[Federal Register Volume 68, Number 138 (Friday, July 18, 2003)]
[Notices]
[Pages 42898-42906]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-18151]



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Part V





Environmental Protection Agency





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Announcement of Regulatory Determinations for Priority Contaminants on 
the Drinking Water Contaminant Candidate List; Notice

  Federal Register / Vol. 68, No. 138 / Friday, July 18, 2003 / 
Notices  

[[Page 42898]]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-7529-2]


Announcement of Regulatory Determinations for Priority 
Contaminants on the Drinking Water Contaminant Candidate List

AGENCY: Environmental Protection Agency.

ACTION: Notice.

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SUMMARY: The Safe Drinking Water Act (SDWA), as amended in 1996, 
directs the United States Environmental Protection Agency (EPA) to 
publish a list of contaminants (referred to as the Contaminant 
Candidate List, or CCL) to assist in priority-setting efforts for the 
Agency's drinking water program. SDWA also directs the Agency to select 
five or more contaminants every five years from the current CCL and 
determine whether or not to regulate these contaminants with a National 
Primary Drinking Water Regulation (NPDWR).
    On June 3, 2002, EPA published preliminary regulatory 
determinations for nine contaminants together with the determination 
process, rationale, and supporting technical information for each 
contaminant to seek comment from the public (67 FR 38222). The nine 
contaminants include three inorganic compounds (IOCs) (manganese, 
sodium, and sulfate); three synthetic organic compounds (SOCs) (aldrin, 
dieldrin, and metribuzin); two volatile organic compounds (VOCs) 
(hexachlorobutadiene and naphthalene); and one microbial contaminant, 
Acanthamoeba. EPA's preliminary determination was that no regulatory 
action was appropriate for any of the nine contaminants.
    EPA received 15 comments from individuals or organizations on the 
preliminary regulatory determinations for the nine contaminants. The 
Agency has reviewed these comments and, after careful consideration, 
decided that no regulatory action is appropriate, at this time, for the 
nine CCL contaminants published in the June 2002 notice. Regulation of 
the nine contaminants would not present a meaningful opportunity for 
health risk reduction for persons served by public water systems 
(PWSs).
    Today's action describes the statutory requirements for the CCL, 
the analysis EPA used to make the regulatory determinations, a summary 
of relevant public comments with the Agency's responses, a summary of 
the nine CCL contaminants, and the Agency's findings for each 
contaminant.

ADDRESSES: The official public docket for this action is located at 
EPA's West Building, Room B-102, 1301 Constitution Avenue, NW., 
Washington, DC.

FOR FURTHER INFORMATION CONTACT: For copies of, and general information 
about this document or information about the nine contaminants 
discussed in this action, contact the Safe Drinking Water Hotline. 
Callers within the United States may reach the Hotline at (800) 426-
4791 or its local number (703) 412-3330. The Hotline is open Monday 
through Friday, excluding Federal holidays, from 9 a.m. to 5:30 p.m., 
Eastern Time. For technical inquiries contact: Thomas Carpenter (202) 
564-4885, e-mail: [email protected] or Harriet Colbert, (202) 
564-4698, e-mail: [email protected].

SUPPLEMENTARY INFORMATION

I. General Information

A. Does This Notice Apply to My Public Water System?

    Today's action does not impose any requirements on anyone. Instead, 
it notifies interested parties of EPA's responses to comments received 
on EPA's preliminary determination and of EPA's final determination not 
to regulate nine CCL contaminants.

B. How Can I Get Copies of Related Information?

    1. Docket. EPA has established an official public docket for this 
action under Docket ID No. OW-2002-0021. The official public docket is 
the collection of materials that is available for public viewing at the 
Water Docket in the EPA Docket Center, (EPA/DC) EPA West, Room B102, 
1301 Constitution Avenue, NW., Washington, DC. The EPA Docket Center 
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through 
Friday, excluding legal holidays. The telephone number for the Public 
Reading Room is (202) 566-1744, and the telephone number for the Water 
Docket is (202) 566-2426.
    2. Electronic Access. You may access this Federal Register document 
electronically through the EPA Internet under the ``Federal Register'' 
listings at http://www.epa.gov/fedrgstr/.
    An electronic version of the public docket is available through 
EPA's electronic public docket and comment system, EPA Dockets. You may 
use EPA Dockets at http://www.epa.gov/edocket/ to view public comments, 
access the index listing of the contents of the official public docket, 
and to access those documents in the public docket that are available 
electronically. Although not all docket materials may be available 
electronically, you may still access any of the publicly available 
docket materials through the docket facility identified in section 
I.B.1. Once in the system, select ``search,'' then key in the 
appropriate docket identification number.

Abbreviations and Acronyms Used in This Action

ATSDR Agency for Toxic Substances and Disease Registry
AWQC Ambient Water Quality Criteria
CASRN Chemical Abstract Services Registry Number
CCL Contaminant Candidate List
CWS Community Water Supply
EPA U.S. Environmental Protection Agency
FDA U.S. Food and Drug Administration
FR Federal Register
g gram
HRL Health reference level
IOC Inorganic compound
kg Kilogram
L Liter
MCL Maximum contaminant level
MCLG Maximum contaminant level goal mg milligram
MTBE Methyl-t-butyl ether
NDWAC National Drinking Water Advisory Council
NIRS National Inorganic and Radionuclide Survey
NPDWR National Primary Drinking Water Regulation
NRC National Research Council
OPP Office of Pesticides Program
ORD Office of Research and Development
PWS Public Water System
RSC Relative Source Contribution
SAB Science Advisory Board
SDWA Safe Drinking Water Act
SOC Synthetic organic compound
TRI Toxic Release Inventory
UCM Unregulated Contaminant Monitoring
USEPA United States Environmental Protection Agency
USGS United States Geological Survey
VOC Volatile organic compound

II. Background

A. What Is the Statutory Requirement for the Contaminant Candidate 
List?

    SDWA, as amended in 1996, directs EPA to publish a list of 
contaminants (referred to as the Contaminant Candidate List, or CCL) to 
assist the Agency in priority-setting efforts. The CCL is a list of 
contaminants which are not subject to any proposed or promulgated 
NPDWRs, are known or anticipated to occur in PWSs, and may require 
regulation under SDWA.

