There is no consensus on the approach to estimating exposure at higher tiers of environmental assessment. Step 1 calculations conducted for a novel herbicide did not exclude the potential for the compound to exhibit effects on higher aquatic plants following transport in drainflow. In a higher tier approach, a model was first validated against field data and then used for distributed modelling for 15 environmental scenarios with 30-year simulations for each. Predicted concentrations of the herbicide for the 15 scenarios were weighted according to their relative abundance within wheat-growing areas. The resulting 450 model outputs were ranked to assess risk and the probability of impact at the national scale.
|Title of host publication||PESTICIDE BEHAVIOUR IN SOILS AND WATER|
|Subtitle of host publication||Proceedings of an International Symposium Held in Brighton, UK on 13-15 November 2001|
|Place of Publication||FARNHAM|
|Publisher||BRITISH CROP PROTECTION COUNCIL|
|Number of pages||6|
|Publication status||Published - 2001|