RESPONSE DOCUMENT Response to Public Comment on " Drinking Water Contaminant Candidate List 2; Notice", April 2, 2004 ( 69 FR 17406)

February 2005 U. S. Environmental Protection Agency Office of Water Office of Ground Water and Drinking Water Washington, D. C. 20004 1 TABLE OF CONTENTS I. INTRODUCTION AND OVERVIEW OF PUBLIC COMMENTERS . . . . . . . . . . . . . . . . . . . 3 II. PUBLIC COMMENTS AND EPA RESPONSES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.0 General Comments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.0 CCL Background and Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.0 Comments on Development of the Draft Drinking Water CCL 2 . . . . . . . . . . . . . . . . . . 8 3.1 Comments on Approach and Rationale for the Draft CCL 2 . . . . . . . . . . . . . . . 8 3.1.1 Organizing and Extracting the Data . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.1.1 Organizing and Extracting the Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 <IP_ADDRESS> Comments Supporting EPA's Approach for Evaluating and Screening Available Chemical Contaminant Data . . . . . . . . . . 10 3.1.1 Organizing and Extracting the Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 <IP_ADDRESS> Comments Critical of EPA's Approach for Evaluating and Screening Available Chemical Contaminant Data . . . . . . . . . . 12 3.1.3 Research and Data Collection for Contaminants on the 1998 CCL . . . 14 <IP_ADDRESS> Comments Critical of EPA's Research on Health Effects, Treatment, and Analytical Methods and Data Collection on Occurrence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.1.4 Development of an Improved Classification Process for Future CCLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 3.14.1 Comments Supporting EPA's Approach for Developing an Improved Classification Process for Future CCLs . . . . . . . . . 18 3.3 Comments on EPA's Draft CCL 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 3.3.1 Comments Supporting EPA's Draft CCL 2 . . . . . . . . . . . . . . . . . . . . 21 3.3.2 Comments Critical of EPA's Draft CCL 2 . . . . . . . . . . . . . . . . . . . . . 22 3.4 Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.4.1 Update CCL 2 Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 3.4.2 Regenerate CCL 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 3.4.3 Add NDMA and enterotoxigenic Escherichia coli ( E. coli) to CCL . . 28 4.0 Comments on the NRC's Recommended Approach for Developing Future CCLs . . . . . 30 4.1 Comments on Screening of the Universe of Contaminants . . . . . . . . . . . . . . . . 30 4.1.2 Comments Critical of the NRC's Approach for Screening the Universe of Contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 4.2 Comments on the Approach for Compiling the Preliminary CCL ( PCCL) . . . . 31 4.2.2 Comments Critical of the NRC's Approach for Compiling the PCCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 4.3 Comments on the Approach for Contaminant Selection from the PCCL to the CCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.3.2 Comments Critical of the NRC's Approach for Contaminant Selection from the PCCL to the CCL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 4.4 Comments on the Virulence Factor Activity Relationships ( VFARs) for Assessing Emerging Waterborne Pathogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 4.4.1 Comments Supporting the NRC's Approach of Using the Virulence Factor Activity Relationships ( VFARs) for Assessing Emerging Waterborne Pathogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 2 4.4.2 Comments Critical of the NRC's Approach of Using the Virulence Factor Activity Relationships ( VFARs) for Assessing Emerging Waterborne Pathogens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 4.5 Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 4.5.1 CCL Transparency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 5.0 Implementation of NRC's Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 5.2 Comments on the Ongoing Analysis of the Classification Approach . . . . . . . . . 40 5.2.1 Organizing and Extracting Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 <IP_ADDRESS> Comments Supporting EPA's Approach for Organizing and Extracting Data for the CCL Universe . . . . . . . . . . . . . . . . . . 40 <IP_ADDRESS> Comments Critical of EPA's Approach for Organizing and Extracting Data for the CCL Universe . . . . . . . . . . . . . . . . . . 42 5.2.3 Classifying Contaminants from the PCCL to the CCL . . . . . . . . . . . . 44 <IP_ADDRESS> Comments Supporting the Ongoing Approach Used for Classifying Contaminants from the PCCL to the CCL . . . . . . 44 <IP_ADDRESS> Comments Critical of the Ongoing Approach Used for Classifying Contaminants from the PCCL to the CCL . . . . . . . . . . . . . . . 47 5.2.4 The VFAR Concept and Classifying Microorganisms . . . . . . . . . . . . . 48 <IP_ADDRESS> Comments Critical of the Use of the VFAR concept for Classifying Microorganisms . . . . . . . . . . . . . . . . . . . . . . . . . 48 5.3 Other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 3 I. INTRODUCTION AND OVERVIEW OF PUBLIC COMMENTERS The second Draft CCL ( CCL 2) was published in the April 2, 2004 edition of the Federal Register ( 69 FR 17406) announcing the U. S. Environmental Protection Agency's ( EPA) preliminary decision to carry forward the remaining 51 contaminants on the 1998 CCL as the Draft CCL 2, provide information on EPA's efforts to expand and strengthen the underlying CCL listing process to be used for future CCL listings, and to seek comment on the draft list as well as EPA's efforts to improve the contaminant selection process for future CCLs. EPA requested public comment on the proposed list. Thirteen comments were received by the June 1, 2004 public comment deadline. [ Note: six of the comments were either cover letters or duplicate comments.]

The purpose of this document is to provide a comprehensive summary of the public comments on the proposed rule and EPA's responses to these comments. EPA has established a docket for this action under Docket ID No. OW 2003 0028. All documents in the docket are listed in the EDOCKET index at http:// www. epa. gov/ edocket. Although listed in the index, some information is not publically available, i. e., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publically available only in hard copy form. Publically available docket materials are available either electronically in EDOCKET or in hard copy at the Water Docket, EPA/ DC, EPA West, Room B102, 1301 Constitution Avenue, NW, Washington, DC. The 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. For access to docket material, please call ( 202) 566 2426 to schedule an appointment.

EPA received comments from a variety of organizations, including state drinking water agencies and related associations, public drinking water systems, national drinking water organizations, and academic institutions. Table 1 below provides the names and affiliations of the major commenters and their docket log identification number. Each comment is identified by the Document ID numbers 0014 through 0026 that was assigned under Docket ID No. OW 2003 0028. Comments ranged from an anonymous e Docket message questioning whether EPA is considering regulation of 1,4 Dioxane to documents with detailed explanations and comments on many aspects of the Draft CCL 2.

EPA received one comment from an anonymous source; six comments from state agencies and related associations ( Texas Commission on Environmental Quality four comments [ two cover letters, one attachment, and one duplicate paper copy of cover letter and attachment] and Association of State Drinking Water Administrators ( ASDWA) two comments [ cover letter and attachment]); four comments from public water systems and related associations ( American Water Works Service Company ( AWWA) two comments [ one duplicate comment], Association of Metropolitan Water Agencies, and the City of Austin, Texas Water Utility ), and two from an academic institution ( Yale University School of Medicine [ comments and attachments].

The majority of comments were supportive of the CCL process. The comments on development of the draft CCL 2 focused on two key topic areas: ( 1) reassembling the CCL taking new available information into account, suggestions on information that should be considered, and contaminants that should be included or deleted from the CCL, and ( 2) requests for information on the status of CCL related research. Comments on the development of future CCLs focused on four key topic areas: ( 1) expert judgement and transparency, ( 2) the role of data quality, ( 3) a simplified approach with adaptive 4 management for future CCLs, and ( 4) the role of virulence factor activity relationships ( VFARs).

Table 1. Commenter and Affiliation by Docket Log I. D. Number Docket I. D. Commenter Name Commenter Affiliation Other 0014 Anonymous Unknown State Drinking Water Agencies and Related Associations 0015 Daniel Burke ( cover letter) Texas Commission on Environmental Quality 0016 Glenn Shankle ( cover letter) Texas Commission on Environmental Quality 0017 Comments ( electronic attachment for 0015 and 0016) Texas Commission on Environmental Quality 0021 Glenn Shankle ( paper copy duplicate of 0017) Texas Commission on Environmental Quality 0022 Matt Corson ( electronic cover letter) Association of State Drinking Water Administrators 0023 James D. Taft ( paper copy cover letter and comments of 0022) Association of State Drinking Water Administrators Public Water Systems, Water System Operators, and/ or Local Water Agencies 0018 Diane VanDe Hei Association of Metropolitan Water Agencies 0019 Thomas W. Curtis American Water Works Association 0020 Thomas Curtis ( Docket duplicate of 0019) American Water Works Association 0024 Chris Lippe, P. E. City of Austin Water Utility ( Texas)

Academic Institution 0025 Stephen C. Edberg, Ph. D, A. B. M. M. Yale University School of Medicine 0026 Attachment for 0025 Yale University School of Medicine 5 II. PUBLIC COMMENTS AND EPA RESPONSES 1.0 General Comments 1.0 General Comments Docket ID  Part # Comment: 0014 1 Is EPA considering the regulation of 1,4 Dioxane?

Response: No, EPA is not considering the regulation of 1,4 Dioxane at this time because it is not on the current CCL. The CCL is the primary source of priority contaminants for evaluation by EPA's drinking water program. Contaminants on the CCL are currently not subject to any proposed or promulgated national primary drinking water regulation, but are known or anticipated to occur in public water systems, and may require regulation under SDWA. The EPA conducts research on health effects, analytical methods, contaminant occurrence, treatment technologies, and treatment effectiveness for priority drinking water contaminants on the CCL. The Agency also develops drinking water guidance and health advisories, and makes regulatory determinations for contaminants on the CCL. This contaminant may be considered as part of the CCL 3 listing process.

Docket ID  Part # Comment: 0018 1 AMWA supports the CCL process. The SDWA states that the Administrator shall regulate contaminants that will provide a " meaningful opportunity for health risk reduction for persons served by public water systems" ( Sec. 1412 ( b)( 1)( A)( iii)). With this end goal in mind, the CCL process must have a clear focus on listing contaminants on the CCL that have an adverse effect on public health, and are likely to occur in drinking water ( Sec. 1412 ( b)( 1)( A)( i and ii)). Listing contaminants on the CCL therefore provides EPA with the ability to focus precious research dollars on those chemical and microbial contaminants that are a potential health risk to drinking water consumers.

The CCL process is a mechanism that has been legislated to help the Agency effectively determine which contaminants to regulate. AMWA supports the process and believes Congress intended it to be the future of determining drinking water regulations. AMWA therefore encourages EPA to work to integrate this process into its regulatory and research programs as it believes Congress intended.

Response: EPA agrees and has made the CCL process central to its drinking water research and regulating program.

Docket ID  Part # Comment: 0023 4 With respect to future CCL development, states support EPA's efforts in which it engaged the NRC and the National Drinking Water Advisory Council ( NDWAC) to improve the CCL listing process. States believe that the information obtained from these two entities will allow 6 EPA to develop a broader, more systematic approach for selecting contaminants for the CCL.

Response: EPA agrees and intends on using such an approach for CCL 3. 7 2.0 CCL Background and Summary 2.0 CCL Background and Summary Docket ID  Part # Comment: 0017 1 We support the EPA efforts to incorporate sound science, occurrence information and healthrisk based priority setting into the regulatory development process.

Response: EPA believes that the CCL process appropriately prioritizes SDWA regulatory development.

Docket ID  Part #

Comment: 0019/ 20 26 A web based research inventory was to be available to the public in 2003 ( DRINK). This tool was unveiled on EPA's web site in May 2004, during the CCL 2 proposal comment period. EPA does not address it in the CCL 2 proposal.

