[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]]

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Part III





Environmental Protection Agency





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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]
BILLING CODE 6560-50-P