Subject: Endocrine Disrupters
V. ENDOCRINE DISRUPTORS
- Check out the hot new Endocrine Disrupting Chemical website
that continues the work of the book Our Stolen Future at:
www.osf-facts.org
- REPORT ON THE ENDOCRINE DISRUPTORS SCREENING AND TESTING
ADVISORY COMMITTEE (EDSTAC) MEETING, HOUSTON
The EPA has convened the Endocrine Disruptors Screening and Testing
Advisory Committee (EDSTAC) to advise EPA on a strategy for screening and
testing chemicals and pesticides for their potential to disrupt endocrine
functions in humans and wildlife. This is an important step in EPA's
(and society's) acknowledgment that endocrine disruptors pose a public
health threat which must be addressed. EDSTAC (and EPA) is under
statutory deadline to accomplish their work for presentation to Congress
by August, 1998. The primary mechanism by which information will be
shared with the public will be a web site, which has recently become
operational. The address is: http://www.epa.gov/opptintr/opptendo
The EDSTAC itself is composed of some 40 members drawn from industry,
academia, government agencies, and public interest organizations.
LYNN GOLDMAN'S COMMENTS IN HOUSTON
Dr. Lynn Goldman, EPA Assistant Administrator for Prevention, Pesticides,
and Toxic Substances, chairs EDSTAC. Although EDSTAC has an enormous
amount of work in front of it, Dr. Goldman said that there is compelling
evidence already which enables us to begin to act. She said she was
pleased with the progress of the committee despite an imperfect process.
She reaffirmed that ecological as well as human effects will be examined;
and that thyroid effects will be addressed as well as sex steroids
effects (estrogenic/anti-estrogenic; androgenic/anti-androgenic); and
that the issue of the synergy of chemical combinations will also be
considered.
PRESENTATIONS TO EDSTAC
At the EDSTAC membership's request, much of the agenda in Houston was
taken up by "mutual education" sessions, which were short tutorials on
Comparative Endocrinology; the State of the Science Regarding Endocrine
Disruption; Quantitative Structure-Activity Relationships; Existing
Screening and Testing Programs; and Decision Analysis Models (this last
was deferred for lack of time).
The short of it is that the issues of endocrine disruption are extremely
complex, and we cannot expect instant answers. Much research still needs
to be done, but many believe that there is enough evidence now (and many
new studies coming out) to support the adoption of the "precautionary
principle" with respect to potential endocrine disruptors. That is, the
onus should be shifted onto industry to show conclusively that there
products are safe rather than assuming that every new chemical is benign
until a health threat is identified after the chemical is already "loose"
in the environment.
Sobering statistics were offered on the volume of substances in the
marketplace today. Annual U.S. chemical production is now more than 6
trillion pounds. There are some 1,500-2,000 chemicals whose production
exceeds one million pounds per year. There are some 70,000 chemicals in
use, with approximately an additional 2,200 new ones introduced every
year. They are virtually untested for toxicity by EPA, much less for
their endocrine disrupting characteristics.
FIFRA and TSCA provide the primary testing tools used today. However, it
was acknowledged that in the 21 years that TSCA has been law, the number
of chemicals that have been tested is in the hundreds at the most. One
EPA staff person put the number at 40.
EDSTAC member John McLachlan, Director of the Tulane-Xavier Center for
Bioenvironmental Research, provided insight into the complexities
involved. He noted that environmental agents can cause genetic mutations
and lead to cancer; and they can impact signal transduction systems. The
period of impact can last for seconds or days. Exposure to some
substances can cause different effects at different times in the life
cycle. For example, the same level of exposure can cause effects that
are different for a mature female as opposed to an embryo, a female
before puberty, a post-menopausal female, or a male.
Both of these pathways of environmental agents can lead to disease and
dysfunction. The signaling can occur in endocrine, immune, and/or
nervous systems - the point is that these systems are integrated. The
implication is that while looking at "endocrine disruptors" per se is a
huge undertaking, it is also still necessary to look beyond the endocrine
system for how these chemicals impact our bodies. Dr. McLachlan also
brought up the issue of ecological effects of signaling between
organisms.
WORK GROUP REPORTS
EDSTAC has identified four working groups which will meet independently
of the plenary sessions. The four are:
* Principles (which will define parameters for how the work is
performed);
* Screening and Testing (how to actually do the work; "screens" are the
first "rough cut" while "tests" zero in on more precise measurements);
* Prioritization (what will be tested first?);
* Communication/Outreach (How and when will findings of EDSTAC be
communicated to the public?).
PRINCIPLES WORK GROUP
The Principles WG is perhaps the most important because it is charged
with developing the Terms of Reference for all of EDSTAC's work.
However, perhaps because this task is so crucial, the work of the
Principles WG has been broken down into two parts. The first continues
to provide the overarching framework for EDSTAC which will reflect values
and philosophy. Some EDSTAC members felt that this task should be taken
up by the entire EDSTAC membership.
The second part of the work of the Principles WG is to develop reference
points that will guide the work of the Screening and Testing WG and the
Prioritization WG.
Among the issues of discussion was how to determine the point at which a
chemical is "cleared" in the process of screening and testing. Does one
test result of "not positive" mean it is not an endocrine disruptor? How
thoroughly should chemicals be tested? How thoroughly CAN they be
tested? What does it mean to "defer" a chemical in the screening and
testing process?
On one side of the debate were industry representatives, who again zeroed
in on "adverse effects," saying that an adverse effect should be
demonstrated before any action was taken to screen and test any given
chemical. Another tack was asking the question, "If there is no
exposure, is there a need for the chemical to be screened at all?"
On the other side were those who pointed out that effects, adverse or
not, might not become apparent for many years. Furthermore, there is a
great deal that is still unknown. There is a need to further refine the
draft flow chart to accommodate chemicals which may be deferred. Some
should be deferred because they have no data whatsoever, and should be
prioritized for more study. Others should be deferred because they have
a high "index of suspicion" despite inconclusive initial screen results.
Finally, there are those that can be deferred because they have a low
index of suspicion, but should be able to be recalled for more testing in
the future as new research emerges.
PRIORITIZATION WORK GROUP
This WG has not yet met.
The stakes are high in this WG because it is here that decisions will be
made about what is tested. It is acknowledged that not everything will
be tested - there is just too much.
SCREENING AND TESTING WORK GROUP
Like the Prioritization WG, this WG has not yet convened as its expanded
membership is still being determined.
COMMUNICATION AND OUTREACH WORK GROUP
The three tasks for this WG are to provide outreach to the public about
the EDSTAC process; to develop guidelines on how testing results will be
conveyed to the public; and to review drafts of the committee's report(s)
as they become available.
The next plenary meeting for EDSTAC will be April 29-May 1, 1997 in
Baltimore (changed from Orlando).
Please send your comments regarding EDSTAC and its substantive or
procedural work to:
Gary Timm
USEPA
401 M
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