The acute toxicity of surfactants on fish cells, Daphnia magna and fish-a comparative study

There is a need to replace acute toxicity tests on fish (LC(50)) with more cost effective assays. The main objective of this study was to explore whether gill epithelial cells, hepatocytes and Daphnia magna could be used to predict acute toxicity of surfactants on fish. The acute toxicity of 10 synthetic surfactants (anionic, cationic, nonionic and zwitterionic) and two resin acids were determined on hepatocytes and gill epithelial cells from rainbow trout (Oncorhynchus mykiss), on Daphnia magna and on fish. Cell viability was measured with the fluorescent viability probe calcein-AM, immobilization was determined for Daphnia and 24-hr LC(50) for rainbow trout. The EC(50) values for the cellular tests were clearly higher than the corresponding values for Daphnia and fish, indicating that the cellular tests with the endpoint used are less sensitive than whole organisms. A combination of the EC(50) values for Daphnia and freshly isolated gill epithelial cells in suspension showed, however, a good correlation with acute toxicity on fish (r(2)=0.91 and slope=1.09). The combination seems to be a promising in vitro alternative to acute toxicity tests on fish (LC(50)), but a more exhaustive comparison, including a broad spectrum of chemicals should be made before the predictive value of the combined in vitro test can be evaluated.