Response: EPA agrees that the status of CCL related research should be publically available. The Agency has taken a number of steps to provide this information through its websites and in documents it has published. EPA's Office of Ground Water and Drinking Water Drinking Water Research Information Network ( DRINK), found at http:// www. epa. gov/ safewater/ drink/ intro. html, is a publicly accessible, web based system that tracks over 1,000 ongoing research projects conducted by EPA and other research partners from national, regional, and international research agencies and organizations. The DRINK system stores, manages, and delivers descriptive summary data on drinking water related projects, including abstracts, status of projects, uniform resource locators to datasets and reports, and contact information on projects. 8 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.1 Comments on Approach and Rationale for the Draft CCL 2 Docket ID  Part #

Comment: 0017 11 The CCL 2 process is not currently adequate to elevate certain health risks. For example, nitrite occurrence can exceed the maximum contaminant level of 1 milligram per liter at locations in chloramination distribution systems that are changing from free chloride to combined chlorine as a result of the Stage 1 Disinfection Byproducts Rule. The suggested surveillance and nomination process to expedite new or emerging contaminants through the CCL process for future CCLs should be taken into consideration for the CCL 2.

Response: EPA recognizes that it is important to ensure timely identification of new and emerging drinking water contaminants. Toward that end, EPA has considerable ongoing surveillance activity, ranging from ongoing literature reviews, to attendance at professional meetings, sponsorship of special meetings and special sessions at meetings dealing with drinking water issues, communications with researchers in the field, and liaisons with foreign institutions. EPA's Office of Water maintains linkage among Offices within EPA ( e. g., Office of Pesticide Programs) and with other agencies and organizations that play a key role in the surveillance process ( e. g., Centers for Disease Control and Prevention, US Geological Survey). Many offices within EPA are also being called upon to conduct surveillance activities.

It is important to note the SDWA does not restrict the EPA from adding contaminants to the CCL at any time and that EPA may make regulatory determinations for any unregulated contaminant not on today's CCL ( see SDWA section 1412( b)( 1)( B)( ii)( III)). Thus, the Agency has the authority to act as necessary to protect public health as new information becomes available. 9 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.1 Comments on Approach and Rationale for the Draft CCL 2 3.1.1 Organizing and Extracting the Data Docket ID  Part #

Comment: 0017 2 Use of Surrogates: When using surrogate data to characterize the relative likelihood of occurrence, we recommend that EPA focus not only on the release of a contaminant, but also on existing data showing the impact of that release. As a specific example, the TCEQ has included the contaminants on the CCL in the source water assessments, with the exception of some of the specific pathogens. We are continuing to develop relationships between potential sources and the contaminants on the CCL. We would encourage EPA to pursue further development of contaminant to source relationships in order to better determine the relative susceptibility of public water systems to these contaminants. The CCL 2 process is not currently adequate to elevate certain health risks.

Response: This kind of information will be used in CCL 3. 10 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.1 Comments on Approach and Rationale for the Draft CCL 2 3.1.1 Organizing and Extracting the Data <IP_ADDRESS> Comments Supporting EPA's Approach for Evaluating and Screening Available Chemical Contaminant Data Docket ID  Part #

Comment: 0024 1 Based on the information provided in the Federal Register notice, it appears that the EPA has an adequate methodology for screening the broad universe of contaminants and identifying those that might belong on a draft CCL. Implementing the National Research Council's recommendations will further strengthen the screening process. The draft CCL however is overly broad and might prevent the EPA, with its limited resources, from developing the necessary scientific data on which to make regulatory decisions.

Response: EPA disagrees with your statement that states the CCL is overly broad and may prevent the Agency from developing the necessary scientific data to base regulatory determinations. EPA has been aggressively conducting research to fill identified 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 note, that under the SDWA, the EPA may make regulatory determinations for any unregulated contaminant not on today's CCL ( see SDWA section 1412( b)( 1)( B)( ii)( III)). Thus, the Agency has the authority to act as necessary to protect public health as new information becomes available.

Docket ID  Part #

Comment: 0019/ 20 25 AWWA strongly supports the agency's efforts toward improving methodologies for identifying and prioritizing drinking water contaminants that merit regulatory consideration. However, it is critical that this new focus not eclipse longstanding demands for research in the areas of analytical method development, occurrence, health effects, and treatment. The magnitude of the challenge EPA faces in obtaining and allocating resources to meet all these research needs is indeed daunting. In its multi year plan, the agency appropriately highlights the importance of research partnerships as a forum for coordinating research and for leveraging funding and expertise. Moreover, effective outreach and transfer of scientific and technical information and communication of research plans are cited as important aspects of EPA's CCL research program. AWWA encourages the agency to engage in effective outreach to its current research partners ( i. e., AwwaRF), other federal agencies ( i. e., Department of Homeland Security, National Institutes of Health, etc.), states, and utilities. AWWA believes that the extent to which outside entities, including AWWA and its member utilities, might contribute to this overall effort will be directly related to how effective EPA is in communicating the progress and status of current research needs.

Response: EPA acknowledges that entities outside of EPA contribute to the overall effort of advancing 11 progress in CCL related research and understands the importance of communicating the status of existing research needs and priorities to the public. Because of this, EPA has made CCL research related information publically available through its websites, public meetings, and documents. 12 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.1 Comments on Approach and Rationale for the Draft CCL 2 3.1.1 Organizing and Extracting the Data <IP_ADDRESS> Comments Critical of EPA's Approach for Evaluating and Screening Available Chemical Contaminant Data Docket ID  Part #

Comment: 0019/ 20 23 The proposal provides virtually no discussion or information about the status of previously identified research needs for the listed contaminants. AWWA finds this to be a serious omission in the proposal. EPA should clearly communicate the results of CCL contaminant related research to the interested public and use the available information to inform the list / do not list decision. Effective outreach and transfer of scientific and technical information and communication of research plans are cited as important aspects of EPA's CCL research program.

Response: EPA agrees that the status of CCL related research should be publically available. The Agency has taken a number of steps to provide this information through its websites and in documents it has published.

EPA websites addressing CCL related research information include the following:

° EPA's Office of Ground Water and Drinking Water Drinking Water Research Information Network ( DRINK), found at http:// www. epa. gov/ safewater/ drink/ intro. html, is a publicly accessible, web based system that tracks over 1,000 ongoing research projects conducted by EPA and other research partners from national, regional, and international research agencies and organizations. The DRINK system stores, manages, and delivers descriptive summary data on drinking water related projects, including abstracts, status of projects, uniform resource locators to datasets and reports, and contact information on projects.

° EPA's Office of Ground Water and Drinking Water website at http:// www. epa. gov/ safewater/ ccl/ cclfs. html has information on the NDWAC ( e. g., reports, meeting announcements, and meeting summaries which includes meetings of the NDWAC CCL Work Group), monitoring of unregulated contaminants from public water systems, the National Contaminant Occurrence Database, analytical methods for compliance monitoring, and treatment technologies.

° EPA's Office of Research and Development ( ORD) environmental information management system website at http:// www. epa. gov/ eims/ maintains information on EPA research projects, including project title, abstract, start and end dates, principal investigator, funding, results and publications, and related technical documents.

° EPA's Office of Science and Technologies website at http:// www. epa. gov/ waterscience/ humanhealth/ has information on EPA's drinking water standards, health and consumer advisories, criteria documents, and related technical documents. 13 A key document addressing CCL related research and information is EPA's Draft Multi Year Plan ( MYP) for the drinking water research program. The Draft MYP describes the Agency's drinking water research program activities and plans for fiscal years 2003  2010 ( see http:// www. epa. gov/ osp/ myp/ dw. pdf). As a tool for planning and communication, the MYP provides: ( 1) a context for annual planning decisions and a basis for describing the impacts of these decisions, ( 2) a framework for integrating research on common issues across the EPA's ORD laboratories and centers, as well as across the various Agency Goals established under the Government Performance and Results Act, and ( 3) a resource for communicating research plans and products within ORD and with EPA programs, the regions and interested parties outside of EPA. MYPs are updated on a biennial basis to provide opportunities for making the necessary adjustments to the research program.

Docket ID  Part #

Comment: 0019/ 20 24 AWWA believes that if EPA evaluates the data currently available, at least some contaminants currently included in CCL1 would not be listed on CCL 2. EPA should clearly communicate the results of CCL contaminant related research to the interested public and use the available information to inform the list/ do not list decision.

Response: EPA believes that the current CCL contains priority drinking water contaminants and is an appropriate list to maintain while work on CCL 3 continues. Where there is adequate information about a particular contaminant, EPA plans to make a regulatory determination which will either remove that contaminant from the CCL or start a national rule making process to set a national primary drinking water regulation. Additionally, see the response to the comment 0019/ 20 part 23, under section <IP_ADDRESS>. 14 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.1 Comments on Approach and Rationale for the Draft CCL 2 3.1.3 Research and Data Collection for Contaminants on the 1998 CCL <IP_ADDRESS> Comments Critical of EPA's Research on Health Effects, Treatment, and Analytical Methods and Data Collection on Occurrence Docket ID  Part #

Comment: 0019/ 20 26 In finalizing CCL 2 AWWA believes it is time for the EPA to update stakeholders on the following specific activities that were discussed during CCL1 development, explaining their current relevance ( or irrelevance if that is the case), current plans, and resource commitments if applicable:

1. The National Contaminant Occurrence Database ( NCOD) was slated to be established by August 1999 and was to be considered for future CCLs. 2. Work on 21 suspected endocrine disruptors were deferred pending an imminent NAS review, research being conducted under OPPTS, an imminent EDSTAC report to be reviewed by EPA and FIFRA SABs, and other activities coordinated with the EU, OECD, and UNEP. 3. Work on 35 pesticides identified by the OPP as having high potential risk for leaching into groundwater was deferred pending further evaluation of their occurrence potential. An occurrence model, expected to be ready for use at the end of 1997, was to be used by the Agency to reevaluate the pesticides for CCL inclusion. Note that 13 of these pesticides are on the draft CCL 2. 4. Pending reassessments of pesticide tolerances for raw and processed food were cited as further rationale for deferring these contaminants. According to the reassessment schedule 66% of applicable tolerances and exemptions were to be completed by August 2002 under the FQPA ( FR 62: 42019). 5. The need for a literature search on Pseudomonas aeruginosa. 6. ILSI project to evaluate microbiological indicators. 7. EPA revision of risk assessment procedures for essential elements, including consideration of WHO's pending document. 8. Occurrence data were not available for 22 chemical contaminants monitored under the 1993 1995 UCMR round. Eight of these contaminants still remain on the proposed CCL 2 list without discussion of monitoring results.

Response: EPA agrees that the status of CCL related research should be publically available. The Agency's approach throughout the CCL process has been and continues to be to encourage a strong partnership with stakeholders. The Agency has taken a number of steps to provide this information through its websites and in documents it has published. See the response to the comment 0019/ 0020 part 23, under section <IP_ADDRESS> above.