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    The first CCL was developed with considerable input from the 
scientific community and stakeholders. EPA published a draft CCL 
requesting public comment on October 6, 1997 (62 FR 52193, USEPA 1997). 
The first final CCL was published on March 2, 1998 (63 FR 10273, USEPA 
1998). The SDWA requires that a new CCL be published every five years. 
EPA is currently preparing the next CCL. The March 1998 CCL contained 
60 contaminants, including 50 chemicals or chemical groups and 10 
microbiological contaminants or microbial groups. Many of these 
contaminants lacked some of the information necessary to support a 
regulatory determination and were identified in the March 1998 CCL 
notice (USEPA 1998) as having data needs. The 60 CCL contaminants were 
divided into categories to represent research and data needs associated 
with each contaminant. The categories were: (1) Regulatory 
determination priorities; (2) health effects research priorities; (3) 
treatment research priorities; (4) analytical methods research 
priorities; and (5) occurrence priorities.
    In 1998, 20 of the 60 contaminants were classified as regulatory 
determination priorities because EPA believed that, at that time, there 
was sufficient data for these contaminants to evaluate both exposure 
and risk to public health and to support a determination of whether or 
not to proceed to promulgation of a NPDWR. Since the March 1998 CCL, 
EPA found that there was insufficient information, in the Agency's 
judgement, to support a regulatory determination for 12 of the 20 
priority contaminants. In addition, the CCL-contaminant, sodium, was 
reclassified and added to the list of regulatory determination 
priorities as a means of reassessing the current guidance level for 
sodium. Thus, EPA is now presenting regulatory determinations for nine 
priority contaminants that have sufficient information to support a 
regulatory determination at this time.
    The Agency however, continues to conduct research and/or to collect 
occurrence information on the remaining 51 CCL contaminants. EPA has 
been aggressively conducting research to fill in the data gaps and 
recognizes that stakeholders may have a particular interest in the 
timing of future regulatory determinations for other contaminants on 
the CCL. Stakeholders may be concerned that regulatory determinations 
for such contaminants should not necessarily wait until the end of the 
next regulatory determination cycle. In this regard, it is important to 
recognize that the Agency is not precluded from monitoring, conducting 
research, developing guidance, or regulating contaminants not included 
on the CCL as necessary and appropriate (see SDWA sections 
1412(b)(1)(B)(ii)(III) and 1412(b)(1)(F)), or from taking action on CCL 
contaminants when information becomes available. Thus, some regulatory 
determinations may be made before the end of the next regulatory 
determination cycle (i.e., August 2006).

B. What Contaminants Did EPA Consider for Regulation?

    EPA published preliminary regulatory determinations in the June 3, 
2002, edition of the Federal Register (67 FR 38222, USEPA 2002a) for 
nine priority contaminants that have sufficient information to support 
a regulatory determination at this time. The nine contaminants include 
three IOCs (manganese, sodium, and sulfate); three SOCs (aldrin, 
dieldrin, and metribuzin); two VOCs (hexachlorobutadiene and 
naphthalene); and one microbial contaminant, Acanthamoeba. Information 
for each of the nine CCL contaminants is available in the EPA Fact 
Sheet (USEPA 2002b), in the Health Effects Support Documents or 
Drinking Water Advisories for each of the nine CCL contaminants (2003a-
h), and in the regulatory determination support documents (USEPA 2001a-
g). This information is available at the Water Docket (No. OW-2002-021) 
and is also available on EPA's Safe Drinking Water Regulatory 
Determination website at http://www.epa.gov/safewater/ccl/cclregdetermine.html. Brief descriptions of each of the nine CCL 
contaminants considered for regulatory determinations are included in 
section V of this notice.

III. What Analyses Did EPA Use To Make the Regulatory Determinations?

    The precepts for guiding EPA in making regulatory determinations 
for a drinking water contaminant are included in Section 1412(b)(1)(A) 
of SDWA. This section of SDWA requires EPA to consider the following 
three evaluation criteria prior to making a regulatory decision: (1) 
Potential adverse health effects from the contaminant; (2) occurrence 
of the contaminant in PWSs with a frequency and at levels of public 
health concern; and (3) whether regulation of the contaminant would 
present a meaningful opportunity for health risk reduction for persons 
served by PWSs.
    EPA developed a comprehensive approach for making regulatory 
determinations with significant expert input and recommendations 
suggested by the National Research Council (NRC), National Drinking 
Water Advisory Council (NDWAC), and stakeholders. The regulatory 
determination approach is largely based on the NDWAC recommendations. 
For each of the nine contaminants, EPA evaluated the best available 
peer reviewed data on health effects, and approximately seven million 
analytical data points on contaminant occurrence. For those 
contaminants with adequate monitoring methods, as well as health 
effects and occurrence data, EPA applied an approach in making 
regulatory determinations that followed the NDWAC recommendations and 
complies with the SDWA requirements under Section 1412(b)(1)(A). In 
June 2002, EPA consulted with the Science Advisory Board (SAB) Drinking 
Water Committee and requested its review and comment on whether the 
protocol EPA developed, based on the NDWAC recommendations, was 
consistently applied and appropriately documented. The SAB provided 
verbal feedback regarding the use of the NRC and NDWAC recommendations 
in EPA's decision criteria for making its regulatory determinations, as 
well as its interest in remaining involved in future regulatory 
determinations. SAB recommended that the Agency provide a transparent 
and clear explanation of the process for making regulatory 
determinations. In today's announcement and in the documentation 
supporting this announcement, the Agency has taken the SAB 
recommendation into consideration in explaining the evaluation process 
used to make today's regulatory determinations.
    EPA characterized the human health effects that may result from 
exposure to a contaminant found in drinking water. Based on this 
characterization, EPA estimated a health reference level (HRL) or 
benchmark value for each contaminant. EPA has prepared Health Effects 
Support Documents or Drinking Water Advisories (USEPA 2002c and 2003a-
g) for each contaminant, which are available at the EPA Water Docket 
and on-line at http://www.epa.gov/edocket/. The support documents 
address the following: Exposure from drinking water and other media; 
toxicokinetics; hazard identification; dose-response assessment; and an 
overall characterization of risk from drinking water.
    Using the Agency's Unregulated Contaminant Monitoring (UCM) program 
data and National Inorganic and Radionuclide Survey (NIRS) data, EPA 
estimated the number of PWSs and the population served by the PWSs at 
the benchmark values, and the

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geographic distribution, using a large amount of State occurrence data 
that are generally indicative of national occurrence. The UCM data form 
part of the Agency's basis for its estimates of national occurrence 
since these data provide occurrence information for several unregulated 
contaminants. The NIRS data provide a statistically representative 
sample of the national occurrence of many other unregulated and 
regulated inorganic contaminants in ground water community water 
supplies (CWSs).
    EPA also employed other State drinking water data, use and 
environmental release information (e.g., EPA's Toxic Release Inventory 
(TRI), academic and private sector publications), as well as ambient 
water quality data (i.e., source water existing in surface waters and 
aquifers before extraction and treatment as drinking water), to augment 
the UCM drinking water data and to evaluate the likelihood of 
contaminant occurrence. EPA included, when available, data from the 
U.S. Geological Survey's (USGS) National Water Quality Assessment 
program.
    A detailed discussion of the data collected and analyses for each 
contaminant can be found in the respective regulatory determination 
support document. The regulatory determination support documents (USEPA 
2001a-g) are available in the EPA Water Docket.
    The underlying data and analysis supporting the findings used by 
the Agency to make the regulatory determinations are summarized in the 
June 2002 notice (USEPA 2002a).

