Experiences with the application of QSAR in the routine of the notification procedure.

On behalf of the Umweltbundesamt the Fraunhofer Gesellschaft has developed a software system (SAR-system) comprising more than 90 estimation models for endpoints relevant in environmental risk assessment. These estimation models are based on the approach of quantitative structure-activity relationships (QSAR). All models were checked for their validity and application range. In the last months the Umweltbundesamt started to test the applicability of some models concerning the endpoints fish acute toxicity, daphnia acute toxicity and ready (i.e., ultimate) biodegradability in the daily routine of the notification procedure. For testing these models the corresponding confidential data given in the dossiers of substances notified 1993 in Germany, were used. We were able to make calculations for 36% of the notified substances. For the remaining 64% of the chemicals it was impossible to accomplish SAR estimations due to several reasons, e.g., ionic structure of the compounds. Different results for the applicability of the mentioned endpoints are obtained. The predictions of the fish and Daphnia toxicity are in sufficient agreement with the experimental results, in case of the fish toxicity we receive 58% agreement, for the Daphnia toxicity 56%. The corresponding values which were obtained in the US EPA/E.C. Joint Project on the evaluation of (quantitative) structure activity relationships were 82.3% and 70.9%. About 300 different models were used for the calculations of these endpoints within the framework of the EPA/EC project. The SAR-system presented here contains 8 models for estimating the fish toxicity and 6 models for the Daphnia toxicity. For the prediction of the biodegradability the results obtained with the SAR-system are rather poor and have to be improved. Meanwhile the SAR-system is commercially available and can be ordered at the Fraunhofer Institute for Environmental Chemistry and Ecotoxicology, Schmallenberg (Germany).

Research aspects in connection with the German Chemicals Act.

The German Chemicals Act of 1980 which came into force on January 1, 1982 aims to protect man and the environment from the unwanted effects of chemicals. As is true for all quality control legislation for chemical products, the scientific goal is to simulate under controlled conditions agent-target interactions as are likely to occur and to estimate the probability of agents reaching the target: the hazard of a chemical is a function of exposure and effect considerations. Beyond attempting to control chemical products, it may soon become necessary to consider the totality of all substances entering the environment as a consequence of technological activities: raw material extraction, production, transport, storage, and waste disposal. The paper aims at identifying important areas of research where it is felt that more systematic knowledge could help to render administrative decision-making processes more transparent, more cost effective, and bring them better in line with the legal mandate of protecting the environment from dangerous chemicals. While the paper focuses on problems surrounding the multitude of "existing chemicals," many an item discussed is significant also for the preventive protection from dangerous "new chemicals."