congeners may

be sterically hindered; the 2,3 dioxygenase system requires

vacant sites at either 2,3 or 5,6 position. If both ortho

positions are filled on the opposite ring to the ring that the

enzyme is attacking, the attack by the enzyme will be

hindered.

3) PCBs containing all the chlorine atoms on a single

ring were generally degraded faster than isomers with the same

total number of chlorines distributed on both rings.

4) Ring cleavage occured more often with congeners that

had fewer chlorines.

5) PCBs having adjacent unchlorinated sites, particularly

at the 2,3 position, were more readily degraded than those

congeners chlorinated at the 2,3 position.

In addition to these factors, it appears that a substrate

for growth may be important since PCB-degrading bacteria are

unable to completely mineralize PCBs.

Cometabolism, as defined by Horvath (1972), is "any

oxidation of substances without the utilization of the energy

derived from the oxidation to support microbial growth. 11

There is evidence that the higher chlorinated congeners cannot

be degraded without additional carbon sources. "Although

complete mineralization of monochlorobiphenyls has been

reported, no culture with the ability to completely mineralize

more highly chlorinated biphenyls or to grow on any congener

that has one or more chlorine on each ring has unequivocally

been described" (Kohler et al., 1988). A variety of

substrates have been used. Biphenyl is by far the most

common; however, acetate has also been used (Clark et al.,

1979).

Brunner and coworkers (1985) found the most important

factor affecting PCB degradation in soil was enrichment of the

soil with biphenyl. After incubating soil for 210 days,

Brunner and coworkers noted that little if any degradation

took place in soil that was not inoculated with a growth

medium (such as biphenyl) or with bacteria (such as

Acinetobacter). In contrast, when the soil was inoculated

with a growth medium such as biphenyl, degradation increased

tenfold. Inoculation with bacteria increased biodegradation,

but not as dramatically. With the exception of 4-

chlorobiphenyl, Acinetobacter cannot grow upon any of the PCBs

because it is unable to dehalogenate the ring fission products

(Brunner et al., 1985).
Kohler also noted that the addition of biphenyl

substantially increased the ability of bacteria to metabolize

PCBs. When bacteria, Acinetobacter and Arthobacter, were

grown in the presence of biphenyl, degradation rates of

Aroclor,1254 increased substantially (Kohler et al, 1988).

Interestingly it has been found that adding Aroclor 1221

increased the ability of the Pseudomonas to degrade Aroclor

1254 (Lui, 1980). This phenomenon is suggestive of

cometabolism. Aroclor 1254 (300 ppm) was degraded in 18 days

to 0.59 ppm. In contrast, when Aroclor 1221 was added, the

bacteria degraded the same concentration of Aroclor 1254 in

8 days. Sodium ligninsulfonate was also added to these

cultures resulting in the formation of an emulsion. It is

hypothesized that the emulsion increased the surface area of

PCBs available to the bacteria and therefore expedited the

biodegradation of these compounds (Lui, 1980).

Another example of cometabolism is a study of four

congeners by Parson and Sijm (1988). Grown on biphenyl and

4-chlorobiphenyl in a continuous culture system, Pseudomonas

-could metabolize 4-chlorobiphenyl, 2,213,31 (congener 40),

2,215,51 (congener 52), 2,3,1415 (congener 70) and 3,314,41

(congener 77). If, however, the Pseudomonas were cultured

on nutrient broth or benzoates they eventually lost the

ability to metabolize these four congeners (IUPAC # 40, 52,

70, 77).

3.2. Anaerobic Degradation of PCBs

3.2.1. Introduction

Although the fate of PCBs in aerobic sediments has been

well studied, very little is known about the fate of PCBs in

anaerobic sediments such as landfills, and confined disposal

facilities. Since anaerobic environments such as river

bottoms and lake bottoms represent the final sink for PCBs

(National Academy of Science, 1979), it is important to

determine what, if any, processes PCBs undergo in anaerobic

environments.

In contrast to the plethora of information that exists

about aerobic microbial degradation, there is surprisingly

little information about anaerobic microbial degradation.

Anaerobic microbial Inetabolic pathways are not well understood

and anaerobic bacteria which can degrade PCBs have not been

isolated.

The first studies presented little if any experimental

evidence of anaerobic degradation. Work by Kaneko and

coworkers (1976) showed that anaerobic incubation of Kaneclor

500 (equivalent to Aroclor 1254) in the presence of sewage

sludge for twenty days resulted in no degradation.

Similarly, when Aroclor 1242 was incubated anaerobically in

soil enriched with biphenyl and Acinetobacter, no evidence for

degradation was seen (Brunner et al., 1985).

Although these studies were useful, they do not

conclusively demonstrate that these compounds do not degrade

in an anaerobic environment. Alternatively, these

experiments may indicate that the environment present in the

experiment was not suitable for anaerobic degradation. A

variety of environmental conditions can affect the type of

microbial degradation and the organisms present. Some of the

more common variables are pH, temperature, nutrients (such as

yeastextract), reduction potential, substrate, andenrichment

techniques.

3.2.2. Anaerobic Degradation of Structurally Similar Compounds

Although initial studies of anaerobic degradation of PCBs

presented little evidence of anaerobic degradation,

structurally similar compounds such as the chlorophenols

(Woods et al., 1989; Mikesell and Boyd, 1988; Krumme and Boyd,

1988), 4-chlororesorcinol (Fathepure et al., 1987) and

chlorobenzoates (Horowitz et al., 1983; Suf lita et al., 1982,

Palmer et al., 1989) have been shown to be degraded by

anaerobic organisms. Chlorobenzoates are perhaps the most

relevant of the three compounds mentioned above because they

are intermediate products in the microbial metabolism of PCBs.

Mono, di, and trihalobenzoates have been found to be

completely mineralized to carbon dioxide and methane using

bacteria from lake sediments and sewage sludge as well as

enriched cultures grown on 3-chlorobenzoate (Suflita et al.,

1982; Horowitz et al., 1983). Dechlorination was always

accompanied by methane production. The proposed reductive

dechlorination pathway is shown in figure 3-2. In contrast

to aerobic degradation, removal of the chlorine was necessary

before the chlorobenzoate could be mineralized to carbon

dioxide and methane.

The dechlorination was thought to be a biologically

mediated reaction for two reasons. First, the reaction was

inhibited if oxygen was present or if the sediments had been

sterilized (e.g., autoclaved, radiated, or poisoned with

formaldehyde). Obligate anaerobes, for obvious reasons, do

not function in the presence of oxygen. Autoclaving

terminates biological degradation because most enzymes are

denatured above 39 degrees C (Keeton, 1980). Zeikus and

Winfrey (1976) also found similar temperature limitations in

their study of methanogenic organisms in aquatic environments.

Second, a lag period was observed that lasted 1 week to

52 weeks depending on the position and number of chlorines on

the benzoate. once the microbes were acclimated, no lag

period was seen. A lag period is commonly found in

biologically mediated degradation. Time is needed to select

for a population with the necessary enzymes for metabolizing

the chemical. There was a preferential loss of the chlorines

in the meta position indicating that position of the chlorine

was important.

COOH C1 COOH CC COOH CH -4

C I C I C I C02

Figure 3-2 Anaerobic Degradation of Chlorobenzoates

(Source: Suflita et al., 1982)

The lag period was found to be correlated to the amount

of substrate present. For example, 4-amino 3,5

dichlorobenzoate at low concentrations (13 to 26 gM) was not

degraded after 21 weeks whereas higher concentrations (820 gM)

were degraded within four weeks (Horowitz et al., 1983).

In experiments with chlorophenol, the position and the

number of chlorines also influenced the degree of degradation.

Ortho chlorinated congeners had the shortest lag period (7-21

days). Meta chlorinated isomers followed with a lag period
of 31-49 days and para chlorinated congeners were not degrad'ed

(Woods et al., 1989). No dechlorination of the

monochlorophenols or chlorines from the position para to the

hydroxyl group (a metabolite) was seen in the entire 7 months

of the experiment.

In studies with 4-chlororescorinol, a product of dye and

pharmaceutical industries, it was found that the lag period

could be decreased from three weeks to two days by adding

yeast extract and trypticase. In addition, the rate of

dechlorination increased (Fathepure et al., 1987).

These studies suggest three generalizations. First,

position and number of chlorines , af f ect the ability of

microorganism to degrade the compound. Second, the

degradation pathway may be a function of the concentration of

the compound. High concentration may induce degradation to

occur whereas low concentrations may not. Third, additional

substrates such as yeast extract may be necessary for

dechlorination to occur.

3.2.3 Anaerobic Microbial Degradation Studies of PCBs

Few articles in the existing literature describe

anaerobic degradation of PCBs. Much of the current knowledge

of anaerobic degradation has come from the General Electric

Research and Development Center in New York. This section

describes their study of anaerobic dechlorination in sediments

from the Hudson River and two other research studies of

anaerobic dechlorination.

Between 1952-1973, an estimated 362,000 kg of Aroclor 1242

was released into the Hudson River in New York (Brown et al.,

.1984) contaminating over 134 metric tons of sediment (Brown

et al., 1987b). Hudson River sediments were analyzed by the

General Electric Research Group to determine the total

concentration of PCBs in the sediment and the distribution of

congeners. The concentrations ranged from 1 ppm to 2700 ppm

(Brown et al., 1984). When the chromatograms from the

sediment samples were compared to a standard chromatogram of

the original source material, Aroclor 1242, a loss of the

higher chlorinated congeners was seen. A corresponding gain

in the lower chlorinated congeners was observed. In

particular, there was a relative decrease in the levels of

tri, tetra and penta chlorobiphenyls and increase in the

levels of mono and di chlorobiphenyls. These results were

attributed to anaerobic microbial degradation.

This finding is particularly significant for at least

three reasons. First, all prior aerobic studies had suggested

that the more highly chlorinated congeners (notably those

containing more than four chlorines) were very resistant to

degradation.

Second, this degradation process appears to dechlorinate
the more highly chlorinated congeners such as the "toxic

congeners" and thus reduce the risk that these congeners

present. The "toxic congeners" have a 4,41 chlorine

substitution with at least two chlorines in the meta position

and no more than one ortho chlorine which is adjacent to the

meta chlorine. Although the overall concentration of PCBs

in the sample remains the same, the reduction in the number

of chlorines increases the potential for aerobic degradation

to occur and decreases potential risk to health and biota.

The lower chlorinated congeners are generally thought to be

less toxic than higher chlorinated congeners.

Lastly, typical PCB residues in the sediment today are

the more highly chlorinated biphenyls, even though they

represent only about 35 percent of the total PCBs manufactured

(Furukawa, 1982). It is important to identify bacteria cr

processes which can degrade the more highly chlorinated

congeners since they are a significant proportion of the PCBs

in the environment.

Brown and coworkers (1984) have identified several

chromatographic patterns which they attribute to different

bacterial strains. Within the Hudson River, five patterns A,

B, C, E, and X (Brown et al., 1984) occur. They are outlined

briefly below and discussed in more detail in chapter seven.

Each of the patterns shows a'loss of meta and para congeners.

The congener distribution of pattern A is similar to

Aroclor 1242. Relative to Aroclor 1242, concentrations of

mono and di chlorinated congeners and tri and tetra

chlorinated congeners are reduced (e.g., congeners 18, 17, 28,

20/21/33, 22, 44, 37, 70/76, 66 and 56/60). Relative

concentrat.ions of the penta and hexa chlorinated congeners are

slightly enhanced. This pattern was typically seen in

sediment samples from surface-water interfaces.

Pattern B was found in many of the Hudson River samples.

Again in comparison to Aroclor 1242, pattern B is

characterized by a decrease in the concentrations of congeners

eluting after congener 52/49/47 as well as a decr ease in

congeners 28/31 and 22. In general, there was an increase in

the mono, di and tri chlorinated congeners. Within the

dichlorinated congeners, congener 6 and congener 8 increase.

Within the trichlorinated congeners, congeners 17, 16, 32 and

27 are substantially increased. Pattern BI was the same as

B with the exception that congener 6 was not present. Table

3-1 shows the homolog weight percents for typical A and A/B

patterns.

In comparison to Pattern B, pattern C showed less removal

of the higher chlorinated congeners with the exception of

congeners 52/49/47, which were readily removed. The di and

tri chlorinated groups decreased, most notably congeners 6,

5/8, 17 16/32 and 27. Congeners 1, 3, and 4/10

correspondingly increased.

Pattern E shows a selective loss of the higher chlorinated

congeners and in general was found in combinations with

pattern B and C. Pattern X was similar to pattern B; however,

levels of congeners 1, 6, and 5/8 were below pattern B; levels

of 19, 24, and 28 were above pattern B.

Brown and coworkers found a significant decrease in the

meta and para chlorines in all of the above patterns.

Thermodynamical analysis shows that the meta and para

dechlorination is favored over ortho dechlorination. The

standard reduction potentials (E) of congeners with chlorines

in the ortho'position, are more negative than isomers

Table 3-1 Homolog Distributions for Pattern AB and B

Pattern Conc of Samples) Wt % of Homolog Group

(ppm) (Number of Chlorines)

1 2 3 4 5

Pattern A+B 162.1 (8) 6.6 26.6 39.6 18.1 8.1

Pattern B 659 (13) 13.0 41.6 30 13.7 4.0

Aroclor 1242 0.7 13.8 46.2 30.5 8.5

(Source: Brown et a l., 1984)

containing the same number of chlorines (Rusling and Miaw,

1989). For example, the toxic congener 3, 3', 4, 41 does not

contain any ortho chlorines and it has a more, positive

standard potential. It is also one of the more easily reduced

compounds. A more positive standard potential indicates a

greater tendency for the reaction to occur as indicated by the

Nernst equation: delta G = -n F (delta E).

Bacteria which are able to anaerobically degrade PCBs may

have a thermodynamic advantage over those that do not (Brown

et al., 1987b). Since the PCB nucleus is not destroyed when

reductive dechlorination occurs, it is possible that the

microbes use the PCBs as electron acceptors rather than a

carbon source (Brown et al., 1987b) Brown and coworkers

compared the calculated values of Gibbs free energies for the

oxidation of glucose for a variety of reactants (table 3-2).

The second highest energy level of any acceptor is

hexachlorobenzene, which is similar in structure to PCBs.

Note the energy value is four times higher than

Table 3-2 Energy Derived from the Oxidation of Glucose
to Carbon Dioxide and Water using Various
Oxidants
Reduced Gibbs Free
Oxidant Eroduct Energy (kcal/mole)

Oxygen Water -676.1
Hexachlorobenzene Benzene -410.16
Monochlorobenzene Benzene -369.5
Sulfate -Sulfur -131.78
Carbon Dioxide Methane - 95.63

(Source: Brown et al., 1987)

carbon dioxide.

Two other research groups have examined the ability of

anaerobes to degrade PCBs. Both groups concluded that

dechlorination occurs. Their experiments were carried out

under different conditions and subsequently their conclusions

are different although not necessarily contradictory.

Quensen et al. (1988) extracted anaerobes from the Hudson

River at a site which ranged in concentration of PCBs from 60@

to 562 ppm. After introducing the anaerobic culture into a

series of sterilized, "clean" Hudson River sediments, PCBs

were added at concentrations of 14 ppm, 140 ppm and 700 ppm.

to different reaction vessels. Controls were established

using sterilized samples and no inoculation.

Reductive dechlorination occured most rapidly in the more

highly contaminated sediments (Quensen et al., 1988). In the

700 ppm sample, 53 percent of the chlorine was removed in four

months with an increase in the mono and di chlorinated

biphenyls of 71 percent. No dechlorination was observed in

the least concentrated sample (14 ppm). The sterilized

control sediments and sediment containing microorganisms from

a PCB-free site in the Hudson River showed no evidence of

dechlorination.

Dechlorination appeared to occur predominantly from meta

and para positions. This finding supports the thermodynamic

advantage of the meta and para positions postulated by Brown

et al. (1987) and Rusling and Miaw (1989). It is interesting

to note that Quensen and coworkers observed a stepwise

decrease in the chlorine composition of the 700 ppm sample

with time.

The Wadsworth Center for Laboratory and Research,

Department of Health, in New York also preformed several

anaerobic experiments. An enriched bacterial culture from the

Hudson River was introduced into a medium containing 20 ppm

of Aroclor 1221 ( a lower chlorinated Aroclor

consisting mainly of mono and di chlorinated biphenyls) and

a 90.6 percent decrease was observed in the monochlorinated

biphenyls and a 65.5 percent decrease in the dichlorinated

biphenyls (Chen et al., 1988).

When bacteria were incubated anaerobically with pure

monochlorinated biphenyls (0.75 ppm) for 80 days, complete

degradation of the chlorinated biphenyls was seen. In

contrast, w hen a higher chlorinated congener, 2,4,21,41

tetrachlorobiphenyl was used, no anaerobic degradation was

seen.

Absence of dechlorination in the higher chlorinated

congener does not conclusively demonstrate the inability of

bacteria to anaerobically degrade the higher chlorinated

congeners. Insufficient incubation period or insufficient

quantities of substrate could inhibit degradation. The

anaerobic bacteria were incubated for 40 days with the higher

chlorinated congeners and 80 days with the lower congeners.

In contrast, Quensen and coworkers used an incubation period

of 112 days. It is possible that a lag period may occur

before significant dehalogenation takes place. A lag was

observed in Quensen's work where very little dechlorination

occured in the first month. In addition, Quensen and

coworkers found dechlorination to occur only in the more

highly concentrated samples (above 700 ppm) and not in the

less concentrated samples (14 ppm) The concentration of

tetrachlorobiphenyl in the experiment by Wadsworth Center was

considerably lower (0.25 ppm (Chen et al., 1988)). This may

be an insufficient quantity of substrate to support microbial

growth.

Recently, this same research group found significant

anaerobic degradation to occur in untreated sediments,

biphenyl -amended sediment, and biphenyl -amended and bacteria-

inoculated sediment from the Hudson River and Moreau sediment

(Rhee et al., 1989). The concentrations of PCBs were much

higher than previous experiments, 707 ppm and 936 ppm

respectively. These sediments were under a nitrogen

atmosphere. No degradation was observed under an anaerobic

carbon dioxide/hydrogen gas environment with similarly treated

sediments. It is unclear why. Quensen and coworkers (1988)

found bacterialidegradation to occur in an environment which

was 80 % nitrogen and 20 % carbon dioxide.

The biphenyl-amended sediments showed a significant

decrease in the higher chlorinated. congeners. This suggests

that biphenyl may be needed for the degradation of the higher

chlorinated congeners, a finding which has also been suggested

for the aerobic cometabolism of the higher chlorinated

congeners.

Chapter 4 Site Description and Historical Use of PCBs

This chapter describes the hydrology and geology of the

study area. The history of PCB usage at the site is

presented as well as a btief summary of the regulatory

precautions that were enacted to protect human health and

the environment.

The Sheboygan River flows westward and drains into Lake

Michigan at the city of Sheboygan. Sheboygan is

approximately 89 km.directly north of Milwaukee. The river

is a total of 220 stream km long and has a drainage basin of

approximately 272 square km (Wisconsin Department of Natural

Resources, 1989). Figure 4-1 shows a map of the Sheboygan

River and drainage basin as well as its two tributaries, the

Onion and the Mullet rivers. Beginning at the Sheboygan

Falls dam and ending at the harbor in Sheboygan, the 22.4 km

river segment studied is a small portion of the total

length. This portion of the river drains approximately 57

square km (Wisconsin Department of Natural Resources, 1989).

The river is slowed by two small dams located near the

village of Kohler.

The Sheboygan River has a mean annual discharge of

approximately 7.3 cubic meters per second ( 258 cfs) based

on data collected from 1942 to 1986. The lowest flow for

this century 0.0283 cubic meters per second (1 cfs) was

Figure 4-1 The Sheboygan River and Tributaries

-N-

0 1 Miles

Ole
.0e

Sheboygan

Kohler
River

Sheboygan
Falls

lrwwpotmtd Area

Dam

Waumbed boundary

(Source: Wisconsin Department of Natural Resources, 1989)

recorded in August, 1922. The highest flow was 217 cubic

meters.per second (7,680 cfs) in March, 1975. Average

annual rainfallduring 1978 to 1986 was 762 cm per year

(Wisconsin Department of Natural Resources, 1989).

Although, the Wisconsin Department of Natural Resources

(WDNR) concluded that the river bottom from Sheboygan Falls

to Sheboygan was generally scoured in 1980, major areas of

deposition were noted, above both of the dams, near Kiwanis

Park in Sheboygan and near the Eight street island in

Sheboygan. The average rate of deposition was calculated to

be 10 cm/yr (Wisconsin Department of Natural Resources,

1989). The river deposits approximately 22,923 cubic

meters (30,000 cubic yards) of sediment a year into.the

harbor (Wisconsin Department of Natural Resources, 1989).

The Sheboygan River lies in the geologic province of the

Eastern ridges and lowlands. The dominant feature is a

plain interspersed with north-south ridges, paralleling Lake

Michigan. 'The sedimentary bedrock is comprised

alternatingly of weather resistant dolomites which form the

ridges, and erodible sandstones and shales which form the

lowlands (Paull and Paull, 1976). Glacial features such as

kames, eskers, drumlins and kettle holes are abundant.

Within the river, the sediment is predominantly fine-grained

sand interspersed with silt and occasionally clay.

The Sheboygan River and harbor have been extensively

studied since the area was first identified as an "Area of

Concern" by the International Joint Commission and as a

I'Superfund site" by the Environmental Protection Agency

(EPA). An "Area of Concern" is defined as a locality where

water quality objectives, standards, criteria or guidelines

are not being met and remedial actions are necessary to

restore the water quality. A I'Superfund site" is an area

which, according to EPA's national ranking system, poses a

substantial risk to human health and the environment. once

an area is designated as a Superfund site,- parties

responsible for cleaning up the site are identified, where

possible, and remediation efforts are initiated under the

supervision of government agencies. If no responsible

party can be identified, money from the national hazardous

waste trust fund can be used to clean up the site. A

lengthy study of the extent of contamination and other

relevant information such as groundwater flow, potential

routes of exposure, and possible treatment alternatives is

necessary before.any remediation can begin.

Contamination of the river sedimehts by PCBs was first

identified in 1978,.when the WDNR found sediment containing
0 190 ppm of PCBs downstream from Tecumseh Products, a die

casting plant located on the river at Sheboygan Falls.

Further sampling at the Tecumseh Products site revealed soil

samples with concentration of PCBs as high as 120,000 ppm.

The samples were found to contain oil-soaked soil as well

as oil soaked rags, pressure hoses and other refuse

(Wisconsin Department of Natural Resources, 1989).

When the Sheboygan River and harbor was identified as a

Superfund site, Tecumseh Products was named as potentially

responsible party. Tecumseh Products and the previous

company at the industrial site, the Die Cast Corporation,

used hydraulic fluids in the manufacture of outdoor motors.

Use of hydraulic fluids containing PCBs commenced after a

large fire occurred at the Die Cast plant. The cause of the

fire was attributed to the combustion of hydraulic fluids.

