November Discussion--Flaws in Risk Assessment

Chuck Miller rellim at MAILHOST.TCS.TULANE.EDU
Thu Nov 2 10:01:39 EST 1995


Posted on behalf of Dr. Kaye----

Part of the 'attack' on toxicology derives from an understandable dislike,
within the scientific community at large, for misinterpretation of the purposes
and findings of rodent tests. Secondly, it arises from a predominantly
American-led focus on cancer per se, although critics do not recognise that the
carcinogenicity legislation fuels an underlying demand for repro tox,
developmental tox, and neuro tox studies from which the public *does* benefit.
Undermining the carcinogenicity legislation would undermine the rest of the
toxicology testing the public expects to be done.

A third contribution to the attack on toxicity testing for carcinogenesis lies
in changing, and anti-libral political trends. Many of the scientist who
campaign against the one-molecule hypothesis and the Delaney Clause do not know
anything of the legislative history whereof they speak: for example, although
Rachel Carson may have been partisan in her writing of Silent Spring, when she
wrote there were virtually no legislative restraints whatsoever on pesticide
distribution and use. Aldrin was licenced for home use to kill ants in 1958.
Even if cancer does not develop from the use of the many chemicals we license,
the other toxic endpoints of interest in public health justify continued, if
different, toxicity tests.

What should we think about?

First, validation of more in-vitro tox tests.

Two, better integration of spatial data with epidemiological data: epi data is
blunt, post-facto, and environmentally and spatially not only atheoretical but
often simply wrong. The idea that people haven't been helped by tox testing
arises partly from aspatial and unrealistic epidemiology results.

Three, better publicity by toxicologists about our work in repro, developmental
and neurotoxicity - both in respect of male and female reproductive function
and in respect of birth defects and learning deficits.

Four, acknowledgement of smoking and diet factors and better experimental
design to accomodate confounding factors. What happens to a
nitrosamine-saturated skin cell culture when it is exposed to the test
chemical? 

Lastly, the people who are attacking tox are not ogres or all right-wing sons
of sea cooks or high-minded scientists who can't cope with the need for
society's demand for a basic approximation of risk; some of them really believe
that the trillion dollars which have gone into tox testing should have gone
elsewhere. They have not thought about the consequences of their thinking and
we need to educate them. My own view is that tox testing can be improved a
great deal, but that a world without it would be immoral, soul-less, inhuman,
and wrong-minded. We only have to look at Bhopal, or 'Atom Lake', or industrial
Siberia to see what an unregulated economy can do to people and the
environment.

Dr. K.J. Kaye, kkaye at vax.ox.ac.uk
School of Geography
Mansfield Road
Oxford OX1 3TB
UK




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