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target and react with some crucial body constituent to produce an adverse
effect. Inmost instances, the proper target is unknown and only for a minority
of pesticides is the toxicologic mode of action in mammals and humans
understood.
Before being allowed on the market, pesticides are extensively and meticulously
tested to ascertain their biological potential in mammals regarding their
carcinogenicity, mutagenicity, embryo toxicity, teratogenicity, and other specific
toxic properties. These studies are normally performed by the manufacturer,
using widely accepted procedures; the results are confidential, but are
made available under specific circumstances.
At present, the only truly international evaluations of the risk of pesticides to
humans and the environment are made by the International Programme on
Chemical Safety (IPCS), a joint venture of the International Labor Organization
(ILO), the United Nations Environment Programme (UNEP), and the
World Health Organization (WHO). The two main roles of the IPCS are to
establish the basis for scientific health and environmental risk assessments for
the safe use of chemicals and to strengthen national capabilities for chemical
safety Because of their great importance and wide use, the IPCS has paid
particular attention to pesticides and, consequently, has developed several
activities.
Joint meeting on pesticide residues in food
The joint meeting on pesticide residues (JMPR), sponsored by the Food and
Agriculture Organization of the United Nations (FAO) and WHO, provides
member states with estimates of the levels at which various pesticides can be
safely tolerated by the human body. The recommended levels are then used
by national regulatory agencies and by the Codex Alimentanus Commission
to establish safe levels of pesticides in foodstuffs. The meetings have been held
annually since 1963. The WHO Group of Experts has described the procedures
in the toxicologic evaluation processes (WHO 1990a).
WHO pesticides evaluation scheme
The JMPR does not evaluate pesticides that do not leave residues in food, such
as household pesticides, and those primarily designed for public-health use.
The latter usually undergo the WHO pesticides evaluation scheme (WHOPES)
and are eventually reviewed by the WHO Expert Committee on the Safe Use
of Pesticides, the results of which are published in WHO's Technical Report
Series (e.g., WHO 1985).
WHOPES is a scheme for the evaluation and testing of new pesticides for
public-health use that has existed since 1960. It was revised in 1982 to take into
account new trends in the field of pesticide development and pest control.
Specifically, WHOPES was established to evaluate new chemical compounds,
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