Bioassays of Cupric Ion Activity and Copper Complexation

Because of its reactivity, copper is both toxic to organisms and tends to be complexed by organic ligands in natural waters (Sunda and Hanson 1979). The extent to which copper is complexed has been found to control its toxicity due to a dependence of copper toxicity on free cupric ion activity rather than on total or complexed copper concentrations (Sunda and Guillard 1976, Anderson and Morel 1978, Jackson and Morgan 1978).