Over the past 25 years the discipline of ecotoxicology has undergone two major developments. Firstly, new assays have been developed, deploying organisms that bear added relevance to the specific environment under investigation. Several new procedures assess the effects on organisms after exposure to environmental samples rather than to spiked water or sediment samples. Also noteworthy is the considerable attention given to effects of chronic exposure to low levels of contaminants. These developments are of great importance for the application of ecotoxicological techniques in riskassessment approaches