IV. Summary of Public Comments and the Agency's Responses on the CCL 
Regulatory Determination Process

    The comment period on the June 3, 2002, notice ended on August 2, 
2002. EPA received 15 comments on the preliminary regulatory 
determinations for the nine CCL contaminants published by EPA in the 
June 2002 notice (USEPA 2002a). Four comments were received from water 
systems and related associations, seven from industry groups, two from 
environmental advocacy groups, one from a State agency and one from a 
State-related association. Although most commenters generally approved 
of EPA's determination not to regulate any new contaminants at this 
time, some commenters expressed concerns about the process associated 
with EPA's regulatory determinations for these nine contaminants, as 
well as with CCL activities not specifically related to the preliminary 
determinations.
    A majority of the comments were focused on five over-arching topic 
areas:
    1. Some commenters expressed concern over the transparency of the 
CCL decision-making process.
    2. Several industry groups expressed a concern that the health 
effects assessments were too conservative.
    3. Several commenters expressed concern with EPA's progress in 
filling research gaps related to the CCL and encouraged EPA to publicly 
track research needs and progress on remaining CCL contaminants.
    4. The majority of commenters generally approved of EPA's 
determination not to regulate any new contaminants at this time. 
However, one commenter questioned the appropriateness of EPA's 
decisions not to regulate any of the nine priority contaminants.
    5. Several comments were received regarding contaminants on the CCL 
for which draft regulatory determinations were not included in the June 
2002 notice, including perchlorate and methyl-t-butyl ether (MTBE).
    A complete copy of the public comments and the Agency's responses 
are included in the Docket for today's action. The remainder of this 
section discusses the five key topic areas identified by commenters in 
response to the June 2002 CCL regulatory determination notice (USEPA 
2002a).

1. Lack of Transparency of Regulatory Determination Approach

    Comment Summary: Several commenters expressed a concern about the 
``lack of transparency'' in the regulatory determination approach used 
by the Agency for the June 2002 notice. Most of those commenters 
suggested that EPA did not provide an adequate explanation for the 
reduction in the number of the priority contaminants from twenty to 
nine since the publication of the first CCL in March 1998 (USEPA 1998). 
These commenters suggested that the Agency needs to provide better 
justification regarding the reasons for excluding the twelve 
contaminants listed in the March 1998 CCL from the regulatory 
determination process.
    Several commenters suggested that this regulatory determination 
process approach does not provide for enough participation from outside 
groups for the development of non-regulatory strategies. These 
commenters suggested that the Agency should allow for more meaningful 
public involvement in the regulatory determination process. One 
commenter stated that, given the Agency's analysis of occurrence and 
health effects data over several years, the 60-day comment period was 
not adequate to allow ``detailed analysis by interested stakeholders.''
    Other commenters, however, observed that the CCL regulatory 
determination approach taken by EPA was ``reliably consistent'' with 
the basic charge of the SDWA and the NDWAC workgroup recommendations. 
Several commenters noted that, by EPA following the protocol 
recommended by the NDWAC Work Group, stakeholders were assured that the 
Agency used the ``best-available, peer-reviewed science'' in these 
determinations.
    Agency Response: EPA developed a consistent regulatory 
determination approach for evaluating CCL contaminants that followed 
NDWAC's recommended protocol for health effects and occurrence 
analysis. The regulatory determination approach for each contaminant on 
the list included an evaluation of the adequacy of current analytical 
and treatment methods, the best available peer-reviewed data on health 
effects, and an occurrence data set of about seven million contaminant 
occurrence data points.
    By using this approach, EPA determined that, at the time of the 
June 2002 notice (USEPA 2002a) of preliminary regulatory determinations 
there was not sufficient information to support a regulatory 
determination on twelve of the twenty priority contaminants. As noted 
previously, the CCL-contaminant, sodium, was moved to the list of 
regulatory determination priorities to allow an update of the Agency's 
position on the issue of sodium in drinking water.
    The NDWAC, which is comprised of representatives from the general 
public, State and local agencies, and private groups concerned with 
drinking water safety, was convened to provide input during the 
regulatory determination process. Throughout the regulatory 
determination process, EPA's approach has been to maintain a strong 
partnership with stakeholders and involve them to the maximum extent 
possible, thereby helping to ensure that stakeholders understand the 
regulatory determination process and provide valuable input.
    The Agency agrees that a meaningful opportunity for discussions 
with stakeholders is an important component of the CCL Regulatory 
Determination process. The Agency utilized a variety of mechanisms to 
involve stakeholders in the process. These included two broad-based 
stakeholder meetings, one in November 1999 and one in July 2002. 
Members of the public also were invited to attend the three sessions of 
the NDWAC Work Group in the Spring/

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Summer of 2000, which focused on protocol recommendations to the 
Agency. In addition, EPA representatives delivered presentations at a 
variety of meetings held by other organizations. Moreover, EPA did ask 
for and considered comments made on the sodium and sulfate Drinking 
Water Advisories during the comment period on the June 2002 notice 
(USEPA 2002a).
    The Agency believes the 60-day public comment period for the June 
2002 notice (USEPA 2002a) was sufficient. The Agency took steps to 
facilitate public review of its preliminary decisions, as well as 
supporting documentation. In addition to the July 2002 stakeholder 
meeting, these steps included making key materials available on the 
Agency's website and providing hard copies of materials upon request.

