An indoor artificial stream system was designed, developed and tested for consistency in behaviour of the system in terms of the kinetics of pollutant (copper) and the organisms contained in it over space and time.

Downstream drift of invertebrates in the system was found to be affected by intensity of light, flow rate, algal biomass in the system and by sublethal concentrations of copper. Bioaccumulation of copper as body burden was also analysed and found to be positively related to ambient copper level and negatively related to dry body weight in GAMMARUS PULEX and HYDROPSYCHE ANGUSTIPENNIS but not in SPHAERIUM sp.

Mortality analysis in terms of LC-50 values for GAMMARUS PULEX (L.) were also estimated in stream system and traditional tank toxicity method and were found to be more up to five times that in the tank system. Similarly LC-50šs estimated using nominal concentrations were found to be double that calculated from integrated mean concentrations.

Downstream drift behaviour showed a decline in the magnitude of response after repeated pulses of sublethal doses while mortality was unaffected over the experimental time. Copper body burden showed a decrease as number of pulses of low concentration increased, but a gradual increase in copper body burden as number of pulses increased in higher concentrations.