The urgent need for in vitro tests in ecotoxicology

Ecotoxicological risk assessment should be regarded as consisting of several elements including molecular biology, cell toxicology, toxicology, ecology, chemistry and computer modelling [including quantitative structure-activity relationship (QSAR) considerations]. A successful risk assessment requires an approach that integrates data and knowledge from all the separate elements. The relative importance of a certain element will vary, depending on the situation or the chemical in question. One important, perhaps the most important, piece of information needed in risk assessment is the information about the concentration range at which a chemical exerts adverse effects on the organisms living in the aquatic environment. Without such information no prediction can be made or safety factors established. A combination of good in vitro tests could provide that information. A proper choice of endpoints in in vitro testing could also provide information on sublethal effects and toxic mechanisms involved, enabling even a more efficient approach than whole animal testing. For aquatic in vitro toxicology to progress further, there is a need for a more integrated, a more comparative and a more mechanistic approach and for large-scale evaluations. It would be beneficial if researchers could agree on using a common set or a few sets of reference chemicals in their studies and if some organization would take the scientific responsibility for aiding in the development of a more integrated strategy.