Docket ID  Part #

Comment: 0019/ 20 28 The April 2004 Federal Register notice for the CCL 2 proposal does not describe CCL related data collection and research that has been undertaken since CCL1. The drinking water research program's multi year plan was mentioned, but no reference to this document or to 15 any other source of information about research project status was provided, including DRINK. The agency should describe what has been learned from research conducted through EPA sponsored projects, in house EPA activities, and externally funded projects, and explain how these results were used to justify the decision to carry over contaminants to CCL 2. Table 2 in the CCL1 Federal Register notice provided a very informative categorization of contaminants according to major research needs ( USEPA 1998). Stakeholders are eager to know how these groupings have changed since 1998. The agency should prepare an updated version of Table 2 for the final CCL 2 rule and provide descriptions or references to specific information used in making any changes in categorization ( i. e., occurrence, health effect, analytical method, and treatment information needs). Additionally, EPA should outline the status and timetables for all identified research needs.

Response: EPA agrees that the status of CCL related research should be publically available. The Agency has taken a number of steps to provide this information through its websites and in documents it has published. See the response to the comment 0019/ 0020 part 23, under section <IP_ADDRESS> above.

Docket ID  Part #

Comment: 0019/ 20 29 As a specific example, health effects, treatment, and analytical methods development were named as research needs for Microsporidia in 1998. Since then, in addition to in house research EPA has expended nearly $ 1 million to fund three Microsporidia method development projects through the EPA STAR program. These three projects have been completed and results were presented in Cincinnati in 2003 ( Research of Microorganisms in Drinking Water Workshop). Additionally, in house and collaborative research projects on treatment technologies for Microsporidia have been conducted and the results published ( Marshall, 2003; Johnson, 2003; Hoffman, 2002). EPA does not cite or describe any of this work in the CCL 2 proposal. More generally, EPA's 2003 Drinking Water Research Program Multi Year Plan lists 12 Annual Performance Measures ( APMs) for fiscal year 2003 related to CCL microbes and seven APMs related to CCL chemical contaminants. EPA should discuss the results and/ or status of research related to these APMs, explain specifically how summary reports can be located, and describe how further progress can be tracked by stakeholders during the time between CCL 2 and future listings.

Response: EPA agrees that the status of CCL related research should be publically available. The Agency has taken a number of steps to provide this information through its websites and in documents it has published. See the response to the comment 0019/ 0020 part 23, under section <IP_ADDRESS> above.

Docket ID  Part #

Comment: 0019/ 20 30 In finalizing CCL 2, EPA should inform the interested public about the agency's progress to date and intended future path for integrating both FIFRA and endocrine disruptor screening information into the CCL process.

Response: 16 As discussed in the draft CCL 2 notice ( 69 FR 17406), EPA plans to consider the deferred pesticides in the context of an improved approach for selecting contaminants for future CCLs ( CCL 3). This will enable the Agency to consider these contaminants in a consistent, reproducible manner with a wide range of other contaminants. In this regard, it is important to note that EPA may conduct research, and make regulatory determinations for any unregulated contaminant not on today's CCL ( see SDWA section 1412( b)( 1)( B)( ii)( III)). Thus, the Agency has the authority to act as necessary to protect public health as new information becomes available.

As with pesticides, EPA believes that suspected endocrine disruptors should be considered when the next CCL is developed. This enables the Agency to use a more refined and improved approach in evaluating these contaminants.

Docket ID  Part #

Comment: 0019/ 20 34 As noted above, an important feature of CCL1 was the inclusion of a matrix or research needs ( i. e., Table 2). It is particularly critical that the agency clearly communicate priorities for analytical method research, as being able to detect contaminants at concentrations in the region of interest is essential to both occurrence and health effects research.

Response: See response to comment 0019/ 0020 part 23, under section <IP_ADDRESS>.

Docket ID  Part #

Comment: 0019/ 20 35 The agency recognized the role of the National Contaminants Occurrence Database ( NCOD) in determining the CCL in its 1997 CCL1 notice ( Figure 2, 62 Federal Register 52215). While the NCOD is not the only source of data available to the agency, Congress clearly intended for the agency to maintain a repository of occurrence data that could be used to support the CCL process. EPA currently maintains the NCOD ( http:// www. epa. gov/ safewater/ data/ ncod. html) and should consider how NCOD could better serve the agency as the CCL process evolves.

Response: The National Contaminants Occurrence Database ( NCOD) is currently being populated with compliance monitoring occurrence data, as well as data now being received as part of the UCMR. For the CCL occurrence analysis, EPA used the Round 1 and Round 2 data available in the NCOD at the time. Because NCOD is not a quality controlled data set, EPA selected a large subset of the Round 1 and Round 2 data by, for example, removing data with obvious unit errors and data from States that did not report non detects.

The Agency is committed to continuing to conduct research to fill identified data gaps and/ or to collect occurrence information on the remaining CCL contaminants and will take appropriate action when information becomes available.

Docket ID  Part # 17 Comment: 0023 2 However, states continue to urge EPA to complete necessary research in order to make regulatory determinations on high priority contaminants such as MTBE and perchlorate.

Response: The Agency continues to conduct research on the remaining CCL contaminants. EPA has been aggressively conducting research to fill identified data gaps and recognizes that stakeholders may have a particular interest in the timing of future regulatory determinations for other contaminants on the CCL ( e. g., perchlorate and methyl t butyl ether ( MTBE)). 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 note, that under the SDWA, the EPA may make regulatory determinations for any unregulated contaminant not on today's CCL ( see SDWA section 1412( b)( 1)( B)( ii)( III)). Thus, the Agency has the authority to act as necessary to protect public health as new information becomes available.

Docket ID  Part #

Comment: 0024 4 30 Contaminant Monitoring Limit. On Page 17410 of the Federal Register notice, there is mention of a 30 contaminant monitoring limit in each five year monitoring cycle under the SDWA's Unregulated Contaminant Monitoring Rule. We feel that the EPA uses an overly stringent interpretation of this section of the SDWA ( Section 1445( a)( 2)( B)( i)). A broader interpretation would support a limit on monitoring of 30 contaminants per public water system rather than a total of 30 contaminants. With a broader interpretation of the limit and by applying statistical principals to sampling plans under the Unregulated Contaminant Monitoring Rule, the EPA could gather occurrence data on 60, 90, or perhaps even 120 contaminants in a five year monitoring cycle. Considering that there may be as many as 10,000 potential contaminants to screen in preparing a CCL, a dramatic increase in monitoring is justifiable. The EPA should reconsider its interpretation of the 30 contaminant monitoring limit to support its regulatory program, especially since it provides valuable information and adds little or no additional costs to the regulated community.

Response: The comment is not germane to CCL 2. EPA anticipates publishing a preliminary UCMR 2 in the summer of 2005 and will consider the comment at that time. 18 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.1 Comments on Approach and Rationale for the Draft CCL 2 3.1.4 Development of an Improved Classification Process for Future CCLs 3.14.1 Comments Supporting EPA's Approach for Developing an Improved Classification Process for Future CCLs Docket ID  Part #

Comment: 0019/ 20 1 Evaluations of the CCL process by NRC and the NDWAC CCL Workgroup have identified a number of complexities and challenges that will be encountered in developing a valid CCL. AWWA recommends that EPA continue diligent pursuit both of a short term process for developing the next CCL and a long term evolution of the CCL process.

Response: The Agency agrees with the commenter that EPA will need to continue to identify key components for the next CCL and that future CCLs will be developed with the knowledge gathered during the initial development process. The National Drinking Water Advisory Council report ( 2004) provides a series of recommendations for the Agency to consider as it develops the CCL process for the next and future CCLs. The National Drinking Water Advisory Council recommendations encourage the Agency to identify which components can be used for the next CCL and how to address challenges to improve the process for future CCL. As the Agency evaluates the National Drinking Water Advisory Council recommendations, it will consider the comments to move to a more simplified approach for the next CCL.

Docket ID  Part #

Comment: 0019/ 20 2 The purpose of the CCL is to identify contaminants whose regulation will increase public health protection. The CCL also should identify those contaminants that need to be prioritized for research. The entire process that is applied to contaminants on the CCL should focus on identifying those contaminants that are likely to be found in drinking water and are likely to pose health risks to the public. Targeted research that improves understanding of contaminants and results in appropriate regulation will improve protection of public health and maintain public confidence in the CCL process.

Response: The Agency continues to conduct research and/ or to collect occurrence information on the remaining CCL contaminants. EPA has been aggressively conducting research to fill identified data gaps and will take appropriate action when information becomes available. The Agency has taken a number of steps to provide this information through its websites and in documents it has published. See the response to the comment 0019/ 0020 part 23, under section <IP_ADDRESS> above.

Docket ID  Part #

Comment: 0019/ 20 3 The CCL should be a list that prioritizes research and furthers investigations into the 19 occurrence and health effects of contaminants.

Response: EPA agrees and believes that the current CCL serves this purpose.

Docket ID  Part #

Comment: 0019/ 20 4/ 5/ 6 AWWA strongly encourages EPA to develop a CCL process not from a theoretical and esoteric perspective, but rather from a very pragmatic perspective. Specifically, the process must have detailed protocols prescribed that address the following questions:

1. How will contaminants to be evaluated be identified? 2. What types and quality of data are required in order to evaluate these contaminants? 3. Do the required data exist? 4. Are they accessible? 5. What attributes can be applied that will enable the evaluators to prioritize contaminants for consideration and for further research?

The approach developed must be transparent, but it also needs to be logistically possible. The approach adopted should be as simple as possible and it should be repeatable. Although AWWA recognizes that the overall CCL process will evolve over time, there are immediate requirements for CCL 3 development and for long term processes for future CCLs.

Response: The Agency agrees with the commenter that it is important to define components and CCL Process steps in future CCLs. The components identified by the commenter are also addressed in the National Drinking Water Advisory Council report on the CCL classification process. As the Agency evaluates the National Drinking Water Advisory Council report recommendations to develop CCL 3 and future CCLs it will take these comments under consideration as well. The commenters' recognition that the " CCL process will evolve over time" is similar to the National Drinking Water Advisory Council recommendation to use an adaptive management approach to develop the CCL process. The Agency agrees with the commenter that EPA will need to identify key components for the next CCL and future CCLs. The National Drinking Water Advisory Council report also provides a series of recommendations and considerations for the Agency to evaluate to develop the CCL process. These steps incorporate the commenters' suggestion to consider the evaluation of information and data quality considerations, and the components required to develop the CCL Classification approach. As the Agency evaluates the National Drinking Water Advisory Council recommendations, it will also consider the comments to move to a more simplified approach for the next CCL. For additional discussion on developing the CCL Process see response to comment 0019/ 0020 part 1, under section <IP_ADDRESS>.

Docket ID  Part #

Comment: 0019/ 20 7/ 8 AWWA does not believe that the agency will be successful in advancing the CCL process unless it abides by two fundamental principles: 20 1. The CCL process should be an expert decision making process assisted by decision support tools, not, as is frequently discussed, an automated algorithm that is periodically checked by experts for its performance.

2. The CCL process must evolve over time based on sound principles and well tested approaches. The agency must be prepared to allocate the substantial resources required to adequately test and verify the performance of such approaches.

These two principles lead AWWA to believe that simpler, streamlined approaches, which use only the attributes of occurrence and health effects, might result in a CCL list that will be more effective in the near term. This approach will provide a logical and logistically possible platform from which to develop more sophisticated expert support systems. The NRC approach can serve as a useful guidance for the agency's long term CCL development effort. However, many details and logistical issues would have to be overcome to employ it in CCL 3.

Response: The Agency agrees that expert input to a CCL process based on sound principles are important for the success of the CCL program. The National Drinking Water Advisory Council recommendations also note that the process should evolve over time and the knowledge gained in successive CCLs. The Agency will consider these comments as it develops the CCL process.

