Chemistry International
Vol. 22, No. 2
March 2000
Reports
from IUPAC-Sponsored Symposia
4th
IUTOX Congress of Toxicology in Developing Countries (4th CTOX-DC)
6-10 November 1999,
Antalya, Turkey
This meeting, sponsored by the Turkish Society of Toxicology
along with IUPAC and the International Union of Toxicology (IUTOX),
covered a wide variety of topics at a high level and was attended by
many of the worldís leading toxicologists. It started with a
workshop on environmental oestrogens that provided an overview of the
problem and stimulated active discussion. The conclusion of the workshop
was that the evidence for significant harmful effects of oestrogenic
substances in the natural environment is still limited to a few examples
and that no definite conclusions can yet be reached about any effect
on the human species. Current research in this area will, we hope, clarify
matters and alleviate public concern.
The workshop was followed by a series of symposia.
Topics included safety issues in developing countries, life styles and
health, pesticides, neurotoxicity of drugs of abuse, advances in understanding
allergic sensitization, occupational exposure to chemicals in the workplace,
risk assessment and chemical management, advances in molecular toxicology,
and ecotoxicology. There were plenary lecture sessions on genetic polymorphism,
xenobiotic toxicity, and clinical toxicology. In addition, there were
two more workshops on chemical risk assessment in theory and practice
and educational needs for developing countries, as well as oral and
poster presentations.
So many issues were raised and discussed that one can
pick out only a few of special note. A recurring theme was the lack
of facilities for local experts to monitor chemical exposures in developing
countries. This situation makes it very difficult to enforce legislation
for chemical safety, and it may be a particular problem with pesticides
made by local manufacturers in developing countries. These pesticides
are bought by farmers because they are cheap, but they may contain harmful
impurities that are no longer permitted in the developed countries.
Underlying many of the presentations was concern about
risk assessment. Toxicology defines the intrinsic hazard associated
with a chemical and relates this hazard to exposure in the form of dose-response
and concentration-response curves. However, it tells us nothing about
risk, which is a function of the way in which a chemical is used and
the probability of a person or other organism being exposed to a sufficient
amount of a chemical to cause harm. Thus, a certain chemical may be
classified as toxic, but this does not mean that it will necessarily
cause harm. If little or no exposure to this chemical occurs, or is
likely to occur, risk of harm may be negligible. Determining exposure
is a challenge for chemists and may require development of new techniques.
For example, guidelines for exposure to elements other than carbon are
largely set in relation to total elemental concentration. Chemical speciation
is ignored at least partly because analytical chemists often do not
speciate elemental analysis. For example, arsenic analysis is rarely
quoted as arsenite, arsenate, or organic species, although we know that
their toxicology is different. Risk assessment based on total arsenic
analysis is meaningless.
Other unifying concerns were related to differential
susceptibility to the effects of chemicals owing to genetic and environmental
differences and the problem of assessing mixed exposures. The effects
of diet were given due attention. Ecotoxicology got less attention than
it deserves, and the organizers of the next congress of this kind may
wish to include more on this area.
The workshop on educational needs for developing countries
was particularly interesting. It is clear that at least some developing
countries are not short of expertise but, rather, lack the facilities
to make full use of the experts available. It also appears that there
is a lack of expertise in certain specialist areas and that the international
organizations should identify these areas in order to help provide necessary
course material. However, there seems to be a lack of coordination between
international bodies in providing such material and in maintaining an
ongoing educational program. Perhaps IUPAC and IUTOX could get together
with the International Union of Pharmacology (IUPHAR) and initiate a
body for coordinating toxicological education at the international level.
Such a body could ensure that educational material of recognized quality
was available, preferably through the Internet, and could respond to
requests for specific courses to be organized.
Nearly 300 people participated in the 4th CTOX-DC,
and it succeeded well in reflecting both our current understanding of
important areas of toxicology and the significance of toxicology for
safe use of chemicals in both developed and developing countries.
Dr. John H. Duffus
Chairman, IUPAC Commission on Toxicology (VII.C.2)
The Edinburgh Centre for Toxicology
Edinburgh EH9 2JD, Scotland, United Kingdom