Estimating the exposure of birds and mammals to pesticides in long-term risk assessments.

This paper reviews current EU pesticide risk assessment guidance [European Commission (2002) Guidance document on risk assessment for birds and mammals under council directive 91/414/EEC, SANCO/4145/2000EC 2002], and examines some of its assumptions and problems arising from them. Issues associated with obtaining data that adequately describes exposure over the appropriate time-scale are common to both acute and long-term risk assessments but are probably less problematic for long-term exposure. Improvements in problem formulation and ways in which temporal and spatial factors might be incorporated into long-term risk assessments are suggested. The most important temporal issue for long-term risk is how best to model the degree to which wildlife habits are predictable from day to day. In relation to spatial factors, it is suggested that long-term risk assessments could make better use of pesticide usage data that sample usage patterns throughout the UK. The usefulness of detailed simulated farming landscapes populated by wildlife represented as agent-based models, should be explored.