Are laboratory-derived toxicity data for freshwater algae worth the effort?

Algal toxicity test results are increasingly being considered in the evaluation of the environmental safety of chemicals and effluents. The ability of the current standard toxicity test methods to provide data useful in the safety assessment process was reviewed. It was concluded that there are too few data supporting the environmental relevance of those results derived using the standard methods in their present format. The current algal toxicity data base shows that interspecific variation in response to chemicals is significant and that field-validation of most laboratory-derived results is lacking. Therefore, multiple test species should be used in algal toxicity tests and the biological significance of the recommended end points, including stimulation, needs definition before the results can be expanded to natural algal communities and be useful in predicting environmental impact.