Exposure of pollinators to plant protection products.

As a general rule, environmental risk for chemicals is characterised by comparing an expected exposure level (e.g. PEC) with an ecotoxicological endpoint. The same approach is generally used for plant protection products (PPPs). However, in some cases, suitable procedures for a precise quantification of exposure are not available. The common risk assessment procedure for pollinators based on the hazard quotient, where the agronomic application rate is assumed as an exposure indicator, is an example. In this work, a semi-quantitative index to assess exposure to PPPs for organisms with a large forage area is presented. The proposed index was already applied in a previous work on risk assessment for pollinators, for this reason the validation steps (sampling area, collected samples, samples distribution) were planned bearing in mind the characteristic and the behaviour of these organisms and using Apis mellifera as representative of pollinators. The starting point for the development of the index is the assumption that exposure depends not only on environmental fate of pesticides but also on the feeding behaviour of the target organisms (in this context meant as target of the assessment). The developed index was applied and validated in different experimental areas of 4 × 4 km located in North-East Italy (Veneto region) characterised by a different level of impact. A sensitivity analysis of the index was performed evaluating the influence of the dataset resolution on the predictive efficiency. The obtained results indicate a good agreement between predicted and measured concentrations, supporting the suitability of the index to improve exposure assessment for pollinators.