Docket ID  Part #

Comment: 0019/ 20 10 AWWA believes that convening a series of expert workshops on the above topics is the most practical approach to resolving many of the issues facing EPA. AWWA believes that for the workshops to be effective there needs to be extensive preparation in advance and the participants need to be chosen for hands on, in depth review of the subjects.

Response: The Agency agrees with the commenter that expert involvement in the development of the CCL process is an important component. The Agency will consider the recommendation to use expert workshops as one approach in developing the CCL process. The Agency will also consider other approaches to include expert input and inform stakeholders and the public on the progress the Agency makes in developing the CCL process. 21 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.3 Comments on EPA's Draft CCL 2 3.3.1 Comments Supporting EPA's Draft CCL 2 Docket ID  Part #

Comment: 0023 1 With respect to the contaminants that should be included on the next CCL, states support EPA's preliminary decision to carry over the remaining 51 contaminants on the 1998 CCL.

Response: EPA agrees and has adopted this approach in the final CCL 2 list. 22 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.3 Comments on EPA's Draft CCL 2 3.3.2 Comments Critical of EPA's Draft CCL 2 Docket ID  Part #

Comment: 0017 6 With respect to the microbiological contaminant candidates listed under Table III 2 Draft Drinking Water CCL 2, the reference to " other freshwater algae", although carried over from CCL1, appears to be too general to be useful. We would encourage EPA to target specific constituents of concern ( i. e. specific algae or their metabolites that have a known or predicted adverse impact on drinking water) for future CCL lists, not broad groups. Those algae that are benign should not be considered contaminants.

Response: EPA will consider targeting specific constituents of concern ( as opposed to broad groups) as we develop an expanded comprehensive system for evaluating a wider range of existing information, identifying new data, and applying revised screening criteria for future CCL lists.

Docket ID  Part #

Comment: 0019/ 20 36 The proposed CCL 2 clearly does not reflect any progress in making the CCL process a core program element, despite five years in which to make substantive progress. AWWA realizes that the agency has invested in two NRC reports and the ongoing NDWAC Workgroup process. Consequently, AWWA believes that the agency must make a serious commitment to advancing a pragmatic process for CCL 3.

Response: EPA disagrees that the CCL 2 does not reflect any progress in making the CCL process a core program element. After the 1998 CCL was published, the Agency asked the National Research Council ( NRC), the operating arm of the National Academy of Sciences, to review the 1998 CCL selection process and provide recommendations on how the process could be improved. These recommendations were developed over several years and provided to the Agency in late 2001. The NRC recommendations provided a framework for evaluating a larger number of contaminants and making decisions about contaminants, for which data are limited, through the use of innovative technologies and expert advice. The EPA requested the assistance of the National Drinking Water Advisory Council ( NDWAC) to evaluate and provide advice on implementing the NRC's recommended classification process. A NDWAC working group met 10 times from September of 2002 to March of 2004. The NDWAC presented the final report to the Administrator on May 19, 2004. The report, entitled National Drinking Water Advisory Council Report on the CCL Classification Process to the U. S. Environmental Protection Agency provides a detailed summary of the questions considered by the NDWAC, the analyses conducted to explore the questions, key points discussed, and the NDWAC's recommendations and rationale for the recommendations. The report is available at http:// www. epa. gov/ safewater/ ndwac/ council. html.

Additionally, after publication of the final 1998 CCL, EPA began collecting occurrence data and conducting research on the CCL contaminants. Data collection efforts include assessing 23 the occurrence of contaminants in public water systems through the Unregulated Contaminant Monitoring Regulation ( 64 FR 50556), as well as evaluating occurrence data from national surveys and considering State level contaminant occurrence information. Research efforts focused on obtaining the information needed to characterize the adverse health effects of contaminants, drinking water treatment options, and the development of analytical methods to detect contaminants in drinking water.

On July 18, 2003, EPA announced its final determinations for a subset of contaminants on the 1998 CCL ( 68 FR 42898), which concluded that sufficient data and information were available to make the determination that a regulation was not appropriate for nine contaminants. The Agency is preparing to make the second round of regulatory determinations in the 2006 time frame using the data collected from these activities.

Docket ID  Part #

Comment: 0025 1 Inadequate attention to host factors in the generation of microbial disease by the notice.

Response: The Agency agrees that the consideration of host factors in microbial disease as an area that should receive more attention. The National Drinking Water Advisory Council report also provides some discussion on this topic. As the Agency develops the CCL process for microbial contaminants we will evaluate approaches to account for host factors and the generation of microbial disease.

Docket ID  Part #

Comment: 0025 2 Inadequate attention to disease sequelae. Nowhere in the regulation is disease sequelae mentioned. It is not adequate to perform risk assessment solely on gastroenteritis as the disease entity. . . As part of the an information collection rule or by contact, the EPA should enhance its knowledge of disease sequelae of gastrointestinal pathogens.

Response: The Agency agrees that the consideration of disease sequelae in the selection of microbial contaminants as an area that should receive more attention. The National Drinking Water Advisory Council report also provides some discussion on this topic, particularly in the evaluation of microbial contaminants as they move from a preliminary CCL to the CCL. As the Agency develops the CCL process for microbial contaminants we will evaluate approaches to account for disease sequelae of pathogens. 24 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.4 Other Docket ID  Part #

Comment: 0023 3 States believe that a consistent national approach would be more appropriate and encourage EPA to make regulatory determinations on these contaminants as soon as the necessary information becomes available, regardless of the timing of the next round of CCL regulatory determinations.

Response: SDWA does not limit EPA to issuing regulatory determinations every five years; EPA intends to make early regulatory determinations where necessary and appropriate. 25 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.4 Other 3.4.1 Update CCL 2 Research Docket ID  Part #

Comment: 0017 3 Carryover of CCL Contaminants: EPA specifically requested comment on carrying over the 51 contaminants presented in the 1998 initial CCL to the CCL 2. We recommend that all occurrence and health risk data be considered when making the determination of whether to carry over a contaminant from the previous CCL.

Response: EPA does not believe that it is appropriate to create a new CCL, or remove any contaminants from the CCL, at this time. Where there is adequate information about a particular contaminant, EPA plans to make a regulatory determination which will either remove that contaminant from the CCL or start a national rule making process to set a national primary drinking water regulation.

Also, see the response to the comment 0019/ 20 part 23, and 0019/ 20 part 24 under section <IP_ADDRESS>.

Docket ID  Part #

Comment: 0018 6 4. AMWA suggests EPA include the status of research on CCL contaminants that have been on the list since 1997 in the final CCL 2 and future list proposals. EPA should use the proposed CCL and future proposals as an opportunity to clearly communicate the progress and results of research on CCL contaminants.

Response: See the responses to the comments 0019/ 20 part 23, under section <IP_ADDRESS>. and 0017 part 3, under section 3.4.1.

Docket ID  Part #

Comment: 0018 7 In addition, EPA should inform the public about its progress in considering information about pesticides under the Federal Insecticide Fungicide and Rodenticide Act ( FIFRA). In developing the first CCL, EPA indicated that it was deferring information under FIFRA ( 63 Federal Register 10284, but did not mention the status of this information in this notice or in the development of the CCL 2.

Response: As discussed in the draft CCL 2 notice ( 69 FR 17406), EPA plans to consider the deferred pesticides in the context of an improved approach for selecting contaminants for future CCLs ( CCL 3). This will enable the Agency to consider these contaminants in a consistent, reproducible manner with a wide range of other contaminants. In this regard, it is important 26 to note that EPA may conduct research, and make regulatory determinations for any unregulated contaminant not on today's CCL ( see SDWA section 1412( b)( 1)( B)( ii)( III)). Thus, the Agency has the authority to act as necessary to protect public health as new information becomes available.

Docket ID  Part #

Comment: 0024 3 It would be appropriate for the EPA to update the public on the status of its regulatory efforts on these contaminants on a contaminant by contaminant basis.

Response: See the responses see to the comments 0019/ 20 part 23, under section <IP_ADDRESS>. and 0017 part 3, under section 3.4.1. 27 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.4 Other 3.4.2 Regenerate CCL 1 Docket ID  Part #

Comment: 0017 4 If updated health and occurrence information does not support concerns for contaminants on previous CCL lists, then we recommend that previous CCL lists be reentered into the CCL process at the CCL " Universe" stage to determine if further screening to the future CCL lists would be warranted.

Response: EPA does not believe that it is appropriate to create a new CCL, or remove any contaminants from the CCL, at this time. Where there is adequate information about a particular contaminant, EPA plans to make a regulatory determination which will either remove that contaminant from the CCL or start a national rule making process to set a national primary drinking water regulation. Also see response to comment 0019/ 20 part 24 under <IP_ADDRESS>.

Docket ID  Part #

Comment: 0019/ 20 22 EPA explicitly requested comment on the agency's decision to carry over the remaining 51 contaminants from the 1998 CCL1 to CCL 2. AWWA believes each CCL should be considered anew. It should be regenerated and, if existing contaminants warrant inclusion, they will emerge thorough the selection process rather than by default. Existing contaminants that do not make it on to the list could be incorporated by nomination if warranted. AWWA is very concerned that the lack of a robust CCL process has resulted in the promulgation of a placeholder CCL and, in doing so, the agency has set an unacceptable precedent, of rolling over contaminants from a previous CCL. AWWA recommends EPA evaluate whether available information actually suggests that inclusion of all the remaining CCL1 contaminants on CCL 2 targets drinking water contaminants that pose the most significant potential public health concerns. AWWA expects that if EPA were to evaluate the data currently available, at least some contaminants currently included in CCL1 would not be listed on CCL 2. The agency's current approach may result in misdirection of scarce research funds for the next six years, not only by the agency but also by others that look to the agency for guidance on research priorities. This approach may also mislead drinking water utilities as they conduct monitoring, select treatment processes, and make other capital investments and operational decisions that affect water quality.

Response: See the response to the comment 0017 part 4, under section 3.4.2 above. 28 3.0 Comments on Development of the Draft Drinking Water CCL 2 3.4 Other 3.4.3 Add NDMA and enterotoxigenic Escherichia coli ( E. coli) to CCL Docket ID  Part #

Comment: 0017 5 For example, we recommend that five of the chemicals ( 1,1,2,2 tetrachloroethane, 1,1 dichloropropene, 1,3 dichloropropane, 1,3 dichloropropene, and 2,2, dichloropropane) that were carried over from the initial CCL to the CCL 2 be reconsidered. These chemicals were monitored as part of the Unregulated Contaminant Monitoring Rule ( UCMR) monitoring during 2001 through 2003. In the state of Texas, the TCEQ has had a total of 54,363 monitoring results for these organic chemicals, and none were ever detected.

Response: See the response to the comment 0017 part 4, under section 3.4.2 above.

Docket ID  Part #

Comment: 0018 5 3. AMWA suggests EPA add N nitrosodimethylamine ( NDMA) to the CCL. Research has shown NDMA is a disinfection by product of chloramination. As more systems turn to chloramination in anticipation of the Stage 2 Microbial and Disinfection Byproducts ( M/ DBP) Rules, understanding more about this " new" DBP is critical, since its occurrence in drinking water may increase. Additionally, EPA classifies NDMA as a probable human carcinogen.

Therefore, listing NDMA on the CCL would fit the SDWA's criteria of being a contaminant that has an adverse effect on public health, and is likely to occur in drinking water. Having NDMA on the CCL will enable EPA to then justify further research on this contaminant.