Subsequently the Die Cast Corporation switched to a

hydraulic fluid which was fire resistant.

Monsanto Company began to manufacture fire resistant

hydraulic fluids containing PCBs in the early 1950's. The

first formulation that they marketed was Pydrol F9, the

formulation believed to be used at Tecumseh Products and the

Die Cast Corporation. Table 4-1 contains the chronology of

PCB use at these two companies. The major formulations used

by Tecumseh contained Aroclor 1248 and 1254. Tecumseh

Products acquired the Die Cast Corporation in 1966 and used

the same equipment as the Die cast corporation. Based on

interviews and available records, it is thought that the Die

Cast Corporation also used Pydrol F9.

Tecumseh Products ceased using hydraulic fluids

containing PCBs in 1971 because the major producer of PCBs

restricted sales to closed systems such as transformers.

The government did not prohibit the 'manufacture of PCBs and

use of PCBs until July 1, 1977 (Federal Register 42 part

6531 and Federal Register 44 part 315141). Before PCBs were

regulated, Tecumseh Products used material from the plant

and soil from around the plant to construct a low dike at

the river's edge. Since the dike sloped at 45 degree angle

into the river, it was relatively easy for sediment to be
introduced into the river during high water events

(Wisconsin Department of Natural Resources, 1989).

In 1979, Tecumseh Products voluntarily removed 2,046

cubic meters (72,300 cubic feet) of PCB-contaminated

material from the dike and surrounding area. This material

was sent to a federally-licensed disposal area outside of

Cincinnati, Ohio.

Since that time the area has been designated an

"Area of Concern" by the IJC as well as "Superfund site".

The EPA has extensively sampled the river and some of the

harbor. The U.S. Army Corps of Engineers has completed

Table 4-1 PCB Mixtures used at the Tecumseh Products Site

Company Date Formulation used

Die Cast Corp 1959-1966 Thought to have used

Pydrol F9,(52.5% 1248)

Tecumseh Products 1966-1969 Pydrol F9 (52.5% 1248 a)

1970-1971 Chemtrend HF30 (65% 1254,
4.6% 1248 a)

a -- The remaining percentage is a non-PCB product

(Source: Wisconsin Department of N atural Resources, 1989;
Mark Thimke, Lawyer for Tecumseh Products, Lauderin and
Associates,,Milwaukee, WI, personal communication; Paul
Micheal, Analytical Chemist, Monsanto, Chicago, IL, personal
communication.)

several studies of the harbor to assess the nature and

extent of contamination. Contaminated sediments in the

harbor have prevented dredging of the harbor since 1969.
This has resulted in a subs@antial loss to the shipping

industry because barges must travel with less than a full

cargo to get in and out of the harbor.

A fish consumption advisory has been in effect since

1978 when it was found that fish from the Sheboygan area

exceeded the'Food and Drug Administration limit of 5 ppm,

which was subsequently lowered to 2 ppm in 1984 (Federal

A waterfowl consumption advisory was issued in 1987 when the

waterfowl were found to exceed the 3 ppm fat based limit set

by the Food and Drug Administration (Wisconsin Department of

Natural Resources, 1989).

Most recently, the EPA has begun the removal this fall

of 1,910 cubic meters (2,500 cubic yards) of sediment from

the river in the vicinity of Tecumseh Products and Rochester

Park. These highly contaminated sediments will be placed in

a.confined disposal facility and monitored to determine.if

anaerobic and aerobic biodegradation is occurring. In

addition, 1,854 square meters (20,000 square feet) of

sediment will be amoured in place by covering the sediments

with a fabric liner, followed by sand and gravel. The

sediments will remain amoured until final treatment

decisions are made in 1991 (United States Environmental

Protection Agency, 1989).

chapter 5 Sample Collection, Materials and Methods

This chapter delineates how sediment, fish and water

samples were collected and prepared for high resolution gas

chromatography analysis. A summary of operating conditions

of the gas chromatographs is included as well as a

discussion of the quality control measures used. Lastly,

the procedure used for analyzing grain size is explained.

5.1. Sample Collection

5.1.1. Sediment

Two sediment sampling trips were made to the Sheboygan

River (December 2, 1988 and April 28, 1989). On the first

trip, five sites were sampled: above the Sheboygan Falls dam

(Sheboygan Falls, site A), at Rochester Park (Sheboygan

Falls, site B), above the upper Kohler dam (Kohler, site C),

above the lower Kohler dam (Kohler, site D) and near Kiwanis

Park (Sheboygan, site E). Figure 5-1 shows the exact

locations. on the second trip, samples were only taken at

Rochester Park (Site T).

Based on information from previous studie s, these five

sampling sites were selected because it was thought they

would represent concentrations varying from high (Rochester

Park) to low (above Sheboygan Falls dam). At each site, an

effort was made to sample areas of deposition, since there

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is evidence that all things equal that finer grained

material contains higher concentrations of PCBs than coarser

grained material (Karickhoff, 1979).

Sediment cores were taken with a hand-held cylindrical

coring device which was plunged into the soft sediment. The

coring device was then slowly removed and a cap placed on

the bottom of the cylinder while it was still under water.

Since the cylinders, approximately 8 cm in diameter and 1.5

meters in length, were made out of clear plexiglass, it was

relatively easy to examine the core. In all cores , the

sediment-water interface remained undisturbed.and intact

with distinct boundaries between different sediment

compositions. The cores were extruded out of the cylinders

using a hydraulic pump. Each core was divided into 15 cm

segments which were put into glass mason jars with teflon

caps and stored at 4 degrees C until time of analysis.

5.1.2. Fish

Fish samples were collected by the Wisconsin Department

of Natural Resources in the summer of 1988. Ten of the fish

were collected in the Kiwanis Park area; the remaining

eleven fish were caught in the harbor area. The fish

tissue was frozen until time of analysis.

5.1.3 Water

Water samples were collected from the Sheboygan River

at five locations corresponding to the five locations of the

sediment cores. Two sampling trips were made. One on

August 3 to collect water from Kiwanis park, above Sheboygan

Falls and Rochester Park; and a second on August 17 to

collect water from Kiwanis park, above the upper Kohler dam,

and below the lower Kohler dam.

At each site, samples were taken from a boat in the

middle of the river. A narrow-neck one liter bottle

enclosed in a steel cage was dropped gently over the edge of

the boat and lowered to the river bottom, usually no more

than one to two meters. The bottle was then pulled at a

rate such that the bottle was just filled when it was a few

centimeters from the water's surface. This method, referred

to as the depth integrated profile method, is thought to

give a more representative sample than a single point-sample

(personal communication, Leo Haus, United States Geologic

Survey, 1989). The one-liter bottle was cleaned according

to State Laboratory of Hygiene's procedure for water

sampling bottles (1989) and was rinsed with river water

before sampling. A clean bottle was used at each site.

The narrow-neck bottle was emptied into a nineteen-

liter beverage canister. The bottle was lowered several

more times until the canister was filled. The canisters

were rinsed with hexane three times before leaving the lab.

The canisters were brought back to the lab and filtered

within three days.

5.2. Materials

5.2.1. Solvents

Solvents: Acetone, Cyclohexane, Ethyl Ether, Hexane,

Iso-octane, Methylene Chloride. High purity (Baxter,

Burdick and Jackson).

5.2.2. Chromatographic Adsorbents

Florisil: Pesticide residue grade, 60/100 mesh,

activated at 130 degrees C for 12 hours and stored until use

in an air tight container at room temperature (Floridin

Co.).

Silica gel: 100-200 mesh, grade 923, activated at 130

degrees and stored until use at 130 degrees C until use.

Deactivated with 5 % distilled water at least one hour

prior to use (Davison Co.).

5.2.3. Standards

Aroclor standards 1232, 1242, 1254, 1260 in methanol

were obtained from the EPA-EMSL Quality Assurance Branch in

Cincinnati, OH and diluted to appropriate levels. Internal

standards, congener 30 and 204, were ordered from Ultra-

scientific.

5.2.4 Other Chemicals and Materials

Sodium Sulfate: granular, heated at 130 degrees

overnight to activate (Mallinckrodt).

Copper: granular, 20-30 mesh (J.T. Baker Inc.)

Glass wool: soxhlet-extracted in 50/50 acetone hexane

for four hours (Corning glassworks).

Boiling Chips: soxhlet-extracted in 50/50 acetone/hexane

for four hours (Cargille Scientific Co).

Glass Filters: 29.3 cm diameter GC 50 grade, wrapped in

aluminum foil and ashed for ten hours at 400 degrees C and

stored in foil packets until used (Micro Filtration

Systems).

XAD-2 Resin: (Sigma Chemical Co.) Resin was extracted

fdr 24 hours each in methanol, acetone, hexane, methylene

chloride and then extracted four hours in acetone, hexane

and acetone. The resin was then rinsed with distilled water

and stored in glass bottles filled with distilled water

until needed.

ASTM Soil Sieves for grain size analysis

19-liter stainless steel canisters (Beverage Industry).

Bio-beads Gel Resin (SX-3): for the Gel Permeation

Column (Biorad).

5.2.5. Equipment

Hewlett Packard 5880 Gas Chromatograph with DB-5 column

and ECD detector.

Hewlett Packard 5890 Gas Chromatograph with DB-1 column

and ECD detector.

Hewlett Packard 5790 Gas Chromatograph with a Packed

Column.

Low Pressure Gel Permeation Column Autoprep 1001

Chromatograph (ABC Labs)

Rotovap and air blowdown apparatus

Filtration apparatus: 293 mm millipore filtration head

5.2.6. Glassware

Cleaning protocol: Glassware was washed with laboratory

detergent, rinsed with hot municipal tap water and two

rinses of distilled water, and dried at 180 C. 'For water

analysis, all glassware was rinsed three times with hexane.

General glassware as well as chromatographic columns (2

cm id and 1 cm id), resin columns (3 cm by 17 cm), 500 ml

separatory funnels, glass soxhlets and flasks were needed.

5.3. Extraction and Cleanup Methods

5.3.1. Sediment

The method used to cleanup sediments was based on the

State Laboratory of Hygiene procedure for congener specific

PCB analysis (State Laboratory of Hygiene, 1989). A

schematic of this process is shown in figure 5-2 and a

summary of the method used is given below.

The sample was removed from the mason jars, placed on

aluminum foil and allowed to air dr
,y until the sample had

less than 30 percent moisture but at least 10 percent

moisture. To insure that a homogenized representative

sample was used, the sediment was sieved through a number 10

sieve and the residuals, predominantly twigs and shell

fragments, discarded. Ten grams of the sediment was dried

overnight at 120 degree C to determine the moisture content

of the soil.

Fifty grams of the sediment was placed in an acetone-

washed filter thimble which was placed into an acetone-

washed soxhlet. Three hundred ml of a 50/50 hexane/acetone

solution was poured into a soxhlet flask. Before the

soxhlet, flask, and distillation column were assembled,

granular copper was added to the soxhlet flask to remove any

sulfur interference and to insure uniform boiling. The

sediment was soxhlet-extracted for 8 hours. The temperature

was set so that the solvent would cycle about five to eight

times an hour.

Once the extraction apparatus had cooled, the sediment

was discarded and the acetone-hexane solution containing the

Figure 5-2 Analysis of PCBs in Sediment

Air dry sediment on
benchto Greater
I than
Deter mi ne 30 %
moisture
I
Soxhlet extract 50 g in
60/50 Hexane/Acetone - 9 hrs

Add Iso-oct and conc
Remove water

Florisil Fractionation
I

Concentrate

Silica gel Fractionation

Analyze by GC-ECD for PCBS

PCBs was placed in a warm water bath and concentrated to

approximately two ml under a gentle stream of filtered air.

The sample was diluted with approximately ten ml of iso-

octane and again concentrated to remove any remaining

acetone. Enough sodium sulfate was added to the sample to

adsorb any water remaining in the beaker after the blowdown

step.

Florisil columns were prepared by pouring hexane into a

twenty ml column until it reached the base of the bulb.

Next the column was filled with two grams of sodium sulfate,

followed by 22 grams of Florisil and then another two grams

of sodium sulfate. The hexane was drained to the top of the

first sodium sulfate layer and the eluant discarded. The

sample was pourbd into the column and eluted at a rate of

five ml/minute. When the sample reached the top of the

sodium sulfate layer, the beaker that had contained the

sample was rinsed with a small amount of.hexane and added to

the column. After the first rinse reached the sodium

sulfate layer., a second rinse was added to the column. The

sample was eluted with 200 ml of a 96/4 percent hexane/ethyl

ether solution.

When all of the solution was eluted, the sample was

concentrated in a warm water bath under a stream of air to

approximately five ml before silica gel fractionation. The

silica gel columns were prepared by filling a column (10 mm)

to the base of the bulb with hexane, adding two grams of

sodium sulfate, five grams of deactivated silica gel and

then another two grams of sodium sulfate. Best results were

found when the silica gel was deactivated with five percent

distilled water and allowed to equilibrate for an hour in a

sealed Erlenmeyer flask.

The sample was eluted by the same procedure used for

the florisil fractionation with the following two

exceptions: the flow rate was 1-2 ml/min and the sample was

eluted with 50 ml of hexane. When all of the hexane had

eluted through the column, the sample was concentrated and

the solvent switched from hexane to iso-octane. Next the

sample was diluted to 50 ml and screened on the packed

column to determine if further dilution (or concentration)

of the sample was necessary before performing high

resolution gas chromatography.

5.3.2. Fish

The procedure for extracting PCBs from fish was similar

to that used for sediment and for water with the exception

that a gel permeation column was necessary to remove fat

which would interfere with high resolution gas

chromatography. The procedure used was that of the State

Laboratory of Hygiene (State Laboratory of Hygiene, 1989)

and is shown schematically in figure 5-3.

The entire sample, weighing approximately 200 grams was

ground up in a high speed blender with dry ice to homogenize

the sample. The dry ice was allowed to sublime overnight.

Ten grams of the sample was mixed with 60 grams of sodium

sulfate to remove any moisture in the sample and then the

sample was poured into a 20 mm i.d. chromatographic column

containing two centimeters of sodium sulfate.

Dichloromethane (230 ml) was used to elute the sample at a

rate of 5 ml/min. once the dichloromethane was through the

column, the sample was concentrated to five ml in a warm

water bath under a gentle strdam of filtered air.

Cyclohexane was added to the sample until a.final volume of

ten ml was reached. A two ml aliquot was taken from the ten

ml sample and was weighed. The solvent was evaporated from

the sample and reweighed to determine the percent fat in the

sample.

To remove the fat from the sample, a gel permeation

column (GPC) was used. GPC is based on the principle of

size exclusion. Larger molecules, such as fats move

relatively quickly through the column; however, smaller

molecules such as PCBs, DDE and toxaphene, move more slowly

because they permeate the multitude of smaller channels in

Figure 5-3 Analysis of PCBs Jn Fish

Homogenize fish sample
Grind sample w/dry ice
I
Mix sample w/sodiurn sulfate
Extract with dichloromethane
Concentrate

Determine
% fat

Gel Permeation
Cleanup

Silica Gel Fractionation
I
Analyze by GC-ECD for PCBS

the gel which are not available to the larger fat molecules.

Five ml of each sample was injected onto the GPC. The first

100 ml of eluate to come off the column was discarded

because it contained the larger fat molecules. The second

160 ml was collected as this fraction contained the PCBs and

was concentrated to five ml.

Silica gel fractionation was performed using the same

procedure as that for sediment: five grams of silica gel (5%

deactivated with water) and 50 ml of hexane for the eluant.

After silica gel fractionation, the sample was concentrated

to five ml in iso-octane and diluted if necessary before

analyzing on the gas chromatograph.

5.3.3. Water

PCBs were extracted from the water using the

filterhead-resin bed method. Although a brief summary of

this procedure is given below, a more detailed discussion

can be found by Marti (1984), Crane (1986) and the State

Laboratory of Hygiene (1989). Figure 5-4 shows a schematic

of the procedure used.

After the samples were brought back to the lab, the 19-

liter beverage canister containing the water sample was

connected to a tank of ultra pure nitrogen gas by a teflon

hose and also connected to the filterhead by copper tubing.

Figure 5-4 Analysis of PCBs in Water

Pressurize cannister
Force sample through
Glass filter. and resin

Place filter and
resin in soxhlets
Soxhlet-extract
for 16 hrs

Liquid-liquid extraction w/hexane

conc

Florisil Fractionation

I
Silica Gel Fractionation

Analyze by GC-ECD for PCBs

An ashed glass filter was placed on the filterhead and

wetted with distilled water before the filterhead was

fastened securely in place. An XAD resin column was

attached to the bottom of the filterhead. The canister was

pressurized with approximately 5 psi of gas; causing the

water to flow from the canister through the filterhead, the

resin and into a carboy located below the filterhead. To

maintain a flow rate of 200 ml/minute, it was necessary to

have the gas pressure at 1 to 2 psi.

The resin columns were prepared by fitting a short bit

of tubing with a clamp over the end of a glass column (3 cm

by 17 cm). The tubing was attached to a water aspirator to

help pack the column. The column was then filled with

distilled water. A small portion of glass wool was pushed

into the column and any air bubbles driven out by tapping

the wool with a glass stirring rod. Enough XAD-resin was

poured into the column so that.the column had a resin bed

depth of 14 cm. A small portion of glass wool was placed on

the top. The packed resin remained in distilled water until

just after the canister was pressurized whereupon the tubing

and clamp at the end of the column were removed and sample

water began to flow through the resin.

Once all of the water had been filtered, the volume of

the filtrate in the carboy was measured and the filtrate

discarded. Next the resin column was uncoupled from the

filterhead, and inverted over a hexane-rinsed soxhlet.

Acetone was added until the resin would flow into the

soxhlet. Both glass wool plugs were added to the soxhlet.

The column was then rinsed with 60 ml of acetone and 40 ml

of hexane. Enough of the 60/40 acetone/hexane solution was

added to insure a final volume in the soxhlet and flask of

350 ml. After boiling chips were dropped into the flask,

the flask and soxhlet were placed on a hot plate and

soxhlet-extracted for 16 hours.

The filter was peeled off the filterhead, wrapped

tightly and placed into a soxhlet. Then the beverage

canister was wiped with a small bit of glass wool to remove

any particles. The canister was rinsed three times with 50

ml of a 60/40 acetone/hexane solution. The filterhead was

also wiped with glass wool to remove particulates and both

pieces of glass wool were placed in the soxhlet containing

the filter. Three consecutive rinses of 50 ml of

hexane/acetone were siphoned from the canister, through the

filterhead and caught in a beaker. These rinses were added

to the other rinses in the soxhlet containing the filter.

Again enough 60/40 acetone/hexane solution was added to the

soxhlet and flask until a final volume of 350 ml was

reached. Boiling chips were added and the filter was

soxhlet-extracted for 16 hours.

Since the filter, resin and glass wool contained water,

all of the samples needed to be liquid-liquid extracted

after soxhlet-extraction. The sample was poured into a 500

ml separatory funnel and extracted three times with 75 ml of

hexane. Next the sample was placed on to a rotovap to

concentrate the sample to approximately 30 ml whereupon it

was transferred to a water bath and concentrated under a

gentle stream of air to ten milliliters. About 20 ml of

iso-octane was added and the sample was concentrated again.

This step was repeated for all of the samples.

Once the samples were concentrated to approximately five

ml, they were ready for florisil fractionation and silica

gel fractionation. The general procedure for preparing and

eluting the compounds was the same as that for sediments;

however, for florisil fractionation, only eight grams of

florisil were needed for the column and only 50 ml of 94/6

hexane-ethyl ether was needed for the eluate. The same

procedure was used for silica gel fractionation.

All samples were concentrated to five ml after

fractionation and screened on the packed column to determine

if further concentration of the sample was necessary before

analyzing the sample on the high resolution gas

chromatograph.

5.4. Gas Chromatography

High resolution gas chromatography was used for the

analysis of PCBs in all matrixes. Table 5-1 contains the

operating conditions for the three machines used. All of

the samples were first screened on the packed column, and

then run on the Hewlett Packard (HP) 5880. Confirmatory

analysis of congeners was done on the HP 5890.

The HP 5880 was calibrated before each run using a 0.61

gg/g standard containing Aroclor 1232, 1248, 1262 at 0.25

mg/l, 0.18 mg/l, 0.18 mg/l respectively; the HP 5890 was

calibrated with a 1.22 gg/g standard of similar composition.

No more than ten samples were run in a single batch and

periodically a standard was run at the end of the batch to

assure that later samples were correctly identified. Each

sample was spiked with internal standards 30 (12.5 ng) and

204 (13.8 ng) to correct for variability in injection sample

size and to correct for drift in the rention times of the

congeners. Ten percent of the samples were run in duplicate

to assess the precision of the analysis. A matrix spike for

each batch of samples was run (a single batch typically

contained 10 samples) to assess the accuracy of the

analysis.

Table 5-1
operating conditions for the Gas Chromatographs

Hewlett-Packard 5880 Gas Chromatograph
60 m DB5 column, 0.2 mm ID
Hydrogen carrier gas, Nitrogen makeup gas
Electron Capture Detector at 320 degrees C
Oven temperature program
@90 C -- 0.5 min
90 150 C at 10 C/min;
150 220 C at 1 C/min;
220 270 C at 3 C/min, hold for 2 min
Injection size of 3A1

Hewlett-Packard 5890 gas chromatograph
60 m DBl column, 0.2 mm ID
Hydrogen carrier gas, Nitrogen makeup gas.
0" Electron Capture Detector at 320 degrees C
Oven temperature program, same as HP 5880
Injection size of 2A1

Hewlett-Packard 5790 gas chromatograph
6 ft x 4 mm column
Pacied with 4% SE 30/ 6% OV 210
Oven temperature of 235 degrees C
Injection size 2gl

Confirmatory analysis was done for approximately ten

percent of the samples using the HP 5890. Additional

confirmatory analysis was done by State Lab of Hygiene

personnel on a mass spectrometer for specific congeners.

Limits of dectection were available for each method from

the State Laboratory of Hygiene (State Laboratory of

Hygiene, 1989). Limit of dectection is defined as the

response that is three times the standard deviation of the

background noise. Congener values which fell below the

limit of dectection were not reported. Limits of

dectection for each method are included in Appendix A. In

addition, congeners which deviated from the standard

retention time by more than a tenth of a minute were not

reported. For congeners which coelute, this value was

relaxed to a twentieth of a minute.

5.5. Grain Size Analysis of Sediment,

Grain size analysis determines the percent of sand,

silt and clay in a sediment sample. The larger particles

such as pebbles and sand can be physically separated and

classified using sieves having different sized apertures;

however, the smaller particles such as clay and silt cannot

be separated using sieves and therefore must be separated by

gravitational methods (such as a sedimentation test).

For sedimentation tests, most often a slurry containing

fine particles and distilled water is made up and a

hydrometer which measures the density of a solution is

placed in the slurry. At given time intervals, readings are

taken. As the time of the analysis increases, the heavier

particles settle out and the solution becomes less dense.

