Friday,

July 18, 2003

Part V

Environmental 

Protection Agency

Announcement of Regulatory 

Determinations for Priority Contaminants 

on the Drinking Water Contaminant 

Candidate List; Notice

42898 Federal Register / Vol. 68, No. 138 / Friday, July 18, 2003 / Notices 

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.

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: 

carpenter.thomas@epa.gov or Harriet 

Colbert, (202) 564–4698, e-mail: 

colbert.harriet@epa.gov.

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. 

Federal Register / Vol. 68, No. 138 / Friday, July 18, 2003 / Notices 42899

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 

42900 Federal Register / Vol. 68, No. 138 / Friday, July 18, 2003 / Notices 

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 ‘‘bestavailable, 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/

Federal Register / Vol. 68, No. 138 / Friday, July 18, 2003 / Notices 42901

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 healthbased 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 nonregulatory 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 online 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 

42902 Federal Register / Vol. 68, No. 138 / Friday, July 18, 2003 / Notices 

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 

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

(μg/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 freeliving 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 

42904 Federal Register / Vol. 68, No. 138 / Friday, July 18, 2003 / Notices 

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 

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

42906 Federal Register / Vol. 68, No. 138 / Friday, July 18, 2003 / Notices 

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