A SIMPLE INDOOR ARTIFICIAL STREAM SYSTEM DESIGNED TO STUDY THE EFFECTS OF TOXICANT PULSES ON AQUATIC ORGANISMS

Intermittent discharges of effluents are a common cause of reduced wat er quality. There have, however, been few studies of the effects of su ch discharges on the flora and fauna of receiving waters. A simple ind oor artificial stream system designed to study the effects of toxicant pulses on aquatic organisms ranging from macroinvertebrates to small fish has been constructed and is described. A computer-controlled toxi cant input system has been developed that is capable of generating and delivering toxicant pulses of varying shape, magnitude, amplitude and duration. Comparisons of predicted and actual toxicant concentrations have been carried out and hydraulic and toxicant conditions were foun d to be reproducible. Sample results are given of the effect of short- term pulses of cadmium on the amphipod Gammarus pulex. Possible future developments of the system are discussed.