Response: There is already a substantive body of health effects research that the Agency has relied upon to classify NDMA as a " probable human carcinogen" ( USEPA, 1993). The key information gap for this contaminant relates to occurrence in public water system distribution systems. Some initial research has been conducted in this area and the Agency plans to collect more comprehensive occurrence information as part of the upcoming national survey of key unregulated contaminants under section 1445( a)( 2). EPA will consider NDMA for listing as part of the CCL 3 process, which will be a comprehensive reevaluation of the contaminants considered for the CCL.

Docket ID  Part #

Comment: 0019/ 20 31 AWWA recommends that the chemical contaminant N nitrosodimethylamine ( NDMA) and the microbial contaminant enterotoxigenic E. coli be included on CCL 2. Both contaminants were considered in developing CCL1, but were not listed. Substantial NDMA research has been conducted since 1998 and evidence exists for its occurrence in U. S. drinking waters at 29 levels of health concern. NDMA is certainly an emerging issue and is precisely the type of contaminant the CCL process was intended to capture. Indeed, EPA has already allocated substantial resources to NDMA analytical methods development under the aegis of the CCL ( EIMS entry #' s 18339, 62563). Similarly, listing of enterotoxigenic E. coli is appropriate at this time and would be consistent with the NDWAC Work Group's recommendation that microbes known to have caused waterborne disease outbreaks receive serious consideration for placement on the CCL.

Response: See the responses to comments 0018 part 5, under section 3.4.3 and 0019/ 20 part 32, under section 3.4.3.

Docket ID  Part #

Comment: 0019/ 20 32 AWWA recommended that enterotoxigenic Escherichia coli ( E. coli) be considered for CCL 2. If the agency rejects inclusion of enterotoxigenic E. coli it will repeat the inconsistent decision logic underlying CCL1 ( i. e., some contaminants were excluded from CCL based on susceptibility to drinking water treatment while others were not) identified in AWWA's comments on the CCL1 proposal.

Response: EPA will be considering this microbe as part of the revised and expanded CCL 3 review process. The Agency believes that this will be a more appropriate and effective approach for evaluating this bacteria in comparison to a wide range of other microbes that will be considered under the broader analytical approach recommended by the NRC and NDWAC.

Docket ID  Part #

Comment: 0019/ 20 33 The available information suggest that we have some indication of health effects and that we know that E. coli survives in water and that there has been an outbreak that is likely to be caused by ingesting drinking water. Therefore enterotoxigenic E. coli should be added to the CCL. AWWA requests that the agency clearly articulate why enterotoxigenic E. coli is not added to CCL 2 if the CCL 2 list is finalized without its inclusion.

Response: See the response to the comment 0019/ 0020 part 32, under section 3.4.3 above. 30 4.0 Comments on the NRC's Recommended Approach for Developing Future CCLs 4.1 Comments on Screening of the Universe of Contaminants 4.1.2 Comments Critical of the NRC's Approach for Screening the Universe of Contaminants Docket ID  Part #

Comment: 0018 8 EPA should maintain a clear focus on contaminants that are likely to occur in drinking water and likely to cause a public health concern. For this reason, AMWA believes it is counterproductive to consider the entire universe of existing chemicals. Because of tight budgets and limited research dollars, EPA should focus research on substances where information is available and quality of data is high.

Response: EPA agrees that the CCL process, as specified by the SDWA, should consider those contaminants with the potential to occur in drinking water and those with the potential to cause adverse health effects. EPA is currently evaluating data sources to identify contaminants for consideration in the next CCL. As the Agency develops the next CCL and evaluates the approaches recommended by the National Academy of Sciences and the National Drinking Water Advisory Council it will also consider the availability of information and the quality of that information.

Docket ID  Part #

Comment: 0019/ 20 60/ 61 How contaminants are evaluated and chosen to move from one category to another ( e. g., Universe to PCCL) is very complicated. The approaches taken are critical since the contaminants that are chosen for the PCCL and therefore, the CCL, will be strongly influenced by the algorithms and methods chosen. So while the NRC approach is attractive and well thought out, it is still a theoretical approach that is not ready for application without a substantial investment of time and resources. Moreover, given the agency's limited resources and compressed time frame, it is reasonable to question the value added nature of the PCCL concept in near term iterations of the CCL process.

The NRC paradigm should be established as an ultimate objective for the evolution of the CCL process. EPA should include the NRC's three steps ( i. e., universe to PCCL to CCL), but the agency should better define the process to describe all the interim steps, which will be required to actually implement the CCL process.

Response: EPA is evaluating and testing the National Research Council's approach, as refined in the National Drinking Water Advisory Council recommendations ( 2204). The Agency will consider this comment during those evaluations. Many EPA programs rely on screening techniques to identify priorities. EPA is currently evaluating alternative approaches for screening criteria in addition to those recommended by the National Drinking Water Advisory Council and will seek external input on these evaluations.

EPA is currently in the process of identifying and describing the interim steps to develop the CCL. As described in the National Drinking Water Advisory Council recommendations 31 these steps may include evaluating alternatives, seeking expert input and review, and documenting each step of the CCL selection process. 4.0 Comments on the NRC's Recommended Approach for Developing Future CCLs 4.2 Comments on the Approach for Compiling the Preliminary CCL ( PCCL) 4.2.2 Comments Critical of the NRC's Approach for Compiling the PCCL Docket ID  Part #

Comment: 0019/ 20 44 AWWA does not believe that the NRC recommendation of going from a universe to a PCCL is of any particular use at this time. NRC recommends this winnowing to the PCCL no matter how the CCL is developed.

Response: See the response to the comment 0019/ 20 part 60 and 61, under section 4.1.2. 32 4.0 Comments on the NRC's Recommended Approach for Developing Future CCLs 4.3 Comments on the Approach for Contaminant Selection from the PCCL to the CCL 4.3.2 Comments Critical of the NRC's Approach for Contaminant Selection from the PCCL to the CCL Docket ID  Part #

Comment: 0024 2 Now that the EPA has experience with the first CCL and monitoring data from the Unregulated Contaminant Monitoring Rule, we recommend that the EPA perform a sensitivity analysis to refine its occurrence screens ( found in a water system serving a population of 100,000 or more, found in at least 10 small public water systems, TRI release estimates, production volume, etc.) to eliminate potential contaminants that are not " known or anticipated to occur in public water systems at a level of public health concern."

Response: In addition to evaluating the National Academy of Sciences and National Drinking Water Advisory Council recommendations the Agency will perform sensitivity analyses in addition to other analytical tools to refine occurrence screens for the CCL selection process. 33 4.0 Comments on the NRC's Recommended Approach for Developing Future CCLs 4.4 Comments on the Virulence Factor Activity Relationships ( VFARs) for Assessing Emerging Waterborne Pathogens 4.4.1 Comments Supporting the NRC's Approach of Using the Virulence Factor Activity Relationships ( VFARs) for Assessing Emerging Waterborne Pathogens Docket ID  Part #

Comment: 0017 7 The virulence factor activity relationship ( VFAR) appears to be a potentially useful tool for future CCLs.

Response: EPA agrees and is evaluating this tool for future CCL development. 34 4.0 Comments on the NRC's Recommended Approach for Developing Future CCLs 4.4 Comments on the Virulence Factor Activity Relationships ( VFARs) for Assessing Emerging Waterborne Pathogens 4.4.2 Comments Critical of the NRC's Approach of Using the Virulence Factor Activity Relationships ( VFARs) for Assessing Emerging Waterborne Pathogens Docket ID  Part #

Comment: 0017 8/ 9 However, while gene mapping is scientifically sound, it may not offer practical solutions to immediate concerns regarding waterborne disease. In addition, it is widely recognized that this particular tool, while promising, still needs further development and testing before incorporation into the CCL process.

We recommend that the EPA consider practical methods for improving the correct, timely identification of actual waterborne illness.

Response: EPA agrees that gene mapping and the virulence factor activity relationship concepts will require further development and testing before it can be incorporated into the CCL process. The National Drinking Water Advisory Council, which noted that these technologies may not be available for the next CCL, provided recommendations that use currently available data to select microbial contaminants for the CCL. The Agency has met with experts in microbial disease and genomics in workshops and at drinking water conferences to discuss how to include genomics data in the future CCLs. The Agency has also formed intra agency workgroups to develop guidelines on the use of genomic data in the future. 35 4.0 Comments on the NRC's Recommended Approach for Developing Future CCLs 4.5 Other Docket ID  Part #

Comment: 0018 9 EPA has also obtained data about potential drinking water exposure to pesticides regulated under the Food Quality Protection Act ( FQPA). This information could be used in an initial screening of substances for the CCL.

Response: EPA's Office of Ground Water and Drinking Water is seeking the input of other offices within EPA to ensure that sources of available data on drinking water occurrence are used in the CCL selection process.

Docket ID  Part #

Comment: 0018 10 OGWDW should work with OPPT to ensure that the screening protocol includes a drinking water exposure component and use this information to inform future CCLs.

Response: EPA's Office of Ground Water and Drinking Water is seeking the input of other offices within EPA to ensure that sources of available data on drinking water occurrence are used in the CCL selection process.

Docket ID  Part #

Comment: 0018 11 On the microbial side, EPA should focus on microbial agents implicated in disease by consulting with CDC and public health agencies that have public health surveillance programs for waterborne disease.

Response: EPA anticipates working with agencies, like the CDC, to collect public health and surveillance information to identify pathogens associated with water borne disease for consideration in the CCL process.

Docket ID  Part #

Comment: 0018 12 Because contaminants on the CCL are placed there to help inform research and to be considered for regulatory determination under the SDWA, EPA has at least two options on how to address this issue:

1) Obtain the missing data so that the contaminants can be screened for inclusion on the CCL. ( This, however, may not be the best use of limited resources). 36 2) Defer the decision on the contaminant until such data is available from other sources, unless there is a strong indication from the known parameters about the contaminant that is likely to pose a health concern in drinking water.

Response: EPA plans to explore alternative approaches for addressing contaminants with missing data in selecting future CCL candidates. 37 4.0 Comments on the NRC's Recommended Approach for Developing Future CCLs 4.5 Other 4.5.1 CCL Transparency Docket ID  Part #

Comment: 0018 2 2. AMWA supports the need for a transparent process. AMWA agrees that the CCL classification process should be transparent so that both the regulated community and the public can understand it.

Response: The Agency agrees with the commenter that the CCL process should be understandable to the regulated community and interested stakeholders. The Agency anticipates developing approaches to clearly communicate the how the CCL process selects contaminants.

Docket ID  Part #

Comment: 0018 3/ 4 AMWA believes expert judgement is as critical to the listing process as it is to its transparency.

AMWA also supports the NDWAC work group's recommendations that external experts should be involved in evaluating the CCL classification process in several key areas including:

° The identification of screening criteria; ° The assessment of an algorithm's training data set; ° The evaluation of a prioritized list of contaminants; ° The data quality review; and ° The review of the proposed CCL, prior to its publication in the Federal Register.

Response: EPA agrees that expert judgment is important component to the CCL selection process and is evaluating approaches to incorporate and document expert input and review in developing the CCL process. We will consider these ideas as we develop the CCL process.

Docket ID  Part #

Comment: 0019/ 20 11 Transparency is a critical aspect of the CCL process and maintaining transparency is of paramount concern for those involved in putting forth recommendations for improving the process. However, the agency perspective on the NRC report appears to be based on an underlying assumption that decisions based on expert judgment are not transparent. This assumption has driven the CCL process toward automation and use of sophisticated tools that are not necessarily valid. AWWA believes that the automation and use of sophisticated computer models, programs, etc., does not change the fact that underlying the entire process is expert judgement. In fact, AWWA believes that the utility of the process proposed by NRC is as a means of applying data processing tools to screen a large number of contaminants and 38 not in imparting transparency.

