Data ranges in aquatic toxicity of chemicals - Consequences for environmental risk analysis

A significant problem for effect assessment of aquatic ecosystems arises fr om the large ranges of toxicity data, which can be found in different datab ases and literature. Here, ranges are given for the aquatic toxicity of 27 high production volume chemicals. Based on these illustrative examples and on the current literature on uncertainty in aquatic effect assessment, toxi city ranges are discussed for their possible causes (variation in experimen tal condition, species, endpoint, time) and ways to handle them (safety fac tors). Implications and recommendations on the procedure of risk analysis o f chemical substances are drawn. Two main requirements for a comprehensive risk assessment are identified, w hich often play a minor role in current practice (as they are often neglect ed) as well as in scientific discussion (as they are means to be trivial). First, data quality must be checked critically before applying any result o f a toxicity test. Secondly, experimental data should rake into account dif ferent species and acme as well as chronic data. If these aspects are consi dered in risk analysis, which is common practice in ecotoxicology but not a lways in the context of practical applications in risk engineering, a more comprehensive picture of the environmental toxicity of a chemical substance can be obtained.