1 

# Six

- Year Review 2

-- Summary of Public Comments

The Safe Drinking Water Act requires EPA to conduct a periodic review of existing National Pri mary Drinking Water Regulations (NPDWRs) and determine which, if any, need to be revised. The purpose of the review, called the Six

- Year Review, is to identify those NPDWRs for which current health effects assessments, changes in technology, and/or other factors provide a health or technical basi s to support a regulatory revision that will improve or strengthen public health protection. On March 29, 2010, EPA announced its completion of its second detailed review of 71 NPDWRs, and nominated 4 NPDWRs as candidates for regulatory revision : acrylamid e, epichlorohydrin, tetrachloroethylene, and trichloroethylene (USEPA, 2010; 75 FR 15500) 1

.
Within the Federal Register (FR) notice
, EPA requested public comment and/or relevant information that would assist the Agency as it move s forward with regulatory action to revise these 4 NPDWRs. EPA included 2 tables listing specific request s for comment:

Table VII

- 1

-- Items f or Which EPA Is Requesting Comment and/or Information f or the Four Candidates f or Revision ; and Table VII

- 2

-- Issues f or Which EPA Is Requ esting Public Input and/or Information

.
EPA received 20 public submissions (in the form of letters, e

- mails, and/or postings to www.regulations.gov ) which addressed the topics listed in these tables , as well as other related topics. Below are 3 tables summarizing public comments received; 2 of these correspond directly to the 2 tables listed above, and a 3 rd table summarizes c omments r eceived on o ther i ssues (i.e., other comments received that did no t relate to the topics listed in the FR notice tables). In addition, the 3 tables below include a column titled “Disposition of Comment Issues
, ” which contains summaries of t he status of EPA’s handling of the
comments. All original public submissions can b e found at www.regulations.gov, under Do cket ID EPA

– HQ

– OW

– 2008

– 0747

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## Table 1: Comment Summary C orresponding to “

Table VII

- 1

-- Items for Which EPA Is Requesting Comment and/or Information for the Four Candidates for Revision ” (75 FR 15500, p. 15568) 2



### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issues

Any new, relevant peer

reviewed data or information that would inform the revision of the NPDWR for acrylamide and epichlorohydrin , including information pertaining to 3 industry
groups Commenters believe that EPA should better

understand dosing ranges used in the United Sta tes, fully assess treatment implications, and allow for short

- term variances for unusual situations. Some commenters were unclear if NSF data regarding lower levels of monomer concentrations were due to EPA will consider these comments when the Agency revises the standards for epichlorhydrin and acrylamide

.

1 USEPA. 2010. National Primary Drinking Water Regulations; Announcement of the Results of EPA’s Review of Existing Drinking Wa ter Standards and Request for Public Comment and/o r Information on Related Issues; Notice. Federal Register . Vol. 75, No. 59, p. 15500, March 29, 2010.
2 Note that commenters may have submitted more than one comment per issue. Each commenter is counted only once, regardless of t he number of comments submi tted.2 

### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issues

extent of use of polyacrylamide and epichlorohydrin

- based polymers/co

- polymers in drinking water facilities

. 3 more refined manufacturing techniques or the fact th at some polymer products contain lower levels of active polymers. Commenters asked that revisions include clarification of the reporting requirements that exist in the current rule to alleviate confusion many are experiencing

now. Many commenters support lowering levels of acrylamide and epichlorohydrin as long as effective treatment can be maintained.

Any new, relevant peer

reviewed data or information that would inform the revision of the NPDWR for tetrachloroethylene (PCE) and trichloroethylene (TCE)
, including information/data about the lowest level of quantitation (and analytical method used) that l aboratories can reliable and consistently achieve

. 4 11 commenters: 3 States ; 3 special interest groups; 4 industry groups; and 1 water system Commenters question whether the PQL can be

demonstrably achieved by public water systems (PWSs). Additional research should be conducted to ensure that laboratories can meet lower detection levels and that laboratory capacity will not be impacted. Some laboratories would have trouble at lower detection levels with EPA M ethod 524.2 because the signal to noise ratio becomes unmanageable. A State reviewed health effects data and PQLs for 19 contaminants. This State review closely agrees with EPA’s findings for TCE and PCE. Some commenters recommended that EPA review source water occurrence data, co

- occ urrence with other volatile organic compounds (VOCs), the laboratory quantitation level, and conduct a multi

laboratory analysis on the Lowest Concentration Minimum Reporting Level (LCMRL). Some commenters thought the final rule revisions EPA will consider these comments as it develops a proposed regulation for a group of carcinogenic volatile organic compounds (c VOCs ) which will include PCE and TCE. EPA plans to propose the
group regulation in 2013.