Sedimentation tests are based on Stoke's Law which

describes the velocity of spherical particles of a known

density in a solution of known density and viscosity
V -4 - 'YW 6L
16TI
where

v - velocity (cm/sec)

- the specific weight of a solid (g/cm)

- the specific weight of water (g/cii)

- the viscosity (g-sec/cm2)

D - the diameter of the particle

The equation can be rewritten to solve for the diameter at

any time since all other variables are known. (The velocity

can be calculated indirectly by knowing the depth of the

hydrometer and the time.)

Grain size analysis was preformed on 18 of the

sediment samples. Because a large amount of fine material

was recommended for the sedimentation test (Das, 1986 and

Head, 1980), a small subset of the total samples (ten

samples) was used for the sedimentation test because other

samples contained insufficient quantities of sediment to do

the test.

The method used for sieving was based on the American

Society for Testing and Materials (ASTM), Standard Method

for Particle Size Analysis, Method D422-63 (American Society

of Testing and Materials, 1987). Slight modifications to

this procedure were suggested by Norm Severson (personal

communication, Department of civil Engineering, Madison, WI

1989).

A summary of the method follows (for further detail,

see ASTM D422). A sediment sample weighing between 100 to

200 grams was placed in a No. 200 mesh ASTM sieve over a

large basin. None of the sample was pretreated with

hydrogen peroxide or hydrochloric acid as it was desired to

determine the particle size distribution in an unaltered

environmental sample. The hydrogen peroxide removes organic

matter and the hydrochloric acid removes carbonate cement

between particles.

The sample was rinsed with a steady stream of tap water

(referred to as "wet-washing") until the water running out

from the sieve was clear. Wet-washing is necessary because

there is a tendency for the finer clay and silt particles to

adhere to the larger particles when a sample is dry sieved.

The turbid, murky water from wet-washing was collected in

the basin and allowed to settle overnight. The water was

siphoned off and the sample was dried, crushed to break up

any aggregation of particles, and weighed.

Fifty grams of the fine sediment was used for the

sedimentation test. A 150 ml of a deflocculating agent was

added to the sediment to disperse large flocs of aggregated

particles which may settle out in the absence of a

deflocculating agent. The deflocculating agent replaces the

divalent and trivalent cation with sodium and causes the

clay micelles to repel (Hillel, 1982). The dispersing agent

was 35.7 grams of sodium hexametaphosphate (commercially

known as Calgon) and 7.94 grams of sodium carbonate in one

liter of distilled water.

The sample was then mixed using a high speed mechanical

stirrer for two minutes. The slurry was transferred into a

one-liter sedimentation cylinder and diluted with distilled

water to the one-liter mark. After a rubber stopper was

placed in the end of the cylinder, the cylinder was inverted

sixty times in one minute. Immediately after the last

inversion, a hydrometer (ASTM 152 H) was placed in the

slurry and readings were taken at the following intervals: 0

seconds, 15 seconds, 30 seconds, 1 minute, 2 minutes, 4

minutes, 8 minutes, 15 minutes, 30 minutes, 60 minutes, I

hour, 2 hours, 4 hours, 8 hours, and 24 hours. Corrections

for temperature, meniscus level and density of the

deflocculating agent were made to the hydrometer readings

(see Das, 1986 for further detail).

The sample remaining on the sieve after being wet-

washed was dried in an oven (120 degrees C) and sieved

through a number 10 sieve and a number 40 sieve. The

former separates the large sand grains from the medium sand

grains while the latter separates the medium sand grains

from the fine sand grains (American Society for Testing and

Materials, 1987). A number 10 sieve is routinely used in

preparation of sediment samples for gas chromatography

analysis. Unfortunately, sediment samples were prepared for

gas chromatography analysis before it was decided that the

samples would be analyzed for grain size and subsequently

the material that remained on the number 10 sieve was

discarded before it was weighed. Since the sediment is a

fine grained fluvial deposit, almost all of the sediment

passed through.a number 10 sieve. In addition, most of the

matter not passing was organic matter such as twigs,

material which would not ordinarily be used in a grain size

test.

Chapter 6 Results

This chapter contains the results of grain size analyses

as well as the concentration and distribution of the PCB

congeners in sediment, water and fish samples collected from

the Sheboygan River.

6.1. Grain Size

In general, the sediment is comprised of fine-grained sand

and silt interspersed with clay and organic debris. The grain

size test results determining the sand, silt, and clay

fractions are also given in table 6-1.

The sediment samples are composed predominantly of fine

sand, although a few samples are comprised of almost equal

percentages of fine sand, and silt and clay. In general, the

proportions of fine sand and fines (silt and clay) remain the

same for different locations, reflecting the relative

homogenity of the fluvial deposits.

The medium sand fraction is probably overestimated since

this fraction was in part composed of organics such as leaf

fragments, and grass. Organic matter can be removed using

hydrogen peroxide. Hydrogen peroxide was not used in the

pretreatment of samples since it was desired to measure the

grain size in an unaltered state representative of field

conditions.

In cases where there was sufficient sample, sedimentation

tests were performed to separate silt from clay. These

results are summarized in table 6-1. As can be seen from the

table, the silt fraction is higher than the clay fraction in

all but one of the samples and in many of the samples the

silt fraction is almost twice the clay fraction. Again the

variation of the percentages of silt and clay with location

is small.

6.2. Sediment Samples from the Sheboygan River

6.2.1. Total Concentrations of PCBs in Sediment

The total PCB concentrations ranged from a high of 1590

ppm found above the Upper Kohler dam to a low of 0.04 ppm

found above the Sheboygan Falls dam (background

concentrations). Although there is considerable variation

among the samples, in general total PCB concentrations

decreased as one moves downstream away from the source. The

average value for each core is shown on a map in figure 6-1.

Values for each individual 15 cm section of core are given in

table 6-2.

As seen from the samples (A samples) collected above

Sheboygan Falls Dam, the background concentrations are very

low (an average of 0.05 ppm). For the remaining cores, the

top 15 cm. of the core, containing the sediment-water

Table 6-1 Results of Sieved Sediment Samvles
Based an ASTM Definitionsa

Sand Fraction Fine Fraction

Sample PCB Conc Lfedi Fine Silt Clay
(ppm, dry wt)
(2.Omm-4254m) (425Am-75Am) (74Am-5Am) (<SAm)

Al-2 0.04 4.9 62.3 20.4 12.6
A2-2 0.02 8.2 66.9 9.7

B1-1 8.5 6.4 64.8 18.9 9.9
B1-2 345.9 8.0 53.9 23.9 14.2
B1-3 334.2 8.8 59.0 19.3 13.1

Cl-3 9.8 5.3 47.3 28.4 18.4

D2-3 300.3 15.9 43.8 41.1*
D2-4 4.2 6.4 61.6 31.7*

E3-1 7.7 8.0 62.9 29.3*

TlA 50.3 8.9 69.4 19.8 9.5
T2B 76.9 5.4 76.4 18.4*
T2C 97.8 4.6 62.3 14.8 18.4
T2D 3.5 5.2 65.4 21.0 8.7
T3B 60.9 5.5 63.8 15.7 15.0
T3C 0.5 2.4 90.5 6.8*
T3D 0.4 3.4 80.7 15.9*
T4B 12.5 5.4 85.0 9.6*

Indicates combined silt and clay fractions
aAmerican Society of Testing and Materials, 1987

.,Ooor

kohler
:7 EM
Above L.
Above Sheboygan I A
Falls Dam DI 88.9
D2= 95.
= 0.044
Al
Above U. Kohle Da
C1 =40.2
2 = 0.049 =534.1
2

_Rochester Park
=173.1

J@3

12
B2
E it
83 = J62.3
TI = 24.1
Rochester Park
T 2 = 49.3
--.2n Falls
T3 = 27,
3.9
T4 = 36.0

Figure 6-1 Map of Sheboygan River illustrating Average
Sediment cor,e Concentrations

0 2n
N7

r
it
ll'- TIOt-All
.4-

-17 CJ3

,It

4L
Kiwanis Park

21
44@-t
El 1.3
E2= 2ol E3
LAID-

I at

21 63

jc
I A-4 Z- V

I j

a I
8 28, 2?.
oll

all

_4
a0i K.r
-61
IT.
;A
IL,41
CP
Lit
A
Xj

ev 'if i
sy "I

Figure 6-1 Map of Sheboygan River (Continued)

Table 6-2 Total PCB Concentrations in River Sediment
(ppm, dry wt)

Sample Concentration

Above Sheboygan Falls
Dam

Al-1 0.0354
A1-2 0.0176
Al-3 0.0381
A1-4 0.0866
Al-5 0.0916
Ave. 0.044
A2-1 0.033
A2-2 0.0235
A2-3 0.0663
A2-4 0.1611
A2-5 0.0581
Ave. 0.049

Rochester Park

B1-1 8.5
B1-2 345.9
B1-3 334.2
B1-4 3.6
Ave. 173.1
B2-1 113.9
B2-2 143.1
B3 (composite) 162.3
Ave. 139.8
Above Upper Kohler Dam -

C1-1 28.7
C1-2 8.6
C1-3 9.8
CI-4 113.6
Ave. 40.2
C2-1 3.9
C2-2 12.4
C2-3 1585.8
Ave. 534.0
Above Lower Kohler Dam

Dl-1 4.4
D1-2 117.9
D1-3 144.5
Ave. 88.9

Table 6-2 Total Concentration of PCBs in River Sediment
(cont.

Sample Concentration

Above Lower Kohler Dam (cont.)

D2-1 8.2
D2-2 70.5
D2-3 300.3
D2-4 4.2
Ave. 95.8
Kiwanis Park

El-l 1.9
E1-2 0.7

E2-1 2.1

E3-1 7.7

Rochester Park (Second Sampling Trip)

T1A 50.3
TlB 21.3
TlC 0.8
Ave. 24.1
T2A 18.8
T2B 76.9
T2C 97.8
T2D 3.5
Ave. 49.3
T3A 1053.7
T3B 60.9
T3C 0.5
T3D 0.4
Ave. 278.9
T4A 8.6
T4B 12.5
T4C 26.8
Ave. 16.0

interface, had relatively low concentrations of PCBs (an

average of 21.4 ppm excluding sample T3A). The next two core

segments (15-30 cm and 30-45 cm) typically had the highest

concentrations (an average of 174.4 ppm), while the bottom

core segment (45-60 cm) had on average the lowest

concentrations (an average of 2.4 ppm excluding sample C1-4).

6.2.2. Hamolog Distribution Patterns in Sediment

Samples from the first sampling trip (in which all sites

were sampled) could be divided into two distinct groups based

on their homolog patterns. One pattern had an enrichment in

the lighter chlorinated congeners relative to the original

Aroclor patterns while the other pattern had a distribution

similar to the original Aroclor patterns. This distinction

appehred to be a function of concentration. Samples

containing PCB concentrations greater than 50 ppm. appeared to

be enriched with the lighter chlorinated congeners, whereas

those with less than 50 ppm PCBs were not.

Samples containing 50 ppm. or more PCBs had significantly

higher concentrations of mono and dichlorinated congeners

compared to the original Aroclors introduced into the river.

Using a multivariate t test, these samples were found to be

statistically different in composition from Aroclor 1248,

Aroclor 1254,- and a 50/50 mixture of Aroclor 1248 and 1254

All p values were less than 0.05. A p value smaller than 0.05

means that the samples are significantly different at the

ninety fifth percentile confidence interval. Thare is less

than a f ive percent chance that the sample came from a

distribution that contained the Aroclor mixes. Figure 6-2

and 6-3 show the homolog distribution of sediment samples with

PCB concentrations above 50 ppm from the first and second

sampling trips. Although the two sets of data are f rom

different sampling trips, there is no statistical difference

between these samples (p=0.8870, using a test of two means).

In samples containing PCBs concentrations less than 50

ppm from the first sampling trip (sites B,C,D,E), the homolog

patterns slightly resembled the original Aroclors introduced

into the river; however, they were statistically different

from Aroclor 1248, Aroclor 1254 and a 50/50 mix 6f Aroclor

1248 and 1254 (using a multivariate t test p values were found

to be less than 0.05 for all comparisons). This is

illustrated graphically in figure 6-4.

There were too few samples with concentrations less than

50 ppm from the second sampling trip (Rochester Park site, T

samples) to.use a multivariate t test. These samples were

found to be statistically different from the di, tri, tetra,

hepta and octa homolog groups of the original Aroclors.using

a univariate t test ( p < 0.05). This is illustrated in

Figure 6-2 Homolog Distribution in
Sediment (Conc.> 60 ppm, Sites B,C,D,E)
60 Wt. percent

50 - .... . .. .. .. .. . . .. ........

....................... .................
40 . ...... .. . ... ... . .....

30- . . ..... ............. .................. ...............

.... ....... ..........
20-- . . ........ ...................... ..............

10 . ................... . ........ ........... .... .................. .... ..............

0
Mono Di Tri Tetra Penta Hexa Hepta Octa Nona
Homolog Group

Sample EM Std 1248 Std 1254

(Ave. of 11 samples)

Figure 6-3 Honnolog Distribution in
Sediment (Conc. > 50 ppm, Site T)

Wt. percent
60

50 - . .... ...... .

..............................
40 . . . .... ... . ......... ..

........... . ......... .....................
30 -

20 . .. .. ... ............. . ........... ..... ....... .................... .......................................... ... ........ ... .....................

10 .............
........... ........................ ..............

0 ...
Mono DI TO Tetra Penta Hexa Hepta Octa Nona
Conc. (ppm)

Sample M Std 1248 ED Std 1254

(Ave. of 5 samples)

Figure 6-4 Homolog Distributio n in
Sediment (Conc.< 60 ppm, Sites B,C,D,E)

Wt. percent
60

50-

................-.................. ..........-..................................
40 . .. .. . ........ .. ....

30-- ... . ........ .... ..... .. .......... ..... .......... ...................... .......... ... .............

20 .. .... .......... ..... .......... .................. ........... ........................................ ...............

................ ........................ ........... . ...-
10 ............

0
Mono DI Tri Tetra Penta Hexa Hepta Octa Nona
Homolog Group

Sample M Std 1248 EEI Std 1254

(Ave. of 14 samples)

figure 6-5. Interestingly, the samples from the second

sampling trip containing less than 50 ppm (Rochester Park, T

samples) were very similar to the distribution of the more

highly concentrated samples from the same area (p= 0.8875).

6.2.3. Most Prominent Congeners in Sediment

The most prominent congeners are listed in table 6-3.

These results are also presented graphically in figure 6-6 and

figure 6-7. Relative to the original Aroclors, particularly

high concentrations of congeners 5/8 (congeners 5 and 8

coelute) were seen. The highest concentrations were found in

samples containing more than 50 ppm PCBs, 29.2 percent on

average. In contrast, samples containing less than 50 ppm of

PCBs, contained only 11.4 percent on average. Areas of high

concentrations of PCBs, such as Rochester Park, had high

concentrations of congener 5/8 throughout the core,

independent of concentration in each individual segment of

core. Samples from Rochester Park had on average 24 percent

congener 5/8 whereas all other sites had on average 11.5

percent. Congeners 4/10, 16/32, 17, 24/27, 47/48 and 26 were

also abundant in comparison to the original percentages in the

Aroclors. Although 28/31, 52, 66/95, and 77/110 were

prominent congeners, they were present in diminished

quantities in the sample relative to the original quantities

Figure 6-6 Homolog Distribution in
Sediment (Conc. ( 60 ppm, Site T)

Wt. percent
60

so- .....................

............................. ................
40

30 - ...... .... ............ ................

20 - . .. .... ..... .. .. ..... .......... ............. .............

...........
.............. ..........
10

1771
0
Mono DI TO TO tra, Penta Hexa Hepta Octa Nona
Conc. (ppm)

Sample EM Std 1248 E:DStd V54

(Ave. of 9 samples)

Table 6-3 Most Prominent congeners in sediment
(Weight Percent of Total)

Congener 1st trip 2nd trip Aroclor Aroclor
samples >50 ppm (R.Park only) 124,a 1254a
samples >50 ppm

4/10 2.1 1.6 0.03
5/8 29.9 27.4 2.1 0.06
17 9.2 10 1.2 <0.1
16/32 10.1 9.8 1.9 <0.1
47/48 7.7 7.2 4.0 0.4
24/27 2.8 3.4 0.18 <0.1
28/31 6.3 6.6 17.7 0.6
66/95 3.7 4.1 9.0 7.6
77/110 2.5 2.5 9.2
26 2.0 2.9 0.4 <0.1
52 2.4 4.4 4.2
49 2.0 3.0 1.0

Congener 1st trip 2nd trip Aroclor Aroclor
samples <50 ppm (R. Park only) 1248a 1254a
samples <50 ppm

5/8 6.3 17.3 2.1 0.06
17 10.3 1.2 <0.1
16/32 4.1 11.3 1.9 <0.1
47/48 6.3 8.3 4.0 0.4
28/31 8.6 9.9 17.7 0.6
66/95 7.9 4.0 9.0 7.6
77/110 4.1 3.0 2.5 9.2
26 3.1 0.4 <0.1
52 4.3 1.8 4.4 4.2
49 4.1 2.2 3.0 1.0
41/64/71 2.9 0.7 <0.1

a Manchester, 1988

Figure 6-6 Most Prominent Congeners
in Sediment (Sites B,C,D,E)

Wt Percent
35-

30 . ................ .... ..-.......... ........................ ..... ........ ........... . .... .. . . .... . .. ....... ... ... . .. .... . ..... .. . ...... . ... . .-.... ...... ..I...... .. . ....... ... ... .... .. ............

25 . ...... .............. ............ ............ . .. . ... ... .................. ..... .. ..... .. I - -- ... - ... - -

20 . ....................... ............................................ . ..... .. ...... .. . . . .. . . .. .. . .......... . ....... ... .. . ..... .I... ..... .. .... ... .. .................... .. .. .. . . ... ......... ........ . ..

is . ............ .......... ............. ...... ....I........... . ... ...... .. . .... ........ . ... ... .. . . ........ .I - - .. - .. .1 .. . .......... .. .. ............ .. . ............................... .. . .... ..... .. ... .

10 . ........... .......... . ............. ................. . ............. . ...... .... . .... .. ............... ... ........... ........... ............. .. ..... ... . .......... ................. ..................... . ......... .... ...........

. . ....... ............ ............... ............ .................. ................... ......................................................

0-
4/10 6/8 16/32 17 24/27 26 28/31 47/48 49 62 66196 77/110
Congener

Samples 60 ppm Samples < 60 ppm 60/60 Std 1248/1264

(Ave of 11 Samples, <50 ppm
Ave of 14 Samples, <50 pprn)

Figure 6-7 Most Promin ent Congeners
in Sediment (Site T)

Wt Percent
30

25 . ... .............................. ......-........ ...I........ . .. ............. . ... ... .... .. ... . .... .. .. ........ .. ... ........... ............... ...... .......... ..... ............... .. ......... ........ .................... .....

20 . ........ I........................................................ ........................................................................................................................................................................................

. ...................................... ..................................................................................................I..........I.................................... I. ................................... ....................................

10 . ................ ...................... ................................................................................................................................................................................ ....................................

......... ...... ... .................................... ................. ..................................................................... ................ . . . ..

0
5/8 17 16/32 24/27 26 28/31 47/48 49 41/64/71 62 66/96 77/110
Homolog Group

50 pprn > 50 ppm 50/50 Std 1248/1254

(Ave of 6 samples >60 ppm
Ave of 9 samples <60 ppm)

in the Aroclor mixtures.

6.2.4. Accuracy, Precision and Confirmatory Analysis for

Sediment Samples

A duplicate sample and a spiked sample were included in

every batch of samples run. Sediment was spiked with an

Aroclor mixture of Aroclor 1232, 1248 and 1262 at a level of

0.61 ppm. The recoveries for the spikes* are listed in the

table below and are calcluated by summing the individual

congener concentration. The recoveries varied from a high

of 108.1 percent to a low of 81.8 percent with an average

recovery of 92.5 percent.

Table 6-4 Percent PCB Recovery from Spiked Sediment

Run 1 81.8
.Run 2 108.3
Run 3 81.9
Run 4 95.4
Run 5 94.4
Run 6 94.5
Run 7 89.2
Run 8 94.4

Values for duplicate samples are given in table' 6-5.

Confirmatory analysis was performed on approximately 25

percent of the samples (15 samples out of a total of 59

samples) using a DB-1 column. Good correlation was found

between the two data sets (correlation coefficient of 0.983).

Since many of the samples had very high concentrations of

congener 5/8, additional confirmatory analysis of this

particular congener was sought. Six of the samples,

containing high concentrations of PCBs (342.8 ppm on average)

and high concentrations of congener 5/8 (43.7 percent on

average), were analyzed using an Electron Impact Gas

Chromatography Mass Spectrometer. All of the spectra

Table 6-5 Duplicate Sediment Samples

Duplicate Results Mean Percent Agreement

1 345.9, 414.8 380.4 90.9
3 4.6, 5.2 4.9 93.9
2 7.0, 8.2 7.6 92.1
7 76.9, 69.3 73.1 94.8
6 0.53, 0.49 0.51 92.2
4 97.8, 134.8 116.3 84.1
5 4.4, 5.1 4.75 92.6
8 20.74, 20.92 20.83 99.6

confirmed that the previously identified congener 5/8 peak

was indeed a dichlorinated biphenyl. The sample spectra were

compared to a library of known spectra compiled by the

National Bureau of Standards. A computer algorithm designed

to match the most significant peaks determined the agreement

between the sample and known standard. Good agreement was

found for all spectra as indicated by the percent match which

varied between 83.2 and 96.6 percent with an average match of

91.8 percent.

6.3. Sediment Samples from the Harbor

Three cores from the Sheboygan Harbor were obtained from

the EPA and analyzed to determine the PCB congener

distribution. The cores were located near the mouth of the

harbor. Two cores were taken at a sediment depth of

approximately 3 0. 5 cm (1 ft) The remaining core ranged from

the surface-water interface to a depth of 50.8 cm (20 inches)

6.3.1. Total PCB Concentrations in Harbor Sediments

Table 6-6 contains boring depths of the core and the

concentration of PCBs found in each segment of the three

cores.

6.3.2. Homolog Distribution in Harbor Sediment

The homolog distribution are similar in distribution to

the original Aroclor mixtures (see figure 6-8). They are

however statistically different (p < 0.05). In addition, the

patterns appear to be similar to the homolog patterns seen for

sediment samples containing less than 50 ppm PCBs.

Table 6-6 Total PCB Concentrations in Harbor Sediment

Core PCB Conc. (Ppm, dry wt.)

H18
0-1.3 cm 36.3-
1.3-5 cm 15.7
5-10 cm 83.6
10-15 cm 30.7
15-20 cm 3.5
20-31 cm 1.4
31-41 cm 0.3
41-51 cm 0.9

Hll
31-41 cm 3.5
41-51 cm 27.7

H15
20-31 cm 91.2

Figure 6-8 Homolog Distribution
in Harbor Sediment

Wt. percent
60

50 - ...... ......... .. ...

