[Dietary risk assessment for pesticide residues in food of plant origin during the plant protection product's registration process]

Abstract

One of the main goals of risk assessment during registration of plant protection product is to approve (or not) the proposed Maximum Residue Levels (MRLs) derived from the field trials conducted under Good Agricultural Practice (GAP). Generally, risk assessment at this stage is based on comparison of potential long- and short-term dietary intake of given pesticide with two earlier established outputs of hazard characterisation, i.e. Acceptable Daily Intake - ADI and Acute Reference Dose--ARfD. The first estimate of long-term hazard, which overestimates the risk, is comparing the Theoretical Maximum Daily Intake (TMDI) to the ADI of the pesticide. TMDI is based on assumption that all food products consumed over the lifetime of the consumer contain residues at level of MRL. Afterwards, the ADI is compared against International/National Estimated Daily Intake (IEDI/NEDI). I(N)EDI values provide a "best estimate" of dietary intake as they take into account residues in edible portions at level of median residue values from supervised trials. In case of short-term dietary exposure to acute toxic pesticides, the intake is compared to ARfD. The calculation of International/National Estimated Short-Term Intake IESTI/NESTI) requires single-day consumption data for the 97.5th percentile for each subgroups of consumers (so called "large portions") together with typical unit weight, and percentage of edible portion for each commodity as well as high, and median residue levels derived from the field trials. Additionally, in intake calculations for commodities with unit weight over 25 g, the variability factor (from 3 to 10) has been introduced, which reflects the possible high deposition of a pesticide on the individual unit, even when the quantified residue level in composite sample is relatively low.