Abstract
The toxicity of heavy metals would be changed by changes in the water chemistry such as the concentration of salts and dissolved organic carbon (DOC) in river water around an estuary basin. Recently, the development of bioassay based on marine biology has been attracting much attention because of a surge of interest in marine pollution caused by various human activities. In this study, the influence of salinity changes on the toxicity of heavy metals is explained using the Biotic Ligand Model (BLM) . The copper-spiked waters of Sagami River and Tsurumi River, which have slightly high DOC and considerably high salinity, were used in the application of the BLM to the prediction of the toxicity of copper under the condition of much interaction among Cu, salinity and DOC. The toxicity of copper chloride depended on the salinity condition, and the prediction of the toxicity of copper by using the BLM was possible at the salinity of 0.028 mol L-1～0.14 mol L-1. Additionally, the copper toxicity was exactly determined by using the copper activity measured with a copper-selective ion electrode under various values of DOC.
