PARENT SESSION
MA4 The Use of Ecological Models and Concepts in Aquatic Higher Tier Risk Assessment.
9:00 AM to 12:30 PM, Monday, 07 May 2001
Session Chair: Paul van den Brink
Room 4

(034) Developing a harmonised approach in Europe for the interpretation of aquatic microcosm and mesocosm studies on pesticides.

Norman, Steve¹, Brock, Theo², Maund, Steve³, Giddings, Jeffrey⁴, Heger, Wolfgang⁵, Heimbach, Fred⁶, Ratte, Toni⁷, Schafers, Christoph⁸, Streloke, Martin⁹, ^{1 2 3 4 5 6 7 8 9}

ABSTRACT- In pesticide ecotoxicology, potential concerns over risk to aquatic organisms may be raised in the lower tiers of risk assessment. In many cases, in order to address these concerns under more realistic conditions, freshwater microcosm or mesocosm studies are performed. These often take the form of outdoor artificial ponds or enclosures, but may also be conducted indoors under more controlled conditions. Population, community and ecosystem-level effects can be studied, as well as the potential for recovery. During assessments under Directive 91/414/EEC some difficult issues have arisen concerning the evaluation and interpretation of these studies. Therefore, a workshop named CLASSIC (Community Level Aquatic System Studies Interpretation Criteria) was organised with the aim of producing guidance in this area. The workshop took place in Schmallenberg, Germany, from 30 May to 2 June 1999. Scientists from government, industry and academia, who were experienced in regulatory aquatic risk assessment, addressed the following issues: 1. Evaluation of experimental design: exposure regimes, test organisms, taxonomic resolution, statistical considerations (e.g. multivariate approaches) 2. Ecological interpretation: effects and recovery, ecological context setting 3. Implementation into the risk assessment: extrapolation to the field, protection aims, landscape ecology Discussions indicated that despite the complexity of the issues, there is a potential for the development of internationally-harmonised guidance to support assessments under Directive 91/414/EEC. A draft guidance document from the workshop has twice been circulated for comments from participants and extensive revisions have been made to take on board their views. The finalised guidance document is planned for publishing through SETAC in early 2001.

Key words: pesticides, freshwater, mesocosms, microcosms