Scientific Opinion on Risk Assessment for a Selected Group of Pesticides from the Triazole Group to Test Possible Methodologies to Assess Cumulative Effects from Exposure through Food from these Pesticides on Human Health

Regulation EC No. 396/2005 from the European Parliament and the Council has required since September 2008 that cumulative and synergistic effects of pesticides be considered when Maximum Residue Levels (MRLs) are adopted. On 15 April 2008, the PPR Panel adopted an opinion on the suitability of existing methodologies and proposed a tiered approach for assessment of the cumulative effects of pesticides. As a second stage of its work in this area, the PPR Panel carried out a cumulative risk assessment for triazole fungicides to test the methods that had been proposed. This exercise applied the tiered approach in different scenarios of relevance for risk management in pre-and post-registration conditions, for both acute and chronic cumulative effects. The PPR Panel describes in this opinion progressive steps of refinement in cumulative risk assessment: (i) establishment of a Cumulative Assessment Group (CAG) through a careful analysis of the specific toxicological effects common to triazole pesticides and their underlying biochemical mechanisms, (ii) refinement of the hazard characterisation, using in successive tiers, regulatory reference values, reference values based on the common specific toxicological effects and benchmark dose modelling, and (iii) refinement of the cumulative exposure assessment making use of deterministic and probabilistic methodologies in successive tiers. Based on the lessons learned from this exercise, the PPR Panel proposes a simplification of the overall tiered approach. The CAG should be as refined as the data allow at an early stage, and exposure assessments should ideally be restricted to one deterministic and one probabilistic tier. Overall, the PPR Panel concludes that although a tiered approach is an appropriate way to address cumulative dietary risk assessment it cannot yet be applied on a routine basis. The PPR Panel identified the following issues that should first be resolved: the basis for and establishment of CAGs on a European level, definition and agreement on desired levels of protection, improvement of the robustness of methodologies of cumulative exposure assessment and development of guidance on their appropriate use.