2. Health Effects Assessments

    Comment Summary: Some commenters suggested that EPA's analysis of 
adverse health effects and calculation of the HRLs were too 
conservative. On the other hand, one commenter questioned how the 
Agency's analysis underlying the regulatory determination approach 
incorporated appropriate safety factors and exposure assessments 
relative to children's health concerns.
    Commenters recommended that EPA use the revised Office of Water 
methodology for deriving ambient water quality criteria (AWQC), (USEPA 
2000), in an effort to protect human health in the final health effects 
support documents. According to the comments, this revised methodology 
establishes five different consumption rates and body weight 
classifications as a means to make the human health exposure 
assessments. One commenter specified that EPA needs to use more 
accurate consumption data for sodium rather than simply incorporating 
U.S. Food and Drug Administration (FDA) assertions.
    Agency Response: EPA believes it is appropriate to use a 
conservative approach to assessing the health effects of an unregulated 
contaminant in the context of a determination of whether it should be 
considered for NPDWR regulation. In order to determine whether to 
propose an NPDWR for an unregulated contaminant, SDWA requires EPA to 
determine whether the contaminant ``may have an adverse effect on the 
health of the persons,'' Section 1412(b)(1)(A)(i), which is a very 
broad criterion. As a result, EPA believes that a conservative health 
effects analysis is appropriate.
    The HRL used by EPA in these determinations is a conservative 
health-based value and is different depending on whether a contaminant 
is considered a carcinogen or a noncarcinogen. For carcinogens, a 10-6 
risk was chosen as the HRL since the maximum contaminant level goal 
(MCLG) for such contaminants will generally be zero. For 
noncarcinogens, the reference dose and a 20 percent relative source 
contribution (RSC) factor was used in conjunction with a 70 kilogram 
(kg) adult body weight and a 2 liter (L) water intake for the HRL 
calculation. EPA uses these standard regulatory assumptions for 
determining the MCLG of a noncarcinogen that lacks specific data on the 
RSC. EPA used best available peer reviewed data and analyses in 
evaluating adverse health effects. Accordingly, EPA disagrees with 
those commenters that felt that EPA was too conservative in 
establishing the HRL. EPA followed practices and policies that are 
similar to those used to establish an NPDWR and that are consistent 
with the SDWA section 1412(b)(1)(A)(i) criterion. If such a 
conservative approach does not result in EPA deciding to initiate a 
regulatory process for a contaminant, the Agency may decide to use a 
non-regulatory approach in addressing the issue, such as issuing a 
Drinking Water Advisory.
    Children's health issues were considered in making regulatory 
determinations for each of the nine contaminants included in this final 
notice. The details of the individual assessments are included in the 
Health Effects Support Documents or Drinking Water Advisories for each 
contaminant. These documents are available for review at the EPA Water 
Docket and on-line at http://www.epa.gov/edocket/.
    The AWQC (USEPA 2000) methodology continues to recommend the use of 
70 kg for adult body weight and 2 liters per day for water intake for 
risk calculations. These are the same parameters used by EPA to derive 
an MCLG. EPA believes that its current methodology, based on adult 
exposures, for the derivation of MCLGs, and for making regulatory 
determinations under SDWA section 1412, remains generally appropriate. 
EPA has not yet determined a protocol for making a regulatory 
determination for a chemical for which an infant's or a particular 
childhood age grouping's body weight and drinking water intake would be 
the basis of a regulatory action. A decision for such a contaminant 
would be made on the basis of the toxicity and exposure data, and could 
utilize the age groupings and body weight information from the AWQC 
human health methodology if it were appropriate.
    EPA did not use FDA's sodium consumption data of 4 to 6 grams/day 
(g/day) in establishing a benchmark value for sodium. EPA decided to 
use a benchmark value for sodium instead of an HRL because sodium lacks 
suitable dose-response data and there is considerable controversy 
regarding the role of sodium in the etiology of hypertension. EPA 
derived the benchmark value for sodium of 120 mg/L in drinking water 
from the National Institutes of Health, National Academy of Sciences, 
American Heart Association, and the U.S. Department of Agriculture 
recommended daily dietary intake of 2.4 g/day.

3. EPA Research Agenda

    Comment Summary: Several commenters expressed concern that, in 
their view, there is a lack of progress by EPA in filling research gaps 
related to the CCL. In particular, commenters focused on high 
visibility contaminants, such as the microbiological contaminants, 
MTBE, and other ``emerging contaminants.'' Commenters also stressed the 
need to establish a vehicle for publicly tracking research needs and 
progress made in research areas.
    Agency Response: Before EPA can determine whether to regulate 
contaminants, additional data on health, treatment technologies, and 
analytical methods, are needed for contaminants on the Research 
Priorities portion of the CCL, and occurrence data is needed for 
contaminants on the Occurrence Data Needs portion of the CCL. The 
remaining 51 CCL contaminants for which decisions are not being made 
today do not have sufficient data to support a regulatory 
determination. The Agency considers obtaining this data to be the 
priority of its research and occurrence monitoring programs. The Agency 
continues to actively conduct research and/or to collect occurrence 
information on these 51 CCL contaminants and other emerging 
contaminants. Because these research issues are broader than those that 
EPA can address alone, it is anticipated that other entities will be 
involved in conducting much of the needed research to support this 
process. For example, EPA already is jointly undertaking research 
efforts, and encourages stakeholders, through close and regular 
consultation, to be partners in filling many of the research gaps. The 
EPA continues to identify and develop new collaborations to conduct 
research and gather the additional data to characterize occurrence and 
adverse

[[Page 42902]]

health effects to support future regulatory determinations of CCL 
contaminants. EPA is also engaged with our stakeholders in a NDWAC work 
group to refine the CCL listing process to address emerging 
contaminants for future efforts.
    EPA agrees with the comment concerning the importance of 
establishing a vehicle that will allow stakeholders to track the status 
of drinking water research projects. EPA is committed to providing a 
means for stakeholders to track research needs and progress made in 
research areas, and is developing a web-based research inventory that 
is expected to be available to the public in 2003. This website will 
serve as a repository of information on drinking water research 
projects currently funded or performed by the EPA.

