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2A - Mixture Toxicity (MO6/3) Identifying mixture toxicity of lubricants. Michel, Karin1, Brinkmann, Corinna1, Hahn, Stefan1, Dott, Wolfgang1, Eisentraeger, Adolf1, 1 RWTH Aachen, Institute of Hygiene and Environmental Medicine, Aachen, Germany ABSTRACT- Environmentally acceptable lubricants are increasingly used in different technical applications. They consist of synthetic esters as base fluids and a variety of additives including anti-wear and extreme-pressure additives, antioxidants and corrosion inhibitors added to base fluids in order to enhance the technical performance. The ecotoxic potential of lubricants is investigated. Ecotoxic effects are detected for the mixture of base fluids with additive packages using extracts with an oil-water ratio of 1:10. Because of the fact that synthetic esters alone are not ecotoxic, the observed results must be due to the additives. Information on single additives and on combinatory effects is required for the design of optimised environmentally acceptable lubricants. For example, tributylphosphate, an anti-wear additive, is toxic to algae in a concentration below 10 mg/L, whereas the mixture of this chemical with a synthetic ester is not. Relevant compounds responsible for toxicity are identified by investigating single additives in a biological test battery and by chemical analysis of the water extract prepared for bioassays. If toxic activity can be related to certain mixtures of chemicals in lubricants and to the chemical structure of ingredients, it will be possible to design an optimised fluid taking both technical performance and environmental characteristics into account. This approach contributes to a sustainable improvement of environmentally acceptable lubricants. Key words: additives, synthetic esters, ecotoxicity, algae |