3 Comments submitted on acrylamide and epichlorohydrin applied to both contaminants, so the issues are combined in this comment summary. 4 Comments submitted on tetrachloroethylene and tetrachloroethylene applied to both contaminants, so the issues are combined in this comment summary.3 

### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issues

should be made a fter the revised risk assessments have been completed (Some commenters suggest that the draft assessments do not support lowering maximum contaminant levels (MCLs), citing a National Academies of Science (NAS) review of the PCE draft
assessment

. ). Many co mmenters believe the costs

— including Superfund site cleanup costs

— outweigh the benefits of lowering the MCL s . Many cite a Tetra Tech Cost analysis. Some commenters noted that the health risk reduction benefits need to be quantified. Some commenters believe EPA should assess treatment technologies to determine if treatment, rather than analytical feasibility will be the determining factor on setting new MCLs. Revising TCE and PCE MCLs provides the opportunity to examine regulating con taminants as a group and to evaluate risk reduction associated with co

- occurring contaminants. Some commenters believe that EPA should evaluate
source water specific data (rather than system

- level), since many systems blend water sources to meet current M CLs. A commenter noted that lower MCLs will result in significant impacts to water systems (including additional treatment and simultaneous compliance issues) and States that assist water systems with compliance. Additional or new treatment could impact the air quality emissions permits. Some commenters support EPA’s decision to revise EPA conducted occurrence and exposure analyses at threshold concentrations that are below current maximum contaminant levels (MCLs) to determine if there is a meaningful opportunity to improve the level of public health protection by reducing MCLs. The doc ument4 

### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issues

MCLs for TCE and PCE. Some commenters asked for clarification on which datasets were used for the PCE and TCE minimum reporting level (MRL) analysis. Some commenters prov ided additional references for PCE and TCE health effects. “ Development of Estimated Quantitation Levels for the Second Six

- Year Review of National Primary Drinking Water Regulations ” ( http://water.epa.gov/lawsregs/rulesregs/ regulatingcontaminants/sixyearreview/ second_review/index.cfm) describes the method EPA used to establish the threshold values (including a detailed discussion on the MRL analysis) that it used for the occurrence analyses.5 

## Table 2: Comment Summary Corresponding to “ Table VII

- 2

-- Issues for Which EPA Is Requesting Public Input and/or Information ” (75 FR 15500, p. 15568) 5



### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issue s

Location for nitrate and nitrite monitoring 4 commenters: 3 industry groups; and 1 State Some commenters support continuing existing entry point

monitoring

– allowing systems to modify management strategies as system

- specific trends warrant. States want flexibility to require distribution system monitoring if conditions make other monitoring locations more appropriate. Some commenters recommend ed that EPA provide guidance on distribution system nitrification. The guidance could describe indicators that can identify nitrification in the distribution system, as well as measurement and managemen t practices for naturally occurring ammonia in source water and distribution systems. Monitoring options permitted by 40 CFR §141.23(a)(2) should be included in the guidance. One commenter would support distribution system monitoring if data supports moni toring from this location. EPA believes current regulations allow for flexibility in determining sampling point locations for nitrate

. Regulations codified in 40 CFR § 141.23(a)(1 ) and § 141.23(a)(2) allow public water supply systems the flexibility to monitor at the sampling point that best represents the source or treatment plant.

