An outdoor artificial stream system designed for ecotoxicological studies

Six outdoor artificial streams were designed to simulate natural stream environments. Their primary intended use is to define acceptable threshold toxicity concentrations for chemicals and effluents in the aquatic environment and so provide data that can be used to define water quality criteria more accurately than is possible on the basis of data obtained solely from laboratory tests. Each stream was divided into pool and riffle sections that were colonized by communities of periphyton and invertebrates. They were operated as partly flow-through, partly recirculating systems. The design and construction of the streams are described in detail, and brief descriptions are given of methods of establishing aquatic communities, measuring water quality parameters, and treating the streams with chemicals and effluents. The performance of the streams in environmental research is illustrated by reference to typical data for primary production, for invertebrate diversity and abundance, and for chemical concentrations measured during an experiment of two weeks duration.