All work done on the evaluation of methods for creating the CCL reach the conclusion that expert judgment will be a critical part of any CCL development ( e. g., NRC 2001, NDWAC 2004). AWWA believes that the CCL process should be characterized as an expert process. Expert judgment does not preclude transparency. In fact, an expert process, especially one supported by good documentation and decision support systems, can be more transparent than an algorithm approach where considerable expert judgment is buried deep within.

To maintain transparency, the role of expert judgment in the process needs to be explicitly defined both relative to where and when the experts will intervene and in which processes. Explicit protocols and rules for the expert selection, deliberations, and decision making need to be clearly documented. The transparency of any expert judgement process is only as clear as the quality of the documentation supplied regarding the underlying expert judgements and the way the algorithms have been developed to support that expert judgement. Rules for the experts will help in transparency and in improving the reproducibility of the process.

Response: EPA agrees that transparency and expert judgment are critical components of the CCL selection process. Any process implemented for selecting the CCL will incorporate both at each step. The process will be documented, and the documentation available for public scrutiny.

Docket ID  Part #

Comment: 0019/ 20 37 It is important that the agency realize that expert processes can be very transparent, and the perception that the CCL1 process was not transparent is not a failing of expert processes, but may have been a failing of the CCL1 process as implemented. The NRC report on which the NDWAC Work Group CCL process recommendation is based appears to AWWA to reflect an over reaction to the perceived lack of transparency in the CCL1 process.

Response: EPA believes that the NRC and NDWAC recommended processes are indeed expert processes, but are structured to allow broader consideration of potential drinking water contaminants. Any process for CCL selection will include experts, and will be made transparent.

Docket ID  Part #

Comment: 0019/ 20 38/ 39 The CCL process should include multiple mechanisms to actively engage interested parties and experts with information needed in the CCL process.

Some mechanisms include:

A. Maintaining an active CCL process that is a routine component of Office of Water activity, rather than a periodic ( i. e., once every 5 years) burst of activity. B. Active surveillance of the peer reviewed literature. As part of its on going work, EPA OGWDW should undertake regular surveillance of appropriate literature to monitor new 39 contaminants, new methods, and new health effects data. C. Involvement in ongoing symposia and profession meeting series on relevant topics.

Response: EPA agrees that the CCL process should involve interested parties and experts. The Agency considers the CCL process an integral component of its activities and actively performs literature reviews, sponsors and participates in forums on relevant topics, and monitors the development of new data and information. While the result appears only every 5 years, activity relating to CCL development and analysis is part of EPA's drinking water program on an ongoing basis. EPA is evaluating approaches to include interested parties in the CCL process. The formation and support of the National Drinking Water Advisory Council CCL Classification Process Work Group is one example of EPA's commitment to engaging interested parties in developing the CCL process. The Agency held a public meeting on September 15, 2004 to present the status of the Regulatory Determination 2 and efforts to refine the CCL selection process. The Agency anticipates informing and seeking the input of interested parties as the development of the CCL process progresses. As the Agency evaluates the National Drinking Water Advisory Council Report recommendations, which are similar to the commenters concerns, we will consider approaches to improve actively engage interested parties. 40 5.0 Implementation of NRC's Recommendations 5.2 Comments on the Ongoing Analysis of the Classification Approach 5.2.1 Organizing and Extracting Data <IP_ADDRESS> Comments Supporting EPA's Approach for Organizing and Extracting Data for the CCL Universe Docket ID  Part #

Comment: 0019/ 20 55/ 56 In principle, AWWA agrees with the workgroup's perspective as excerpted. AWWA believes that the data quality criteria for each step in the CCL process should be directed by the objectives of the process overall and by that specific step in the CCL process.

An expert workshop would be one way to explore the above questions in a timely manner. AWWA is interested in participating in ongoing development and application of a quality system for the CCL process that will not eliminate the usefulness of all available data but will still insist on data of appropriate quality for each step in the CCL process.

Response: The Agency agrees that the types of information and data need to be described and documented so that interested parties can understand how they are used in the CCL process. The Agency looks forward to AWWA's continued interest in developing the CCL process and more specific comments on data of appropriate quality. See response to comment 0019/ 20 part 10 under section <IP_ADDRESS>.

Docket ID  Part #

Comment: 0019/ 20 57 EPA should identify compilations of information on potential contaminants. These compilations should be evaluated and characterized. If they contain relevant information and the data are of adequate quality, then they could be used to compile the CCL universe and develop data needed to determine contaminant attributes. EPA initiated such an effort in support of the NDWAC CCL Work Group process.

Response: EPA continues to identify and evaluate compilations of data on potential contaminants from the initial efforts conducted during the National Drinking Water Advisory Council CCL CP Work Group process.

Docket ID  Part #

Comment: 0019/ 20 58 Some potential activities EPA could pursue that could be effective in identifying emerging contaminants include:

1. Regular review of toxic release data to identify contaminants not previously observed or being released in large quantities. 2. Regular review of chemical production data bases coupled with QSARs. 3. Repeating EPA's 1997 query of commercial and state laboratories that conduct environmental monitoring for the unregulated contaminants that are appearing in the 41 samples they process. 4. Developing a network of academics ( such as those that research analytical methods development) in order to detect new contaminants in the environment. 5. Developing a process for regular review and evaluation of clinical data perhaps in conjunction with CDC.

Response: EPA is currently evaluating how to use chemical production and toxic release data in the CCL process. The additional recommended activities are also being assessed as on going surveillance activities to identify contaminants for consideration in the CCL process. As surveillance activities are developed for the CCL process these activities will be considered with other options for identifying potential contaminants. 42 5.0 Implementation of NRC's Recommendations 5.2 Comments on the Ongoing Analysis of the Classification Approach 5.2.1 Organizing and Extracting Data <IP_ADDRESS> Comments Critical of EPA's Approach for Organizing and Extracting Data for the CCL Universe Docket ID  Part #

Comment: 0017 10 In addition, we believe that EPA should consider existing or developing risks, rather than be restricted to historical lists developed in the initial rule.

Response: EPA recognizes that it is important to identify new and emerging contaminants as part of the CCL selection process. The Agency is evaluating a process that will incorporate the nomination of contaminants and will undertake activities to enhance surveillance of contaminants for future CCLs.

Docket ID  Part #

Comment: 0019/ 20 52 The CCL effort should access existing information systems from EPA and from other federal agencies. Lists of recommended data sources are presented below relating to the key issue: the appropriate data to be used. Data is the foundation of the process and existing EPA information systems do not currently meet the needs of the CCL process.

This following list contains information sources that could be extracted in an automated manner ( The list is in alphabetical order.).

° ATSDR CERCLA Priority List ° ATSDR Internet HazDat  Site Contaminant Query ° Carcinogenic Potency Project ° ChemIDplus  Chemical Identification Plus ° EAFUS Database  Everything Added to Food in the United States ° EDPSD  Endocrine Disruptor Priority Setting Database ° GRAS  Generally Regarded As Safe Substance List ° HPV  High Production Volume Chemical List ° IARC  International Agency for Research on Cancer Monographs ° ITER Database  International Toxicity Estimates for Risk ° JMPR ( Joint Meeting On Pesticide Residues  Inventory through 2002)  WHO, FAO ° Master Summary Table for HPV Chemical Hazard Data Availability Study ° National Reconnaissance of Emerging Contaminants  USGS Toxic Substances ° Hydrology Program ( NREC) ° National Stream Quality Accounting Network ( NASQAN) ° NCOD  National Drinking Water Contaminant Occurrence Database Unregulated Contaminant Monitoring Rule UCMR ° Pesticides Pilot Monitoring Program  USGS/ EPA ° Risk Assessment Information System ( RAIS)  Department of Energy ° Toxicity Criteria Database  California Office of Environmental Health Hazard Assessment ° UCMR  Round 2 ( SDWIS/ FED)  Unregulated Contaminant Monitoring 43 Response: EPA is in the process of evaluating data sources for possible inclusion in the CCL process but disagrees with the commenter that EPA information sources do not meet the needs of the CCL. The sources AWWA identified will be considered as part of this evaluation.

Docket ID  Part #

Comment: 0019/ 20 59 The exclusion of these data or the demotion of these data to a secondary source will result in a loss of a great deal of useful important information. EPA needs to address how the text data and information will be monitored and incorporated into the process.

Response: EPA is currently evaluating options for including text data and information into the CCL process and will consider these comments in developing future CCLs. 44 5.0 Implementation of NRC's Recommendations 5.2 Comments on the Ongoing Analysis of the Classification Approach 5.2.3 Classifying Contaminants from the PCCL to the CCL <IP_ADDRESS> Comments Supporting the Ongoing Approach Used for Classifying Contaminants from the PCCL to the CCL Docket ID  Part #

Comment: 0019/ 20 45 Experts need to be involved in developing the training data set, and then, once the training set is chosen, experts need to be involved in scoring the attributes for the training data set.

Response: EPA recognizes the need to involve experts in the CCL process. The Agency will consider approaches to incorporate expert input during the selection of contaminants for the CCL from the preliminary PCCL as noted by the commenter.

Docket ID  Part #

Comment: 0019/ 20 46 In developing the algorithm, it should reflect and document the same logical process experts would use if an expert process were employed. To achieve this objective, development of the algorithm will need to reflect an ongoing effort to capture and mirror the decision making logic of an expert process.

Once an algorithm is given parameters and initial runs appear adequate to the technicians working on this portion of the analysis, experts should be involved in evaluating the classification abilities of the algorithm.

Response: The Agency will consider this comment as it evaluates the National Drinking Water Advisory Council recommendations on how to move from a preliminary CCL and select contaminants for the CCL. As the Agency develops the CCL process there will be a need for expert involvement. EPA is considering approaches such as public meetings and expert workshops to facilitate expert input.

Docket ID  Part #

Comment: 0019/ 20 48 AWWA recommends using a Delphi like process and then comparing the expert decision for each test contaminant with the decision from the algorithm.

Response: EPA will consider this approach as it develops the CCL process, particularly in the selection of CCL contaminants from a preliminary CCL.

Docket ID  Part # 45 Comment: 0019/ 20 49 Once the process and algorithms are validated, experts still need to be involved in evaluation of the draft list emerging from the CCL classification algorithm.

Response: EPA agrees that expert involvement is a necessary component of any proposed CCL process, and plans to involve experts at key milestones in the CCL development process.

Docket ID  Part #

Comment: 0019/ 20 51 The NDWAC CCL Workgroup included a process for microbial contaminants that is a very pragmatic approach to filtering and identifying pathogens for the CCL. It involves specific expert judgments that are applied in a systematic manner. This approach emerged from a careful review of the objectives and realities of the available data. AWWA believes this is an appropriate direction and a parallel approach for chemical contaminants could be developed and would, if properly developed, provide the necessary framework for developing future iterations of the CCL chemical contaminant selection process.

