
[Federal Register Volume 82, Number 178 (Friday, September 15, 2017)]
[Notices]
[Pages 43354-43356]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2017-19703]


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ENVIRONMENTAL PROTECTION AGENCY

[EPA-HQ-OW-2016-0438; FRL-9967-69-OW]


Request for Public Comments To Be Sent to EPA on Peer Review 
Materials To Inform the Safe Drinking Water Act Decision Making on 
Perchlorate

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of request for public comment.

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SUMMARY: The U.S. Environmental Protection Agency (EPA) is announcing 
the release of materials for public comment. These materials will 
undergo expert peer review in support of EPA's Safe Drinking Water Act 
decision making for perchlorate. This request is one of two Federal 
Register notices being published concurrently, seeking public comment 
on two separate sets of peer review materials. This notice requests 
comments (to be sent to EPA) on a draft report entitled ``Draft Report: 
Proposed Approaches to Inform the Derivation of a Maximum Contaminant 
Level Goal for Perchlorate in Drinking Water'' (draft MCLG Approaches 
Report). The companion notice requests comments (to be sent to EPA's 
contractor, Versar, Inc.) on an interim list of peer reviewers and 
draft charge questions.

DATES: Comments must be received by EPA on or before October 30, 2017.

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ADDRESSES: Submit your comments, identified by Docket ID No. EPA-HQ-OW-
2016-0438 to the Federal eRulemaking Portal: http://www.regulations.gov. Follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or withdrawn. The 
EPA may publish any comment received to its public docket. Do not 
submit electronically any information you consider to be Confidential 
Business Information (CBI) or other information whose disclosure is 
restricted by statute. Multimedia submissions (audio, video, etc.) must 
be accompanied by a written comment. The written comment is considered 
the official comment and should include discussion of all points you 
wish to make. The EPA will generally not consider comments or comment 
contents located outside of the primary submission (i.e., on the web, 
cloud, or other file sharing system). For additional submission 
methods, the full EPA public comment policy, information about CBI or 
multimedia submissions, and general guidance on making effective 
comments, please visit http://www2.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: For additional information concerning 
the draft MCLG Approaches Report, please contact Samuel Hernandez at 
U.S. EPA, Office of Ground Water and Drinking Water, Standards and Risk 
Management Division, (Mail Code 4607M), 1200 Pennsylvania Avenue NW., 
Washington, DC 20460; telephone: 202-564-1735; or email: 
Hernandez.Samuel@epa.gov.

SUPPLEMENTARY INFORMATION:

I. Information on EPA's Revised Biologically Based Dose-Response (BBDR) 
Model

    As a part of the national primary drinking water regulation (NPDWR) 
development process for perchlorate, in accordance with the 
requirements of the Safe Drinking Water Act, in 2012, EPA requested 
comment from EPA's Science Advisory Board (SAB) prior to proposing an 
MCLG and a NPDWR for perchlorate. EPA sought guidance on how best to 
consider and interpret life stage information, epidemiologic and 
biomonitoring data, physiologically-based pharmacokinetic analyses and 
the totality of perchlorate health related information to derive a 
perchlorate MCLG.
    In 2013, the SAB recommended that, ``. . . EPA derive a perchlorate 
MCLG that addresses sensitive life stages through physiologically-based 
pharmacokinetic/pharmacodynamic (PBPK/PD) modeling based upon its mode 
of action rather than the default MCLG approach using the reference 
dose and specific chemical exposure parameters'' (Advice on Approaches 
to Derive a Maximum Contaminant Level Goal for Perchlorate, EPA-SAB-13-
004).
    Based on the SAB's recommendations, EPA, with contributions from 
Food and Drug Administration scientists, developed a biologically based 
dose response (BBDR) (also known as a PBPK/PD) model, to predict the 
effects of perchlorate on serum thyroid hormone concentrations in 
pregnant and lactating women exposed to perchlorate in drinking water 
and in infants exposed via ingestion of perchlorate in formula or 
breast milk.
    On January 10 and 11, 2017, EPA's contractor (Versar, Inc.) 
conducted an independent, scientific peer review of EPA's draft BBDR 
model and draft model report. The purpose of the peer review was to 
provide a documented, independent, and critical review of the draft 
BBDR model and draft model report and to identify any necessary 
improvements to the model prior to being finalized. On March 29, 2017, 
EPA received the final peer review report entitled, ``External Peer 
Review for EPA's Draft Biologically Based Dose-Response (BBDR) Model 
and Draft BBDR Model Report for Perchlorate in Drinking Water,'' which 
is available through the EPA docket at https://www.regulations.gov/docket?D=EPA-HQ-OW-2016-0439.
    In developing the draft MCLG Approaches Report, EPA revised the 
BBDR model to address those peer review recommendations that had the 
greatest influence on the scientific rigor of the model and modeling 
results. Those changes are described in the draft MCLG Approaches 
Report. EPA will consider other peer review recommendations and public 
comments in future revisions to the BBDR model and report.