Monitoring frequency for ground water systems with low nitrate and nitrite concentrations 6 commenters: 3 industry
grou ps; 1 State; and 2 water systems Commenters suggest ed that if the monitoring frequencies were

to be reduced for ground water systems, the schedule should be aligned with the existing standardized monitoring framework, while some commenters believe the curr ent monitoring frequency should not change. Some commenters noted that monitoring schedules are an important indicator that utilities and States can use to identify unanticipated changes in ground water characteristics due to changes in land use managemen t. Some commenters would support using some very low trigger (detection limit, one half the MCL or some other low percentage EPA does not believe it is appropriate to consider revisions to the nit r ate and nitrite standar d s or monitoring protocol at this time because EPA identified n itrate as a candidate for a new risk assessment. When an updated human

5 Note that commenters may have submitted more than one comment per issue. Each commenter is counted only once, regardless of t he number of comments submitted.6 

### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issue s of the MCL), so States could allow reduced monitoring without reducing public health protection. In States that evaluated the pote ntial impact of such a change in monitoring requirements, as many as half the water systems could qualify for reduced monitoring under revisions states would support. Another commenter believes that monitoring should be decreased to no less frequently tha n once every three years if very low levels of nitrate and nitrite are detected. health risk assessment is finalized, EPA wil l carefully review the conclusions and consider all relevant information to determine if a new standard or monitoring protocol is needed

. E PA would also like to note that States are offered monitoring relief under provisions set forth in SDWA 1418 Alternative Monitoring Guidelines (AMG ), and detailed in 62 FR 42990

. SDWA, therefore, provides that a state may allow a system to implement the alternative monitoring offered by these guidelines, if the state has an approved source
water assessment program, and has completed a source water assessment for that system. The A MG allows biennial monitoring waiver s for nitrate for groundwater systems whose nitrate7 

### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issue s

concentrations have not exceeded 2 mg/L at any time in the past 10
years. EPA recognizes that the AMG require s states to go through the rule adoption and primacy revis ion process, and can be burdensome; AMG does however provide the monitoring relief requested by states.

Monitoring requirements for non community water systems (NCWSs) 3 commenters: 2 industry groups; and 1 State Some commenters recommend ed that states have the flexibility

to establish N CWS monitoring for all contaminants, consistent with the relative health risks of each type of water system and the population served. One commenter noted that non

- transient non

- community water systems shoul d monitor for radionuclides, and states should have the flexibility to increase monitoring for transient non

- community water systems. One commenter recommend ed no change for NCWS monitoring. EPA has previously taken comment on whether NCW S should be requi red to monitor for the same contaminants as community water systems (CWS). Commenter’s responses were not definitive on the issue (52 FR 25690, p 25694) (65 FR 76708, p 76719) (66 FR 6975, p 7025)

. Regarding applicability of regulations to non

community water systems, EPA considers the merits of each rulemaking on a case

- by

-8 

### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issue s case basis using a consistent set of criteria namely the cost/ benefit analysis as required under SDWA section 1412(b)(4). EP A will continue to evaluate the applicability of new regula tions to NCWS

. Further, EPA believes States currently have the discretion to choose to regulate NCWS either under a targeted rule or otherwise.

Detection limits as triggers to determine synthetic organic chemical monitoring frequency 5 commenters: 1 industry group; 1 State; 1 water system; and 2 laboratory associations Laboratories can meet the detection limits for synthetic organic

chemicals (SOCs). Specifically, benzo(a)pyrene, endrin, and methoxychlor detection limits can be met using EPA M ethod 50 5. One commenter suggest ed that EPA use MRLs rather than method detection limits (MDLs) . Meeting MRLs should then be used as a requirement for drinking water laboratories to receive certification. EPA will consider the efficacy of using MRLs in future ru lemaking activities.

Health effects data for chromium health assessment 2 commenters: 1 industry group; and 1 State One commenter agrees with concerns that the large doses

administered in the National Toxicology Program (NTP) led to health effects that cannot be extrapolated to low

- dose exposures in drinking water. The commenter recommends that EPA incorporate “The Hamner Institutes for Health Sciences, Research Framework for Evaluating the Potential Mode(s) of Action Underlying the Carcinogenicity of He xavalent Chromium Following Exposure in Drinking Water” framework into its risk assessment for chromium. One commenter provided a link to the final New Jersey EPA began a rigorous and comprehensi ve review of chromium

- 6 health effe cts following the release of the toxicity studies by the National Toxicology Program in 2008. In September 2010, EPA released a draft of9 

### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issue s Department of Environmental Protection (NJDEP) risk assessment: http://www.state.nj.us/dep/dsr/ch romium/soil

cleanup

- derivation.pdf. In addition, the State is evaluating the risk assessment and deciding whether or not to recommend an MCL for hexavalent chromium in drinking water. the scientific assessment

“ Toxicological Review of Hexavalent Chromium ” for public comment and external peer review. When this human health risk ass essment is finalized, EPA will carefully review the conclusions and consider all rel evant information to determine if a new standard is needed

Health effects data for nitrate and nitrite health assessment 4 commenters: 1 industry group; 2 special interest groups; and 1 State Commenters believe that EPA should not invest limited resources

in a further analysis of nitrate because the inhibition of iodine is not an adverse affect, it is a precursor effect. EPA should develop strategies to increase maternal iodide intake to health y levels. Some commenters believe that the scientific literature does not support conclusions reached in the federal register notice, and does not warrant a new health assessment for nitrate and nitrite, while some commenters believe that a new risk asses sment for nitrate and nitrite should be completed. EPA must consider a more comprehensive body of scientific literature in examining developmental effects and carcinogenicity of nitrate and nitrite. EPA is still considering the need for a health

assessmen t revision for nitrate and nitrite along with other programmatic priorities.

Health effects data for selenium health assessment No comments received No comments received. No action.

Health effects data for 1,2,4

- trichlorobenzene health
assessment 1 State One commenter supports EPA conducting a new health effects assessment of 1,2,4

- trichlorobenzene . The commenter cited several studies that would support changing the MCL to 20 μ g/L. EPA’s Office of G round Water and Drinking Water identified 1,2,4

- tric hlorobenzene as a
program priority for a10 

### Issue Number of Commenters and Affiliation General Summary of Comments Disposition of Comment Issue s

revised IRIS risk
assessment.11 

## Table 3: Comment Summary Corresponding to Other Issues Related to the Six

- Year Review Federal Register Notice (75 FR 15500) 6



### Issue Number of

Commenters and Affiliation General Summary of Comments Disposition of Comment Issues

General
comments agreeing with EPA 3

commenters: 2 industry groups; and 1 State Some commenters support EPA’s efforts to review existing drinking water

contaminants and the decision to revise standards for some contaminants. No Action. Thank you for your
comments.

General
comments disagreeing with EPA 2

commenters: 1 special interest group; and 1 environmental
group Commenters believe that EPA has not clearly demonstrated the benefits of

reducing MCLs for TCE and PCE to justify cost of compliance and impacts to Superfund clean

- up. Commenters also oppose the inclusion of “Category 5” and “Category 9” (option to raise MCL) in EPA’s review categorization. EPA will evaluate the cost and benefits of revising the MCLs for TCE and PCE as it develops a proposed regulation for a group of carcinogenic volatile organic compounds (cVOC). In evaluating costs, Superfund cleanup i s not a consideration because SDWA 1412 (b)(3)(C)(i)(III) excludes cost considerations resulting in compliance with other regulations. The categorization was simply intended to organize/present the health effects information identified during the extensive literature review conducted to identify peer

- reviewed studies that
may potentially affect the MCLG s

. Climate change impacts 2 industry

groups One commenter suggested that EPA conduct long

- term studies on the effects

of climate change on drinking water systems, rather than focusing on individual events. In 2008, EPA released its “ National Water Program Strategy: Response to Climate Change ” which provides

6 Note that commenters may have submitted more than one co mment per issue. Each commenter is counted only once, regardless of the number of comments submitted.12 

### Issue Number of

Commenters and Affiliation General Summary of Comments Disposition of Comment Issues

EPA may also want to develop a guidance document to describe potential indicators of climate change to be measured. One commenter note d that climate change impacts will vary by region. an overview of the likely effects of climate change on water resources and the Nation’s clean water and safe drinking water programs. It also describes specific actions the National Water Program intends to take to adapt program implementation in light of climate change. To view the strategy go to: http://water.ep a.gov/scitech/climat echange/upload/20081016_nwpsre sponse_to_climate_change_revised .pdf

In addition, the agency released

“ The National Water Program Strategy: Response to Climate Change, 2010

- 2011 National and Regional Highlights of Progre s s ”. This report is the third progress report of the 2008 s trategy, highlighting the accomplishments of the National Water Program in 2010 and 2011.