40-

30 . ......

20-

. . . ........ . . ... .................. ................... ........... . ......
10- . . .. ......

0
Mono DI TO Tetra Penta Hexa Hepta Octa Nona
Hornolog Group

sarnpie 20 Arocior 1248 Aroclor 1254

(Ave. of 11 samples)

6.3.3. Most Prominent Congeners in Harbor Sediment

The most prominent congeners are listed in table 6-7.

Most of these congeners are also found in high concentrations

in the original Aroclor mixtures 1248 and 1254 as noted in the

table below. The most prominent congeners are also presented

graphically in figure 6-9.

Table 6-7 Most Prominent Congeners found in Harbor Samples
(Weight percents)

Congener Samnle Aroclor 1248 Aroclor 12544

28/31 13.9 17.7 0.6
47/48 7.4 4.0 0.4
66/95 7.2 9.0 7.6
17/110 @6.6 2.5 9.2
49 5.5 3.0 1.0
52 5.6 4.4 4.2
26 4.9 0.4 <.1
41/64/71 4.3 0.7 0.4.
44 3.6 5.2 3.0
16/32 3.7 1.9 <.l

a Manchester, 1988

Congener 28/31 is the most abundant congener in the

harbor samples. It is also the most abundant congener in

Aroclor 1248. Congeners 47/48, 49, 52, 26, 41/64/71, and

16/32 are enriched in the harbor sediment relative to their

concentrations in the Aroclors. The only congener found in

diminished quantities relative to. the Aroclor mixtures was

congener 66/95.

Figure 6-9 Most Prominent Congeners
in Harbor Sediment

Wt Percent
16

14 . ... .................... ... ........ ... . .......... .......... . .......... .... . ... ............ ... .. ........ ........ ... . .. . . . ................ . ...... . ...... .. .... ... . .

12 . ........................ ...... ......... .. ...... ...... .... . ... ......

10 . ........................ . ........................... ............ ............. .......................................... .................... ....................................................................

............... . ........
8 . ........................ ... ........................ .......... ............. ........................... ............................. ...................................................................................
..... .....

..... .....
................ ................................. ............
6 . ........................ ... ..... .............. .................................. ............
.... .... ....
..... ..... .....
.... .... ....
..... ..... .....
.... .... ....
... .... ....
..... ..... .....
.... .... ....
..... ..... .....
.... .... ....
............... .............. ............... .... ............
4 . .. ..................... .
..... .... ...
..... .... ...
..... .... .....
.... ..... .... ... .....
.... .... ..... ....
.... ..... .....
.... .... ..... ..... ....
..... .... ... .....
.... ..... ..... ....
.............. ................ .. ..........
2
.... ..... .....

0
16/32 26 28/31 47/48 49 52 66/95 77/110 44 41/71
Congener

Harbor Sediment 50/50 1248/1254

(Ave of 11 Samples)

6.3.4. Precision and Accuracy for Harbor Samples

The recovery from spiked sediment was 101.6 percent and

was calculated by summing the individual congeners. The

results of the duplicate analysis preformed on the samples

were 1.4 ppm and 1.5 ppm.

6.4. Water Samples from the Sheboygan River

6.4.1. Total PCB Concentrations in Water

The water samples are divided into particulate and

dissolved concentrations based on an operational definition.

The portion of the sample that was able to pass through the

0.7 micron filter was defined as the dissolved fraction and

the portion that remained on the filter was the particulate

fraction. The particulate and dissolved concentrations are

given in table 6-8.

The background concentrations were low, 0.007 and 0.003

ppb for the particulate and dissolved fraction, respectively.

The particulate concentrations in the non-background samples

varied from an average low of 0.162 to an average high of

0.502 ppb. The lowest particulate concentration in the water

occured at Rochester Park, the site of the highest average

sediment PCB concentrations, 173.1 and 139.8 ppm. This would

be expected since the river water has been in relatively short

contact with the contaminated sediment. The highest

Table 6-8 Total PCB Concentrations in Water (Pnb)

Site Concentration

Above Sheboygan Falls Dam
(Background)

Dissolved
Water sample 1 0.003
Particulate
Water sample 1 0.007

Rochester Park

Dissolved
Water sample 1 0.028
Water sample 2 0.047
Particulate
Water sample 1 0.162
Water sample 2 0.301

Above Upper Kohler Dam

Dissolved
Water sample 1 0.190
Water sample 2 0.204
Particulate
Water sample 1 0.464
Water sample 2 0.432

Above Lower Kohler Dam

Dissolved
Water sample 1 0.152
Water sample 2 0.179
Particulate
Water sample 1 0.508
Water sample 2 0.452

Kiwanis Park

Dissolved
Water sample 1 0.071
Water sample 2 0.069
Particulate
Water sample 1 0.275
Water sample 2 0.327

particulate concentration in the water was above the Lower

Kohler dam which had average sediment core concentrations of

88.9 and 95.8 ppm.

The dissolved concentrations varied between 0.028 and

0.204 ppb. The lowest concentrations were again found at

Rochester Park, the site of highest PCB sediment

concentrations. The highest dissolved concentrations were

found above the Upper Kohler dam which had sediment

concentrations of 40.2 and 534 ppm, (the average of 534 ppm was

disceptively high because the highest single 15 cm sediment

concentration was found in this core, the remainder of the

core had low concentrations of PCBs).

6.4.2. PCB Homolog Distribution in water

The homolog groups for the dissolved and particulate

fractions are illustrated in figure 6-10. In the dissolved

fraction, there is a dramatic increase in the lighter

chlorinated congeners relative to the original Aroclor

mixture, particularly the mono, di and trichlorinated

congeners. Correspondingly, there is a decrease of the

heavier chlorinated congeners, notably the penta, hexa, hepta

and octachlorinated homolog groups.

In comparison to the dissolved fraction, the particulate

fraction contains decreased quantities of the mono, di and

Figure 6-10 Homolog Distribution
in Water

Wt. percent
60

...................-
so -

................ ... ........... ............
40

. .............. . ................ . ..... ..........
30-

. ............... .......... .............
20 . ........... ..... ...

...... ..... ........... ... ............. ...............
10
0 IL
Mono DI TO Tetra Penta Hexa Hepta Octa Nona
Homolog Group

Dissolved Particulate Std 1248 Std 1254

(Ave. of 8 samples)

trichlorinated congeners; however, there is still an

enrichment of these lower chlorinated congeners relative to

the original Aroclors. In general, the distribution is much

more similar to the original Aroclors than the dissolved

fraction.

Not surprisingly, the homolog distribution for the

dissolved fraction was not found to be statistically similar

to the original Aroclors or a 50/50 mix of the original

Aroclors ( p < 0.05 for univariate t tests of each homolog

group). The particulate fraction was also not statistically

similar to the original Aroclors with the exception of the

monochlorinated congeners and the nanochlorinated congeners

which are in very small concentrations in both the sample and

in the Aroclors ( p < 0. 05 for univariate t tests of each

homolog group).

6.4.3. Most Prominent Congeners in Water

The most prominent congeners found in water are listed

in table 6-9 and shown graphically in figure 6-11.

Congeners 1, 4/10, 5/8, 17, 16/32, and 41/64/71 were in

higher concentrations in the water samples than in the

original Aroclors. Congener 70/76 was in lower

concentrations than the Aroclors but still remained one of the

most prominent congeners in the' sample. The remaining

Table 6-9 Most Prominent Congeners in Water
(Dissolved and Particulate Fraction)

Congene Diss. Part. Aroclor 1248 a Aroclor 12548

1 3.4 <0.1 <0.1
4/10 2.9 1.59 0.03
5/8 26.0 7.6 2.1 0.06
17 7.9 3.6 1.2 <0.1
16/32 3.6 1.9 <0.1
28/31 10.7 9.7 17.74 0.6
47/48 3.4 6.1 4.0 0.4
41/64/71 2.8 4.7 0.74 0.4
52 4.0 3.5 4.4 4.2
66/95 3.3 7.8 9.0 7.6
70/76 4.2 7.1 4.4
77/110 5.9 2.5 9.2
44 3.1 5.2 3.0

a Manchester, 1988

congeners were of intermediate value..

6.4.4. Accuracy, Precision and Confirmatory Analysis for Water

The recoveries from spiking water with an Aroclor mixture

of 1232/1248/1262 in acetone were 83.1 and 91.7. All samples

with the exception of the background sample were run in

duplicate and are shown in table 6-8.

Confirmatory Analysis was performed on approximately

thirty percent of the samples (six samples) using a DB-1

column. The correlation coefficient for the two data sets

indicate good agreement (Correlation coefficient = 0.977).

Figure 6-11 Most Prominent Congeners
in Water

Wt Percent
30-

'25 - ......... .......... .......... ................... .

20-

15- .............. ...........- ... .............. ..............

10- . .. ....... . . ... .. ..... . .. . ........

....................... ............................-F-1
5 . ........ .. . ............... .. ... . . . ......
0- Ifl w] N:@:,
1 4/10 5/8 17 16/32 28/31 41/71 44 47/48 62 66/9570/7677/110
Congener

=Dissolved Particulate 50/50 Std 1248/1254

(Ave of 8 samples)

6.5. Fish

6.5.1. Total PCB Concentrations in Fish

The fish concentrations varied from a low of 1.3 ppm to

a high of 22.0 ppm. These results are summarized in table 6-

10. The highest values were found in carp and channel

catfish; both of which are bottom feeding fish and have high

concentrations of fat.

6.5.2. Homolog PCB Distribution Patterns in Fish

The average homolog distribution pattern is shown in

figure 6-12 with the Aroclor 1248 and 1254 and in figure 6-13

with the homolog distribution for the river sediment and the

harbor sediment. Relative to the Aroclors, there was a slight

increase in the mono and dichlorinated congeners in the fish

samples, probably due to the significant concentrations of

the mono and di chlorinated congeners in the water and

sediment.

Although the fish samples were enriched in the higher

chlorinated congeners and appeared to be more similar to the

Aroclors than the water or sediment samples, the samples were

not found to be statistically similar to Aroclor 1248, Aroclor

1254 or a 50/50 mix of Aroclor 1248 and 1254 using a

multivariate t test (p < 0.0001).

Table 6-10 Total PCB Concentrations in Fish

species Capillary Column Packed Column % Fat

Small Mouth Bass 3.4 3.7 0.6
it 4.3 4.2 0.7
if 3.9 3.5 0.4
If 4.3 4.2 0.8
It 5.8 4.4 1.2
6.8 9.0 3.0
2.3 2.6 0.8
2.0 2.3 0.5
Bluegill 2.7 2.2 1.4
Walleye 10.1 6.7 1.8
Northern Pike 3.6 6.6 0.5
If 4.6 3.9 1.0
if 6.9 6.2 1.0
it 6.4 3.8 1.6
Rock Bass 5.1 6.0 2.1
It 1.3 1.4 0.4
Channel Catfish 9.5 13.0 5.1
11 22.0 32.0 3.4
of 13.9 26.0 6.5
Carp 22.0 21.0 4.1
18.9 15.0 13.0

Figure 6-12 Homolog Distribution
in Fish

Wt. percent
60

so . .... .. ..... .

40 ........... ........................ .............

........... .... . .............
30--

.................. .................... - -

10 ..........
......................- ..................

0
Mono Di TO Tetra Penta Hexa Hepta Octa Nona
Homolog Group

Sample Std 1246 Std 1254

(Ave. of 21 samples)

Figure 6-13 Homolog Distribution
in Fish and Sediments

Wt. percent
40

30 - .......... ......................

..............................
20 . . .. .. ... ...... ..

...................
10 . .. .... . .. ..... ......... . . ... ....

0
Mono Di TO Te tra Penta Hexa Hepta Octa Nona
Homolog Group

Sample Harbor River Sediment

(Ave. of 21 samples)

6.5.3. Most Prominent Congeners in Fish

The most prominent congeners are listed in table 6-11

and also presented in figure 6-14.

Table 6-11 Most Prominent Congeners in Fish

Congene Sample Aroclor 124 a Aroclor 1254a

28/31 5.7 17.7 <0.1
47/48 6.8 4.0 0.4
49 4.0 3.0 1.0
41/64/71 4.0 0.7 <0.1
66/95 8.5 9.0 7.6
77/110 7.7 2.5 9.5
101 4.2 1.7 7.1
118 4.5 0.8 3.0
132/153/105 4.9 1.5 11.0
138/163 4.8 1.8 5.6

aManchester, 1988

Figure 6-14 Most Prominent Congener
in Fish

Wt. Percent
20

15 . ... . .... . . . . . ........ ......

10 - ................. ........... ........... ......

.......... . . ..... ...........

0
28/31 47/48 49 41/71 66/95 77/110 101 118 132/163138/163
Congener

Fish Aroclor 1248 ED Aroclor 1254

101

Chapter 7 Discussion of Results

In this section results f rom the sediment, water and f ish

analyses are compared to results from the literature.

Explanations for the congener patterns are evaluated by

comparing predicted patterns to observed patterns.

7.1. Discussion of Sediment Results

7.1.1. Grain Size Correlations with PCB Concentration

Since sediment samples composed of smaller particles have

greater surf ace area f or adsorption relative to samples of the

same volume consisting of larger particles, it is predicted

that smaller particles will have higher concentrations of PCBs

relative to larger particles (Simmons et al., 1980). This

tendency is enhanced by the fact that smaller particles are

often comprised of organic carbon which has been positively

correlated with PCB content (Elzerman and Coates, 1987). In

this study, to examine the effect of grain size on PCB

concentration, the two variables were correlated.

The correlation of grain size and concentration of PCBs

is confounded by spatial effects such as distance from the

source and the depth of the core. To control for spatial

variation, samples from only one site (Rochester Park, samples

B and T) were correlated with the grain size. other samples

were not correlated because there were too few samples at each

102

site to give a meaningful correlation. PCB concentration

depends slightly on grain size; as the grain size decreased,
the concentration of PCBs increased (R2 value of 0.52 for a

log log plot). The outlying points were samples from either

the surface of the core or from the bottom of the core. One

possible explanation for these outlying points is that

sediment which is in the bottom of the core is older sediment

and may not have been exposed to significant concentrations

of PCBs. Conversely, sediment at the top of the core may be

newer and cleaner sediment. Both of these samples would

therefore be likely to have low concentrations of PCBs because

they were not exposed to the same amount of PCBs as the middle

section of core.

7.1.2. Total PCB concentrations in Sediment

Total sediment concentrations of PCBs ranged from 0.016

ppm to 1586 ppm as seen in table 6-2. Although higher

concentrations were found by the Superfund remedial

investigation on the Sheboygan River, the range of

concentrations are comparable (table 7-1). The sediment

results show a decreasing trend with distance from the source,

similar to the results found in this study.

Although reported concentrations from other highly

contaminated sites is comparable to Sheboygan River

103

Table 7-1 PCB Concentrations in Sheboygan River Sediment'
This Studyb Remedial Investigationc
Core Concentration (ppm) care Concentration (ppm)

B1 173.1 R4 4300
R5 59

B2/B3 139.8 R6 15
Tl 24.1 R7 4500
T2 49.3 R8 0.4
T3 278.9 R9 28.0
T4 16

Cl 40.2 R19 250
C2 534 R20 2.8
R21 5.4
R22 93

D1 88.9 R34 110
R103 72
R104 5.4

D2 95.8 R37 <1.5
R35 2.0

El 0.8 R85 0.3
E2 2.1 R86 4.2
E3 7.7 R87 4.6

The two sets of cores are grouped according to general
roximity
Samples are averages of cores which were 30 to 45 cm deep
c Remedial investigation (EPA Superfund study) samples are
composite core samples which were 30 to 45 cm deep (Blasland
and Bouck Engineers, 1988)

104

sediments, the PCB, concentrations in Sheboygan River sediments

are considerably higher than other sites in the Great Lakes

region. Brown and coworkers found concentrations as high as

2600 ppm in Hudson River sediments with an average

concentration in the hot spot areas of 75 ppm (Brown et al.,

1984). In the tidal Hudson, sediment PCB concentrations

dropped to an average of 10 ppm (Bopp et al., 1981). PCB

concentrations in the Great Lakes are much lower. In Lake

Ontario, sediment values were found in the range of 200-1200

ppb (Oliver et al., 1989).

Within the cores, as mentioned in Chapter 6, the top

section of the core generally contained low concentrations of

PCBs. The middle section of core usually contained the

highest concentrations of PCBs and the bottom section of core

typically had the lowest concentrations of PCBs. One possible

explanation for this distribution is that the bottom section

of sediment was deposited before significant contamination

occured.whereas the top section of core was deposited after

significant contamination took place and contains the newer

cleaner sediment.

There was one exception to this general trend. In sample

T3A the highest concentration was in the top segment of core.

T cores were collected four months after all other cores.

During these four months, federal and state remedial

105

investigations of the site continued and it is possible that

the sediments were disturbed by other investigators.

7.2 Discussion of Possible Mechanisms Causing the Congener

Distribution in Sediment

The results from the sediment analysis clearly indicate

that the sediment PCB patterns are significantly different

from the Aroclor originally introduced into the river. The

mechanisms which can alter the congener distribution in the

sediment can be divided into three processes-- chemical,

physical-chemical and biological.

Abiotic chemical reactions in the sediment affecting the

PCB congener distribution are unlikely. Photolysis and

oxidation reactions are unlikely to occur in the subsurface

anaerobic. environment present in most of the sediments.

Although chlorinated methanes and ethanes have been found to

undergo reductive dechlorination (Wade et al., 1969; Klecka

and Gonsoir, 1984), reductive dechlorination of PCBs is

thought not to occur in the conditions present in anaerobic

sediments (Quensen et al., 1988; Brown et al., 1987b;

Hutzinger et al., 1974). For example, reductive

dechlorination of PCBs has been demonstrated to occur by Boyer

and colleagues (1985) at 50-90 degrees C using sodium

hypophosphite. These temperatures are well above the

106

temperatures f ound in the environment. Furthermore, the

reduction of chlorinated ethanes and methanes by iron is not

strictly abiotic because iron is present as iron porphyrin

which is a biological enzyme present in hemeglobin,

cytochromes and chlorophyll (Fessenden and Fessenden, 1982).

In general, there are very few abiotic pathways which

completely mineralize organic compounds (Alexander, 1981).

7. 2. 1. Physical-Chemical Processes Af f ecting the Distribution

.of PCBs in Sediment

Four physical-chemical processes can affect the

distribution of PCB congeners in sediment: sediment-water

partitioning, diffusion, air-water partitioning, and colloidal

partitioning. A discussion of each follows with an

evaluation of the predicted congener distribution based on the

mechanism compared to the observed distribution.

Sediment-Water Partitioning. Probably, the most

significant partitioning process affecting the distribution

of congeners in the sediment is the partitioning between

sediment and water (Bopp et al., 1981, Burkhard, 1985a) . The

partitioning of hydrophobic compounds between sediment and

water can be described by the following relationship

(Karickhoff, 1981):
Kp=Se Pe

107

where Kp is the equilibrium partition coefficient'.

S' is the equilibrium sorbed pollutant concentration,
P' is the equilibrium aqueous phase concentration.

The partition coefficient is corrected for the organic carbon

present in the sediment. The corrected partition coefficient

is expressed as the organic carbon based partition

coefficient, K,,, and is related to the partition coefficient

by the following equation:

KOC =KP*oc
where k.,--is-the---or anic carbon based partition coefficient,
KP is the partition coefficient,
oc is the fraction of organic carbon.

The octanol-water partition coefficient (Kow) can be related

to the organic carbon based partition coefficient ('Koc) by the

following relationship (Karickhoff et al., 1979):
Log Koc=1.0 Log Kow -0-21 (R'= 1. 0 0)
Using this relationship, the Kc can be estimated from the Kow.

Since the octanol-water partition coefficient t ends to

increase with increasing chlorination (Shiu and Mackay, 1986),

the partition coefficient for PCBs should also increase with

increasing chlorination.

The above relationships predict that the higher

chlorinated congeners should remain in the sediment while the

lower chlorinated congeners should partition into the water.

108

Field studies at other sites show an -enrichment of the higher

chlorinated congeners in sediment which has been attributed

to partitioning (Furukawa, 1982; Hansen, 1987). For example,

sediment from the Puget Sound in Washington shows an

enrichment of the higher chlorinated congeners and loss of

lower chlorinated congeners to the water (Pavlou and Dexter,

1979).

Using the relationships of Karickhoff (1979) and

predictions of Henry's Law constants and octanol-water

partition coefficients, Burkhard (1984) and Burkhard et al.

(1985) modelled the partitioning of Aroclor mixtures in a

three phase system containing air, water and suspended

particulate matter. Beginning with an equimolar distribution

of congeners in all phases, Burkhard and colleagues examined

the effects of partitioning into different phases on the

congener distribution in each phase.

The air phase was found to be depleted in the higher

chlorinated congeners above IUPAC 160. In the water phase

there was some enrichment of the lower chlorinated congeners

below IUPAC 40 and some depletion of congeners above IUPAC

120. The most dramatic change was found in the distribution

of the congeners in the suspended particulate matter phase.-

Congeners below IUPAC 80 were significantly depleted while

congeners above IUPAC 80 were significantly enriched. The

109

results of Burkhard (1984) and Burkhard et al. (1985)

illustrate that the distribution of congeners in sediment is

dramatically affected by the sediment-water partition

coefficients. Equilibrium modelling using sediment-water

partition coefficients predicts increases in higher

chlorinated congeners and decreases in lower chlorinated

congeners in the sediment.

Diffusion. Diffusion of congeners from the sediment back

to the water is slow relative to sedimentation rates and is

inversely related to the partition coefficient (Fisher et al.,

1983; DiToro et al., 1985). The diffusion rate of PCBs in
the presence of sediment (D*s) is function of the inverse'of
the partition coefficient and is described by the following

relationship (DiToro et al., 1985):

D S= DS/ (1+m*KP/@)
where D*, is the diffusion rate in the presence of sediment
(CM2/day),

D. is the aqueous diffusion rate (no sediment present)
(CM2/day) ,

m is the sediment solids concentration,
KP is the partition coefficient,
is the porosity of the sediment.

microns such as humic and fulvic acids, microemulsions and

mineral precipitates (McCarthy and Zachara, 1989). The

overall effect of colloids in the partitioning of organic

contaminants is to increase the "apparent" solubility of a

compound in water and decrease the "apparent" partition

coefficient.

The effect of colloidal partitioning on the sediments may

be limited since PCBs were probably introduced into the

Sheboygan River adsorbed to sediment (Wisconsin Department of

Natural Resources, 1989). Hydraulic fluid containing PCBs

was spilled on to dirt and debris which were later used to

build a flood dike. Since the PCBs were already adsorbed to

dirt that later became river sediment, colloidal partitioning

could only occur after the PCBs were desorbed from the

sediment into the water and eventually adsorbed onto the

colloids. The first step of this process is governed by

sediment-water partition coefficients which, as explained

before, gives a distribution that is enriched in the higher

chlorinated congeners and depleted in the lower chlorinated

congeners. Therefore, it appears unlikely that colloidal

partitioning has a major influence on the distribution of

congeners in the Sheboygan River sediments.