4. Criticism of Regulatory Decisions Made

    Comment Summary: One commenter expressed concern that EPA's 
decision not to regulate any of the nine priority contaminants was not 
appropriate. A comment submitted and co-signed by 22 environmental 
organizations disagreed with the regulatory determinations for four 
contaminants, hexachlorobutadiene, manganese, sodium and sulfate. The 
commenters believe that EPA's monitoring data presented in the June 
2002 notice shows that over 22,000 people were exposed to 
hexachlorobutadiene at concentrations above the HRL. The commenters 
assert that although EPA says manganese has low toxicity, EPA finds 
that nearly 3% of the population exceeded EPA's HRL. The commenters 
also disagreed with the Agency determination that regulation is not 
warranted because food sources of sodium are a more significant 
contribution to sodium in the diet than drinking water. The commenters 
also assert that EPA should regulate sulfate because EPA's monitoring 
data shows that millions of Americans are likely to have sulfate levels 
above the HRL in their drinking water, which puts infants and other 
subpopulations at risk.
    Agency Response: The preliminary regulatory determinations on 
whether or not to regulate the nine priority contaminants were based on 
the three SDWA statutory requirements, and the contaminants were 
evaluated in terms of national significance. EPA's assessment of the 
health effects and national occurrence were discussed in detail in the 
June 2002 notice. EPA disagrees that each of the contaminants 
identified by the commenters should be regulated. The rationale 
supporting the regulatory determination is provided below.
    EPA found that hexachlorobutadiene occurs in systems, but not at a 
frequency or level of public health concern. The commenter has 
misinterpreted the monitoring data presented in the June 2002 notice. 
The number 22,736 in the notice refers to the number of reporting PWSs 
in the monitoring data set and does not reflect the number of people 
exposed to hexachlorobutadiene concentrations above the HRL. The June 
2002 notice states that 0.02% (4 out of 22,736) reporting systems 
detected hexachlorobutadiene above the HRL affecting 0.005% (3,350 out 
of the 67 million) of the population served by these systems (67 FR 
38235). Because of this low frequency, EPA believes it is most 
appropriate at this time to address occurrence of hexachlorobutadiene 
at the State level rather than at the national level.
    EPA disagrees with the commenter's criticism of the decision not to 
regulate manganese. Manganese is an essential trace element needed for 
the normal healthy growth and function of animals as well as human 
beings. Therefore, the decision whether or not to regulate manganese 
needs to balance the concern for the potential toxic effects from high 
oral exposure with the concern for adverse effects from manganese 
deficiency. In 2001, the Institute of Medicine (IOM) set an adequate 
level for manganese at 2.3 mg/day for men and 1.8 mg/day for woman.
    Furthermore, in 2001, the IOM set a tolerable upper intake level 
for manganese at 11 mg/day. While 3% of the population may be exposed 
to manganese at levels above the 0.30 mg/L HRL for drinking water, this 
level is well below the IOM tolerable level. For example, assuming a 
daily intake of 2 liters of drinking water with manganese at the HRL of 
0.30 mg/L, the daily intake of manganese from drinking water at the HRL 
would only expose a person to 0.6 mg/day. This value is well below 
IOM's 11 mg/L adequate level for manganese and represents only 5.5% of 
IOM's upper limit for manganese. Public drinking water accounts for a 
relatively small proportion of a person's manganese intake, even at the 
HRL. Therefore, the Agency concludes that regulation of drinking water 
for manganese does not provide a meaningful opportunity to reduce the 
risk of adverse health effects. The commenter is referred to the CCL 
Preliminary Regulatory Determination Support Document for Manganese 
(EPA 815-R-01-013) for a more detailed discussion of this issue.
    EPA disagrees with the commenter's criticism of the decision not to 
regulate sodium. Because sodium in drinking water is a very small 
contributor to daily dietary intake and because the levels at which 
sodium intake can contribute to increasing the blood pressure of 
individuals with normal blood pressures is not clearly established, EPA 
does not believe that a NPDWR for sodium presents a meaningful 
opportunity for public health protection at this time.
    EPA disagrees with the commenter's criticism of the decision not to 
regulate sulfate. EPA used current data (Round 2 of the UCM program) 
that indicate that about 1.8% of the reporting systems serving 
approximately 2 million people from a 20-state cross section of the 
unregulated contaminant monitoring study exceeded 500 mg/L. Although 
additional data from six states had very similar results, EPA found 
that the weight of evidence suggests that the adverse health effect is 
generally mild, of short duration, and generally occurs at 
concentrations considerably greater than 500 mg/L, except in very 
limited circumstances when contaminants that exacerbate the effects of 
sulfate are also present in the water. Therefore, EPA has made the 
determination not to regulate sulfate with a NPDWR at this time because 
regulation would not present a meaningful opportunity for health risk 
reduction for persons served by public drinking water systems. However, 
EPA prepared a Drinking Water Advisory to provide guidance to 
communities that may be exposed to drinking water with high sulfate 
concentrations. This advisory contains information of use to sensitive 
sub-populations, such as infants and travelers.

5. Stakeholder's Highest Priority for Future Regulatory Determinations

    Comment Summary: Commenters encouraged EPA to be aggressive and 
consider an expedited regulatory determination for several CCL 
contaminants including MTBE and perchlorate.
    Agency Response: For this regulatory determination, EPA developed a 
comprehensive evaluation approach based on the recommendations from NRC 
and NDWAC. As explained in the June 2002 notice (USEPA 2002a), this 
evaluation satisfies the three SDWA requirements under section 
1412(b)(1)(A)(i)-(iii). For each of the contaminants, the Agency 
evaluated the adequacy of current analytical and treatment methods, the 
best available peer-reviewed data on health effects, and an occurrence 
data set of approximately seven million analytical data points. At this 
time, EPA does not believe adequate data exists in these key areas to 
make a regulatory

[[Page 42903]]

determination either for perchlorate or MTBE. EPA is gathering 
information to fill the data gaps for these contaminants.
    With respect to perchlorate, EPA is gathering national occurrence 
data on perchlorate in drinking water through the Unregulated 
Contaminant Monitoring (UCM) Rule. The Agency is also completing a 
rigorous peer review of health effects studies and is developing a 
final toxicity review and risk characterization. As part of this 
effort, EPA has asked the National Academy of Sciences to review 
science issues related to the 2002 draft EPA risk assessment for 
perchlorate. In addition, the Agency is funding research studies on 
treatability of perchlorate for PWSs. Some of the technology currently 
in use at hazardous waste sites is being evaluated for the feasibility 
of using it in water treatment at community water systems. At the same 
time, EPA is seeking to improve the analytical method sensitivity that 
would allow concentrations of perchlorate to be quantified at lower 
levels than are presently possible. The Agency is moving concurrently 
in each of these areas to meet data and research needs as quickly as 
possible. When the necessary information is collected, we plan to move 
forward with a regulatory determination. In this regard, it should be 
emphasized that where EPA determines there is sufficient information on 
this or any other unregulated contaminant, the Agency is prepared to 
act in advance of the next five year regulatory determination cycle.
    Regarding MTBE, on-going activities will provide the Agency with 
improved health effects and occurrence data. At this time, EPA is 
preparing its revised risk assessment for MTBE for peer review. The 
Agency established the 1997 Drinking Water Advisory for MTBE at 20-40 
micrograms per liter ([mu]g/L, or parts per billion, ppb) to avoid 
unacceptable taste and odor and provide a protective margin of exposure 
for adverse health effects. The 20-40 ppb level was not based on the 
possible cancer risks. As a result of the UCM Rule, data from PWSs 
required to monitor for MTBE will be available in the middle of 2004.

