[Federal Register Volume 64, Number 28 (Thursday, February 11, 1999)]
[Notices]
[Pages 7028-7030]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-3427]
[[Page 7027]]
_______________________________________________________________________
Part III
Environmental Protection Agency
_______________________________________________________________________
Health Effects From Exposure to High Levels of Sulfate in Drinking
Water Study and Sulfate Workshop; Notice
Federal Register / Vol. 64, No. 28 / Thursday, February 11, 1999 /
Notices
[[Page 7028]]
ENVIRONMENTAL PROTECTION AGENCY
[FRL-6232-5]
Health Effects from Exposure to High Levels of Sulfate in
Drinking Water Study and Sulfate Workshop
AGENCY: Environmental Protection Agency.
ACTION: Notice of data availability and request for comments.
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SUMMARY: The Safe Drinking Water Act (SDWA), as amended in 1996,
directs the U.S. Environmental Protection Agency (EPA) and the Centers
for Disease Control and Prevention (CDC) to jointly conduct a study to
establish a reliable dose-response relationship for the adverse human
health effects from exposure to sulfate in drinking water, including
the health effects that may be experienced by sensitive subpopulations
(infants and travelers). EPA and CDC are to complete the study by
February 1999.
The purpose of this notice is to inform the public of the
completion of the ``Health Effects from Exposure to High Levels of
Sulfate in Drinking Water Study'' (``Sulfate Study'') and announce the
availability of both the Sulfate Study report and the September 28,
1998 Sulfate Workshop summary. This notice provides a summary of these
two documents and discusses EPA's next steps on sulfate in drinking
water regulatory activities. Comments are requested on the two
documents being made available. Today's notice does not include any
decisions regarding the determination of whether or not to regulate
sulfate.
DATES: Submit comments on or before May 12, 1999.
ADDRESSES: Send written comments to the Comment Clerk, docket number W-
99-01, Water Docket (MC4101), USEPA, 401 M St, SW, Washington 20460.
Please submit an original and three copies of your comments and
enclosures (including references). Comments must be received or
postmarked by midnight May 12, 1999.
Commenters who want EPA to acknowledge receipt of their comments
should enclose a self-addressed, stamped envelope. No facsimiles
(faxes) will be accepted. Comments may also be submitted electronically
to [email protected]. Electronic comments must be submitted as an ASCII
file avoiding the use of special characters and form of encryption or
in WordPerfect 5.1 or 6.1. Electronic comments must be identified by
the docket number W-99-01. Comments and data will also be accepted on
disks in WordPerfect 5.1, 6.1 or ASCII file format. Electronic comments
on this notice may be filed online at many Federal Depository
Libraries.
Documents discussed in the notice and supporting documentation
(i.e., sulfate literature review and relevant literature provided to
participants at the Sulfate Workshop), as well as public comments are
in docket number W-99-01. The record is available for inspection from 9
to 4 p.m. Monday through Friday, excluding legal holidays at the Water
Docket, EB 57, USEPA Headquarters, 401 M. St., S.W., Washington, D.C.
For access to the docket materials, please call 202-260-3027 to
schedule an appointment.
FOR FURTHER INFORMATION CONTACT: For general information and for copies
of the Sulfate Study report and Sulfate Workshop summary, please
contact the Safe Drinking Water Hotline at 1-800-426-4791 or 703-285-
1093 between 9:00 a.m. and 5:30 p.m. Eastern Time. The documents can
also be accessed on the internet at http://www.epa.gov/safewater/
sulfate.html.
For specific information and technical inquiries, contact Jennifer Wu
at 202-260-0425 or [email protected].
Abbreviations Used in This Document
CCL: Contaminant Candidate List
CDC: Centers for Disease Control and Prevention
EPA: U.S. Environmental Protection Agency
MCL: Maximum Contaminant Level
MCLG: Maximum Contaminant Level Goal
NPDWR: National Primary Drinking Water Regulation
SAQ: self-administered questionnaire
SDWA: Safe Drinking Water Act, as amended
SMCL: secondary maximum contaminant level
WHO: World Health Organization
WIC: Women, Infants and Children
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Introduction
II. Sulfate Background Information
III. Statutory Authority and Regulatory History
IV. Health Effects from Exposure to High Levels of Sulfate in
Drinking Water Study
V. Sulfate Workshop
VI. Next Steps on Sulfate in Drinking Water Regulatory Activities
I. Introduction
The Safe Drinking Water Act (SDWA), as amended in 1996, directs the
U.S. Environmental Protection Agency (EPA) and the Centers for Disease
Control and Prevention (CDC) to ``jointly conduct an additional study
to establish a reliable dose-response relationship for the adverse
human health effects that may result from exposure to sulfate in
drinking water, including the health effects that may be experienced by
groups within the general population (including infants and travelers)
that are potentially at greater risk.'' Section 1412 (b)(12)(B). SDWA
specifies that the study be based on the best available peer-reviewed
science and supporting studies, conducted in consultation with
interested States, and completed in February 1999.