None of the processes described above adequately explain

the distribution seen in the Sheboygan River sediments. Since

110

This relationship illustrates that higher chlorinated

congeners are more likely to remain in the sediment than the

lower chlorinated congeners because the higher chlorinated

congeners have higher partition coefficients and subsequently

lower diffusion rates.

Air-Water Partitioning. The distribution of congeners

between water and air phase can be important because it can

affect the distribution between the water and sediment. The

effect of air-water partitioning of congeners on the overall

distribution of PCB congeners in sediment is likely to be

small in comparison to sediment-water partitioning because the

sediments are not in direct contact with the air. The vapor

partitioning of PCBs from sediment in the Hudson River was

calculated to have a small effect relative to sediment-water

partitioning (Bopp et al., 1981). Even if one were to assume

that the transport of PCBs from the sediment to the water and

then to air were significant, the congener patterns seen in

the Sheboygan sediments still would not be predicted. Henry's

Law constants, which describe the partitioning of PCBs between

the air and water, show no particular trend with regard to

molecular weight (Burkhard et al., 1985b).

Colloidal Partitioning. Currently, there is considerable

debate about the effect colloids have on partitioning.

Colloids are defined as particles with diameters less than 10

112

sediment-water partition coefficients increase with molecular

weight, an enrichment of the higher chlorinated congeners and

a depletion of the lighter chlorinated congeners is predicted

based on the partition coefficients. Equilibrium

partitioning models such as Burkhard's do not predict the

specific enrichment of a select small group of congeners such

as 5/8, 17, and 24/27 which were found in this study.

Instead, these models predict a gradual continuum of

increasing concentrations of the higher chlorinated congeners

in the sediments.

Henry's Law constants show no particular trend with

molecular weight. The most prominent congeners seen in the

sediment do not exhibit particularly low Henry Is Law constants

and therefore their presence cannot be explained in terms of

these constants.

In summary, neither physical-chemical processes nor

abiotic chemical reactions readily explain the distribution

of congeners in Sheboygan River- sediments. Consequently, one

or more biological processes may better explain the measured

distribution. Possible biological processes are discussed

next.

7.2.2. Biological Processes affecting the Distribution of

PCBs in the Sediment

113

Aerobic and anaerobic microbial degradation are probably

the most likely biological processes that could affect the PCB

distribution in sediment. Aerobic degradation, if it occurs

at all, occurs in the top few centimeters of sediment where

oxygen is present. Because most of the samples analyzed were

slices of the core located 45 to 60 cm below the sediment

surface, very little of the sediment was thought to be

aerobic. Aerobic PCB-degrading microbes metabolize the lower

chlorinated congeners, those with less than four chlorines,

but generally do not metabolize the higher chlorinated

congeners (Furukawa, 1982).

The pattern seen in the sediments is more typical of

anaerobic degradation in which the higher chlorinated

congeners are metabolized to produce lower chlorinated

congeners. Several results in this study suggest anaerobic

microbial degradation. First, there is a shift in the

congener pattern from the higher chlorinated congeners to the

lower chlorinated congeners. This cannot be accounted for by

simple physical -chemical partitioning. Second, there appears

to be some selectivity as to which congeners were lost that

is characteristic of enzymatic microbial degradation.

Lastly, the congener patterns appear to be a function of the

concentration of PCBs in the sediment that is typical of

biological degradation.

114

A shift in congener distribution from the higher

chlorinated congeners to the lower chlorinated congeners was

seen by Quensen and coworkers (1988) in their laboratory study

of dechlorination by anaerobic bacteria. Over a period of

four months, Quensen and coworkers saw a stepwise

dechlorination of the higher chlorinated congeners to produce

the lower chlorinated congeners. Brown and coworkers (1987a

and 1987b) postulated such a stepwise dechlorination process

based on their results from Hudson River sediment cores.

With regard to congener selectivity, there is a loss of

meta and para chlorinated congeners compared to ortho

chlorinated congeners. Figure 7-1 contains the average

number of meta and para chlorines and ortho chlorines

calculated for each sediment sample along with averages

calculated for the Aroclor mixtures (General Electric Research

and Development, 1987). When Aroclor mixture averages are

plotted, a linear relationship can, be seen, indicating that

any combination of Aroclors will also fall on this line.

Therefore, any deviation from this linearity may be attributed

to a physical or biological process and not a simple mixing

of different Aroclors (General Electric Research and

Development, 1987). Brown and coworkers maintain that an

upward deviation indicates evaporation, elution and oxidative

biodegradation whereas a downward deviation indicates

Figure 7-1 Ortho vs Meta/Para Congener
in Sediment Samples

Meta/Para CI
5

4- ..... ..... .-

2 . . . . ........ ......................
4- ;V, X
x
X +X D<X x 0
X 0 -t-
......... . . . . . ........ ... ..... ............ ................... ..... ... .................. .. ...... ....

Ol I
0 0. 5 1.5 2 2.5
Ortho CI

- Aroclors 4- Env. Samples (13) Env. Samples (C)
13 Env. Samples (D) x Env. Samples (T) 0 Env. Samples (E)
xx
4t3

115

Fig 7-1

116

anaerobic dechlorination (General Electric Research and

Development, 1987).

Most of the sediment samples from the Sheboygan River

fall below the Aroclor mixture line indicating a depletion in

the meta/para chlorines relative to the ortho chlorines. For

comparison, the average meta and para and ortho chlorines for

the spiked sediment samples ("clean" sediments spiked with

Aroclors) were calculated. The spiked sediments could be

thought of as a control since they do not undergo microbial

degradation. These are shown in figure 7-2. Note that they

all lie along the line as predicted (General Electric Research

and Development, 1987). In a laboratory study of anaerobic

dechlorination a marked loss in average number of meta/para

chlorines per biphenyl molecule was also seen (Quensen et al.,

1988). Brown and coworkers found similar results in their

field study of Hudson River sediments (1987a).

Exactly why bacteria selectively dechlorinate meta and

para chlorines is unclear. Rusling and Miaw (1989) have shown

that reductive dechlorination of meta and para chlorines gives

a greater Gibbs free energy value than reductive

dechlorination of ortho chlorines. It is possible that

bacteria which selectively dechlorinate meta and para

chlorines have a biological advantage over those that do not.

With regards to specific congeners, several congeners are

117

Fig 7-2
0

Figure 7-2 Ortho vs Meta/Para Congeners
in Spiked Sediments

Meta/Para Cl

4 . .. ...... ... . . . . ..... . ..........

3- ............ .... .......

2 - . .. .. ....... ...............

0
0 0.5 1 1.5 2 2.5
Ortho CI

Spiked Samples Aroclors

118

found in abundance which would not be expected based simply

on physical partitioning or on the original weight percents

present in the Aroclor mixtures. Table 7-2 contains the

average weight percent of each congener in the samples

containing over 50 ppm, PCBs as well as the weight percents of

congeners in Aroclor 1248, Aroclor 1254 and a 50/50

combination of Aroclors 1248 and 1254.

In the sediment samples, there is a general trend of

enrichment of the lighter chlorinated congeners and depletion

of the heavier chlorinated congeners. In particular, several

congeners were significantly enriched in comparison to the

50/50 combination of Aroclor 1248 and Aroclor 1254. Congeners

with a greater than two percentage point increase, relative

to the 50/50 mixture, were congeners 5/8, 19, 17, 24/27,

16/32, 26 and 47/48. Congeners with a greater than two

percentage point decrease were 18, 28/31, 52, 44, 70/76,

66/95, 56/60, 101, 77/110, 132/153/105, and 138/163.

It is interesting to note that these results are

comparable to the results of Brown and coworkers (1987b).

Table 7-3 shows the congeners Brown and coworkers found to be

significantly depleted and enriched in the sediments. With

the exception of congener 16 which coelutes with congener 32

in this study, and congeners 47 and 49, all of the congeners

119

Table 7-2 Changes in congeners in Sheboygan River
Sediment Relative to Aroclors (Sediment
Samples with conc. greater than 50 ppm)

Congener Concentration (Wt. Percent)
Sample Aroclor' Aroclor a 50/50
Average 1248 1254 Mixture

1 0.6 <0.1 <0.1
3 b.d. <0.1 <0.1
4/10 2.1 0.8 <0.1
7 0.1 0.1 <0.1
6 0.8 0.1 <0.1
5/8 29.1 2.1 0.1 ++
19 2.5 0.5 0.1 ++
18 0.1 5.0 0.1
17 9.4 1.2 <0.1 ++
24/27 3.0 0.2 <0.1 ++
16/32 10.0 2.0 <0.1 ++
26 2.3 0.4 <0.1 ++
28/31 6.4 17.7 0.6
33 0.1 2.9 <0.1
22 0.5 0.6 <0.1
45 0.4 0.9 <0.1
46 0.1 0.5 <0.1
52 2.1 4.4 4.2
49 2.4 3.0 1.0
47/48 7.5 4.0 0.4 ++
44 1.1 5.2 3.0
37/42 1.4 5.2 0.1
41/64/71 2.0 2.5 0.4
40 0.1 1.1 .0.1
74 0.4 2.6 0.9
70/76 0.3 7.1 4.4
66/95 3.8 9.0 7.7
91 0.9 <0.1 0.9
56/60 0.13 5.9 0.9
84/92 1.4 1.4 4.0
101 0.8 1.7 7.1
99 0.5 0.9 2.5
97 0.2 0.9 2.2
87 0.1 0.9 3.1
85 0.1 0.9 1.5
136 0.1 0.1 1.0
77/110 2.4 2.5 9.2
82 b.d. <0.1 0.9
151 0.2 0.1 0.8

120

Table 7-2 Continued

Congener Sample Aroclor 1248 Aroclor 1254
Average

135/144 .0.2 0.1 1.4
149 0.8 0.4 6.0
118 0.4 0.8 3.0
146 0.3 <0.1 2.2
132/153/105 1.1 1.5 11.0
141 b.d. <0.1 0.5
137/176 b.d. <0.1 0.5
138/163 0.6 0.3 5.6
182/187 0.2 0.1 0.2
183 0.1 <0.1 0.3
185 b.d. <0.1 0.1
174 b.d. 0.1 0.4
177 0.1 <0.1 0.1
171/202 b.d. <0.1 0.1
172/197 b.d. <0.1 0.1
180 0.1 0.8 1.0-
170/190 0.2 <0.1 1.0
201 0.1 0.1 <0.1
196/203 b.d. 0.1 <0.1
195/208 b.d. <0.1 <0.1
194 b.d. <0.1 <0.1
206 b.d. <0.1 <0.1

a -- data from Manchester, 1988
b.d..-- indicates below detection

-- indicates a decrease by at least two percentage points from
50/50 ratio

++ indicates an increase by at least two percentage points
from 50/50 ratio

121

Table 7-3 Comparison of Congeners Predicted by Brown et
al.(1987b) based on Anaerobic Degradation to Congeners
observed in this Study

Diminished This Enriched This
Congeners Study a Congeners Studya

33 2 +
22 6 +
74 8 ++
70 4 +
66 10 +
56 17 ++
60 27 ++
118 32 ++
105 19 ++
18 53 n.m.
16 ++
44
42 n.m.
87
85
82
101
99
97
153
138
141
52
49 +
47 ++

a indicates samples with concentration above 50 ppm
- indicates present in diminished quantities relative to
50/50 ratio
-- indicates a decrease by at least two percentage points from
50/50 ratio
+ indicates present in increased quantities relative to 50/50
ratio
++ indicates an increase by at least two percentage points
from 50/.50 ratio
n.m. not measured in this study

122

which were found to Pe depleted in Brown's study were also

found to be depleted in this study.

The concentration of PCBs in the sediment appeared to be

a significant variable. As mentioned before in areas of low

PCB concentrations, the sediment chromatograms appeared to be

similar to the original Aroclors. Chromatograms from areas

of high concentration had much higher weight percents of the

lower chlorinated congeners relative to the original Aroclors.

other researchers have noted that anaerobic dechlorination

appears to occur only when there are high concentrations of

PCBs present (Brown et al., 1984, Brown et al., 1987b, Quensen

et al., 1988, Rhee et al., 1989).

Microbial degradation is often restricted to areas of high

substrate concentrations. For example, toluene, xylene and

naphthalene are metabolized by bacteria at high concentrations

but not at low concentrations (Alexander, 1985). The minimum

concentration of a chemical which is needed to support growth

of a microbial population is referred to as the threshold

concentration (Alexander, 1985). Above the threshold

concentration organisms are able to obtain sufficient energy

for both maintenance and growth. As the concentration of a

chemical compound decreases, the amount of the compound

available to the organism by diffusion decreases until

insufficient quantities are available for both growth and

123

maintenance (Alexander, 1985). Below this threshold

concentration, additional energy sources must be f ound to

support growth of the population, since the organism is no

longer able to completely mineralize the substrate.

Cometabolism occurs below the threshold concentration to

provide additional sources of nutrients for the organism.

Anaerobic dechlorination of higher chlorinated congeners in

some cases has been shown to occur by cometabolism with the

addition of biphenyl (Rhee et al., 1989). Based on the

different chromatographic patterns seen for high and low

concentrations of PCBs, it is quite possible that some

threshold concentration exists for the anaerobic

dechlorination of PCBs.

7.3. Discussion of Water Results

7.3.1. Total PCB Concentrations in Water

The total PCB concentrations in water are similar to

other values which have been reported for the Sheboygan River

(see table 7-4). In a survey of Wisconsin Rivers, Marti

(1984) found the Sheboygan River contained 0.103 (s.d. 0.036)

ppb total PCB in the river. The values reported in this study

are considerably higher than the concentrations found by Crane

(Crane, 1990) in the Fox River which ranged from 1.43 to 34.4

ppt for the dissolved fraction and 2.11 to 103 ppt for the

124

particulate fraction or by Swackhammer (1985) in Lake Michigan

which ranged f rom 0. 3 to 3 ppt total PCBs. Mudroch and

coworkers (1989) found the Wheately Harbor in Lake Erie to

have concentrations ranging from 0.086 ppb to 0.291 ppb total

PCBs. In Hamilton Harbor in Lake Ontario, concentrations

ranged from 0.086 ppb to 0.213 ppb total PCBs (Mudroch et al.,

1989). However, the concentrations in sediment from the

Great Lakes are lower than those from the Sheboygan River.

Table 7-4 Total PCB Concentrations in Water

site Concentration (Dpb)

WDNR Remedial Investigation This Study
1978 1987
Above Sheboygan
Falls Dam <0.3 <0.05 P 0.007 P
<0.05 D 0.003 D

Rochester Park <0.4 0.213 P
0.038 D

Above Upper
Kohler Dam <0.2 0.267 P 0.448 P
0.118 D 0.197 D

Above Lower
Kohler Dam 0.150 P 0.480 P
0.078 D 0.166 D

Sheboygan 0.3 0.159 P 0.301 P
0.059 D 0.070 D

P - Particulate Fraction
D - Dissolved Fraction

Source: Wisconsin Department,of Natural Resources, 1989

125

7.3.2. Homolog and Congener Distribution in Water

The weight percents of each of the homolog groups did not

vary greatly among the samples. Higher concentrations of the

lower chlorinated congeners were found in the dissolved phase

than in the particulate phase. This would be expected since

the lower chlorinated congeners are in general more soluble

and less likely to partition onto the particulate fraction.

Congeners 1, 4/10, 5/8, 17, 16/32, 28/31, 41/64/71, 47/48,

52 and 66/95 were the most prominent congeners in the

dissolved fraction. Congeners 5/8, 17, 28/31, 47/48,

41/64/71, 52, 66/95, 70/76, 44 and 77/110 were the most

prominent congeners in the'particulate fraction. Since the

solubility of PCB congeners generally decreases ' with

increasing chlorination and since the most, prominent congeners

listed in table 6-9 do not show particularly high solubilities

(Shiu and MacKay, 1986), it is likely that their abundance in

the water column is a function of their high concentrations

in the sediment.

The distribution and relative percentages of the most

prominent congeners in the water increasingly reflect the

congener distribution of the sediments in the lower reaches.

For example, at Rochester Park congener 5/8 constitutes 2.9

percent of the particulate fraction of PCBs. In contrast, at

126

the other sites, congener 5/8 is 9.2 percent of the

particulate fraction. The weight percents of congeners 47/48

and congener 17 also increase at the other sites. In the

dissolved phase, this trend is more pronounced. At Rochester

Park, congener 5/8 constitutes 14.6 percent of the dissolved

PCB concentration. The average for the other sites for

congener 5/8 is 30 percent. The weight percents of congeners

171, 16/32 and 47/48 in the dissolved phase also increase.

Most likely, these increases in specific congeners, which are

seen in abundance in the sediment, are due to the scouring of

the river bottom.

7.4. Discussion of Fish Results

7.4.1 Total PCB concentrations in Fish

The total PCB concentrations found in the fish that were

analyzed are similar to other reports in the literature.

The Wisconsin Department of Natural Resources routinely has

fish analyzed from the Sheboygan River. Recent results are

listed in table 7-5. In the Kiwanis Park area, the

Wisconsin Department of Natural Resources found the fish to

contain an average total PCB concentration of 8.4 ppm which

is comparable to 7.6 ppm found in this study (Wisconsin

Department of Natural Resources, 1989). In the Harbor area,

the average totals of 42.7 ppm are considerably higher than

127

those found in this study.

Ten of the fish in this study were from the Kiwanis Park

area and eleven were from the harbor. In a survey of fish in

Wisconsin rivers (including the Sheboygan River) values ranged

from 0.07 to 7.0 ppm (Maack and Sonzogni, 1988). Carp and

lake trout from the Wisconsin side of Lake Michigan were found

to have PCB concentrations similar to those reported in carp

and other fish in this study (16.3 ppm for carp and a range

of 2.9- 33.8 ppm for trout (Kleinert, 1976 in Swain, 1983)).

Table 7-5 Total PCB Concentration in Fish from the Sheboygan
River (ppm)

Site Year of Fish Ave Conc-(Ppm) Species

Above Sheb.
Falls 1987 6 <0.30 varied

Below Sheb.
Falls 1987 7 24.9 Carp,
Sm Bass

Upper Kohler
Dam 1987 3 7.67 Sm Bass

Lower Kohler
Dam 1985 9 9.65 Varied

Kiwanis Park 1986 9 8.4 Varied

Sheboygan 1983 17 42.7 varied

(Source: Wisconsin Department of Natural Resources, 1989)

128

In the more highly contaminated Hudson River, fish were found

to have total PCB concentrations ranging f rom below detection

to 7.07 ppm (Califano et al., 1982).

The highest total PCB concentrations were found in fish

that had high concentrations of f at to body weight. This

finding suggests a positive correlation between percent fat

and the level of PCBs in fish. To test this hypothesis, the

percent fat was regressed against the total PCB concentration.

The results are plotted in figure 7-3. The regression

equation for this line follows:
Log PCB = 1.061 log fat - 0.644 R2 value of 0.71.

The correlation between percentage of fat in the fish and the

PCB contamination is significant.

The fish samples were analyzed using both a capillary

column and a packed column. The two methods were compared

to see how well they agreed. Twenty one samples were

analyzed with both types of columns. The measurements are

compared by regression:
Log Cap Col = 1.05 log Packed Col + 0.0005 R2 value o.ss.

These results are plotted in figure 7-4. This result is

important since it implies that packed column measurements

made over the last twenty years (by comparing chromatographic

patterns of a sample with that of pure Aroclars

(Erickson,1986)) produce results similar to that

Figure 7-3 Correlation between
Fish Fat and PCB Concentration

Log PCB Cone.
1.4

1.2-

..........

......... .- . ....... . ........
0.8- . ..... .

0.6 . ... ............. .. ....... ..........................
........... . ......

0.4 . . . ... . .. ..... .... .. .. ... . ............. ..............- .......... ............................

0.2 . .......

0
-0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2
Log Percent Fat

Figure 7-4 Correlation between
Packed and Capillary Column Results

Log Capillary
1.4

1.2 . .. ..... ...

........ ... .. ............... . ..................- ..........
0.8 -

0.6 . . ........... .. .. . . . . ..... ........... . ..... ....................... . .....-........... ................

0.2 . . . ..... ... .. . . .. .......

01
0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6
Log Packed

131

obtained by summing individual congeners. Maack and Sonzogni

(1988) also found good agreement for total PCBs measured by

packed and capillary column chromatography.

7.4.2. Homolog Patterns in Fish

The enrichment of the higher chlorinated congeners and

depletions of the lower chlorinated congeners seen in the fish

homolog patterns (figure 6-12) has been observed by others.

In the heavily PCB contaminated Hudson River, Califano and

coworkers (1982) found that fish congener patterns were more

typical of Aroclor 1254 than of the material introduced into

the river, Aroclor 1242. Because fish generally are unable

to metabolize the higher chlorinated congeners (Niimi and

Oliver, 1989; Dekock and Lord, 1988; Bruggeman et al., 1981;

Lech and Peterson, 1983), it is not surprising to see an

enrichment in the higher chlorinated congeners. Work by

Peterson and Lech (1983) suggests that fish are only able to

metabolize mono, di and tri chlorinated biphenyls. It is

interesting to note that fish tend to metabolize PCBs much

more slowly than mammals (Lech and Peterson, 1983).

The higher chlorinated congeners tend to bioaccumulate not

only within the fish but also within the entire food chain.

Since many of the fish in this study are carnivorous and are

132

therefore higher on the food chain, it would be expected that

higher total concentrations of PCBs should be f ound in the

fish in comparison to other biological compartments (van der

Oost et al., 1988; Oliver and Niimi, 1988). In particular,

higher concentrations of the higher chlorinated congeners is

expected (Oliver and Niimi, 1988). The data collected in

this study support these findings as the fish are

significantly enriched in the higher chlorinated congeners

relative to the water and overall are enriched in total PCB

concentration relative to the water.

7.4.3 Most Prominent Congeners in Fish

The most abundant congeners found by Maack and Sonzogni

(1988), and Niimi and Oliver (1988) are listed in table 7-6.

The standard deviations for the most abundant congeners found

in this study were fairly small indicating that the

percentages of each congener amongst the samples was

relatively constant. This occured despite the variation in

species, PCB content and weight of the fish.

As mentioned before several of the congeners seen in high

concentrations in the fish in this study are prominent in

commercial Aroclors. For example, in Aroclor 1248 the top

three congeners are 28/31, 70/76, and 66 in the following

percentages, 17.7, 7.1 and 7.1 (Manchester, 1988).