II. Information on EPA's Draft Approaches To Inform the Derivation of a 
Perchlorate MCLG

    The SAB also recommended that EPA, ``utilize a mode of action (MOA) 
framework for developing the MCLG that links the steps in the proposed 
mechanism leading from perchlorate exposure through iodide uptake 
inhibition to thyroid hormone changes and finally neurodevelopmental 
impacts.''
    EPA used the modeled thyroid hormone levels to predict potential 
adverse health effects based on published epidemiology data 
demonstrating a relationship between changes in thyroid hormone levels 
and neurodevelopmental effects. This approach involved a focused review 
of the literature connecting altered thyroid hormone levels to 
neurodevelopmental outcomes for women in early pregnancy. EPA focused 
on studies that provided a quantitative description of the relationship 
between free thyroxine and neurodevelopment in infants and children 
(e.g., intelligence quotient, verbal and problem solving skills and 
motor coordination).
    EPA will present an array of approaches to inform the derivation of 
an MCLG for perchlorate for expert peer review. Using the revised BBDR 
model output, EPA linked statistical relationships derived from five 
studies to implement the MOA framework linking perchlorate exposure to 
neurodevelopmental impacts. All five studies assess the relationship 
between thyroid hormone levels in women in early pregnancy and various 
neurodevelopmental effects on children at various ages. Two studies 
assess the relationship on the IQ of children 5 to 10 years of age, two 
other studies assess the relationship on Bayley Scales of Infant 
Development of children 1 to 2 years of age, and a fifth study assesses 
the relationship on reaction time of children 5 to 6 years of age. An 
additional approach uses the revised BBDR model output to predict the 
percent change in the population of hypothyroxinemic (or the low-end of 
normal thyroid hormone levels) pregnant women due to perchlorate 
exposure.

III. How To Obtain the Draft MCLG Approaches Report and Revised BBDR 
Model

    EPA's draft report entitled ``Draft Report: Proposed Approaches to 
Inform the Derivation of a Maximum Contaminant Level Goal for 
Perchlorate in Drinking Water'' is available electronically and can be 
accessed using EPA's public docket at https://www.regulations.gov/docket?D=EPA-HQ-OW-2016-0438. The revised BBDR model code files can be 
accessed at https://hero.epa.gov/hero/index.cfm/reference/details/reference_id/3352518. All written comments must be submitted during the 
public comment period.

IV. Exclusion for Peer Review Candidates

    Important: Anyone wishing to be considered as an expert peer 
reviewer must not submit comments during the public comment period. 
Candidates on the interim list not selected for the

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panel peer review (see companion Peer Review Federal Register notice, 
published on September 15, 2017) will be given a limited opportunity to 
submit public comments once the final peer reviewers are selected by 
Versar, Inc., the EPA contractor managing this peer review process.

    Dated: September 6, 2017.
Michael H. Shapiro,
Acting Assistant Administrator, Office of Water.
[FR Doc. 2017-19703 Filed 9-14-17; 8:45 am]
 BILLING CODE 6560-50-P


