October 24, 1997
EPA Endocrine Program Unlikely to Change Despite Retraction
of Synergy Study
The U.S. Environmental Protection Agency (EPA) has indicated
that it will not change its research or policy regarding
endocrine disruption, despite the recent retraction of an
influential Tulane University study on synergy among
estrogenic chemicals. EPA said that while the retraction
invalidates the methods used by the Tulane researchers, it
does not negate the substantial body of scientific literature
on endocrine disruption and synergism.
Tulane researchers formally retracted their findings due to
repeated failures to replicate their original results. The
study, "Synergistic Activation of Estrogen Receptor with
Combinations of Environmental Chemicals," which appeared in
the June 7, 1996 issue of Science, found that combinations of
certain weakly estrogenic chemicals, including the pesticides
chlordane, endosulfan, dieldrin and toxaphene, could pose
risks of cancer, birth-defects and reproductive problems up
to 1,000 times greater than they pose individually. These
findings have played an important role in policy debates
about endocrine disrupting chemicals.
In a recent letter to Science, the study's authors said, "It
seems evident that there must have been a fundamental flaw in
the design of our original experiment." Scientists at the
Chemical Industry Institute of Toxicology, Duke University
Medical School, the National Institute of Environmental
Health Sciences, Texas A&M University and the Zeneca Central
Toxicology Laboratory all tried unsuccessfully to replicate
According to Dr. Lynn Goldman, EPA's Assistant Administrator
at the Office of Pesticides, Pollution and Toxic Substances
(OPPTS), "The retraction clearly invalidates general use of
the Tulane researchers' yeast-estrogen test system for
routine examination of synergistic effects of chemicals.
However, it does not overturn the substantial scientific
literature on either endocrine disruptors or synergistic
James Aidala, Associate Administrator at OPPTS, stated that
the Agency will "continue developing screening mechanisms for
endocrine disrupting chemicals, and the fact that Dr.
McLachlan (the lead researcher in the Tulane study) could not
replicate it given the context of the study does not mean
there is not synergy going on out there, it just means we
have not found it yet."
According to Aidala, "many people say that if there is all
this endocrine disruption going on, then we should see it in
individual chemicals. Well, we don't see it. We do not see
the predicted potencies if you look at these chemicals
individually. That is why the synergy theory was and is still
a good theory."
Under the Food Quality Protection Act and the re-
authorization of the Safe Drinking Water Act, EPA must
develop and present a screening and testing program for
endocrine disrupting chemicals to Congress by August 1999.
EPA established the Endocrine Disruptors Screening and
Advisory Committee (EDSTAC) to develop guidelines for
screening chemicals for their endocrine disrupting potential.
The committee, which meets every two months over the course
of a year, is comprised of approximately ten representatives
from industry, ten from government, ten from academic
institutions and ten from nonprofit public interest
In related news, EPA has released a schedule for reassessing
pesticide tolerances, as required by the 1996 Food Quality
Protection Act. EPA must reassess 9,728 food tolerances
(allowable levels of pesticides that can remain in or on
food) which were established before August 3, 1996. The ten
year schedule prioritizes chemicals that pose the greatest
health risks, including organophosphates, organochlorines and
carbamates. The Agency is also planning to revoke over 1,000
tolerances for canceled pesticides, suspended or canceled
uses, and commodities which are no longer considered
"significant livestock feed items."
According to EPA, the health of children and infants will be
emphasized throughout this process. Of the 1,800
organophosphate tolerances under review, more than 300 are
for residues on crops that are among the top 20 foods
consumed by children and infants. The Agency must review 33%
of the 9,728 tolerances by August 1999, 66% by August 2002
and 100% by August 2006.
Sources: National Coalition Against the Misuse of Pesticides'
(NCAMP) Technical Report, Vol. 12, No. 10, October 1997;
NCAMP Technical Report, Vol. 12, No. 8/9, August/September
1997; Washington Post, August 17, 1997.
Contact: NCAMP, 701 E Street, SE, Suite 200, Washington, DC
20003; phone (202) 543-5450; fax (202) 543-4791; email
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