Update to ATSDR Policy Guideline for Dioxins and Dioxin-Like Compounds in
Residential Soil
AGENCY: Agency for Toxic Substances and Disease Registry (ATSDR), U.S.
Department of Health and Human Services (HHS).
ACTION: Request for public comments on the revised Policy Guideline
document used by health assessors to evaluate health hazards associated
with exposure to dioxins and dioxin-like compounds in residential soil.
-----------------------------------------------------------------------
SUMMARY: ATSDR is seeking public comment on the draft revision of its
1998 Policy Guideline for Dioxins and Dioxin-Like Compounds in Residential
Soil.
The policy is intended to assist health assessors who must evaluate the
public health implications of dioxin and dioxin-like compounds (e.g.,
2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD], chlorinated dibenzodioxins
[CDDs], chlorinated dibenzofurans [CDFs], and other structurally related
groups of chemicals from the family of halogenated aromatic
hydrocarbons) in residential soils near or on hazardous waste sites. The 1998
policy
established a screening level of 0.05 ppb TEQ (50 ppt), an evaluation
level (>0.05 ppb TEQ, <1 ppb), and an action level of 1 ppb TEQ (1,000 ppt)
for dioxins in residential soil. ATSDR revised the 1998 policy because it
has been used inconsistently over the past eight years. The ATSDR ``action''
level has been misinterpreted by health assessors and others as ... (1)
A soil concentration that defines a public health hazard, (2) an ATSDR
clean-up level which implies the need for site remediation, and (3) an
initial screening level that defines a safe level of exposure, below
which there is no public health concern. In addition, the ``action'' level
triggered a set of ``potential public health actions'', including
surveillance, research, health studies, community education, and
exposure investigations. However, ATSDR believes that these actions could be
considered in some circumstances when the 1 ppb level in soil is not
exceeded. In response to these concerns ATSDR has updated its Policy
Guideline for Dioxins and Dioxin-Like Compounds in Residential Soil. The
key elements in the updated ATSDR Policy Guideline for Dioxins and
Dioxin-Like Compounds in Residential Soil are as follows: ? Deletion of
the 1 ppb action level as the criteria for taking specific public health
actions. The 1-ppb dioxin soil concentration should not be used as a
comparison value for defining public health hazards in public health
assessments and consultations. The 1-ppb action level can be cited by
health assessors as the Superfund Dioxin Cleanup policy criteria (EPA
1989, 1998). Retention of the 0.05 ppb Screening Level The minimal risk
level (MRL)-based environmental media evaluation guide (EMEG) of 0.05 ppb for
dioxin TEQ in soil is retained as the basis for screening soil concentrations.
Levels exceeding this screening level should be evaluated
as described in the ATSDR Public Health Assessment Guidance Manual
(PHAGM) (ATSDR 2005). This clarification will ensure that evaluation of dioxins
and dioxin-like compounds in soil will be done in the same manner as all
other soil contaminants. Recommendation To Conduct Exposure Pathways Analyses
for Dioxins and Dioxin-Like Compounds The focus of the guideline is the
assessment of direct exposure to soil contamination, particularly soil
ingestion. However, health assessors should be aware of the potential
impact of indirect exposure pathways on exposed populations in
site-specific health assessments. This document does not provide
specific guidance on how these indirect pathways should be assessed. However,
the
PHAGM document does provide assistance in evaluating indirect exposure
pathways such as food chain contamination (ATSDR 2005). Updated TEFs
The 2006 World Health Organization Toxicity Equivalency Factors (TEFs) for
dioxins and dioxin-like compounds have been included in the updated
document. Background Information In 1998, the Agency for Toxic
Substances and Disease Registry (ATSDR) adopted a Final Policy Guideline for
Dioxin
and Dioxin-Like Compounds (De Rosa et al. 1999a). The 1998 policy
guideline was accompanied by a Technical Support Document for ATSDR Policy
Guideline (De Rosa et al. 1999b). The initiative to develop this policy
guideline