133

Table 7-6 A Comparison of Most Prominent Congeners
(Weight Percent)
This Study Niimj and Oliver Maack and Sonzpgn ib
Species Br. Lk. Rainbow Species
Variedc Trout Trout Trout Varied
Congener Percent

28/31 5.7 (1.4) 7.9

47/48 6.8 (0.9)

49 4.0 (0.47)

41/64/71 4.0 (0.66)

66/95 8.5 (0.78) 7.4

70/76 4.5

101 4.2 (0.3) 6.3 6.1 7.2 6.0

118 4.5 (0.6) 5.5 6.3 5.6 2.7

77/110 7.7 (0.9) 5.6 4.8 5.8 6.8

132/153 4.9 (0.85) 7.3 10.8 9.1 11.0d
/105 2.6

138/163 e 4.8 (0.81) 5.4 5.9 5.7 8.1

146 3.4

149 5.1 3.4 4.8 4.3

180 4.2 4.6 4.5 3.7

'Oliver and Niimi, 1989
bMaack and Sonzogni, 1988
cParentheses indicate standard deviation
dCongener 105 was reported separately from congeners 132/153
e Congener 138/163 was reported together in this study;
however the other researchers reported congener 138 alone.

134

In Aroclor 1254, the top three congeners 153/132/105, 110 and

95 constitute the following percentages, 11.0, 9.2, and 7.6

(Manchester, 1988). Congeners 47/48, 49, 41/64/71 were

prominent congeners in the sediment which may account f or

their presence in the fish.

Oliver and Niimi (1988) found that twelve congeners, 153,

101, 84, 138, 110, 180, 87/97, 149, 187/182 and 105,

contributed to over half the total percentage of PCBs in fish.

Maack and Sonzogni (1988) found the ten most prominent

congeners contributed over half of the total percentage (66

percent). In this study, it was also f ound that the ten most

abundant congeners contributed over half the total percentage

of PCBs in fish (55 percent).

Several congeners have been identified as bei ng

significantly more toxic than other congeners (Safe et al.,

1985). They are characterized as containing at most one ortho

chlorine and two para and at least two meta chlorines.

Congeners containing no ortho chlorines are considered the

most toxic; their structure is similar to TCDD and elicits

similar toxic responses (Safe et al., 1985). Of the nonortho

chlorines, only congener 77/110 was detected using the methods

described in this study (see table 6-11). Although congeners

77/110 were detected, it is unlikely that the contribution of
congener 77' is significant (Hansen, 1987; Maack and Sonzogni,

135

1988). Of the mono ortho chlorinated congeners, 105 and 118

were detected (see table 6-11). The precise quantities of

congener 105 are not known since this congener coelutes with

153 and 132; however, Maack and Sonzogni (1988) found congener

105 to contribute approximately twenty percent of the combined

total of the three congeners in their study of Wisconsin fish.

Congener 118 was found in all fish (see table 6-11).

Maack and Sonzogni (1988) found only two of the

monochlorinated biphenyls, congener 118 and 105, in their

study. They were unable to determine the presence or absence

of congener 77 si4ce it coeluted with congener 110 which was

present in large concentrations in the sample. Congener 77

has been found in fish from the Waukegan Harbor in Lake

Michigan in quantities slightly diminished from the original

Aroclor introduced, Aroclor 1254 (Huckins et al., 1988).

Congener 105 was also found in fish from the Waukegan Harbor

in approximately the same quantities as that in Aroclor 1254.

The retention of the various PCB congeners is thought to

be a function of selective elimination of congeners rather

than selective uptake (Bruggeman et al., 1981). Uptake

efficiencies have been found to be independent of their

partition coefficients (Oppenhuizen and Schrap, 1988; van der

Oost et al., 1988). However, the elimination rates are found

to be a function of hydrophobicity. For the higher

136

chlorinated congeners, elimination rates are very low (van der

Oost et al., 1988; Bruggeman et al., 1981). Conversely, the

lower chlorinated congeners have been found to have high rates

of clearance. In one study of dichlorobiphenyl, the compound

was found to be completely excreted 14 days after the fish had

been switched from a contaminated environment to a clean one

(Bruggeman et al., 1984). Table 7-7 gives a f ew of the

clearance rates for PCBs as reported in the literature. Note

that the clearance rates increase with increasing molecular

weight.

Table 7-7 Clearance Rates for Specific Congeners

Congene Halflife (days) Source

2,5 10 Bruggeman et al., 1981
2,31,41,5 60 11
2,21,5 14.4 11

3,3,4,4 34.6 Huckins et al., 1988
2,3,5 2.5 11

2,21,3,315,51 139* Oppenhuizen and Schrap, 1988
2,21,3,31,4,41,6,61 139* It

Based on elimination rates given in their paper

It is well known that PCBs can be bioaccumulated to rather

high levels in aquatic organisms even though the ambient

concentrations in the water may be considerably lower (Oliver

137

and Niimi, 1988; Gooch and Hamdy, 1983). The ability of an

organism to accumulate a chemical from water is often

characterized by the bioconcentration factor, i.e., the

concentration of the chemical in the organism divided by the

concentration in the surrounding water (MacKay, 1982).

Mackay predicted a relationship between the

bioconcentration factor and the octanol-water partition

coefficient based on thermodynamics. Incorporating laboratory

data from a Veith et al. (1979) into the thermodynamic

prediction, Mackay developed the following equation:
Log BCF= Log KOW -1. 32 . (R'=O. 9 5) .

Figure 7-5 is a comparison between the BCF values calculated

from this study and Mackay's predicted relationship. The

bioconcentration factors found in this study were obtained by

dividing the average fish concentration of a particular

congener by the concentration in water of that particular

congener. Then the octanol-water coefficient for the

particular congener was found and a second BCF value

calculated using the relationship of Mackay.

With the exception of the first two congeners and two

other congeners, the BCF values calculated in this field study

were lower than those predicted by Mackay (1982). This is

surprising because the BCF calculated from laboratory studies

usually underestimates the amount actually accumulated by f ish

Figure 7-5 Predicted BCF from Mackay
versus Calculated BCF from Field data

I oc@
6 Measured@BCF from.Sheboygan River

Line if there is a one to one
. ................................................................................................................................................... ............ ..............................................
correlation between predicted
and measured BCF values

4 . .............................. ...... ............................................ .............................. ............. . ................................................................

.... ..... ... .... ... .... ... .... . ... ....
3 . .............................................................................. ..............................................B.. C..Fc.a..I.. c..u..I..a..t.. e..d..........
from observed PCBs
2 . ....................................................... ...................I................................ con ci i-n fish a-n-d wate-1

. ......................... .....................................................................................................................................................................................

0.
0 1 2 3 4 5 6 7
Predicted BCF from Mackay (1982)
Predicted BCF is calulated from Log.BCF = Log Kow -1.32
BGF (from data)

BCF (from data) Is (conc. POB In fish)/(conc. PCB In water,)

138

I .

fig 7-5

1
0

139

in the environment, in part because it ignores diet as a

contributipn of PCBs. It has been shown that the diet is a

major source of PCBs to fish particularly with regards to the

higher chlorinated PCBs (Niimi and Oliver, 1988; Rubenstein

et al., 1984; Bruggeman et al., 1984). Although the BCF

values in this study were slightly lower than the values

suggested by Mackay, these values are within the range of

values reported by Mackay (1982) in a survey of the literature

(see table 7-8).

Above a log octanol-water partition coefficient of about

six, the relationship between the octanol-water partition

coefficient and bioconcentration factor is no longer a simple

linear relationship. This deviation can be seen in figure

7-5 in which Mackay's predicted line continues upward whereas

the BCF values based on field data start to decrease at a log

BCF value of about five, corresponding to a log KOW of about

six. It is therefore difficult to predict the

bioconcentration factor for chemicals having log octanol-water

partition coefficients above six. Other researchers also

have reported that the relationship between bioconcentration

factor and the octanol-water partition coefficient is no

longer linear after there are six or more chlorines on the

biphenyl (Bruggeman et al., 1984).

140

Table 7-8 BCF Values Reported in the Literature
(from Mackay, 1982)
Relationship Cite

BCF = 0.907log Kow -0.361 Baughman et al., 1984
BCF = 0.837log Kow -0.770 it
BCF = 1.160log Kow -0.75 Metcalf et al. 1975
BCF = 0.85log Kow -0.7 Veith et al. 1979
BCF = 0.542log Kow +0.124 Neeley et al. 1974

Log BCF =1.15 log Kow -0.4 This study

Several reasons have been suggested for this decline.

The more highly chlorinated compounds may not be as readily

available to the fish relative to the lower chlorinated

congeners due to their low solubility in water. In addition,

the higher chlorinated congeners are more likely to form

colloids that can not permeate fish membranes and therefore

will not be adsorbed (Bruggeman et al., 1984). It is also

thought that compounds with molecular weight (greater than

600) or large volumes may not be adsorbed because they are too

large to permeate membranes (Oliver and Niimi, 1986).

140

Chapter 8 Conclusions

8.1. Sediment

The overall finding from this study is that the PCB

congener distributions from highly contaminated sediments

(greater than 50 ppm) are considerably different from the PCB

congener distributions of the Aroclors originally used at the

industrial site. The highly contaminated sediments are

enriched in mono, di, and tri chlorinated congeners relative

to the original Aroclors. In sediments containing

concentrations of PCBs less than 50 ppm, the congener

distributions were similar to the original Aroclors.

The enrichment in the'highly contaminated sediments with

lower chlorinated congeners is not easily explained by

existing physical -chemical partitioning relationships or known

abiotic chemical reactions. This suggests that a biotic
process Jrs@@may be responsible for the enrichment. Anaerobic

dechlorination by bacteria has been shown to occur in other

highly contaminated river sediments. The similarity of the

PCB congener distribution in highly contaminated areas of the

Sheboygan River to the results from other anaerobic microbial

degradation studies at highly contaminated sites suggests that

the congener distribution is the result of microbial

degradation. Microbial degradation is also suggested by the

concentration dependence of the patterns seen in the

141

sediments. Other studies of anaerobic microbial degradation

of organic compounds have found a similar concentration

dependency.

Specific findings are listed below:

1) The river sediment is largely composed of fine grain sand

(40 to 90 percent of the sample). Grain size correlated with

PCB content. Smaller particles were found to contain higher

concentrations of PCBs relative to larger particles of the

same volume.

2) Total PCB concentrations varied spatially in the river

sediment. With depth, PCB concentrations in sediment cores

were the lowest in surface sediments (top 15 cm of the

sediment core) and the bottom sediments (greater than 45 cm

from the sediment-water interface). Highest concentrations

were found in the center of the core (15-45 cm down from the

sediment-water interface).

3) The total concentration of PCBs diminished with distance

from the source, presumably due to the transport of PCBs

downstream.

4) In sediment samples with greater than 50 ppm PCBs

142

concentrations of congeners 4/10, 5/8, 17, 24/27, 16/32,

47/48, and 26 were found to be enriched in the sediment

compared to the original Aroclors. Congeners 5/8 were in the

greatest abundance (29.2 percent on average). In six of the

samples, congeners 5/8 were found to comprise a large

percentage of the sample (43.7 percent on average).

5) Congeners with a greater than two percent increase relative

to a 50/50 mix of Aroclor 1248 and Aroclor 1254 were 5/8, 19,

17, 24/27, 16/32, 26 and 47/48. Congeners 5/8, 17, 24/27 and

16/32 were also prominent congeners in the Hudson River where

anaerobic dechlorination has been reported to occur.

6) Congeners with a greater than two.percent decrease relative

to a 50/50 mixture of Aroclor 1248 and 1254 were 18, 28/31,

52, 44, 70/76, 66/95, 56/60, 101, 77/110, 132/153/105, and

138/163. In the Hudson River, congeners 44, 70/76, 66/95,

132/153/105, and 138 were also found in diminished quantities.

7) Harbor sediment samples had congener patterns similar to

the original Aroclors and to the river sediments containing

less than 50 ppm.

8.2. Water

143

The total PCB concentrations in water were highest

several miles downstream from the source. The water samples

were less contaminated directly at the source and in the

harbor. The variation of total PCBs in water is most likely

due to the transport of PCBs downstream. The fact that the

highest concentrations were found several miles downstream

from the source is not surprising. Water concentrations at

the source would be lower because of constant inflow of "clean

water" at Rochester Park and subsequent dilution of the

contaminated river water.

Other findings are summarized below:

1) With distance from the source, the water developed a

congener profile that was similar to the sediments.

Presumably, this is due to the entrainment of sediment

particles in the water column as a result of turbulent

scouring.

2) Higher concentrations of the lighter chlorinated congeners

were found in the dissolved phase compared to the particulate

phase. These results would be expected based on the partition

coefficients and solubility constants for these congeners.

3) Congeners 4/10, 5/8, 17, 16/32, 41/64/71 were found to be

144

in high concentrations in the water'relative to the original

Aroclors used at the source. These congeners were found to

be prominent congeners in the sediment.

8.3. Fish

The congener distribution in fish bore little resemblance

to the sediment or water distribution. From a modelling and

regulatory perspective, this finding is significant because

some researchers have advocated using s ediment as a predictor

of congener distributions in fish. Clearly, for rivers such

as the Sheboygan River or Hudson River, use of these models

is inappropriate since the fish are enriched in higher

chlorinated congeners while the sediment is not.

Specific findings are listed below:

1) In contrast to the water distribution, the f ish do not

contain the lighter chlorinated congeners. This is consistent

with previous studies of fish that show the lighter

chlorinated congeners are metabolized and the heavier

chlorinated congeners are bioaccumulated.

2) There was a positive correlation between the weight percent

fat in fish and PCB content.

3) Fish samples were analyzed for total PCBs using both

145

capillary column and packed column techniques. Total PCBs

measured by both techniques were similar.

4) Congeners 28/31, 47/48, 49, 41/64/71, 66/95, 101, 118,

77/110, 132/153/105 and 138/163 were prominent in fish.

Congeners 28/31, 70/76, 66, 153/132/105, 110, 95 are the top

three congeners in Aroclor 1248 and Aroclor 1254 respectively.

Congeners 47/48, 49, 41/64/71 were found to be in abundance

in the sediment. Congeners 77, 105, and 118, which are

considered to be among the most toxic PCBs, coelute so their

relative importance (in terms of concentration in fish) is not

clear.

8.4. Concluding Remarks

Further studies of anaerobic dechlorination of PCBs is

warranted to determine if environmental conditions can be

enhanced to encourage reductive dechlorination of PCBs.

Specifically, investigations are needed to identify the

microorganisms responsible for dechlorination, to determine

the necessity of additional substrates (cometabolism), and to

determine the type of anaerobic environment necessary

(nitrogen atmosphere versus carbon dioxide atmosphere).

In addition, further research is warranted to determine

the feasibility of using anaerobic microbial degradation as

146

a large-scale treatment option for PCBs. Currently, the

Environmental Protection Agency (EPA) is conducting a pilot

project on anaerobic microbial degradation of PCBs using

highly contaminated Sheboygan River sediments. At present

however, much remains to be learned before microbial anaerobic

degradation can be thought of as a efficient and cost-

effective, large-scale treatment option.

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Concentrations of Toxic Polychlorinated Biphenyl Congeners

in Sheboygan River (USA) Sediments

by W. Sonzogni

L. Maack

T. Gibson

J. Lawrence

Laboratory of Hygiene

and Water Chemistry Program

UnIversity of Wisconsin

Madison, WI 53706

In the U. S. polychlorinated biphenyls (PCBs) were
produced in mixtures (Aroclors) of the 209 different PCB
congeners. The Aroclors dif f er not only in the congeners
contained.in the mixture, but also in the weight percent
of the congeners. Until recently almost all
environmental and biological samples were analyzed for
PCBs by matching the chromatographic pattern to the
pattern of pure Aroclors (Webb and McCall 1973; Erickson
1986), and results were reported as an Aroclor or mixture
of Aroclors. How'ever, with the refinement. of. high
.resolution capillary gas chromatographic techniques, it
is now possible to identify and quantify individual PCB
congeners in environmental samples (Mullin et al. 1984;
Maack and Sonzogni 1988). Note that in this paper
congeners will be referred to by their International
Union of Pure Applied Chemistry (IUPAC) numbers and by an
abbreviation of their structure. For example, 3, 3', 4,
4' tetrachlorinated biphenyl is referred to as congener
77 (34-34).

Interest in individual congener concentrations has also
increased because recent toxicological data indicate the
potency of congeners varies widely (Safe 1987; Tanabe et
al. 1987). Those congeners presently thought to be most
toxic are the non-ortho chlorinated PCBs, since these co-
planer compounds structurally resemble the highly potent
2,3,7,8-tetrachlorodibenzo-dioxin (TCDD) Congeners 77
(34-34), 126(345-34) and 169 (345-345) are non-ortho
chlorinated and most resemble dioxin. They are believed
to be the most toxic congeners, at least in terms of
dioxin-like properties (Safe et al. 1985; Tanabe et al.
1987). Congener 81 (345-4) also has no ortho chlorines;
however, it is structurally different enough from TCDD
that it is not considered to be as toxic as the compounds
above. The mono-ortho congeners, such as 105

Send reprint requests to W. Sonzogni at the above
address.

(234-34) , 118 (245-34) , 123 (345-24) , 114 (2345-4) and
167 (245-345) are also thought to be toxic (have toxic
properties related to dioxin) , although they are less
potent.(Safe et al. 1985; Safe 1987).

Unfortunately, most of the congeners mentioned above are
difficult to analyze, even by high resolution gas
chromatography. These compounds tend to co-elute with
other congeners. Special separation techniques are
required to identify them. To date, the only separation
techniques reported in the literature are (1) carbon
column absorption (Stalling et al. 1983) and
multidimensional gas chromatography (Duinker et al.
1988). The purpose here is to present results of
analyses of river sediments for these toxic PCB congeners
using a multidimensional chromatography technique.

MATERIALS AND METHODS

Sediment samples were col lected from the Sheboygan River,
a Wisconsin tributary to Lake Michigan. The river is
polluted with PCBs from the mouth to about 22.6 km (14
miles) upstream. Waste hydraulic fluids containing
Aroclor 1248 and Aroclor 1254, were the source of the
contamination (David 1990). The polluted se'?--tion of the
river is a U.S. federal "Superfund" site as well as one
of the Great Lakes "Areas of Concern" As defined by the
U.S./Canadian International Joint Commission.

Sediment cores were collected in December of 1988 and
April of 1989 using a metal corer 90 cm (3 ft) long and
7.6 cm (3 in.) in diameter. All samples were collected
,near the original source of PCBs at Rochester Park (about
22.6 km upstream from the mouth). A hydraulic extruder
was used to remove the sediment from the corer. The
cores were segmented into 15 cm sections and kept cool
(40C) until analysis.

Sediment was air dried and sieved to form a homogeneous
sample. PCBs were extracted from 50 g sediment samples
by soxhleting for eight hours with acetone and hexane
(1: 1) . Granular copper was: added to the soxhlet f lask to
insure uniform boiling and to remove sulfur
interferences. After concentrating the sample, anhydrous
sodium sulfate was added to remove water from the
extract. The hexane-acetone solution was then exchanged
for 2,2,4-trimethyl pentane (iso-octane) . PCBs were
separated from other contaminants using Florisil and
silica gel. Hexane and 6% ethyl ether were the eluting
solvents used for the Florisil fractionation and hexane
for the silica gel fractionation. The first silica gel
fraction was subsequently used for PCB quantitation.
Hexane was exchanged with isooctane prior to gas
chromatographic analysis. Samples were concentrated to

10 or 50 mL prior to injection of an aliquot into the gas
chromatograph.

PCB congeners were quantitated using a Siemens Sichromat
2-8 multidimensional gas chromatograph. The instrument
was equipped with two 30 m capillary columns (DB-5 and
DB-1; J and W Scientific). Each column was connected to
an individual "Ni electron capture detector. The columns
were also contained in separate ovens. Eluate from the
DB-5 column passed through the column's detector
producing a chromatogram similar to that produced in
conventional high resolution gas chromatography.
However, when a 'IT-piece" connecting the DB-5 column to
the DB-1 column was activated, eluate was diverted to the
DB-1 column. Thus, a selected part of the eluate (e.g.,
the eluate eluting between a specific time interval) was
cut to the DB-1 column. The cut is accomplished on a
real time basis according to pneumatic (gas flow)
differences between the two columns, the timing,of which
is controlled by the analyst.

The temperature of the oven containing the DB-5 column
was ramped from 900C to 1600C at a rate of 200C per
minute, then from 1600C to 2600C at a rate of 40C per
minute. The final temperature was held for one minute.
The temperature of the column containing the DB-1 oven
was held at 1600C for 20 minutes and then increased at a
rate of 40C per minute to 2400C. The final temperature
was held for eight minutes. The injector temperature was
2500C. the detectors were heated to 3000C. The carrier
gas and make-up gas were hydrogen and nitrogen,
respectively.

By cutting a portion of the eluate after it passed
through the DB-5 column to and through the less polar DB-
1 column, increased separation of the compounds in the
cut was obtained. The chromatogram produced from the
second (DB-1) column and its associated detector
represented the response of the cut components, while the
chromatogram of the first column (DB-5) represented the
rest of the compounds in the injected mixture (the
chromatogram for the first column is interrupted by the
cut). For a further discussion of the instrument, see
Duinker et al. (1988).

For the eight congeners studied, pure standards were used
for identification (based on retention times) and
quantification. A detector limit of 1 ng/g, based on a
signal to noise ratio of approximately 3, was made.
Although replicate analyses were made to check results,
no alternate method was available to confirm the
identification of the congeners in the unknown.

RESULTS AND DISCUSSION

Results of the analyses of Sheboygan River sediment
samples f or total PCBs and eight "toxic" congeners are
summarized in Table 1. Each of these congeners was
.identified and quantified in at least one of the samples.
Note that all sediment core samples analyzed had total
PCB concentrations greater than 50 Ag1q.

Congeners 118 (245-34), 105 (234-34), and 77 (34-34) were
detected in all of the samples reported here.
Concentrations ranged from about 5 to 1500 ng/g. The
remaining toxic congeners, 81 (245-4), 114 (2345-4), 167
(245-345), 126 (345-34), and 169 (345-345), were detected
less frequently in the analyzed samples. Concentrations
of these congeners ranged from non-detectable to slightly
over 100 ng/g.

Very few measurements of toxic congeners in environmental
samples have as yet been reported in the literature.
Tanabe et al. (1987) reported various levels of congeners
77 (34-34), 126(345-34), and 169 (345-345) in fish,
marine mammals, and terrestrial animals in Japan.
Duinker et al. (1988) reported seal blubber from the
Dutch Wadden Sea contained 100, 800 and 5200 ng/g of
congeners 77 (34-34), 118 (245-34) , and 105 (234-34) ,
respectively. Congeners 126 (345-3A), 81 (345-4), 167
(245-345), and 114 (23 45-4) were all found in seal
,blubber at concentrations less than 10 ng/g. Note that
for the Sheboygan sediments reported here, congeners 77
(34-34), 118 (245-34), and 105 (234-34) were also found
at concentrations higher than the rest of the congeners.
To the best of the authors' knowledge, no other data on
concentrations of these congeners in aquatic sediment
have been published.

