Impact of Metabolic and Degradation Processes on the Toxicological Properties of Residues of Pesticides in Food Commodities

Residues arising from the use of plant protection products (PPPs) on food commodities can consist not only of the active substances but also of their degradation products and metabolites. The toxicological properties of the active substance are normally extensively investigated in toxicological studies, while only very limited experimental data are usually available on the toxicological properties of metabolites and reaction products. Requests for further toxicological studies should be restricted as much as possible to minimise the use of test animals. In many cases toxicological testing would also not be feasible due to the sheer number of metabolites and reaction products.
<P>
Dietary risk assessment should nevertheless take into account all compounds contributing to risks. Therefore, the applicability of alternative assessment methods is currently explored. EFSA considered the impact of metabolic and degradation processes on the toxicity of pesticides for this task.
<P>
The present project contains: <ol> <li> an evaluation of how and when the toxicological profiles of metabolites can be considered as covered by the assessments of the respective parent compounds, which is based on the assessment of PRAPeR and JMPR decisions and the screening of relevant scientific literature and guidance documents.
<li> a classification of structural molecular changes observed following metabolic and abiotic degradation processes of active substances and an analysis of the possible related changes in regard to toxicological effects.
<li> a proposal for an evaluation tool addressing the toxicological significance of metabolites/degradation products.