wasbased on a request from the U.S. Environmental Protection Agency (EPA)
to evaluate the protectiveness of the EPA Superfund Policy for Dioxins in
Residential Soils, which established 1 part per billion (ppb) (1,000
parts per trillion [ppt]) total dioxin toxicity equivalents (TEQ) as the
starting point for making clean-up decisions. In addition, the 1998 policy
guideline was to provide guidance to health assessors in evaluating the public
health implications of dioxin and dioxin-like compounds (e.g.,
2,3,7,8-tetrachlorodibenzo-p-dioxin [TCDD], chlorinated dibenzodioxins
[CDDs], chlorinated dibenzofurans [CDFs], and other structurally related
groups of chemicals from the family of halogenated aromatic
hydrocarbons) in residential soils near or on hazardous waste sites. As stated
in the
1998 document, ``these guidelines and procedures apply to human exposure
for direct ingestion of soils contaminated with dioxin and dioxin-like
compounds in residential areas and may not be appropriate for other
exposure scenarios.'' The 1998 Policy Guideline established a screening
level of 0.05 ppb TEQ (50 ppt), an evaluation level (>0.05 ppb TEQ, <1
ppb), and an action level of 1 ppb TEQ (1,000 ppt) for dioxins in
residential soil and made recommendations for specific considerations or
public health actions. ATSDR has established environmental screening
values for chemicals to be used by health assessors to assess exposures. No
other chemical has an action level as was established for dioxins in soil in
the 1998 policy guideline. This inconsistency alone has led to confusion
regarding the appropriate screening value for soil dioxin levels. The
primary objectives of the updated Policy Guidelines are to provide
greater consistency in ATSDR Health Assessments and to bring dioxin assessments
in line with how all other chemicals are evaluated by the agency. Summary
of Peer Review for Document The public comment draft of the revised policy
has undergone internal review and clearance within ATSDR. In addition,
the revised draft was reviewed by the National Center for Environmental
Health/Agency for Toxic Substances and Disease Registry (NCEH/ATSDR) Board of
Scientific Counselors (BSC). Public testimony was received during the
meeting of the NCEH/ATSDR BSC. ATSDR also received peer review comments
from health assessors in several state health departments. Information
about the ``Update to ATSDR Policy Guideline for Dioxins and Dioxin-Like
Compounds in Residential Soil'', including the draft document, fact
sheet, peer review comments and ATSDR responses, is available on the ATSDR Web
site at:
http://www.atsdr.cdc.gov/substances/dioxin/policy/index.html.
DATES: Comments concerning this document must be received by February
27, 2007.
ADDRESSES: Public comments should be forwarded to Ms. Athena Gemella,
ATSDR, Office of Science, 1600 Clifton Road, N.E., Mail stop E-28.
Atlanta, GA. 30333, or e-mail at <A
HREF="mailto:AGemella@cdc.gov">AGemella@cdc.gov</A>.
FOR FURTHER INFORMATION CONTACT: Ms. Athena Gemella, Office of Science,
telephone (404) 498-0621.
Dated: December 22, 2006.
Kenneth Rose, Acting Director, Office of Policy, Planning and
Evaluation,
National
Center for Environmental Health/Agency for Toxic Substances and Disease
Registry.
[FR Doc. E6-22388 Filed 12-28-06; 8:45 am] BILLING CODE 4163-70-P
http://epa.gov/EPA-WASTE/2006/December/Day-29/[Federal Register:
December 29, 2006 (Volume 71, Number 250)][Notices][Page
78441-78442][wais.access.gpo.gov][DOCID:fr29de06-80]
DEPARTMENT OF HEALTH AND HUMAN SERVICES Agency for Toxic Substances and
Disease Registry [ATSDR-228]
Update to ATSDR Policy Guideline for Dioxins and Dioxin-LikeCompounds in
Residential Soil AGENCY: Agency for Toxic Substances and Disease Registry
(ATSDR), U.S.
Department of Health and Human Services (HHS).
Source: TRW
For additional articles like this one, go to the Tittabawassee River Watch web site www.trwnews.net. for complete coverage of the Tittabawassee River Dow Chemical dioxin contamination saga.. The source organization's web site link is listed above. The Newspaper / Media page of our site contains an extensive archive of media articles dating back to January 2002. The Newspaper / Media page may be accessed by scrolling down to the bottom of the CONTENTS section and clicking on the Newspaper/Media link.