Development of methods to assess the effects of xenobiotics in outdoor artificial streams.

Two collaborative research projects were designed to develop and validate methods for determining the chronic effects of xenobiotics in freshwater ecosystems. The work reported here focuses on the development of methods for measuring effects on fish, invertebrates, and algae in outdoor artificial streams. 3,4-Dichloroaniline (3,4-DCA), has been used as a reference xenobiotic in two artificial stream experiments. The first used five stream channels: a control and treatments ranging from 70 to 2400 microg/liter. The second used eight stream channels--a control and treatments ranging from 0.45 to 4700 microg/liter and four coupled, 510-liter-capacity, downstream ponds-a control and treatments of 1.7, 37, and 820 microg/liter. Effects on the biota of the stream channels and the downstream ponds were examined using a range of sampling techniques and in situ toxicity tests.