Establishment of common mechanism groups for pesticides and similar
substances: A pilot study to establish resource requirements
In 2002, the Committee on Toxicity of Chemicals in Food, Consumer Products
and the Environment (COT) published a report from a COT Working Group for
the Risk Assessment of Mixtures of Pesticides and Veterinary Medicines
(WiGRAMP). The COT concluded that the likelihood of combinations of small
amounts of pesticides and similar substances (each present within regulatory
limits at residue levels in food) having a damaging effect on people’s health
was small.
However, there remains concern that the regulatory system for pesticides and
veterinary medicines does not routinely address the toxic effects of different
substances in combination. The COT recommended that the effect of
mixtures of these chemicals and any damaging effect they might have on
people’s health should be evaluated when carrying out risk assessments and
when establishing acceptable residue levels in food.
Some classes of pesticides and veterinary medicines work, toxicologically,
through the same mechanism. Identifying these common mechanism groups
was a recommendation of the COT report and is key to enabling combined
risk assessments to be performed.
Some common mechanism groups have already been proposed by the
Environmental Protection Agency in the USA, including organophosphates, Nmethylcarbamates and triazines. The Science Group of the Food Standards
Agency has prioritised five classes of pesticides/veterinary medicines to be
assessed for common mechanism grouping: triazines, avermectins,
conazoles, phenoxy herbicides, and pyrethroids and natural pyrethrins.
This report from the Institute for Environment and Health describes a pilot
study to evaluate the amount of work and resources needed to establish
common mechanism groups, and to test procedures for gathering and
evaluating data for selected chemicals from each of the five prioritised classes
of chemicals. The Food Standards Agency considers this pilot study useful
for guiding data collection and analysis and to identify resources needed to
identify common mechanism groups for these prioritised classes of pesticides
and veterinary medicines.