Response: EPA agrees that the microbial approach to identify CCL microorganisms recommended by the National Drinking water Advisory Council Differs from the National Academy of Sciences recommendations. As the Agency evaluates the CCL process it will consider how a parallel approach for chemical contaminants might be developed. One area of divergence, however, is that the nature and volume of the available information for chemical and microbial contaminants are vastly different. For microbes, there are few compilations of data that identify the occurrence and effects of microbes, while for chemicals there are numerous sources. While the National Drinking Water Advisory Council recommended that the approach for microbes be based on the nature and type of data available it made a similar recommendation for chemical contaminants and recognized that those differences would allow a process to select chemical contaminants that more closely follows the National Academy of Sciences recommendations.

Docket ID  Part #

Comment: 0019/ 20 64 Once the attribute is scored, it is difficult to factor in the effects of using different underlying data elements. Therefore, EPA needs to establish an understanding of the attributes, their data elements and the methods for scoring the attributes. This clarification should also evaluate the effects of using different data elements to score the attributes.

Response: EPA agrees that evaluation of input data and approaches for attribute scoring are an important components of the CCL classification process recommendations. The Agency will consider a range of analyses with available data to evaluate attribute scoring approaches as well as alternative approaches to characterize and evaluate contaminants.

Docket ID  Part # 46 Comment: 0019/ 20 65 In developing the CCL process it is essential that EPA identify what critical information is necessary to adequately characterize occurrence and health effects for any contaminant. What this critical information is should be determined through expert processes, and reflect ( 1) information required by experts evaluating contaminants for inclusion on the CCL and ( 2) appropriate for the specific analytical tools the agency uses to produce the CCL ( i. e., the screening and classification algorithms).

Response: EPA will consider this recommendation as it evaluates and refines the CCL process. The Agency is evaluating the nature and types of information available to characterize occurrence and health effects. As the evaluations proceed the Agency will seek expert input on the evaluations and the information identified by those evaluations.

Docket ID  Part #

Comment: 0019/ 20 66 EPA can still focus resources on generating the data missing for any contaminants. It can then evaluate them in future CCL efforts or nominated them for immediate consideration.

Response: EPA is considering options for addressing missing data for potential drinking water contaminants. 47 5.0 Implementation of NRC's Recommendations 5.2 Comments on the Ongoing Analysis of the Classification Approach 5.2.3 Classifying Contaminants from the PCCL to the CCL <IP_ADDRESS> Comments Critical of the Ongoing Approach Used for Classifying Contaminants from the PCCL to the CCL Docket ID  Part #

Comment: 0019/ 20 63 AWWA proposes a simplified approach that will eliminate some of the major complications associated with the NRC three step ( i. e., Universe to PCCL to CCL), five attribute CCL process. For each contaminant that is included in the PCCL, the existing attributes should be combined along two simple axises: health effects and occurrence ( or exposure).

Response: EPA is evaluating the feasibility of implementing the National Drinking Water Advisory Council recommendations on the National Academy of Sciences' three step approach. It is important to note that the National Drinking Water Advisory Council also recommended that EPA consider approaches that may be appropriate for the next CCL and modify or refine the process for future CCLs as information is garnered in successive CCLs. As the Agency develops the CCL process for the next publication it will consider the commenters proposal. 48 5.0 Implementation of NRC's Recommendations 5.2 Comments on the Ongoing Analysis of the Classification Approach 5.2.4 The VFAR Concept and Classifying Microorganisms <IP_ADDRESS> Comments Critical of the Use of the VFAR concept for Classifying Microorganisms Docket ID  Part #

Comment: 0019/ 20 12/ 13/ 14 Virulence factor activity relationships ( VFARs) are proposed as an alternative to identifying and characterizing microbiological contaminants for which there is little information. Molecular tools including genomics, microarray technologies, and VFARs are certainly powerful tools that should be developed with the CCL in mind. However, although these are advanced technologies, their application to environmental samples is not sufficiently advanced to have an immediate impact on the CCL process. The disproportionate emphasis on VFARs in the proposal is a cause for concern and suggests that the agency is pinning its hopes on the latest novel technology. The rapidly evolving nature of this technical field and the apparent high importance placed on the VFAR approach by the EPA warrants a somewhat detailed and technical response. The use of phrases such as " sophisticated computer software program" and lack of details explaining exactly how technologies will be applied suggests that the agency may have unrealistic expectations of what can be achieved with emerging technologies.

Despite the extensive discussion of VFAR in the Federal Register notice, the actual mechanisms by which VFARs, microarrays, and genomic technologies will be applied to the CCL process are not clear. The agency recognizes that the use of the VFAR approach to identify potential waterborne pathogens " would require a multi year commitment and significant cooperation and collaboration by EPA and other participating organizations." However, by placing such a prominent focus on this technology in the current notice, the agency will precipitate a wholesale dive into the technology by researchers looking for the next novelty. This will result in a series of reports and papers that demonstrate the utility of microarrays to detect a few select pathogens, or to discriminate between strains of a particular pathogen in the laboratory, but with no clear application to the CCL process. As with PCR, the industry may be presented with a wonderful detection technology with great sensitivity, specificity, high throughput, etc, but no consistent way to apply it to environmental samples. PCR is still not in widespread use for environmental samples because no effort has been expended to overcome problems of inhibition, sample matrix effects, very low concentrations of genomic material in very large sample volumes, techniques for sample size reduction, applicable extraction methods, etc.

Many of the problems that have plagued the application of PCR to drinking water will also have a significant negative impact on the use of VFARs and microarrays. There needs to be a greater effort on developing methods to overcome sample processing problems for the application of molecular methods to environmental samples, particularly water samples. For example, recently completed Water Environment Research Foundation ( WERF) funded projects addressed sample processing but did not overcome all problems ( Higgins, DiGiovanni, and Harwood, 2002). Molecular tools have proved very useful in the clinical and food industries where the challenge is to detect relatively large numbers of pathogens in relatively small sample volumes of tissue, fluid, or food product. However, the application of such tools within the drinking water field presents the converse situation  typically very low concentrations of target organisms in very large sample volumes ( 10   1,000 L or greater). 49 Response: EPA's agrees with the commenter that molecular and genomic tools are powerful and that approach may offer significant opportunities for identifying emerging microbial contaminants in the future. However, it may not be sufficiently developed in time for the next CCL. The discussion of the process of bioinformatics research was to inform the public of the steps in that process, not to suggest that the agency plans to focus solely on virulence factor activity relationships research to the exclusion of alternative microbial contaminant approaches that can be implemented in the short term. Preliminary research on virulence factor activity relationships conducted during the National Drinking Water Advisory Council Contaminants Candidate List Classification Process Workgroup suggested there may be complexities in developing virulence factor activity relationships that were not considered by the National Academy of Sciences in their recommendations. EPA will consider the commenters suggestions as the new information on genomic and molecular techniques becomes available for future application to microbial drinking water contaminant identification, but recognizes they may be well enough developed for the short term.

Docket ID  Part #

Comment: 0019/ 20 15 As stated above, there is a disproportionate emphasis on VFAR technology within this notice, but what happens if the VFAR approach does not bear fruit? What parallel approaches will be pursued along with VFARs? In the next to last paragraph of the proposal, EPA states that it will explore alternatives such as " an approach that would construct a microbiological universe, define microbiological attributes, and score the attributes." This does not give any indication at all of what this alternative approach might actually be and does not inspire confidence that the agency has actually thought through alternatives to VFARs.

Response: EPA has been working toward an alternative approach for selecting microbial contaminants for the next CCL based on the National Drinking Water Advisory Council recommendations. Their recommendation parallels the process for selecting chemical contaminants. The process may include identification of organisms and defining a microbial CCL universe of pathogens, criteria for screening the microbial universe to a PCCL based on the organism ability to transmit disease via water, and prioritizing PCCL contaminants for consideration for the next CCL based on the occurrence and adverse health effects. As the Agency continues to evaluate this approach it will consider the commenters suggestions and questions.

Docket ID  Part #

Comment: 0019/ 20 16 The NRC also recommended the exploration of microarray based technologies and these technologies should play a pivotal role in any future VFAR approach. Consequently, the agency should strive for accurate descriptions of technologies in public documents. Microarrays do not involve placing " tiny cells" on glass wafers. A more appropriate description may be that microarrays comprise a large number of nucleic acid probes attached to small glass or nylon wafers ( slides), and that these microarrays can range in capacity from a few hundred probes per array to many thousands per array. There are some examples of the use of microarrays for environmental and water related applications ( Straub et al., 2002; Call et al., 2003). Some biotechnology companies claim their microarrays can detect and identify 50 thousands of pathogens in a single reaction ( www. tekes. fi), but the actual utility for the detection of pathogens in water has not been demonstrated.

Response: See response to 0019/ 20 part 15 in section <IP_ADDRESS>.

Docket ID  Part #

Comment: 0019/ 20 17 It is not clear how the agency is proposing to use VFAR technology. An interpretation of the various sections in the notice leads to two possible applications:

1. Comparing the genetic sequence of a defined organism with unknown properties against the GenBank database to determine whether the organism possesses virulence genes; and 2. Using a microarray containing probes specific for a variety of virulence factors to screen nucleic acids extracted from environmental water samples.

Response: EPA remains cautiously optimistic about the future application of VFAR to microbial drinking water contaminant identification. Until further evaluation, it is not appropriate to speculate on exactly how VFAR would be used, rather, these two potential applications reflect possible future uses of VFARs for microbial contaminant identification.

Docket ID  Part #

Comment: 0019/ 20 18 The notice states " The VFAR principle can be described as comparing the gene structure of newly identified waterborne pathogens to pathogens with known genetic structures which have been associated with human disease." If we already know they are waterborne pathogens, why do we need to do a VFAR analysis? What else is VFAR going to tell us about these organisms?

Response: The virulence factor activity relationship concept would identify potential waterborne pathogens by comparing an uncharacterized organism's genetic sequence to a known sequence that is associated with human disease. In addition, characterizing a newly identified pathogen and the number of factors that could lead to human disease may also assist in prioritization among similarly identified organisms. It may also identify similarities within the gene structure of waterborne pathogens to genetic elements of pathogens associated with human disease, that have not been identified as waterborne. This could indicate the need to consider these organisms for future CCLs. Also see the response to comment 19/ 20 part 12, 13, and 14 in section <IP_ADDRESS> on the use of virulence factor activity relationships.

Docket ID  Part # 51 Comment: 0019/ 20 19 The notice also states that EPA searched for genetic sequences associated with virulence using the NCBI GenBank database, but " the data were in a form that proved difficult to use for this purpose." The information provided in GenBank is raw nucleic acid sequences so it is not clear why this would be unsuitable. What else would be needed other than nucleic acid sequences and what was the agency expecting to get from this piece of work?

Response: GenBank contains an immense amount of genetic sequence data on virulence related genes. GenBank is a very rich data source, but the overwhelming amount of data makes its interpretation very difficult. There is currently little standardization of gene identification or use of keywords, and there is significant overlap of genetic sequences. The specificity of keyword searches is problematic because of the uncertain relationship of sequences identified by keyword searches to expressed virulence of the pathogen in the host, and the function of shared sequences in different organisms. The genetic sequence similarity search results were often of little use in finding virulence genes in other organisms. Similarities were often found between partial sequences from the same gene in the same species in the database, or similarities were found with small areas of human or fruit fly genes. In many cases results included ribosomal or other structural genes which are unlikely to confer virulence. The lack of convincing identification of genes for bacteria and the complete lack of identification of viral gene function in GenBank makes interpretation of data difficult. When homologous sequences are identified some means of recognizing the significance of sequence matches is needed, particularly when the percentage of homology between two or more sequences is low, or only a portion of a gene aligns. The search for virulence genes using keywords proved to be very difficult on the GenBank database which is really a warehouse of mostly raw data. Many sequences are the result of different laboratories working to sequence the same gene, and some of these may overlap while others can be in different regions of the gene. The identification of the gene and its function is often based on genetic similarities to genes of known function in a family, but this does not guarantee the same function. This means that many genes that occur in GenBank entries are for hypothetical proteins or that they code for proteins with a putative function. This makes interpretation very difficult. Another difficulty with keyword searches on GenBank is that they return positive results not only when the keyword is a descriptor for a gene, but also when it appears in the title of the source paper or anywhere else in the text of the page that contains the data. Other databases of genomic information, for example The Institute for Genomic Research Comprehensive Microbial Resource ( TIGR), are much smaller than GenBank, but are more organized and easier to search.

