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U.S. Environmental Protection Agency	2006-P-00041
?	\	Hffirp nf Insnprtnr ^pnpral	September 28, 2006
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Office of Inspector General
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At a Glance
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Catalyst for Improving the Environment
Why We Did This Review
We conducted this review to
evaluate issues and concerns
raised by an environmental
group and other concerned
citizens regarding the potential
for exposure to hazardous
substances in McFarland,
California. This case was
transferred from the U.S.
Environmental Protection
Agency's (EPA's) former
National Ombudsman in April
2002, when the EPA
Administrator assigned the
Ombudsman function to the
Office of Inspector General.
Background
During the 1980s, residents of
McFarland noticed health
problems that they attributed to
water, air, and soil
contamination. A study by
State and county officials
concluded that McFarland had
unusually high rates of cancer,
but no causal association could
be made between health data
and the contaminants identified
during sampling. EPA's
National Ombudsman
recommended that EPA
conduct comprehensive
environmental studies.
For further information,
contact our Office of
Congressional and Public
Liaison at (202) 566-2391.
To view the full report,
click on the following link:
www.epa.aov/oia/reports/2006/
20060928-2006-P-00041 .pdf
Review of Environmental Concerns at
McFarland, California
What We Found
EPA developed preliminary remediation goals for McFarland using a lifetime
residential exposure assumption of 30 years based on Agency Superfund guidance.
We believe a 70-year exposure assumption may be more appropriate where there
are multiple contaminants and multiple exposure pathways. We believe that this
more accurately reflects the intent of the National Contingency Plan to be more
protective under such environmental conditions.
EPA appears to have conducted air and soil sampling activities appropriately.
However, when analyzing drinking water sampling results, Region 9 did not
consider the synergistic effects of multiple contaminants and multiple exposure
pathways due to limited available information on such effects. A new arsenic
Maximum Contaminant Level was not effective until January 2006; thus, it is too
early to determine whether the States are properly implementing it. The Region is
helping States to acquire funding to install treatment systems and is conducting
training on new treatment technologies to help them meet the new standard.
Region 9 exceeded requirements in its efforts to keep the McFarland community
informed, but can take some actions to further strengthen community relations.
What We Recommend
We recommend that the Office of Research and Development identify and provide
public access to sources of information on the toxicology of contaminant mixtures
that may be found in drinking water, and continue to support research
characterizing the joint toxic action of contaminants in drinking water. That Office
generally agreed with the recommendations in our draft report, but suggested
minor revisions, with which we generally concurred. We also make several
suggestions for Region 9 to consider. The Region should provide an explanation
for not using a 70-year lifetime exposure assumption when issuing preliminary
remediation goals for specific sites, including McFarland. It should also provide
an explanation for not using a lifetime excess cancer risk level of 1 per every
1,000,000 residents in setting preliminary remediation goals for water that could be
used as a drinking water source where multiple contaminants are present.
Region 9 disagreed with our interpretation of the National Contingency Plan.
We continue to believe a 70-year exposure assumption and a lifetime excess cancer
risk of 1 per every 1,000,000 residents may be more appropriate where there are
multiple contaminants and exposure pathways, such as at McFarland.

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