Environmental impact of land-based pollutants on Izmit Bay (Turkey): short-term algal bioassays and simulation of toxicity distribution in the marine environment.

The eight dominant discharges of land-based waste entering Izmit Bay, Turkey, as a result of its burgeoning development are characterized here. Chemical analyses of the discharges are described and their toxicity has been quantified as a result of short term 14C algal bioassays. Predictions of toxicity distributions in the upper layer of the bay are obtained by combining the inflow rates of the eight discharges and their quantified toxicities with a two-dimensional dispersion equation. Uptake by phytoplankton appears to be the dominant mechanism reducing toxicity in the bay. The second mechanism reducing the toxicity of the waste is dispersion by wind-induced current. The results show that although most of the factories contributing to the discharges have treatment plants, the treatment is insufficient to eliminate toxicity.