THE EFFECTS OF SALINITY, TEMPERATURE AND SEDIMENT ON THE TOXICITY OF COPPER TO JUVENILE HEDISTE (NEREIS) DIVERSICOLOR (MULLER,O.F.)

Without sediment, increasing salinity (7.3 to 29.2 parts per thousand) and increasing temperature (12 to 22-degrees-C) reduced the toxicity of copper to juvenile Hediste diversicolor. The LC50 values ranged from 357-mu-g L-1 in 7.3 parts per thousand to 513-mu-g L-1 in 29.2 parts per thousand at 12-degrees-C and from 247 to 500-mu-g L-1 at 22-degrees-C. In deionized water all the juvenile were dead in all solutions to which copper was added (100 to 600-mu-g L-1). Dead worms were swollen and everted their pharynxs. In higher doses of copper (500 to 600-mu-g L-1) the worms were abnormal in behaviour in all salinities (0 to 29.2 parts per thousand). The ability to swim or crawl was disturbed. With sediments increasing temperature and increasing salinity increased the toxicity of copper to the worms. The LC50 values ranged from 3200 to 4100-mu-g L-1 at 22-degrees-C. The response of the juvenile to copper was antagonistic to increasing temperature and salinity and synergistic to increasing salinity and increasing temperature without and with the sediment respectively.