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2P Modelling ecotoxic effects (MOP/146) Evaluation of the Biotic Ligand Model (BLM) for copper in field and laboratory waters. Lipton, J.1, Cacela, D.1, Beltman, D.1, 1 Stratus Consulting Inc., Boulder, Colorado, USA ABSTRACT- The Biotic Ligand Model (BLM) has been proposed as an approach for improving predictions of Cu toxicity and for use in water quality criteria. A series of 30 individual acute toxicity tests were performed to evaluate Cu lethality to rainbow trout (Oncorhynchus mykiss) and Chinook salmon (Oncorhynchus tshawytscha). Testing included field-collected waters (n=10 tests collected from 3 different sites) and laboratory waters (n=20 tests). pH, hardness, Ca:Mg, and Na were varied in laboratory tests, providing a range of water quality conditions in which to evaluate changes in Cu toxicity. In addition to inorganic water quality parameters, Cu binding characteristics of the site waters were determined to further assess site specific factors influencing Cu toxicity. LC50 values varied by a factor of nearly 30 over the range of conditions assessed. We evaluate the performance of the Biotic Ligand Model (BLM) for Cu for this relatively large within-laboratory database by comparing predicted and measured lethality responses over a range of water quality conditions. In addition, we present data on gill tissue uptake of Cu as another means of evaluating model performance. Key words: salmonids, copper, BLM |
