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Introduction to Assessment of Pesticide Toxicology

This area of the HSE pesticides website provides information relating to the toxicological evaluation of pesticide (chemical) active substances and their formulated products, also called plant protection products (PPPs).

Assessment of effects on human health is a key element of the regulation of pesticides. The toxicology evaluation of pesticide (chemical) active substances involves the identification, characterisation and GB/NI CLP classification of potential human health hazards. At the hazard characterisation stage, specific values for use in risk assessments (for example, dietary and non-dietary reference values and dermal absorption values) are also determined. The toxicology assessment may also consider other factors such as toxicological relevance of chemical impurities and metabolites in plants, livestock or groundwater.

The toxicological assessment of pesticide (chemical) active substances involves the independent evaluation of data that inform on their effects on human health. These data are used to derive conclusions on the toxicity of the pesticide substance which are used to make formal regulatory recommendations. These data are submitted by chemical companies and, depending on the chemical, may include metabolism and kinetic investigations, single and repeated dose toxicity studies ranging from acute to lifetime via oral, dermal or inhalation routes, tests on mutagenicity and reproductive (fertility and developmental) effects and other specific investigative studies.

The toxicological assessment of PPPs, which are mixtures containing one or more active substances,U involves the identification and GB/NI CLP classification of the human health hazards of the formulation. In addition, consideration is given to other factors such as dermal absorption of the active substance from the product for the non-dietary risk assessment and assessment of the toxicological relevance of metabolites in groundwater. For PPPs, a quantitative human health risk assessment is only performed for the active substance(s) and/or co-formulants of concern for which extensive toxicological datasets, enabling the establishment of reference values, are available. In addition, specific toxicological data may be required for the authorisation of PPPs. This includes data that inform on the acute toxicological hazard of the formulation and dermal absorption of the active substance(s) from the formulated product.

Updated 2021-01-08