V. Summary of the Agency's Findings on the Nine CCL Contaminants

A. Acanthamoeba

    Description: Acanthamoeba is a free-living protozoa commonly found 
in water, soil, and air. Species of this microbe have been isolated 
worldwide from brackish and sea water, tap water, bottled water, 
airborne dust, swimming pools, hot springs, thermal effluents of power 
plants, ocean sediments, vegetables, and hot tubs. Acanthamoeba species 
have been associated with human infections affecting the eye, lung, 
brain, and skin. Acanthamoeba has been recovered from the nose and 
throat of humans with impaired respiratory function and from apparently 
healthy persons, suggesting that the amoeba is commonly inhaled.
    Agency Findings: After reviewing the best available public health 
and occurrence information, EPA has made the determination not to 
regulate Acanthamoeba with a NPDWR at this time, because regulation 
would not present a meaningful opportunity for health risk reduction 
for the people served by public drinking water systems (PWSs). As noted 
in the June 2002 notice (USEPA 2002a), EPA has no national monitoring 
data to indicate occurrence of Acanthamoeba cysts in drinking water, 
and filtration practices commonly used to treat drinking water remove 
Acanthamoeba cysts.
    A complete review of EPA's analysis of the health effects, 
occurrence, and exposure for Acanthamoeba were presented in the June 
2002 notice (USEPA 2002a) and in the health effects support document 
for Acanthamoeba (USEPA 2003h). EPA intends to release a guidance 
document for Acanthamoeba that will be directed mainly to contact lens 
wearers and will address the risks of Acanthamoeba eye infection 
associated with improper care of contact lenses.

B. Aldrin and Dieldrin

    Description: Aldrin and dieldrin (Chemical Abstract Services 
Registry Number (CASRN) 309-00-2 and 60-57-1, respectively) are the 
common names of two structurally similar insecticides. They are 
discussed together because aldrin readily changes to dieldrin in the 
body and in the environment, and they cause similar adverse health 
effects. From 1950-1970, aldrin and dieldrin were popular pesticides 
used for crops, such as corn and cotton. Because of concerns about 
damage to the environment and the potential harm to human health, EPA 
banned most uses of aldrin and dieldrin in 1974, except for the control 
of termites, and banned all uses outright since 1987. According to the 
Agency for Toxic Substances and Disease Registry (ATSDR), aldrin and 
dieldrin have not been produced in the United States since 1974 (ATSDR 
1993).
    Agency Findings: After reviewing the best available public health 
and occurrence information, EPA has made the determination not to 
regulate aldrin or dieldrin with a NPDWR at this time, because 
regulation would not present a meaningful opportunity for health risk 
reduction for the people served by PWSs. EPA recognizes that aldrin and 
dieldrin are probable human carcinogens, but the chemicals have been 
banned for most uses since 1974, and have a low frequency and low level 
of occurrence in drinking water supplies.
    A complete review of EPA's analysis of the health effects, 
occurrence, and exposure for aldrin and dieldrin were presented in the 
June 2002 notice (USEPA 2002a) and in the regulatory determination 
(USEPA 2001a) and health effects (USEPA 2003a) support documents for 
aldrin and dieldrin.

C. Hexachlorobutadiene

    Description: Hexachlorobutadiene (CASRN 87-68-3) is a VOC that is 
relatively insoluble in water (solubility of 2-2.55 mg/L). 
Hexachlorobutadiene is mainly used to make rubber compounds. It is also 
used in gyroscopes, as a heat transfer liquid, as a hydraulic fluid, as 
a solvent, and to make lubricants. It has never been manufactured as a 
commercial product in the United States, however, it is imported and 
significant quantities of the chemical are generated in the United 
States as a waste by-product from the chlorination of hydrocarbons.
    Most exposure to hexachlorobutadiene comes from breathing 
contaminated air in the workplace environment. People living near 
hazardous waste sites containing hexachlorobutadiene may be exposed to 
it by breathing air or by drinking contaminated water.
    Agency Findings: After reviewing the best available public health 
and occurrence information, EPA has made the determination not to 
regulate hexachlorobutadiene with a NPDWR at this time, because it 
would not present a meaningful opportunity for health risk reduction 
for persons served by PWSs. Hexachlorobutadiene occurs in PWSs, but not 
at a frequency or level of public health concern.
    A complete review of EPA's analysis of the health effects, 
occurrence, and exposure for hexachlorobutadiene were presented in the 
June 2002 notice (USEPA 2002a) and in the regulatory determination 
(USEPA 2001b) and health effects (USEPA 2003b) support documents for 
hexachlorobutadiene.

D. Manganese

    Description: Manganese (CASRN 7439-96-5) is a naturally occurring 
element found at low levels in soil, water, and food. It is an 
essential trace element for humans and all animal species. It 
constitutes approximately 0.1

[[Page 42904]]

percent of the earth's crust, however, it does not occur in the 
environment in its pure metal form, but is ubiquitous as a component of 
more than 100 minerals including many silicates, carbonates, sulfides, 
oxides, phosphates, and borates (ATSDR 2000).
    Manganese is generally considered to have low toxicity when 
ingested orally. The major source of manganese intake in humans (with 
the exception of possible occupational exposure) is dietary ingestion; 
manganese is a nutrient and is not considered to be very toxic when 
ingested with food. Reports of adverse effects following oral exposure 
are rare.
    Agency Findings: After reviewing the best available public health 
and occurrence information, EPA has made the determination not to 
regulate manganese with a NPDWR at this time, because it would not 
present a meaningful opportunity for health risk reduction for persons 
served by PWSs. Manganese is generally not considered to be very toxic 
when ingested with the diet and drinking water accounts for a 
relatively small proportion of manganese intake.
    A complete review of EPA's analysis of the health effects, 
occurrence, and exposure for manganese were presented in the June 2002 
notice (USEPA 2002a) and in the regulatory determination (USEPA 2001c) 
and health effects (USEPA 2003c) support documents for manganese. EPA 
is developing a Drinking Water Advisory for manganese to provide 
guidance to communities that might be exposed to elevated 
concentrations of manganese in their drinking water.