Table 2 presents the weight percents of the congeners in
the samples. Also included are the weight percents of
congeners in several Aroclors as determined by Duinker et
al. (1988). The weight percents of the toxic congeners
in the sediments were generally lower than those found in
Aroclors 1248 and 1254 (the primary PCB mixtures
discharged to the river) and in the other Aroclor
mixtures listed in Table 2. The weight percents of the
,most prominent toxic congeners (77,,118, and 105) were
about one order of magnitude lower than the weight
percents of these congeners in Aroclor 1248. Some weight
percents for congener 81 (345-4) were higher than
reported for the Aroclors, although the congener was
detected only in four of the eight samples reported.

Anaerobic reductive dechlorination of PCBs, similar to
that reported by Brown et al. (1987), Quensen et al.
(1988), and Rhee et al. (1989), has been reported to

occur in Sheboygan River sediments (David 1990).
Dechlorination of non-ortho chlorinated congeners has
been found to occur more readily than dechlorination of
ortho chlorinated PCBS (Brown and Wagner 1990).
Congeners 77 (34-34), 118 (245-34), and 105 (234-23) are
all non-ortho chlorinated PCBs, suggesting that
dechlorination might play a role in the depletion.

of the toxic congeners, congener 118 (245-34) was found
in Sheboygan River sediments in the highest weight
percent. Congener 118 is also found in all the Aroclors
in Table 2 in the highest weight percent of the toxic
congeners. It also appears to be the most common toxic
congener in environmental samples. It was f ound in
highest concentrations (relative to other toxic
congeners) in seal blubber (Duinker et al. 1988) , as, well
as in the sediments collected for this study. Congener
118, unlike the other toxic congeners, can of ten be
resolved and quantified without multidimensional gas
chromatography or other special techniques. It has thus
been reported in a variety of matrices, such as fish and
the blood of sport fish eaters (Maack and Sonzogni 1988;
Fiore et al. 1989 and Sonzogni et al. 1991).

The eight toxic PCBs studied here appear to be present in
the sediment, but in relatively low concentrations
compared to total PCBs or other more abundant
congeners. The concentrations of the eight congeners are
low relative to the congeners with which they co-elute as
well. For example, toxic congener 77 (34-34) co-elutes
with congener 110 (236-34), but 77, in the sediments
studied here, made up less than 4 percent of the total of
the co-eluting pair. It should again be emphasized that
the toxic congeners have been so labeled because of their
dioxin-like structure and the potential health effects
of dioxin. More research needs to be conducted on the
toxicological effects of the PCB congeners. The effects
of exposure to environmental levels needs to be
considered as well as toxicological endpoints other than
that for dioxin. For example, the neurotoxicological
impacts of specific congeners or combinations of
congeners needs to be studied. Perhaps new analytical
toolst such as multidimensional gas chromatography, will
help make such research more feasible.

Acknowledgements: The authors gratefully acknowledge the
sampling assistance of William Wawrzyn and Thomas Aartila
of the Wisconsin Department of Natural Resources. This
research was supported under a grant from the Wisconsin
Coastal Management Program.

Table 1. Concentration of various toxic PCB congeners in Sheboygan River
sediment samples of different total PCB concentrations.

Total PCB
in sample Congener (IUPAC Number)
(Ag/g) 77 118 105 167 114 126 169 81
(ng/g)

50.3 31 140 80 44 NDa ND ND ND

1050 360 1480 490 80 110 10 19 90

76.9 24 129 27 ND ND 9 9 ND

97.8 21 318 41 ND ND ND ND ND

256 46 395 15 ND ND ND ND 75

73.4 5 103 11 ND ND ND ND ND

97.5 11 162 6 ND ND ND 11 ND

124 16 86 11 ND ND ND ND 50

"ND not detected (concentration less than 1 ng/g)

Table 2. Weight Percent of Various Toxic PCB Congeners in
.Sheboygan River Sediment Samples and Weight Percent of
Congeners in Several Aroclors'.

Total PCB
in Sample Congener (IUPAC Number)
GLg/g) 77 118 167 114 126 169 81
(weight
50.3 0.06 0.27 0.15 0.09 - -b
1050 0.03 0.14 0.05 0.01 0.01 <0.01 <0.01 0.01
76.9 0.03 0.16 0.04 0.01 0.01

97.8 0.02 0.33 0.04 - - - -
256 0.02 0.15 0.01 - - - - 0.03

73.4 0.01 0.14 0.01 - - - -
97.5 0.01 0.17 0.01 - - - - 0.01
124 0.01 0.07 0.01 - - - - 0.04
Aroclor 1242 0.50 1.80 0.33 <0.01 <0.01 <0.01 <0.01 <0.01
Aroclor 1248 0.30 3.35 0.55 <0.01 <0.01 <0.01 <0.01 <0.01
Aroclor 1254 <0-01 8.45 2.03 0.05 <0.01 0.08 0.08 <0.01
Aroclor 1260 <0-01 1.15 0.08 0.15 <0.01 0.05 0.05 <0.01

'Aroclor weight percents f rom. Duinker et al. 1988
bCongeners not detected in samples (weight percents less than 0.002%).

References

Brown JF, Bedard DL, Brennan MJ, Carnahan JC, Feng H,
Wagner RE (1987) Polychlorinated biphenyl
dechlorination in aquatic sediments. Science
236:709-712
Brown JF, Wagner RE (1990) PCB movement, dechlorination,
and detoxication in the Acushnet Estuary Environ
Toxicol Chem 9:1215-1233
David M (1990) PCB congener distribution in Sheboygan
River sediment, fish and water. MS Thesis, Water
Chemistry Program, Univ of WI, Madison 159p
Duinker JC, Schultz DE, Petrick G (1988) Multidimensional
gas chromatography with electron capture detection
for the determination of toxic congeners
polychlorinated biphenyl mixtures. Anal Chem
60:478-482
Erickson MD (1986) Analytical Chemistry of' PCBs.
Butterworth Publishers, Stoneham, MA
F iore BJ, Anderson HA, Hanrahan LP, Olson LJ, Sonzogni
WC (1989) Sport fish consumption and body burden
levels of chlorinated hydrocarbons; A study of
Wisbonsin anglers. Archives of Environ Health
44:82-88
Maack L, Sonzogni WC (1988) Analysis of
polychlorobiphenyl congeners in Wisconsin fish.
Arch Environ Contam Toxicol 17:711-719
Mullin MD, Pochini CM, McCrindle S, Romkes M, Safe SH,
Safe LM (1984) High resolution PCB analysis:
Synthesis and chromatographic properties of all
209 PCB congeners. Environ Sci Technol 18:468-476
Safe S, Safe L, Mullin M (1985) Polychlorinated
biphenyls: Congener-specificanalysis of commercial
mixture and a human milk extract. J Agric Food
Chem 33:24-29
Safe S (1987) Determination of 2,3,7,8-TCDD toxic
equivalent factors (TEFs) ; Support for the use of
the in vitro AHH induction assay. Chemosphere
16:791-802
Sonzogni W, Maack L, Gibson T, Degenhardt D, Anderson H,
Fiore B (1991) Polychlorinated biphenyls congeners
in blood of Wisconsin sport fish consumers. Arch
Environ Contam Toxicol, in press
Stalling DL, Smith LM, Petty JD, Hogan JW, Johnson JL,
Rappe C, Buser HR (1983) Residues of
polychlorinated debenzo-p-dioxins and
debenzofurans in Laurentean Great Lakes fish. In:
Tucker RE, Young AL, Gray AP (ed) Human and
environmental risks of chlorinated dioxins and
related compounds, Plenum
Tanabe S, Kannan N, Subramanian A, Watanabe S, Tatsukawa
R (1987) Highly toxic coplanar PCBs: Occurrence,
source, persistency, and toxic implications to
wildlife and humans. Environ Pollut 47:147-163
Webb RG, McCall AC (1972) Identities of polychlorinated
biphenyl isomers in aroclors. J Assoc Offic Anal
Chem 55: 746-752

PCB Dechlorination in the Sheboygan River, Wisconsin

Extended Abstract to be Published in Proceedings of a Workshop on
Biological Remediation of Contaminated Sediments

by William C. Sonzogni and Margaret M. David
Laboratory of Hygiene and Water Chemistry Program
University of Wisconsin
Madison, WI 53706

The Sheboygan River in Wisconsin flows into Lake Michigan at

the city of Sheboygan, located 90 km north of Milwaukee. Due to

the high concentrations of PCBs in the river sediment, the

Sheboygan River and Harbor area has received national attention.

The main source of contamination was from a die casting plant

located in the Village of Sheboygan Falls. The contamination

source area is about 22 km upstream from the mouth of the river.

Hydraulic fluids containing PCBs were used by the die

casting plant from 195.9 to 1971 (11). Apparently, a large fire

occurred at the plant prior to 1959 that was caused by combustion

of the hydraulic fluids then in use. Fluids containing PCBs were

subsequently put in use because of their fire resistance. Based

on interviews and available records, a product called Pydrol F9

was used between 1959 and 1969 and a product called Chemtrend

HP30 was used between 1970 and 1971. Pydrol F9 contains Aroclor

1248, while Chemtrend HF30 contains, mostly Aroclor 1254 with a

small percentage of Aroclor 1248. In 1971 the use of hydraulic

fluids containing PCBs ceased.

Material from the plant (oil soaked rags, hoses and other

refuse) and soil from around the plant was used to construct a

low dike at the edge of the Sheboygan River. The dike sloped at

a 45 degree angle to the river, so erosion of the diked material
into the river occurred relatively easily (11). Concentrations

of PCBs in the soil samples were as high as 120,000 gg/g. The

die casting plant is the only known major source of PCBs to the
river, therefore, the congeners deposited in the sediments were

most likely the components of Aroclor 1248 and 1254.

In an article in science it was reported that biological

reductive dechlorination of PCBs was occurring in Hudson River

sediment. There was evidence that anaerobic dechlorination was

also occurring in other aquatic sediments, including Sheboygan

River sediments (4). The Sheboygan evidence was based on

observations of chromatograms obtained from the U.S. Army Corps

of Engineers.

As result of the published reports that dechlorination could

occur and because of new analytical capabilities to do congener

specific PCB analysis, research was begun to examine the

distribution of PCB congeners in the Sheboygan River sediment and

to determine whether anaerobic dechlorination may be occurring.

The intent was to determine the congener distribution in

Sheboygan River sediment and assess whether some transformations

had occurred. Results of congener distributions in Sheboygan

River sediment relative to distributions in Aroclors will be

summarized below as well as information on the occurrence of

"toxic" congeners. Finally, a summary of evidence so far to

degrade PCBs in the laboratory using bacteria from Sheboygan

River sediments will be made.

Total PCB concentrations ranged from 1586 Ag/g found

downstream from the source to 0.04 gg/g above the source
(considered to represent background levels). Although there is

considerable variation in the sediment PCB concentrations, in

general, the values were found in areas of sediment deposition in

the river. In the individual cores, the top segment of core (0-

15 cm) and the bottom segment of core (45-60) cm had relatively

low concentrations of PCBs. The highest concentrations were

found in the 15-45 cm segments.

Sediment samples were also analyzed for PCB congeners using

high resolution gas chromatography. Samples containing total PCB

concentrations greater than 50 Ag/g appeared to be enriched with

the lower chlorinated congeners whereas those with less than 50

Mg/g PCBs were not. Samples containing 50 gg/g or more PCBs and

significantly higher concentrations of mono- and di- chlorinated

congeners when compared to aroclors 1248 and 1254 which were

originally introduced into the river. Using a mulltivariate ANOVA

statistical test, samples containing PCB concentrations less than

50 Ag/g, were found to be statistically different from Aroclor

1248, Aroclor 1254 and an equal parts mixture of Aroclors 1248

and 1254.(p values were <0.05). In sediment samples containing

PCB concentrations less than 50 Ag/g, the homolog patterns were

more similar to the patterns of the Aroclor'1248 and 1254 than

the more contaminated sediments.

The most prominent congeners in the sediments with total PCB

concentrations greater than 50 Ag/g were (IUPAC #) 5/8, 17,

16/32, 47/48, and 28/31. Relative to the, original Aroclors,

particularly high concentrations of congeners 5 and 8 were seen

(congeners 5 and 8 co'elute). To confirm the presence of
congeners 5/8 six of the samples containing high concentrations
of PCBs (342.8 Ag1g on average) and high concentrations of
congener 5/8 (43.7 percent on average) were analyzed using an

electron impact gas chromatography mass spectrometer. All

samples contained high concentrations of dechlorinated congeners.

In samples containing less than 50 gg/g of PCBs, the most

prominent congeners were similar, but their weight percents were

generally reduced.

The result from the sediment analyses indicate that the PCB

congeners and their respective weight percentages in sediments

with high PCB concentrations are significantly different from the

Aroclors originally introduced into the river. Although

physical-chemical processes such a sediment-water partitioning

are important in determining the distribution of congeners in

sediments, it is unlikely that it is the dominant process

influencing the distribution of congeners. Sediment-water

partition coefficients generally increase with molecular weight

and thus an enrichment of the higher chlorinated congeners in the

sediments not lower chlorinated congeners as observed would be

predicted.

Diffusion of congeners out of the sediment and into the

water is slow relative to sedimentation rates and is inversely

related to partition coefficients (7,8). Therefore, a

distribution enriched in the higher chlorinated PCBs would be

predicted (opposite of what was observed in this study).

Another possibility to account for the change in congener

patterns in abiotic chemical reactions. PCBs have been shown to
undergo abiotic reductive dechlorination in the labor atory;

however, the conditions in the laboratory (high temperatures,

excess base, and the presence of a catalyst) are considerably

different from those in the environment (3). In general, it is

thought that there are very few abiotic pathways which completely

mineralize organic contaminants (1).

It is possible, however, that the Aroclors undergo

biological dechlorination. Recent work by Quensen et al. (9),

Chen et al. (6), Rhee et al. (10), and Brown et al. (4,5) suggest

that PCBs can undergo.anaerobic microbial degradation. Several

results in this study suggest such a process.

First, there is a shift in the congener pattern from the

higher chlorinated congeners to the lower chlorinated congeners

as observed by Quensen et al. (9) in a laboratory experiment and

as noted by Brown et al. (4,5) in a field study of hudson River

sediments. This enrichment in lower chlorinated congeners cannot

be accounted for by physical-chemical partitioning relationships

or diffusion processes.

Second, there appears to be a structural selectivity as to

which congeners are depleted in the sediment. Congeners

containing chlorines in the ortho position are enriched, whereas

congeners containing chlorines in the meta or para position are

depleted. This is consistent with the results obtained by

Quensen et al. (9) and Brown et al. (4) in their anaerobic

microbial dechlorination work.

Third, several congeners are found in abundance that would

not be expected based on physical-chemical partitioning
relationships or on the original weight percentages present in

the Aroclor mixtures. In sediment samples with concentrations of

PCBs above 50 Ag/g, congeners that were significantly enriched

are 5/8, 19, 17, 24/27, 16/32, 26, and 47/48. Congeners that

were significantly depleted are 18, 28/31, 52, 44, 70/76, 66/95,

56/60, 101, 77/110, 132/153/105, and 138/163. These changes are

comparable to Brown et al.'s (5) findings.

Fourth, the concentration of PCBs in the sediment appears to

be important. Microbial degradation is often restricted to areas

of high substrate concentrations. For example, toluenel xylene,

and naphthalene are metabolized by bacteria at high

concentrations but not at low concentrations (2). Threshold

concentrati ons exist for many contaminants and are the minimum

concentration of a chemical which is needed to support growth of

a microbial population (2). Below the threshold concentration,

additional energy sources must be found to support growth of the

population, since the organism is no longer able to completely

mineralize the substrate. Based on the different chromatographic

patterns seen for high and low concentrations of PCBs in the

Sheboygan River, it may be that a threshold concentration exists

for the anaerobic dechlorination of PCBs.

To confirm that microbial processes are actually responsible

for degrading PCBs, laboratory experiments have been conducted

similar to those reported by Quensen et al. (9) and Rhee et al.

(10). Using bacteria extracted from Sheboygan sediments,

degradation was attempted using growth medium and anaerobic

conditions suitable for microbial dechlorination of PCBs.

However, to date no dechlorination has been observed in the
experiments. The reason for the lack of dechlorination activity
is not clear, but it is suspected that the conditions that favor
degradation are very complicated (e.g., may involve very precise
Eh conditions and may involve several different species or stains

or organisms) and may be difficult to consistently reproduce in

the laboratory.

Finally, Sheboygan sediments have been analyzed for the

presence of non-ortho or coplanar PCBs. These congeners are

believed to be the most toxic (at least in terms of dioxin like

toxic properties), but generally coelute with other congeners

using capillary column gas chromatography. A multidimensional

("heart cutting") gas chromatograph that uses two high resolution

columns in series was used to separate coeluting congeners.

Results to date indicate that several congeners of toxicological

interest are found in sediment samples, albeit at low

concentrations. Congeners 118, 105 and 77 were detected in 83

percent of the samples analyzed, at average concentrations of

about 0.25, 0.06, and 0.04 Mg/g respectively. The average

composition of these congeners was 0.13, 0.03, and 0.02 percent,

respectively. congeners 81, 114, 167, 126, and 169 were also

detected in some of the samples all at concentrations less than

0.03 Ag1g. While the concentrations of these congeners are low

relative to total concentrations of PCBs or to the congener they

coelute with, the fact that they are present may be important

toxicologically. Research is ongoing in this area.

This work was supported by grants from the Wisconsin Coastal

Management Program and the Wisconsin Sea Grant Program.

References

1. Alexander, M. (1981). Biodegradation of chemicals of

environmental concern. Science, 211: 132-138.

2. Alexander, M (1985) Biodegradation of organic chemicals.

Environ. Sci. Technol., 18:106-111.

3. Boyer, S.K., J McKenna, J. Karliner, and M. Nitsberger

(1985). A mind and efficient process for detoxifying

polychlorinated biphenyls. Tetrahedron Letters, 26; 3677-

3680.

4. Brown, J.F., D.L. Bedard, M.J. Brennan, J.C. Carnahan, H.

Feng, and R.E. Wagner (1987a). Polychlorinated biphenyl

dechlorination in aquatic sediments. Science, 236: 709-712.

5. Brown, J.F., R.E. Wagner, H. Fend, D.L. Bedard, M.J.

Brennan, J.C. Carnahan, and R.J. May (1987b). Environmental

dechlorination of polychlorinated biphenyls. Environ.

Toxicology and Chemistry, 6: 579-593.

6. Chen, M., C.S. Hong, B Bush, and G.Y. Rhee (1988).

Anaerobic biodegradation of PCBs by bacteria from Hudson

River sediments. Ecotoxicology and Environ. Safety, 16: 95-

105.

7. DiToro, D.M., J.M. Jeris, and D. Clarcia (1985)'. Diffusion

and partitioning of hexachlorobiphenyl in sediments.

Environ. Sci. Technol., 19: 1169-1172.

8. Fisher, J.B., R.L. Petty, and W. Lick (1983) Release of

polychlorinated biphenyls from contaminated lake sediments:

flux and apparent diffusivities of four individual PCBs.

Environ. Pollut. Series B., 5: 121-132.

9i Quensen, J.F., J.M.'Tiedje, and S.A. Boyd (1988). Reductive

dechlorination of polychlorinated biphenyls by anaerobic

microorganisms form sediments. Science, 24211 752-754.

10. Rhee, C.Y.j B. Bush, M.P. Brown, M. Kane, and L. Shane

(1989). anaerobic biodegradation of polychlorinated

biphenyls in Hudson River sediments and dredged sediments in

encapsulation. Water Research, 23: 957-964.

11. Wisconsin Department of Natural Resources (1989). Sheboygan

River remedial action plan. Environmental Quality Division,

Madison, Wisconsin.

SUMMARY OF LABORATORY EXPERIMENTS TO

DECHLORINATE PCBs USING BACTERIA EXTRACTED

FROM SHEBOYGAN,RIVER SEDIMENTS

In May of 1989 the first experiments were run to induce

dechlorination of PCBs in the laboratory. Anaerobic bacteria

were extracted from three sediment cores using the procedure that

will be described subsequently with the exception that a chopped

mean anaerobe media was used. PCBs were added to nine vials to

produce concentrations of 60 ppm, and to nine vials to produce

concentrations of 600 ppms (to give 18 incubating vials,

excluding controls).

After initial PCB analysis, this run was abandoned for the

following reasons. First, the sediment from which the anaerobes

were extracted had low PCB concentrations (18 ppm) so that

dechlorinating anaerobes may not have been established in the

sample. Second, the media used (a standard chopped meat

carbohydrate based anaerobic media) was different than used by

Quenson et al. (1988) in their original work. This media

presented sampling and extraction problems for PCB analysis.

Thus, a new experiment was started.

In the second experiment medium was prepared after Quensen

(1988 and personal communication, Michigan State University,

1989).

The composition of the medium (in mg/L) is listed below:

KH2PO4 270

K2HP04 350

NH4Cl 530

CaC12 15

MgC12 100

MnC12 0.5

ZnCl2 0.05

CUC 12 - 2 H20 0.038

COC12 - 6H20 0.05

FeC12 - 4H20 20

H3BO3 0.05

NaMn04 - 2H,20 0.01

N'C12 - 6H20 0.05

Na2SeO3 - 5H20 0.05

The medium was not buf f ered with NaHC03 nor reduced with sulfide,

as these additions were noted in Quensen's procedures as

optional. After autoclaving for about thirty minutes, the pH of

the mineral medium was adjusted to 7.0 with dilute sodium

hydroxide.

A sediment sample was obtained from an area of known high

PCB contamination with the expectation that it would contain

bacteria capable of dechlorinating PCBs. An additional sample

was obtained from a site, upriver from the contamination source,

to serve as an uncontaminated sediment source. The samples with

high PCB contamination, which tested anaerobic to *methylene blue,

were placed in anaerobe jars with 10 mL of sterile water.

Twenty grams of uncontaminated sediment and 35 mL mineral

medium were added to each of eight serum bottles in a CO /H2 glove

box. The bottles were left open for 24 hours in the glove box,

injected with 50 gL ethanol, sealed, incubated at 370C until

methane production was observed, and, after two weeks, were

autoclaved at 1210C for 1 hr.

Anaerobic microbes were obtained from the PCB-contaminated

sediment by first transferring the sediment from the anaerobe jar

to a glove box. In the glove box (C02/H2 atmosphere) a sample of

several hundred grams of PCB-contaminated sediment was shaken

vigorously with 500 mL of the mineral medium. After 15 min

settling, the liquid was decanted and saved. Aliquots (35 mL) of

the decanted liquid were added to each of the eight autoclaved

serum bottles of uncontaminated sediment.

Aroclors 1248 and 1254 (1:1 mixture dissolved in

dimethylsulfoxide) were added to serum bottles (containing

sediment and inoculated medium) in two concentrations. The

resulting concentrations of PCBs in the vials were 55 ppm and 436

ppm. Duplicate vials were prepared at each concentration. The

remaining four bottles, used as controls, were inoculated with

anaerobic medium, but were then twice autoclaved for 15 minutes

before addition of the Aroclor standards. All eight sealed serum

bottles were stored in the dark at room temperature (23-260C).