The purpose of this notice is to inform the public of the
completion of the ``Health Effects from Exposure to High Levels of
Sulfate in Drinking Water Study'' (``Sulfate Study'') and to announce
the availability of both the Sulfate Study report and the September 28,
1998 Sulfate Workshop summary. This notice provides a summary of the
Sulfate Study report and the Sulfate Workshop summary, as well as
discusses EPA's next steps on sulfate in drinking water regulatory
activities. Today's notice does not include any decisions regarding the
determination of whether or not to regulate sulfate.
II. Sulfate Background Information
Sulfate is a substance that occurs naturally in drinking water.
Health concerns regarding sulfate in drinking water have been raised
because of reports that diarrhea may be associated with the ingestion
of water containing high levels of sulfate. Of particular concern are
groups within the general population that may be at greater risk from
the laxative effects of sulfate when they experience an abrupt change
from drinking water with low sulfate concentrations to drinking water
with high sulfate concentrations. One potentially sensitive population
is infants receiving their first bottles containing tap water, either
as water alone or as formula mixed with water. Other groups of people
who could potentially be adversely affected by water with high sulfate
concentrations include transient populations (i.e., tourists, hunters,
students, and other temporary visitors) and people moving from areas
with low sulfate concentrations in drinking water into areas with high
concentrations.
III. Statutory Authority and Regulatory History
On July 19, 1979 (44 FR 42195) EPA published a secondary maximum
contaminant level (SMCL) for sulfate in drinking water of 250
milligrams per liter (mg/L), based on aesthetic effects
[[Page 7029]]
(i.e., taste and odor). This regulation is not a Federally enforceable
standard, but is provided as a guideline for States. States are
encouraged to implement SMCLs so that the public will drink water
provided by public water systems. The World Health Organization's (WHO)
recommended sulfate guideline is 400 mg/L, which is based on taste.
In an advance notice of proposed rule making published in the
Federal Register on October 5, 1983 (48 FR 45502), EPA recommended
developing a health advisory for sulfate instead of establishing an
enforceable level. On November 13, 1985, EPA proposed a health advisory
at 400 mg/L to protect infants (50 FR 46936). However, the proposed
health advisory was never finalized.
Under Section 1412 of the 1986 SDWA, EPA was required to establish
maximum contaminant level goals (MCLGs) and promulgate National Primary
Drinking Water Regulations (NPDWRs) for 83 contaminants, including
sulfate. EPA proposed alternative levels of 400 mg/L and 500 mg/L for
the MCLG for sulfate on July 25, 1990 (55 FR 30370). However, EPA
deferred promulgation of an enforceable sulfate standard in order to
identify an implementation approach which was tailored to the target
populations. The SMCL guideline of 250 mg/L remains in place. 40 CFR
143.3.
On December 20, 1994 (59 FR 65578), EPA reproposed an MCLG and MCL
for sulfate of 500 mg/L. The proposal contained four alternate
compliance options designed to allow flexible implementation. EPA had
not issued a final enforceable MCL for sulfate when Congress amended
the SDWA in 1996.
The SDWA, as amended in 1996, provides specific authority as to
sulfate. The statute directs EPA and CDC to jointly conduct a study to
establish a reliable dose-response relationship for the adverse health
effects from exposure to sulfate in drinking water, including effects
on sensitive subpopulations. The SDWA also directs EPA to include
sulfate among the five or more contaminants for which the Agency will
determine by August, 2001 whether or not to regulate. Sulfate is one of
the 50 chemical and 10 microbiological contaminants/contaminant groups
included on the Drinking Water Contaminant Candidate List (CCL)
published on March 2, 1998 (63 FR 10273). The CCL list is the primary
source of priority contaminants for the Agency's drinking water
program. Contaminants for priority drinking water research, occurrence
monitoring, and guidance development, including health advisories, will
also be drawn from the CCL.
IV. Health Effects From Exposure to High Levels of Sulfate in
Drinking Water Study
Through an interagency agreement, EPA and CDC jointly conducted a
study to establish a reliable dose-response relationship for health
effects from exposure to sulfate and to examine the effects in
sensitive subpopulations of infants and transients (i.e., tourists,
hunters, students, and other temporary visitors). EPA's role in the
``Health Effects from Exposure to High Levels of Sulfate in Drinking
Water Study'' (``Sulfate Study'') included participation in planning
sessions on study design and execution and in meetings to discuss
progress and preliminary results, as well as review of draft documents
and the draft Sulfate Study report. This section provides a brief
summary of the Sulfate Study report. (For a copy of the report, see
section FOR FURTHER INFORMATION above.)
