	

	Office of Water

4301T	           SEQ CHAPTER \h \r 1 EPA-822-F-09-003

September 2009

	Methodology for Deriving Ambient Water Quality Criteria  for the
Protection of Human Health (2000)

Technical Support Document, 

Volume 3: Development of Site-Specific Bioaccumulation Factors



EPA has released a third technical support document to accompany the
Methodology for Deriving Ambient Water Quality Criteria for the
Protection of Human Health (Human Health Methodology), published in
2000. The Technical Support Document, Volume 3: Development of
Site-specific Bioaccumulation Factors (Site-Specific TSD) contains
technical details on how states and tribes may develop site-specific
bioaccumulation factors (BAFs) for use in deriving site-specific ambient
water quality criteria for protecting human health.  The first two
technical support documents are entitled Technical Support Document,
Volume 1: Risk Assessment and Technical Support Document, Volume 2:
Development of National Bioaccumulation Factors (National TSD).

Background

Aquatic organisms can accumulate chemicals in their bodies when they are
exposed to these chemicals through water, their diet, and sediment. This
process is called bioaccumulation. 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. 

In order to prevent harmful exposures to chemicals in water through
eating contaminated fish and shellfish, Clean Water Act Section 304(a)
national water quality criteria recommendations (“304(a) criteria”)
for protecting human health address chemical bioaccumulation in aquatic
organisms.  The National TSD describes how to calculate national
bioaccumulation factors for use in 304(a) criteria.  

In developing the National TSD, EPA envisioned the development of a
second technical support document to address bioaccumulation and provide
guidance on how to modify the national BAFs to derive BAFs that are more
representative of the bioaccumulation potential at a given location
(i.e., site-specific BAFs).  The Site-Specific TSD provides guidance on
different approaches that investigators can take to develop
site-specific BAFs, and the factors that should be considered when
selecting an approach for a given situation.  Neither of the
bioaccumulation TSDs should be used alone to derive BAFs, but rather
should be used in conjunction with the 2000 Human Health Methodology. 
The intended audience for the Site-Specific 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.  

About this Technical Support Document

In 2000, EPA published the Human Health Methodology, which updated and
revised the existing 1980 Ambient Water Quality Criteria National
Guidelines. The 2000 Human Health Methodology incorporates scientific
advances made over the past two decades in chemical risk assessment,
exposure assessment and bioaccumulation.

EPA developed detailed procedures and guidelines described in the 2000
Human Health Methodology for estimating BAF values for use in deriving
or revising ambient water quality criteria. The National 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 TSD expands on the information presented in the National
TSD by providing users with specific information on how to calculate
site-specific BAFs for use in modifying the national 304(a) criteria. 
The Site-Specific 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.  The
Site-specific TSD follows the same methodology presented in National
TSD.  

Technical Information

Using the 2000 Human Health Methodology, water quality criteria are
derived using a bioaccumulation factor to reflect the uptake and
retention of a chemical by fish and shellfish from all sources (e.g.,
water, food, sediment).  The National TSD and the Site-Specific TSD
include a framework for selecting the appropriate procedure for deriving
a BAF that is based on chemical properties, biological activity and
scientific information.  The Site-Specific TSD expands on this
information by providing information on sampling and statistical
techniques, modification of existing national BAFs for site-specific
application, and empirical calculations of site-specific BAFs.  

How do I get a copy of the technical support document?

You can get copies of “Methodology for Deriving Ambient Water Quality
Criteria for the Protection of Human Health,  Technical Support
Document, Volume 3: Development of Site-Specific Bioaccumulation
Factors” (EPA 822-R-09-008) by   HYPERLINK
"http://www.epa.gov/waterscience/criteria/humanhealth/method/" 
downloading the document from EPA’s web site  at   HYPERLINK
"http://www.epa.gov/waterscience/criteria/humanhealth/method/index.html"
 www.epa.gov/waterscience/criteria/humanhealth/method/index.html .  For
further information, contact Heidi L. Bethel at   HYPERLINK
"mailto:bethel.heidi@epa.gov"  bethel.heidi@epa.gov  or 202-566-2054.

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