Part way through the experiment it was feared that the

sediment sample from which the bacteria were extracted may not

have had enough dechlorinating bacteria. Therefore, an

additional sediment sample was obtained to maximize the

probability of the existence of dechlorinating anaerobes. The

sample obtained was subsequently analyzed for PCBs and it

contained more than 100 ppm of PCBs. Therefore, this sample

should have contained dechlorinating bacteria. This sediment was

extracted and the extract added to the media as described above.

However, PCBs were spiked to give a resulting concentration of

436 ppm. Two vials were set up this way (no additional controls

were prepared).

Samples of slurry, 2 mL each, were withdrawn from the vials

for PCB analysis on an approximately monthly schedule. The

.samples were withdrawn into centrifuge tubes with 2 mL acetone

and 10 mL hexane, agitated on a mechanical shaker for 10 min,

decanted, agitated with an additional 10 mL hexane for 10 min,

decanted and the liquid added to the previous extracts. The

liquid was then blown down to near dryness and taken into about 3

mL iso-octane. The iso-octane extracts were then each eluted

through a column of 8g f lorisil and 2g Na2SO4 with 200 mL 6%

ether/hexane. An aliquot of the sample was diluted in iso-octane

until packed column GC screening indicated a suitable

concentration for congener analysis with capillary GC. The

samples were then analyzed for PCB congeners using a Hewlett

Packard 5880 gas chromatograph equipped with a

60 m DB-5 coated capillary column.

The PCB concentrations measured in the monthly analyses were

only about 30 percent of the expected concentration. Apparently,

the procedure used to extract PCBs from the media was incomplete.

However, the distribution of PCB congeners that were extracted

were nearly identical to the PCB congener distribution of the

original Aroclors added. Cross streak plate tests of the samples

after three months did reveal anaerobic activity (Clostridium and

Bacillus organisms were tentatively identified). Consequently,

despite'anaerobic conditions, anaerobic dechlorination apparently

did not occur (at least not measurably) in this experiment.

Part way through the experiment, the two vials that were set

up using extracts from the sediments with PCBs greater than 100

ppm were opened in the glove box and cysteine sulfide was added

along with 40 mL of ethanol. The cysteine sulfide was added in

an amount equivalent to the amount of sodium sulfide specified by

Quenson (Michigan State University, East Lansing, MI, 1989;

personal communication) as an optional addition. These chemicals

ensure that fully reducing conditions are occurring in the

sample. It was thought that this addition would remove any

uncertainty posed by not originally adding the sulfide.

After seven months the incubation was ended. All analyses

up to this point indicated that no dechlorination was occurring,

although the amount of PCBs extracted from subsamples was always

less than expected. Either the vials were subsampled in such a

way that the subsample obtained was unrepresentative (unlikely),

or the extraction procedure was not fully removing the PCBs from

the sediment/media mixture.

For a final analysis for PCBs after the seven month

incubation, special procedures were taken to ensure better

extraction of the sediment/media mixture. The vials (2)

containing bacteria extracted from sediment with high PCBs and to

which the sulfide was added were analyzed by this special

procedure. These vials were most likely to show dechlorination.,

PCBs were first extracted from the decant of the vial with

50 mL of hexane. The extraction was repeated four times and the

extract was saved. The residue left in the vial was then

vigorously shaken with 35 mL of acetone in order to suspend all

the material. The vial was then sonicated for three minutes to

break up the particles as finely as possible to ensure good

contact with the solvent. After the contents settled, the

acetone was poured off and saved with the hexane extracts. This

acetone extraction procedure was repeated three more times, so

that the sonicated sediment/media mixture was extracted a total

of four times with acetone.

The sediment/media mixture was further extracted with 35 mL

of hexane. The mixture was sonicated for three minutes during

each of the four successive extractions. After settling, the

decant from each extraction was saved.

For PCB analysis, all the decants following extraction were

mixed together. The resulting mixture was concentrated to 10 mL

by rotoevaporation. The concentrated solution was cleaned up on

a co lumn containing 22.0 g of florisil and two I cm layers of

Na2SO4 (to remove water and other interferences). The.column was

eluted with 220 mL of 6% either/hexane. The solvent leaving the

column was evaporated by blow-down. Iso-octane was added to

adjust the volume to 250 mL. Finally, a 1.0 mL aliquot was

diluted to 50 mL with iso-octane.

Following screening by packed column chromatography, the

iso-octane extracts were analyzed by capillary column gas

chromatography. For the two vials analyzed by this procedure,

88% and 89% of the PCBs were recovered. Thus, repeated

extractions of sonicated samples was effective at extracting PCBs

from the sediment/media mixture.

Despite the good recoveries, no evidence was found of

dechlorination. Congener patterns closely resembled the

distributions of congeners originally spiked into the vials.

Consequently, none of the laboratory experiments produced

evidence that bacteria extracted from Sheboygan River sediments

produce dechlorination.

Despite the negative results of the experiments conducted,

it is believed that more work would produce laboratory evidence

of dechlorination. Several other laboratories around the country

have now reported successful laboratory PCB dechlorination

experiments. Dr. G-Yull Rhee of the New York Department of

Health has now duplicated Quenson et al.'s experiments with

bacteria extracted from the Hudson River (Rhee et al. 1989).

However, Dr. Rhee (New York State Department of Health and School

of Public Health, SUNY at Albany, Albany, NY, 1990; personal

communication) has indicated that getting the bacteria to grow

properly is very tricky. He indicated that in his work it would

not be unusual to have only one of four replicates show

dechlorination. Both Dr. Rhee and Dr. Quenson agree that the

factors that may effect dechlorination in the laboratory are not

clear. For example, it is not clear whether the addition of

sulfide and ethanol are necessary or what electrode potential

should be obtained for the organisms to grow. Both believe that

a consortium or organisms, rather that an individual species, is

responsible for the dechlorination activity. Thus, while these

studies laboratory experiments were not positive, it is believed

that additional work, including a larger number of replicate

samples, would produce evidence of dechlorination. The

laboratory experiments of this study do show, however, that the

conditions under which dechlorination occurs are not clear and

that more needs to be learned if anaerobic dechlorination is to

be used as a bioremediation tool.

References

1. Quensen, J.Fi, J.M. Tiedje, and S.A.Boyd (1988). Reductive

dechlorination of polychlorinated biphenyls by anaerobic

microorganisms form sediments. Science, 242: 752-754.

Rhee, C.Y., B. Bush, M.P. Brown, M. Kane, and L. Shane

(1989). Anaerobic biodegradation of polychlorinated

biphenyls in Hudson River sediments and dredged sediments in

encapsulation. Water Research, 23: 957-964.

An Evaluation of the Potential for PCB Dechlorination in

Confined Disposal Facilities

Wisconsin State Laboratory of Hygiene
University of Wisconsin
Madison, WI 53706

EXISTING CONFINED DISPOSAL FACILITIES

Dredging of Great Lakes harbors to maintain navigation

dates back to the early 1800's. Natural siltation from tributary

rivers prompted periodic dredging, and dredging has been

generally accepted as necessary and normal harbor maintenance.

Typical disposal methods were to side cast the dredgings to

adjacent areas or, mor e commonly, to deposit the material into

deeper waters.

Until the mid 1960's immediate economic concerns governed

the focus of this disposal. However, a new awareness of lake

eutrophication problems led to a questioning of open water

disposal techniques. The U.S. Army Corps of Engineers (1969) in

a study titled "Dredging and Water Quality Problems in the Great

Lakes" concluded that "in-lake disposal of heavily polluted

dredging must be considered presumptively undesirable." In 1970,

Congress generated PL 91-611 to create the Dike Disposal Program

for the Great Lakes (Anonymous, 1989)., The intent was to hold,

in a confined facility, a ten year supply of dredgings, and to

initiate a Dredged Material Research Program (DMRP). The U. S.

Army Corps of Engineers (COE) conducted the DMRP at their

Vicksburg (Mississippi) Waterways Experimental Station (WES).

The DMRP study was a comprehensive project, involving

universities, private research laboratories, and other federal

agencies. The main conclusions of the DMRP study, as indicated

in U.S. Environmental Protection Agency (1987), were fourfold:

1. No single disposal alternative is suitable

for a region, nor should any single alternative be

dismissed from consideration.

2. Environmental considerations.are stronger than other

considerations to necessitate long.range regional

planning as a lasting, effective solution to disposal

problems.

3. Fears concerning short term release of contaminants to

site waters are unfounded especially if the geochemical

environment is not changed.

4. To be environmentally effective, a confined site must

retain a high percentage of finer particles, since this

is where contaminants are carried.

Since 1978 there has been some additional dredged material

research. However, the research focus has shifted from

eutrophication to toxic substances. During the late 1970's and

1980's many harbor sediments were found to contain high

concentrations of heavy metals and organic pollutants, such as

PCBs. The research has not, however, provided a clear

understanding of the impact that toxic substances in a CDF may be

having on the Great Lakes or what happens to toxic chemicals over

time when placed.in a CDF.

Existing confined disposal facilities (CDFIS) in the Great

Lakes basin are listed in Table 1. Other than the Superior/

Duluth facility (constructed in 1978), Wisconsin's CDFIS are all

sited in or along Lake Michigan. In addition to the six

Wisconsin facilities listed in Table 1, three additional sites

have been proposed (Menominee, Sturgeon Bay, and Sheboygan) for

construction. The U. S. COE is responsible for dredge and fill

operations, including the operation of CDFIS. Guidelines and

criteria for dredging and filling are, however, set by the U.S.

Environmental Protection Agency (EPA).

The Sheboygan Harbor was dredged by the COE in the mid

1950 Is and annually up to 1969 when dredging stopped due to
controversy over the presence of heavy metals. Some contaminated

harbor sediments were removed in 1981 and 1984. As stricter

disposal regulations, particularly for PCBs have been put into

effect, dredging has been halted due to the lack of a means of

disposal.

GENERAL DESIGN OF CONFINED DISPOSAL FACILITIES

Each CDF is unique to the needs of the individual site.

Upland CDFIS generally have earthen dikes, whereas in-lake CDFIS

generally are encased by stone dikes to withstand wave action.

The overall design goals are to hold within the facility as high

a percent of the sediment particles dredged as possible.

The design of CDFIS has evolved since the first facility was

constructed in the early 1960's to a point where there are now

certain design similarities (U.S. Army Corps of Engineerst

1986). Designs now allow limited permeability so precipitation

can drain into the lake. As environmental requirements became

more stringent, steel sheet pile was incorporated into the

design. This pile was used in the three Wisconsin CDFIS, thus

further ensuring the dredged material is retained in the dike.

Recently constructed dikes have utilized a core of limestone

which "cements" over time. A layer of locally available lake

sand is now typically incorporated by layering the sand. on the

disposal side of the dike. This sand is uniform, has low

permeability, and will not change or deteriorate in time. Some

designs incorporate a weir with a skimmer to retain possible

sediment overflow as the permeability of the CDF approaches zero.

PCBIS IN CDFIS

Very little data are available on PCB concentrations within

CDFIS. Published data exists for only a few sites. The

concentrations of PCBIS would be expected to vary from one CDF to

another depending on the concentration of PCB's in the sediment

which was dredged. Since PCB's in sediment can vary widely even

within a small area (sediments are not homogeneous),

concentrations within CDF's also undoubtedly vary widely.

The few data that are available on PCB's measured from

samples collected from CDF's indicate relatively low total PCB

levels. Clark (1988) reported a value of 1.1 Ag/g. from

sediments in the Calumet harbor CDF. Rathburn (1988), in a study

of the Saginaw Bay diked facility, reported concentrations of

PCB's congeners in water collected from inside the facility

(indike), immediately outside the facility in Saginaw Bay

(outdike), and at an adjacent site in the Saginaw River channel.

An example of these data are shown in Table 2. The data show PCB

concentrations are higher in water inside the facility than

outside the facility. However, concentrations in water outside

the facility are generally higher than PCBs in the reference

station (Saginaw River channel).

The specific congeners found in highest concentration in the

Saginaw Bay study (Table 2) are similar to those found in highest

concentration in the Sheboygan River. For example, co-eluting

congeners 28/31 are the most prevalent in the Saginaw Bay study

samples (Table 2), as they were in most Sheboygan samples.

Whether or not PCB's leak from a CDF continues to be a major

uncertainty. The Saginaw Bay study was initiated to find the

extent of leakage (as well biological uptake of the PCB's). The

general conclusion of the study was that no appreciable leakage

from the CDP was occurring.

If polychlorinated biphenyls (PCBs) can be dechlorinated in

river sediments, a logical question to ask is whether PCBs

contained in confined disposal facilities (CDFs) also undergo

bacterial dechlorination. If dechlorination does occur in

confined disposal facilities, these facilities would be an

attractive way of detoxifying dredged PCB contaminated sediment.

In the case.of the Sheboygan River, these is interest in building

a marina in Lake Michigan just north of the harbor. If such a

facility could be designed in concert with the concept of a

confined disposal facility, it would be especially attractive if

it also promoted dechlorination of any PCBs in the sediment.

In this study the likelihood of dechlorination occurring in

confined disposal facilities along the Wisconsin shore of Lake

Michigan was considered. Attempts were made to gather

information on PCBs in confined disposal facilities to see if any

evidence for dechlorination was available. Evidence for

dechlorination in similar facilities, notably sewage sludge

lagoons, was also sought. Finally, some samples were taken from

the confined sludge facility off of Milwaukee and analyzed for

PCBs.

Two samples were collected from the Milwaukee CDF. The CDF

might be expected to contain relative high amounts of PCBs

because of the industry in the area. However, s pecific data on

the PCB content of the dredged material originally placed in the

facility was not found. Nor wasany data found from past

measurements of PCBs made on samples taken from the facility.

Two "soil" samples were taken from the Milwaukee facility

with the permission of the Corps of Engineers. Because the soil

was hard, crusted and contained surface vegetation, sampling was

difficult. It was also unclear what would be a representative

sample, or where to sample to get high PCB concentrations.

The two samples analyzed had low PCB concentrations. No

evidence of dechlorination was discernable from the PCB pattern.

It was hoped that samples with higher PCB concentrations could be

obtained, as such samples might show a greater tendency for

dechlorination (analogous to Sheboygan River sediments). As it

was, there was no evidence to suggest that dechlorination may be

occurring, or at least occurring at a rate that would be

noticeable.

A question that comes up is whether sediments below the top

of the facility are anaerobic. Deeper core samples would be

desirable in this regard, as dredged material several feet below

the surface might be anaerobic while near the surface the dredged

material might be aerobic. Based on what was available in the

literature, such measurements have not been made.

one indication that dechlorination might not occur (at least

not at, a meaningful rate), is that a'sewage lagoon with PCB

contamination has been extensively studied and there is no

evidence of any PCB dechlorination occurring there. The Madison

Metropolitan Sewerage District has several lagoons that have been

filled for many years and now pose a disposal problem because of

the high concentration of PCBs (about 50 ppm) in the sludge. The

lagoons, which do go anaerobic, have been extensively monitored

over the years. However, monitoring results indicate that the

PCBs have been very stable over the years (Nemke, J., Director,

Madison Metropolitan Sewerage District, Madison, WI, 1990;

personal communication). While there may be special conditions in

these specific lagoons that prevent dechlorination, one might

expect the conditions in an anaerobic lagoon to be conducive to

dechlorination.

Based on experiments attempting to achieve bacterial

dechlorination in the laboratory, it is clear that the

dechlorination process is highly sensitive to a variety of

factors (some of which are not known or understood). Whether the

right conditions are in place in CDFs or lagoons is not known.

It is also clear that for dechlorination to occur in a measurable

fashion or at a fast enough rate, PCB concentrations must be

relatively high. Unless "hot spots" or areas of high

concentration occur in CDFs, concentrations may be too low to see

measurable PCB dechlorination.

Thus, an analysis of the available information suggest that

dechlorination probably does not occur to any important extent in

CDFs. More research should probably be conducted to confirm this

hypothesis, including more rigorous sampling to assay PCBs in

CDFs. Alternately, research might be conducted on how to promote

or accelerate PCB dechlorination. Current research conducted on

sediments from the Sheboygan River in pilot confined treatment

facilities (in conjunction with Superfund cleanup of the river)

may uncover some ways of promoting dechlorination that could be

applied to CDFs.

b:\cdfl.jan

Table 1. Great Lakes Confined Disposal Facilities

size Capacity
Location Type (acres) (cu. yd.)- Year

Calumet Harbor,
Chicago, IL L 42 1,300,000 19-84

Michigan City, IN U 3.3 25,000 1978

Bolles Harbor, MI L 24.6 335,000 1977
Monroe County, MI 1 685 18,640,000 1978/
1981
Frankfort, MI U 107,000 1982
Detroit, MI 1 80 1,900,000 1960
Dickinson Island, MI U 174 2,000,000 1976
Grand Haven, MI U 36 310,000 1974
Holland, MI U 27.7 370,000 1977
Inland Route, MI U 8.6 19,500 1982
Monroe, MI L 89 4,200,000 1985
Saginaw Bay, Village of
Sebewaing, MI U 180 84,000 1979

Erie Pier, MN L 82 1,000,000. 1978

Buffalo, NY L 33 1,500,000 1968
Buffalo, NY L 45 1,500,000 1972
Buffalo, NY L 40 6,900,000 1977

Cleveland, OH L 56 2,760,000 1974
Cleveland, OH L 88 6,130,000 1979
Huron, bH 1 63 2,150,000 1975
Lorain, OH L 58 1,850,000 1977
Toledo, OH L 150 5,000,000 1977
Toledo, OH L 242 10,000,000 1976

Erie, PA L 23 1,600,000 1979

Green Bay, WI 1 60 1,200,000 1979
Green Bay, WI U 400 @300,000 1965
Kenosha, WI L 25 750,000 1975
Kewaunee, WI L 28 500,000 1982
Manitowoc, WI 24 800,000 1975
Milwaukee, WI, 1 454 1,600,000 1975

L In-lake adjacent to land
I In-lake CDF island
U Upland

Table 2. PCB Congener Concentrations (ng/L) in Saginaw Bay CDF
Water Samples (Prom Rathburn et al. 1988)

Sacfina
Congener Number Indike Outdike River Channel

004 + 010 0.27 0.04 0.043
006 1.4 0.055 0.023
007 0.061 0 0.013
012 0 0.032 0.043
013 0.08 0 -----
016 1.2 0.1 0.04
017 3.4 0.19 0.1
018 3.6 0.31 0.092
019 0.3 0.032 0
022 2 0.13 0.019
024 0.05 0.017 0
025 ---- ---- 0.073
@027 0.39 0.036 0.017
029 0.035 0.021 0
031 + 028 13 0.96 0.4
032 3.5 0.43 0.16
033 2.1 0.027 0.052
037 --- ----- 0.064
040 1.7 0.1 0.029
041 + b7l 3.1 0.23 0.13
042 2.4 0.19 0.083
043 0.5 0 0
044 5.2 0.51 0.28
045 1.2 0.093 0.03
046 0.58 0.051 0.027
047 + 048 1.6 0.15 0.17
049 0.43 0.23
051 0.36 0.013 ----
052 0.57 0.17
053 1.2 0.1 0.049
056 +060 2 0.25 0.13
063 0.37 0.031 0.0075
064 2.2 0.019 0.092
066 3.4 0.4 0.23
070 + 076 3.4 0.41 0.19
074 1.3 0.13 0.068
077 0.65 0.068 0.034
081 0.17 0.024 0.0083
082 0.51 0.057 0.021
083 0.29 0.027 0 @
085 0.78 0.097 0.052
087 0.98 0.13 0.072
089 0.12 0.011 0
091 0.79 0.073 0.041
092 + 084 2.6 0.25 0.14

100 0.21 0 0
101 2.1 0.28 0.092
105 + 132 153 2 - 0.35 0.16
107 0.18 0.027 0.013
110 3.5 0.4 0.2
118 1.4 0.19 0.1
119 0.2 0.017 0.015
128 0.29 0.044 0.092
129 0 0 0.0083
130 0.14 0.023 0.028
134 + 114 0.3 0.04 0.028
135 + 144 0.16 0.047 0.0092
136 0.12 0.017 0
137 + 176 0 0 0
141 0.2 0.036 0.028
146 0.27 0.044 0.021
149 0.87 0.12 0.083
151 0.23 0.033 0.021
156 0.19 0.025 0.011
157 + 200 0 0.027 0.019
158 0.021 0.033 0.036
163 + 138 1.4 0.25 0.15
167 ---- ---- 0.0075
170 + 190 0.48 0.083 0.051
172 + 197 0.16 0.021 0.0092
173 0 0
174 0.23 0.047 0.03
175 0.23 0.036 0
177 0.16 0.031 0.02
178 0.098 0.039 0.0083
180 0.67 0.13 0.049
183 0.22 0.033 0.019
185 0 0 0.0045
187 + 182 0.29 0.059 0.035
189 0.089 0 0
191 0.4 0.016 ----
193, 0.044 0.0093 0.011
194 0.14 0.031 0.016
196 0.14 0.032 0.016
198 0.084 0.019 0.006
199 0 0 0.0047
201 0.23 0.052 0.033
202 + 171 0.12 0.019 0.0042
203 0.072 0.027 0.018
205 0 0 0.0033
206 0.11 0.037 0.013
207 0.044 0.0093 0.0033
208 +* 195 0.42 0.072 0.026
209 0.005 0.001 0.0008

Total PCBIS 91.4 10.2 5.2

Blanks = rejected congeners; zeros = concentrations lower than
analytical detection limit.

REFERENCES:

1. Anonymous (1989) Diked Disposal Program - Resume (P.L. 91-
611), Q/A section, U.S. Army Corps of Engineers, Buffalo,
NY.

2. Clark, J.U., McFarland, V.A., and Dorkin, J. (1988)
Evaluating Bioavailability of Neutral organic Chemicals in
Sediments: A confined Disposal Facility Case Study. Water
Quality 88 Seminar Proceedings., Feb. 23-24, Charleston, SC,
U.S. Army Corps of Engineers, Vicksburg, MS.

3. Rathburn, J., Kreis, R., Lancaster, E., Mac, M., and Zabik,
M. (1988) Pilot Confided Disposal Facility Biomon.itoring
Study: Channel/Shelter Island Dike Facilityj Saginaw Bay,
Bay City, Michigan, Report of the Environmental Research
Laboratory, U.S. Environmental Protection Agency, Duluth, MN

4. U.S. Army Corps of Engineers (1969) Dredging and Water
Quality Problems in the Great Lakes, Buffalo District,
Buffalo, NY.

5. U.S. Army Corps of Engineers (1986) Appendix B, Dredged
Material Disposal Facilities an the Great Lakes, Draft
Environmental Impact Statement, Indiana Harbor Confined
Disposal Facility, North Central District, Chicago, IL.

6. U.S. Environmental Protection Agency (1987) Report on Great
Lakes Confined Disposal Facilities, draft, Great Lakes
Program Office, Region V, Chicaao. IL.

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