Trichloroethylene
To date, ATSDR has established agreements
(memorandum of understanding [MOU])
During fiscal year 2002, HSIA submitted a
with the American Chemistry Council (ACC),
study protocol in which physiologically based
formerly called the Chemical Manufacturers
pharmacokinetic (PBPK) modeling will be used
Association, General Electric Company (GE),
to estimate oral intakes of trichloroethylene-
and the Halogenated Solvents Industry Alliance
contaminated environmental media that would
(HSIA), Inc. to conduct substance-specific
not produce human developmental toxicity. The
research. Through the voluntary research efforts
modeling study will be based on data obtained
of these organizations, at least 16 research
from a previous HSIA study in rats that assessed
needs for 5 substances are being addressed.
the developmental toxicity of trichloroethylene.
These research needs include the remaining
priority data needs for tetrachloroethylene and
Methylene Chloride
trichloroethylene which HSIA proposed to fill
in a letter of agreement signed with ATSDR
During fiscal year 2002, ATSDR reviewed and
during fiscal year 2002.
accepted the conclusions of an HSIA study
assessing the potential immunotoxicity of
In addition to the substance-specific MOUs with
methylene chloride following oral exposure.
these three organizations, ATSDR has signed
The recent study, conducted by PBPK model-
an MOU with the Electric Power Research
ing, used data from a 2000 HSIA study (also
Institute, Inc. (EPRI). EPRI volunteered to sup-
sponsored by HSIA and accepted by ATSDR)
port a study, "Verification of Techniques for
that assessed the potential toxic effects on the
Assessing the Effects of Neurotoxicants on
immune system of rats exposed to methylene
Neurodevelopment in Children," that is being
chloride for 28 days via inhalation. The results
administered by a grant from ATSDR to the
of the recent PBPK modeling study predicted
University of Rochester. The objective of the
that no adverse health effects would be expected
study is to validate a battery of neurodevel-
to occur to the human immune system from
opmental tests for use in assessing the effects
drinking water containing about 8,000 parts per
of prenatal or postnatal exposure to develop-
million (ppm) of methylene chloride during a
mental neurotoxicants. Once validation is com-
short time period. The need for research data for
plete, these tests will be useful for assessing
oral exposure is a priority because ATSDR has
the potential developmental neurotoxicity of
identified ingestion of contaminated media (e.g.,
ATSDR priority substances such as PCBs,
water, soil) as the most common exposure route
methylmercury, and lead. In addition to the pri-
for methylene chloride at hazardous waste sites.
vate sector support, ATSDR is coordinating a
Methylene chloride is found in at least 884
federal effort (via interagency agreements with
hazardous waste sites on the EPA NPL sites.
EPA, the Food and Drug Administration, and
The chemical is currently ranked No. 78 on
the National Institute of Environmental Health
ATSDR's Priority List of Hazardous Substances
Sciences) to support the study. The study con-
found at NPL sites.
tinued during fiscal year 2002, and it is expected
to be completed in fiscal year 2003.
Tetrachloroethylene
During fiscal year 2002, ATSDR accepted
HSIA's study protocol for assessing the poten-
tial developmental toxicity of tetrachloroethyl-
ene. HSIA recently initiated the study, which is
chapter 2 35
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