The application of bioassays in the resolution of environmental problems; past, present and future

Literature on bioassays for freshwater systems has been reviewed (between 1979 and 1987) and classified into studies concerned with prediction and assessment and, within these categories, into studies concerned with single- and multi-species bioassays. Changing trends in the response criteria and types of organisms used in the predictive tests are judged against results from a similar review carried out in 1979. This leads to the conclusion that though there may have been changes in detail, bioassays have remained surprisingly unchanged in general features over this time. The relative merits of, and relationship between single- and multi-species studies for both predicting and assessing the biological impact of toxicants are discussed. The conclusion is that some bioassays have more severe problems than others, but a concern with all of them is that responses observed in particular systems may not be relevant in general. The possibility of developing a general theoretical infrastructure for bioassays that addresses this problem is considered.