E. Metribuzin

    Description: Metribuzin (CASRN 21087-64-9) is a pesticide that does 
not volatilize readily, yet is relatively soluble in water. It is 
relatively persistent in the environment and degrades primarily through 
exposure to sunlight. Metribuzin is used as an herbicide on soybeans, 
potatoes, alfalfa, sugar cane, lentils, asparagus, tomatoes, carrots, 
peas, barley, wheat, range grasses, and Christmas trees. Metribuzin has 
limited non-agricultural utility. Metribuzin is not classifiable as a 
human carcinogen, but there may be effects on the liver and body weight 
from chronic exposure to high doses.
    Agency Findings: After reviewing the best available public health 
and occurrence information, EPA has made the determination not to 
regulate metribuzin with a NPDWR at this time, because it would not 
present a meaningful opportunity for health risk reduction for persons 
served by PWSs. Metribuzin is not known to occur in PWSs at levels of 
public health concern. National monitoring data indicate that 
metribuzin is infrequently detected in public water supplies.
    A complete review of EPA's analysis of the health effects, 
occurrence, and exposure for metribuzin were presented in the June 2002 
notice (USEPA 2002a) and in the regulatory determination (USEPA 2001d) 
and health effects (USEPA 2003d) support documents for metribuzin.

F. Naphthalene

    Description: Naphthalene (CASRN 91-20-3) is a VOC that is naturally 
present in fossil fuels, such as petroleum and coal, and is formed when 
wood or tobacco are burned. Naphthalene is produced in commercial 
quantities from either coal tar or petroleum. Most naphthalene use 
(60%) is as an intermediary in the production of phthalate 
plasticizers, resins, phthaleins, dyes, pharmaceuticals, and insect 
repellents. Crystalline naphthalene is used as a moth repellent and as 
a solid block deodorizer for diaper pails and toilets.
    The major source of human exposure to naphthalene is through the 
use of moth-balls containing naphthalene. This exposure can be from 
breathing the vapors or handling the mothballs. People also may be 
exposed by breathing tobacco smoke and air near industries that use or 
produce naphthalene. Usually naphthalene is not found in water because 
it evaporates or biodegrades quickly. When it is found in water, it is 
usually at levels lower than 0.01 mg/L (ATSDR 1995).
    Agency Findings: After reviewing the best available public health 
and occurrence information, EPA has made the determination not to 
regulate naphthalene with a NPDWR at this time, because it would not 
present a meaningful opportunity for health risk reduction for persons 
served by PWSs. Naphthalene is not known to occur in PWSs at levels of 
public health concern. National monitoring data indicate that 
naphthalene is infrequently detected in public water supplies.
    A complete review of EPA's analysis of the health effects, 
occurrence, and exposure for naphthalene were presented in the June 
2002 notice (USEPA 2002a) and in the regulatory determination (USEPA 
2001e) and health effects (USEPA 2003e) support documents for 
naphthalene.

G. Sodium

    Description: Sodium (CASRN 7440-23-5) is the sixth most abundant 
element on earth and is widely distributed in soils, plants, water, and 
foods. Ground water typically contains higher concentrations of 
minerals including sodium salts than do surface waters. In addition to 
naturally occurring sources of sodium, sodium compounds are used in 
deicing roads, as water treatment chemicals, and in domestic water 
softeners. Sewage effluents can also contribute significant quantities 
of sodium to water.
    Sodium is an essential trace element, and adequate levels of sodium 
are required for good health. Food is the main source of daily human 
exposure to sodium, primarily in the form of sodium chloride (table 
salt). Most of the sodium in our diet is added during food processing 
and preparation.
    Agency Findings: After reviewing the best available public health 
and occurrence information, EPA has made the determination not to 
regulate sodium with a NPDWR at this time, because it would not present 
a meaningful opportunity for health risk reduction for persons served 
by PWSs. The contribution of drinking water to daily sodium intake is 
very small when compared to the total dietary intake. Short-term 
excursions beyond the benchmark values pose no adverse health risk for 
most individuals, including the majority of persons with hypertension. 
Sodium in drinking water is a very small contributor to daily dietary 
intake and the levels at which sodium intake can contribute to 
increasing the blood pressure of individuals with normal blood 
pressures are not clearly established. The Agency currently does, 
however, require monitoring for sodium at the entry point to the 
distribution system and that results be reported annually to public 
health officials for surface water systems, and every three years for 
ground water systems (as defined in 40 CFR 141.41). The water supplier 
must report sodium test results to local and State public health 
officials, unless this responsibility is assumed by the State. This 
requirement is intended to provide the public health community with 
information on sodium levels in drinking water to be used in counseling 
patients and is the most direct route for gaining the attention of the 
affected population.
    A complete review of EPA's analysis of the health effects, 
occurrence, and exposure for sodium were presented in the June 2002 
notice (USEPA 2002a) as well as in the regulatory determination (USEPA 
2001f) support document for sodium. EPA is issuing a final Drinking 
Water Advisory for sodium concurrent with today's action (USEPA 2003f). 
The sodium advisory provides guidance to

[[Page 42905]]

communities that might be exposed to elevated concentrations of sodium 
chloride or other sodium salts in their drinking water. This sodium 
advisory also provides appropriate cautions for individuals on low-
sodium or sodium-restricted diets.

H. Sulfate

    Description: Sulfate (SO4-2, CASRN 14808-79-
8) exists in a variety of inorganic salts. Sulfate salts such as 
sodium, potassium, and magnesium are very water soluble and are often 
found in natural waters. Sulfate salts of metals such as barium, iron, 
or lead have very low water solubility. Sulfate is found in soil, 
sediments, and rocks and occurs in the environment as a result of both 
natural processes and human activities. Sulfate compounds are used for 
a variety of commercial and industrial purposes.
    Sulfate may enter surface or ground water as a result of discharge 
or disposal of sulfate-containing wastes. In addition, sulfur oxides 
produced during the combustion of fossil fuels are transformed to 
sulfuric acid in the atmosphere. Through precipitation (acid rain), 
sulfuric acid can enter surface waters, lowering the pH and raising 
sulfate levels.
    Sulfate is present in the diet. A number of food additives are 
sulfate salts and most (such as copper sulfate and zinc sulfate) are 
approved for use as nutritional supplements.
    Sulfate may have adverse health affects on persons, primarily 
through its laxative effect following high-level, acute exposures. The 
adverse health effect from ingesting high levels of sulfate is 
increased water in the fecal matter (diarrhea), possibly contributing 
to dehydration. Because local populations usually acclimate to high 
sulfate levels, the impact is primarily on infants, transient 
populations (e.g., business travelers, visitors, and vacationers), and 
new residents.
    Agency Finding: After reviewing the best available public health 
and occurrence information, EPA has made the determination not to 
regulate sulfate with a NPDWR at this time, because it would not 
present a meaningful opportunity for health risk reduction for persons 
served by PWSs. Although sulfate occurs in many PWSs nationally, the 
weight of evidence suggests that the adverse health effect is generally 
mild, of short duration, and generally occurs at concentrations 
considerably greater than 500 mg/L, except in very limited 
circumstances when sulfate co-occurs with magnesium and high total 
dissolved solids, which exacerbate its laxative effects. EPA is issuing 
a final Drinking Water Advisory to provide guidance to communities that 
may be exposed to drinking water with high sulfate concentrations.
    A complete review of EPA's analysis of the health effects, 
occurrence, and exposure for sulfate were presented in the June 2002 
notice (USEPA 2002a) as well as in the regulatory determination (USEPA 
2001g) support document for sulfate. EPA will issue a final Drinking 
Water Advisory for sulfate concurrent with today's action (USEPA 
2003g). The advisory for sulfate provides guidance to communities that 
may be exposed to drinking water contaminated with high sulfate 
concentrations. This advisory contains information of use to sensitive 
sub-populations, such as infants and travelers.

