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###### Environmental Protection Agency

          - [FRL-8964-1]

# AGENCY:

Environmental Protection Agency (EPA).

# ACTION:

Notice of availability of final document.

# SUMMARY:

                        In 2000, EPA announced the availability of final revisions to the                         *Methodology for Deriving Ambient Water Quality Criteria for the Protection of Human Health (2000)*                         (hereafter “2000 Human Health Methodology”) published pursuant to section 304(a) (1) of the Clean Water Act (CWA). Along with the 2000 Human Health Methodology, EPA committed to publishing several technical support documents to provide additional detail to the Methodology document, including two documents that describe the development of bioaccumulation factors for use in ambient water quality criteria calculations. In 2003, EPA announced the release of the                         *Technical Support Document Volume 2: Development of National Bioaccumulation Factors*                         (hereafter “National BAF TSD”). Today, the Agency is releasing the                         *Technical Support Document, Volume 3: Development of Site-Specific Bioaccumulation Factors*                         (hereafter “Site-Specific BAF TSD”) that accompanies the Methodology and the National BAF TSD. EPA accepted scientific views on the draft document in two separate                         **Federal Register**                         Notices. The National BAF TSD contains technical details on how EPA develops national bioaccumulation factors for use in deriving national recommended ambient water quality criteria for protecting human health. The Site-Specific BAF TSD contains technical details on how States and Tribes may develop site-specific bioaccumulation factors for use in deriving site-specific ambient water quality criteria for protecting human health. The goal in deriving site-specific BAFs is to determine the most accurate estimates of bioaccumulation feasible for each site.                    

# FOR FURTHER INFORMATION CONTACT:

                        Heidi L. Bethel, Health and Ecological Criteria Division (4304T), U.S. EPA, 1200 Pennsylvania Ave., NW., Washington, DC 20460; (202) 566-2054;                         *bethel.heidi@epa.gov*.                    

# SUPPLEMENTARY INFORMATION:

## I. General Information

### A. Where can I find additional information on this document?

                    EPA solicited scientific views on the draft document in two separate                     **Federal Register**                     Notices (73 FR 36866 and 73 FR 46624). Scientific views were accepted at                     *http://www.regulations.gov*                     at Docket ID No. EPA-HQ-OW-2008-0494. Publicly available docket materials are available either electronically in                     *http://www.regulations.gov*                     or in hard copy at the Office of Water Docket/EPA/DC, 1301 Constitution Ave, NW., EPA West, Room 3334, Washington DC. This Docket Facility is open from 8:30 a.m. until 4:30 p.m., EDT, Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Office of Water is (202) 566-2426.                

Scientific views received by EPA and a document indicating EPA's response to scientific views can also be found at the docket locations listed above. A range of scientific views were received on the document. Views received did result in some minor changes to the document including some changes to table and figure captions; an example calculation correction and clarification of chemical types for which the document applies. A comprehensive list of changes to the document can be found in the response document. Other comments were addressed in the comment document, but did not result in changes to the document.

### A. Does This Action Apply to Me?

The intended audience for the Site-Specific BAF TSD includes State and Tribal water quality staff scientists or risk assessors (“investigators”) who are responsible for deriving State or Tribal water quality standards, stakeholders interested in developing site-specific BAFs, and other users interested in site-specific bioaccumulation issues for other applications.

## II. What Are Water Quality Criteria?

                    Water quality criteria are scientifically derived numeric and/or narrative values that protect applicable designated uses,                     *e.g.*, aquatic life or human health, from the deleterious effects of pollutants in ambient water. Section 304(a)(1) of the Clean Water Act requires EPA to develop and publish and, from time to time, revise water quality criteria to accurately reflect the latest scientific knowledge. Water quality criteria developed under section 304(a) are based solely on data and scientific judgments on the relationship between pollutant concentrations and environmental and human health effects. Section 304(a) criteria do not reflect consideration of economic impacts or the technological feasibility of meeting the chemical concentrations in ambient water. Section 304(a) criteria provide guidance to States and authorized Tribes in adopting water quality standards that ultimately provide a basis for controlling discharges or releases of pollutants. The criteria also provide guidance to EPA when promulgating Federal regulations                           ( print page 50183)                        under section 303(c) when such action is necessary.                

The 2000 Human Health Methodology, along with the Technical Support Documents, provides States and authorized Tribes with guidance to adjust water quality criteria developed by EPA under section 304 to reflect local conditions or to develop their own water quality criteria using scientifically defensible methods. EPA believes that ambient water quality criteria inherently require several risk management decisions that are, in many cases, better made at the State, Tribal, or regional level. EPA encourages States and authorized Tribes to use the final Methodology and Technical Support Documents to develop site-specific water quality criteria to appropriately reflect local conditions. The Site-Specific BAF TSD, released with today's announcement, will assist States and authorized Tribes in development of site-specific BAFs for use in site-specific ambient water quality criteria calculations.

## III. Background Information on the Bioaccumulation Factors Technical Support Document Volume III (Site-Specific BAF TSD)

                    In order to prevent harmful exposures to chemicals in water through eating contaminated fish and shellfish, national section 304(a) water quality criteria for protecting human health address chemical bioaccumulation in aquatic organisms. Bioaccumulation occurs when aquatic organisms accumulate chemicals in their bodies when they are exposed to these chemicals through the surrounding media (                    *e.g.,*                     water, food, sediment). The extent of bioaccumulation by aquatic organisms varies widely depending on the chemical and the species, but it can be extremely high for some highly persistent and lipid-soluble chemicals. For such highly bioaccumulative chemicals, concentrations in aquatic organisms may pose unacceptable human health risks from eating fish and shellfish even when concentrations in water are too low to cause unacceptable health risks from drinking the water.                

                    EPA developed detailed procedures and guidelines described in the 2000 Human Health Methodology for estimating bioaccumulation factor (BAF) values for use in deriving or revising ambient water quality criteria. The National BAF TSD discusses the technical basis for developing national BAFs, the underlying assumptions and uncertainties inherent to the approach, and applying the bioaccumulation component of the 2000 Human Health Methodology. The Site-Specific BAF TSD expands on the information presented in the National BAF TSD by providing users with specific information on how to calculate site-specific BAFs for use in modifying the national section 304(a) criteria, and is available on EPA's Web site at                     *http://www.epa.gov/​waterscience/​criteria/​humanhealth/​method/​index.html*. Both documents rely on a framework for selecting the appropriate procedure for deriving BAFs that is based on chemical properties, biological activity and scientific information. The Site-Specific BAF TSD presents methods for States, Tribes and other interested parties to calculate BAFs that are specific to their site. The goal in deriving site-specific BAFs is to determine the most accurate estimates of bioaccumulation feasible for each site.                

Dated: September 21, 2009.

Michael H. Shapiro,

Acting Assistant Administrator, Office of Water.

[FR Doc. E9-23631 Filed 9-29-09; 8:45 am]

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