The objective of the study was to provide additional information
regarding whether sensitive populations (infants and travelers) may be
adversely affected by sudden exposure to drinking water containing high
levels of sulfate. Specifically, CDC researchers designed a field
investigation to recruit 880 infants naturally exposed to high levels
of sulfate in the drinking water provided by public water systems and
an experimental trial of exposure in adults.
CDC researchers planned a prospective cohort study of infants born
in geographic areas with naturally occurring high levels of sulfate in
the drinking water provided by public water systems in New Mexico,
South Dakota, and Texas. Infants were to be enrolled at birth and
followed for four weeks to determine if there was an association
between exposure to drinking water containing varying levels of sulfate
and reported cases of diarrhea.
CDC researchers conducted a pilot study of the planned recruitment
methods and study instruments in four counties in South Dakota with
high levels of sulfate in the drinking water provided by the public
water systems. Because the CDC researchers experienced recruiting
problems during the pilot study, they developed a self-administered
questionnaire (SAQ) to examine tap water use. The questionnaires were
provided to all women who received care during a two-week period from
one of 32 Women, Infants and Children (WIC) clinics in New Mexico,
South Dakota, and Texas. The clinics were located in geographic areas
with a range of sulfate levels (from less than 100 mg/L to greater than
1000 mg/L) in the drinking water provided by public water systems. The
SAQ asked questions about the source of the women's home tap water,
what mothers of infants less than or equal to 3 months old were
currently feeding their babies, and how pregnant women planned to feed
their new infants.
To determine how many of the 1388 women who completed the SAQ would
have been eligible to participate in the study based on the drinking
water source and use criteria, the CDC researchers examined the
responses of the 1164 women (84%) who received their tap water from
public water systems and who did not have filters on their home taps.
Of the women who use or planned to use infant formula mixed with water,
most (80%) used or planned to use water other than tap water, leaving
only 74 infants who were or would be exposed to tap water with equal to
or greater than 250 mg/L of sulfate. These results are consistent with
the findings during the pilot study and indicate that only a very small
number of women who live in areas with high levels of sulfate in the
tap water provided by public water systems plan to give this water to
their infants.
The other population potentially sensitive to abrupt exposure to
high levels of sulfate in drinking water is transient adults (students,
visitors, hunters, etc.). To study the effects in adults of suddenly
changing drinking water sources from one that has little or no sulfate
to one that is high in sulfate, CDC researchers conducted an
experimental study involving volunteers from Atlanta, Georgia,
including CDC employees and employees at the EPA Region IV office.
Volunteers were randomly assigned to one of five sulfate exposure
groups (i.e., 0, 250, 500, 800, or 1200 mg/L sulfate from sodium
sulfate in bottled drinking water) and were provided with bottled
drinking water for six days. The bottled water for days 1, 2, and 6
contained plain water, while the bottles for days 3 through 5 contained
water with added sulfate. Volunteers were blinded to the level of
sulfate in their drinking water.
One hundred and five study participants were divided among the dose
groups as follows: 24 received 0 mg/L sulfate; 10 received 250 mg/L
sulfate; 10 received 500 mg/L sulfate; 33 received 800 mg/L sulfate;
and 28 received 1200 mg/L sulfate. CDC researchers analyzed the number,
consistency, and volume of bowel movements recorded each day by study
participants. There were no statistically significant differences in
the bowel movements among the groups on days 3,
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4, 5, or 6. There were also no statistically significant differences in
the bowel movements reported when comparing days 1 and 2 (the days when
there was no sulfate in the water) with days 3, 4, and 5 within each
dose group.
To examine the data for a trend toward increased frequency of
reports of diarrhea with increased dose of sulfate, CDC researchers
included the dose as an ordinal variable in a logistic regression model
of osmotic diarrhea. There was no statistically significant increase in
reports of diarrhea with increasing dose (one-sided p = 0.099).
The overall purpose of these studies was to examine the association
between consumption of tap water containing high levels of sulfate and
reports of osmotic diarrhea in susceptible populations (infants and
transients). EPA and CDC were unable to conduct a study of infants
because the researchers could not identify enough exposed individuals
from which to draw a study population. The results of the SAQ indicated
that more than half of the pregnant women who completed the survey
planned to breast-feed their infants. Of those who planned to use
formula mixed with water, most did not plan to use tap water to mix the
formula. In the experimental trials with adult volunteers, CDC
researchers did not find an association between acute exposure to
sodium sulfate in tap water (up to 1200 mg/L) and reports of diarrhea.