VI. How Will EPA Address the Data Needs of the Remaining 51 CCL 
Contaminants?

    The Agency continues to conduct research and/or to collect 
occurrence information on the remaining CCL contaminants. EPA has been 
conducting research to fill identified data gaps. The Agency will take 
action as appropriate when information becomes available and will not 
necessarily wait until the end of the next regulatory determination 
cycle before making other regulatory determinations.
    To support decisions on CCL contaminants, the Agency is required to 
evaluate when and where these contaminants occur, the extent of 
exposure, and their risk to public health. EPA must also determine if 
regulating the contaminant presents a meaningful opportunity for 
reducing public health risk. Contaminants deemed ready for regulatory 
determination, which include those that are the subject of today's 
decisions, are determined to have sufficient data to support a decision 
as to whether or not to regulate based on evaluation of both exposure 
and risk to public health.
    The remaining 51 CCL contaminants for which decisions are not being 
made today do not have sufficient data to support regulatory decisions. 
The Agency continues to conduct research and/or collect occurrence 
information on these remaining contaminants. The research issues are 
broader than those that EPA can address alone. It is anticipated that 
other entities will be involved in conducting much of the needed 
research to support this process. EPA continues to identify and develop 
new collaborations to conduct research and gather the additional data 
to characterize occurrence and adverse health effects to support future 
regulatory determinations of CCL contaminants. EPA is also engaged with 
our stakeholders in a NDWAC work group to refine the CCL listing 
process to address emerging contaminants for future efforts
    EPA is committed to providing a means for our stakeholders to track 
progress of research on remaining CCL contaminants. The Agency is 
currently developing a web-based system that will be available to the 
public in 2003. This website will serve as a repository of information 
on drinking water research projects currently funded or performed by 
EPA.

VII. References

ATSDR, 1993. Toxicological Profile for Aldrin/Dieldrin (Update). 
Atlanta, Georgia. U.S. Department of Health and Human Services, 
Public Health Service. 184 pp.
ATSDR, 1995. Toxicological Profile for Naphthalene (Update). 
Atlanta, Georgia. U.S. Department of Health and Human Services, 
Public Health Service. 200 pp.
ATSDR, 2000. Toxicological Profile for Manganese (Update). Atlanta, 
Georgia. U.S. Department of Health and Human Services, Public Health 
Service. 466 pp. and Appendices.
USEPA, 1997. Announcement of the Draft Drinking Water Contaminant 
Candidate List; Notice. Federal Register. Vol. 62, No. 193, p. 
52193, October 6, 1997.
USEPA, 1998. Announcement of the Draft Drinking Water Contaminant 
Candidate List; Notice. Federal Register. Vol. 63, No. 40, p. 10273, 
March 2, 1998.
USEPA, 2000. Methodology for Deriving Ambient Water Quality Criteria 
for the Protection of Human Health (2000). EPA-822-B-00-004. October 
2000.
USEPA, 2001a. Regulatory Determination Support Document for Aldrin 
and Dieldrin. EPA 815 R-01-011.
USEPA, 2001b. Regulatory Determination Support Document for 
Hexachlorobutadiene. EPA 815 R-01-009.
USEPA, 2001c. Regulatory Determination Support Document for 
Manganese. EPA 815 R-01-013.
USEPA, 2001d. Regulatory Determination Support Document for 
Metribuzin. EPA 815 R-01-010.
USEPA, 2001e. Regulatory Determination Support Document for 
Naphthalene. EPA 815 R-01-008.
USEPA, 2001f. Regulatory Determination Support Document for Sodium. 
EPA 815 R-01-014.
USEPA, 2001g. Regulatory Determination Support Document for Sulfate. 
EPA 815 R-01-015.
USEPA, 2002a. Announcement of Preliminary Regulatory Determinations 
for Priority Contaminants on the Drinking Water Contaminant 
Candidate List. Federal Register. Vol. 67, No. 106, p. 38222, June 
3, 2002.
USEPA, 2002b. Fact Sheet: Announcement of Preliminary Regulatory 
Determinations for Priority Contaminants on the

[[Page 42906]]

Drinking Water Contaminant Candidate List. EPA 815-F-02-003.
USEPA, 2003a. Health Effects Support Document for Aldrin and 
Dieldrin. EPA 822 R-03-001.
USEPA, 2003b. Health Effects Support Document for 
Hexachlorobutadiene. EPA 822 R-03-002.
USEPA, 2003c. Health Effects Support Document for Manganese. EPA 822 
R-03-003.
USEPA, 2003d. Health Effects Support Document for Metribuzin. EPA 
822 R-03-004.
USEPA, 2003e. Health Effects Support Document for Naphthalene. EPA 
822 R-03-005.
USEPA, 2003f. Drinking Water Advisory: Consumer Acceptability Advice 
and Health Effects Analysis on Sodium. EPA 822 R-03-006.
USEPA, 2003g. Drinking Water Advisory: Consumer Acceptability Advice 
and Health Effects Analysis on Sulfate. EPA 822 R-03-007.
USEPA, 2003h. Health Effects Support Document for Acanthamoeba. EPA 
822 R-03-012.

    Dated: July 11, 2003.
Linda J. Fisher,
Acting Administrator.
[FR Doc. 03-18151 Filed 7-17-03; 8:45 am]
BILLING CODE 6560-50-P