Mock Assessment: Acute prospective cumulative risk assessment

Abstract

This Mock assessment is a part of the Framework Partnership Agreement between ANSES and EFSA with the help of RIVM to investigate the feasibility of a tiered approach proposed by EFSA for prospective acute cumulative risk assessment (CRA). Three tiers address successively a need for prospective CRA (Tier 0), the safety of the MRL (Tier I) and the safety of the intended GAP (Tier II). ANSES tested this approach with an application for change of MRL for the active substance tefluthrin (with acute effects on functional alterations of the motor division) on carrot based on a new intended use. For each tier, the Margin of Exposure (MOE) was calculated for 9 populations with MCRA software using input data provided by EFSA. At P99.9 of exposure, all the adjusted MOET at Tier I and Tier II of all populations were below the threshold of 100. Different settings were tested (IESTI equation, consumption data, adjustment for uncertainties, cycle of monitoring data…). With respect to Tier I, the trigger value of 1000 for the MOE_{Tier 0} is pragmatic. In the vast majority of cases, when the MOE_{Tier 0} is above 1000, the MOET_{Tier I} would be above 100. With respect to Tier II, a MOE_{Tier 0} higher than 1000 ensures a MOET_{Tier II} above 100. Tier I could be considered a good first estimate for a prospective CRA with conservative parameters for the foreground. Two routes were tested to account for uncertainties. One was not possible. The second resulted in a new median multiplicative factor (MF)_{exposure*toxicology} of 2.82 that differs significantly from the value of 5.13 found in the retrospective assessment. Despite the simplifications envisaged, the uncertainty analysis seems difficult to be implemented on a routine basis and it might be useful to define criteria to identify cases where an uncertainty analysis is really needed.