V. Sulfate Workshop
As a supplement to the Sulfate Study and literature review, CDC, in
coordination with EPA, convened an expert workshop, open to the public,
in Atlanta, Georgia on September 28, 1998, whose members reviewed the
available literature and the Sulfate Study results, and provided their
expert opinions in response to a series of questions about the health
effects from exposure to sulfate in drinking water. The following are
the questions and summaries of the discussion (for the complete Sulfate
Workshop summary, see section FOR FURTHER INFORMATION above.):
(1) Do reported studies suggest that a certain sulfate level would
not be likely to cause adverse effects? Existing data do not identify
the level of sulfate in drinking water that would be unlikely to cause
adverse human health effects. The panel members noted that the
available published literature included reports that piglets in
experimental feeding trials and some people experience a laxative
effect when consuming tap water containing from 1,000 to 1,200 mg/L of
sulfate (as sodium sulfate). However, none of the studies found an
increase in diarrhea, dehydration, or weight loss.
(2) Does the literature support acclimatization or adaptation (what
process and time frame does it take)? Based on biologic plausibility
and anecdotal reports, evidence indicates that people acclimate to the
presence of sulfate in drinking water. In addition, serum sulfate
levels are high (compared to adults) in human fetuses and neonates (to
support rapid growth and development). However, data describing
acclimation and the changes in sulfate metabolism during growth and
development are limited.
(3) Can an infant study be done for dose-response anywhere in the
U.S. or Canada? The difficulty of locating a population of women
feeding their infants formula mixed with unfiltered tap water
containing high levels of sulfate hinders the completion of a dose-
response study in infants. A study using neonatal pigs could assess a
dose response for both magnesium and sodium sulfates.
(4) Is there enough scientific evidence of adverse health effects
from sulfate in drinking water to support regulation? [Congress
directed EPA to use the best available science to set drinking water
goals and regulations.] There is not enough scientific evidence on
which to base a regulation, but panelists favored a health advisory in
places where drinking water has sulfate levels of 500 mg/L or higher.
VI. Next Steps on Sulfate in Drinking Water Regulatory Activities
EPA is very interested in receiving written comments on the two
documents being made available with today's notice. EPA will be further
evaluating the two documents referenced in today's notice, analyzing
all public comments on the present documents, reviewing all comments on
its previously proposed National Primary Drinking Water Regulation
(NPDWR) for sulfate (December 20, 1994; 59 FR 65578), and reviewing any
other pertinent information that could have a bearing on its decision
of whether or not to regulate sulfate as a NPDWR. In so doing, EPA will
be evaluating whether or not the statutory tests provided at Section
1412(b)(1)(A) of SDWA for proceeding with such regulation are met:
(1) ``* * * the contaminant may have an adverse effect on the
health of persons;
(2) The contaminant is known to occur or there is a substantial
likelihood that the contaminant will occur in public water systems with
a frequency and at levels of public health concern; and
(3) In the sole judgment of the Administrator, regulation of such
contaminant presents a meaningful opportunity for health risk reduction
for person served by public water systems.''
In making this determination, EPA will review, in addition to the
dose-response data and information described in today's notice, a host
of applicable risk management factors, including, but not limited to:
occurrence data on concentrations of sulfate in public water systems;
information relative to treatment technologies (particularly,
technologies applicable to small public water systems); availability
and costs of analytical methods for sulfate; and overall costs and
benefits attributable to any likely rule.
Two principal outcomes of this evaluation are possible. The Agency
could decide to proceed with a NPDWR for sulfate. In this case, EPA
would be required, in accordance with Section 1412(b)(1)(E), to propose
a regulation within 24 months after the determination to regulate and
issue a final regulation within 18 months after proposal.
Alternatively, the Agency could decide not to regulate sulfate as a
NPDWR. Such a finding would be considered final Agency action and would
be subject to judicial review. Section 1412(b)(1)(B)(ii)(IV). In either
case, EPA's rationale for making a determination relative to sulfate
would need to be documented and available for public comment.
Section1412(b)(1)(B)(iii). It is important to recognize that a decision
not to regulate does not prohibit other control actions short of a
NPDWR. These other actions could include a National Health Advisory or
Consumer Advisory, that would indicate the Agency's view of safe levels
of sulfate in drinking water and provide guidance to public water
systems and to States that might want to develop drinking water
regulations for sulfate.
The Agency will continue to use a variety of means to conduct
outreach relative to sulfate and to communicate information about
sulfate including the Office of Ground Water and Drinking Water's
(OGWDW) web site (http://www.epa.gov/safewater), possible additional
Federal Register notices, and possible future stakeholder meetings.
Dated: February 5, 1999.
Dana D. Minerva,
Acting Assistant Administrator for Water.
[FR Doc. 99-3427 Filed 2-10-99; 8:45 am]
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