Other non MCL issues 1 water

system EPA is encouraged to address implementation issues in each Six

- Y ear R eview. No action. Thank you for your
comment.

Fluoride 9

commenters: 6 citizens; 1 special Many commenters believe that the fluoride MCL should be revised, suggest a

number of toxic endpoints, and that any water fluoridation is unsafe. Some commenters pointed out that a prescription is normally needed to

consume fluoride and public water should not be used as a “drug delivery” The Agency released a new risk assessment for fluoride on January 7, 2011. Bas ed on the new assessment, EPA began the process13 

### Issue Number of

Commenters and Affiliation General Summary of Comments Disposition of Comment Issues

interest group; 1 industry group; and 1 environmental
group system.

Commenters felt that EPA has been remiss in not responding to the 20 06 National Research Council report, and that an interim MCL and MCLG should be set. Commenters submitted numerous references and studies on health effects of fluoride. One commenter is concerned with the multiple public notification requirements which create confusion for PWSs and the public, and suggests that EPA develop additional guidance. of reviewing the current drinking water standards ( primary and secondary MCL s ) for fluoride to decide whether revisions are appropriate. Comments received are being reviewed and considered as a part of th is review.

Other contaminants 4

commenters: 1 water system; 1 consultant; 1 environmental
group; and 1 State One commenter suggested that nitrogen and iodine species of disinfection

byproducts (DBPs) should be added to the list of regulated DBPs. Another commenter believes the MCL and maximum contaminant level goal (MCLG) for lindane should be reduced based on new health effects information. This change would reduce costs for superfund sites. One commenter believes that the health effects of alach lor do not support weakening the MCL, and that EPA’s reference dose should be based on health effects to vulnerable populations. One commenter also asked EPA to require more frequent monitoring for atrazine. One commenter requests clarification on how EP A defined the threshold for sufficient occurrence and exposure in determining whether MCLs should be revised, and noted that standards should be revised where PQLs could be lowered. The disinfection byproduct rules
were not su bject to this Six

- Year Review, but will be evaluated in the 3 rd Six Year Review. Although there were data that supported a consideration to revise the MCLG / MCL for lindane, EPA did not believe a revision to the NPDWR for lindane is appropriate at this time. In evaluating costs, Superfund cleanup i s not a consideration because SDWA 1412(b)(3)(C)(i)(III) excludes cost considerations resulting in compliance with other regulations. Although there were new data that support consideration of whether to revise the MCLG / MCL for alachlor, EPA does not believe a revision to the NPDWR for alachlor i s appropriate at this time.14 

### Issue Number of

Commenters and Affiliation General Summary of Comments Disposition of Comment Issues

On October 7, 2009, the Agency announced its intent to launch a comprehensive new evaluation of atrazine to determine its effects on humans. At the end of this
proces s, the Agency will decide whether to revise its current risk assessment for atrazine and whether new restrictions or monitoring requirements are necessary to better protect public health. The Agency does not have a threshold for occurrence in drinking water that triggers a MCL revision. T here are a number of factors consider ed including, but not limited to, the level the contaminant is found in drinking water, how frequently the contaminant is found, the geographic distributi on, new health affects assessments, and changes in technology

. EPA considers all of these factors in determining if a revision to a NPDWR maintains or strengths public health protection.

Miscellaneous
comments 1 water

system One commenter believes that consumer confidence reports (CCRs) should be

reviewed as part of the Six

- Year Review process. The consumer confidence report rule is being reviewed under Executive Order 13563. In August,15 

### Issue Number of

Commenters and Affiliation General Summary of Comments Disposition of Comment Issues

2011, EPA released

“ Improving Our Reg ulations: Final Plan for Periodic Retrospective Reviews of Existing Regulations ”. In this plan, EPA defines 35 regulatory reviews for our initial review period. For more information on the plan go to: http://www.epa.gov/improvingregu lations/documents/eparetroreview plan

- aug2011.pdf