Docket ID  Part #

Comment: 0019/ 20 20 In addition, the notice states that the agency is working with the NDWAC CCL Work Group to evaluate bioinformatics for extracting relevant information from databases and literature sources. The information " could provide the gene sequences needed to demonstrate the potential use of gene chip technology in performing VFAR analysis." It is not at all clear how such an effort will provide gene sequences.

Response: The results of bioinformatics searches conducted in support of the national Drinking Water 52 Advisory Councils's Work Group may identify virulence gene sequences in the available literature and data sources. By identifying gene sequences from previous and on going scientific sequences could be identified and one day used with gene chip technology to look for their presence in drinking water samples in outbreak situations. This type of evaluation across research efforts could provide additional information in feasibility of molecular and genomic techniques for future efforts.

Docket ID  Part #

Comment: 0019/ 20 21 The take home lesson is simply that just because an organism has the genes for a given cellular product does not mean it can use them for the predicted function.

Molecular detection tools applied to environmental samples do not necessarily correlate with presence of either actual organisms or viable organisms. Nucleic acids can persist inside dead organisms, exist free in the environment for considerable periods of time ( depending on the particular characteristics of the sample matrix), and will be detected by many molecular methods. An approach to avoid this limitation is to target RNA instead of DNA, but this presents even more sample processing problems than targeting DNA.

Finally, a question that the agency should ask and answer is, " What is the benefit of spending money to pursue the VFAR approach that provides a probability that a pathogen may cause adverse health effects, rather than getting a better handle on what is actually making people sick through increased public health surveillance?"

Response: We will consider these ideas as we develop the CCL process. It is also important to note that the virulence factor activity relationship is one tool in a tool box to identify evaluate pathogens for the CCL. The National Drinking Water Advisory Council specifically recommends that EPA works with other Agencies involved in public health surveillance, consider methods to identify waterborne disease and outbreak information, and confer with experts to identify new water related disease agents. As the Agency evaluates these recommendation it will also consider the commenters concerns. 53 5.0 Implementation of NRC's Recommendations 5.3 Other Docket ID  Part #

Comment: 0019/ 20 9 Given the current short time line and limited resource base for developing CCL 3, AWWA has identified the following tasks as critical path issues that must be addressed in order for the agency to actually begin to prepare CCL 3. Each of these issues must be addressed in the next 6 12 months:

° Determine how to involve experts in the CCL process. Identify the specific roles, tools, and points in the process in which the experts should have input. Identify specific points in the CCL process at which EPA will convene the experts and precisely what they will review, what decisions they will make, and how their input will be documented and communicated.

° Incorporate data quality. This means in depth discussion and evaluation of options for incorporating data quality into the CCL process. Options should be tested and evaluated. The process should lead to reporting on challenges, limitations, and specific recommendations for the incorporation of data quality into the CCL process.

° Continuous evaluation of data sources. EPA has begun this effort. Proposed information sources need to be reviewed in depth and documentation developed for availability of relevant data for the CCL process.

° Select and characterize contaminant attributes. Develop recommendations for research that needs to be done so that the attributes and the data elements are better understood. These may include the development of scales and scoring protocols for the attributes and the effects of using different data elements to score the same attribute. Identify different ways of combining different data elements to score each attribute.

° Address process performance and protocols for algorithm applications. Examine in detail the performance of alternative CCL development processes, including the different statistical approaches proposed. Assess the pragmatic requirements and features of each of the alternative CCL processes. Review complete CCL classification algorithm runs for a few alternatives. Assess points of failure, ease of execution, knowledge base requirements, and likelihood of success for each method.

° Develop required training data sets. Develop specific principles for the development of the training data set and then apply the principles to evaluating and listing contaminants on the training set.

° Determine if contaminant short listing is necessary. Determine the need for creating and managing a PCCL versus a single step process that goes from the universe to a draft CCL.

Response: Your comments will be considered as EPA works toward a CCL Classification Process. 54 Docket ID  Part #

Comment: 0019/ 20 40 Microbial contaminants should be given the same consideration as the chemical contaminants. For example, if chemicals and microbes are evaluated ( i. e., attributes weighed, contaminants scored) through different processes in developing the CCL, contaminants of similar potential public health concern should have the same chance of placement on the CCL whether the contaminants are chemicals or microbes. The NDWAC CCL Workgroup also stressed this recommendation.

Response: The Agency thanks the commenter for their suggestion and refers the reader to the response to comments 0019/ 20 parts 15 and 51, under sections <IP_ADDRESS> and <IP_ADDRESS>.

Docket ID  Part #

Comment: 0019/ 20 41 The current research program is inadequate for CCL1, as the agency has made little progress in moving these contaminants further through the regulatory process. EPA must align drinking water research funding with the CCL process.

Response: See the response to the comment 0019/ 20 part 23, under section <IP_ADDRESS> above.

Docket ID  Part #

Comment: 0019/ 20 42 Developing a CCL process that includes some practical consideration based on likely costs and benefits would be consistent with both CCL1 and regulatory determinations made to date.

Response: The Safe Drinking Water Acts in sections 1412( b)( 1) paragraphs ( B) and ( C) provide the principles and considerations for developing the CCL considerations to select contaminants.

Docket ID  Part #

Comment: 0019/ 20 43 It is not clear from either the NRC or NDWAC CCL Workgroup report what the actual role of experts will be, or equally important, how the experts' input will be captured, tested, or employed.

Response: EPA agrees that expert judgment and involvement is important component to the CCL selection process, and is evaluating approaches to incorporate and document expert input and review in developing the CCL process. The Agency is considering recommendations to use expert workshops as one approach in developing the CCL process. Additional approaches to 55 incorporate expert participation in developing the CCL are interim product reviews and public stakeholder meetings. The agency will also consider other approaches to include expert input and inform stakeholders and the public on the progress the Agency makes in developing the CCL process. EPA intends to incorporate transparency and expert involvement as key aspects of the CCL. Also see response to comment 0019/ 20 part 10 under section <IP_ADDRESS>.

Docket ID  Part #

Comment: 0019/ 20 50 Since expert judgment will be an integral part of the CCL selection process, it would be useful to understand how experts are chosen and by whom. It is likely that experts with different affiliations will come up with dramatically different training sets, decisions, and proposed contaminants for the CCL. Assuming that the expert panels convened will include experts with divergent perspectives, the EPA should specify the logistics and rules of the expert panels. This needs to include methods for resolving disagreements and reaching final agreement on the critical elements of the process.

Response: The Agency will consider this input as it develops the logistics, charge to experts, and how best to conduct reviews, workshops, and meetings to support the development of the CCL process in a transparent manner. See the response to comment 0019/ 20 part 43, under section 5.3.

Docket ID  Part #

Comment: 0019/ 20 53 The intent of Section 1412( b) and 1445( g) are further re enforced by Section 1412( b)(( 3)( A) which reads as follows:

" Use of Science in Decision making.   In carrying out this section, and, to the degree that an Agency action is based on science, the Administrator shall use   i. the best available, peer reviewed science and supporting studies conducted in accordance with sound and objective scientific practices; and ii. data collected by accepted methods or best available methods ( if the reliability of the method and the nature of the decision justifies use of the data). [ emphasis added]

All of the above provisions in Section 1412 clearly apply to the CCL. Consequently, the agency has a legal responsibility to employ data developed using sound and objective scientific practice and to use reliable observations, such as health effects or occurrence values.

Response: To the extent that the commenters interpretation is that Section 1412( b)(( 3)( A) supercedes the consideration of data and information that indicate anticipated occurrence in public water systems, EPA disagrees. Section 1412( b)( 1) paragraphs ( B)( i) and ( C) address the statutory requirements to list contaminants for consideration. These sections identify the organizations that shall be consulted and the data and information that must considering in listing contaminants. The section further directs the Agency to publish a list of contaminants " that 56 at the time of publication are not subject to any proposed or promulgated national primary drinking water regulation, which are known or anticipated to occur in public water systems, and which may require regulation under this title." It is important to note that the Administrator is directed to evaluate anticipated occurrence.

Section 1412( b)(( 3)( A) directs the Administrator to use " i. the best available, peer reviewed science and supporting studies conducted in accordance with sound and objective scientific practices; and ii. data collected by accepted methods or best available methods ( if the reliability of the method and the nature of the decision justifies use of the data).

Therefore, in developing the CCL, EPA will use the best available data in accordance with sound and objective scientific practices but does not agree that the CCL should be limited solely to the use of occurrence values cited by the commenter.

Docket ID  Part #

Comment: 0019/ 20 54 From the regulatory perspective, EPA and the drinking water community are accustomed to data with substantial and well defined quality assurance measures. Typically data are collected under strict methodological and quality control constraints. As the EPA explores emerging and/ or previously unregulated contaminants, the available data are likely to be scarce and have been obtained using non standard and/ or poorly defined methodologies. Consequently, EPA faces a very challenging environment in which to meet the SDWA requirements outlined above.

Response: EPA believes that its approach to CCL development will meet the Congressional objectives set out in both 1412( b)( 1)( B) and 1412 ( B)( 3)( A).

Docket ID  Part #

Comment: 0019/ 20 67 AWWA asks that the agency address this issue in finalizing CCL 2 by answering the following questions: 1. Will contaminants only be placed on the CCL as individual contaminants and not in groups ( i. e., Such groups would be a product of the regulatory determination or rulemaking phase of contaminant evaluation)? 2. Will selection of groups of contaminants for placement on the CCL take place in the " evaluation and expert review" stage of preparing the proposed CCL or will groups of contaminants be generated prior to consideration by the classification algorithm? Understanding the agency's perspective on these issues will assist other stakeholders determining how to best structure data development efforts.

Response: The Agency is evaluating recommendations and comments to develop the next CCL and refine the process for selecting contaminants or groups of contaminants for future CCLs. As the Agency identifies and evaluates contaminants for consideration some of these contaminants will have similar modes of toxicologic action, similarities in occurrence, and 57 closely related biology that provide an economy of scale to be considered as a group rather than individual contaminants. The Agency will consider the available data for occurrence and health effects, input from experts, and the commenters request as it identifies contaminants or groups of contaminants for the next and future CCLs.

Docket ID  Part #

Comment: 0025 4 " While virulence factor analysis shows great promise, VFAR is even further removed from practical utility should be treated with extreme caution. Too many unknown variables not exist to go directly to VFAR and bypass a diligent acquisition of knowledge of virulence factors and expression."

Response: The potential to identify emerging pathogens remains an important goal for the Agency, but our current evaluation suggests the data do not exist to support a virulence factor activity relationship implementation for the next CCL. Important research steps can be taken at this time to advance the field of virulence factor identification. See the response to the comment 0019/ 0020 part 12, under section <IP_ADDRESS> above.