Aquatic toxicology in vitro: a brief review

By Isomaa, B. - Lilius, H. - Rabergh, C.

There is an urgent need for effective in vitro tests in aquatic toxicology, because only a very small proportion of the chemicals in common use have been adequately tested for their toxicity to aquatic organisms and aquatic ecosystems. Toxicity tests with higher animals, besides being time-consuming and expensive, are ethically questionable, which further increases the importance of developing efficient in vitro toxicity tests. In developing in vitro tests for toxicity assessments, aquatic toxicology lags behind mammalian toxicology. Aqueous environmental chemistry is complex, and the sensitivity of the organisms living in a particular aquatic environment may vary considerably. The predictive value of single-species or cell culture tests is therefore generally considered to be low. Nevertheless, single-species tests, utilising bacteria, algae, protozoans and invertebrates, have frequently been used in in vitro toxicity studies of aquatic pollutants (mainly as screening tests). Attempts at large-scale validations are few. Such attempts seem to be hampered by the complexity of the aquatic ecosystem. Although cells from aquatic organisms have been isolated and cultured for many years, the use of isolated or cultured cells in aquatic toxicology has been limited. However, during the last few years, interest in the use of fish cells in toxicity testing has grown rapidly. For aquatic in vitro toxicology to develop further, a more comparative and mechanistic approach needs to be adopted.