Ever since Rachel Carson's Silent Spring, we have generally become aware of environmental contaminants and their effects on the ecosystem. The findin~ of PCB's in fish by Soren Jensen in Sweden, the recognition of mirex as contaminant in fish from Lake Ontario, and the discoveries of contaminant laden leachates from dumpsites such as the Love Canal have become milestones in the search for and charac terization of contaminants in our environment. At this time, the problem no longer is so much the identifi cation of contaminants and their sources. Rather, we are now faced with solving questions on the fates and effects of such compounds. This includes the search for mechanisms to deal effectively with the large number of chemicals already found in water, air and biota. One of such time and cost saving scientific avenues is the field of quantitative structure-activity correlations for the prediction of the environmental behavior and effects of compounds.