Individual and combined cytotoxic effects of cadmium, copper, and nickel on brown cells of Mercenaria mercenaria.

An assay based on the lysosomal incorporation of neutral red dye by brown cells of Mercenaria mercenaria (Bivalvia) was used to measure the cytotoxicity of Cd2+, Cu2+, and Ni2+ singly and in combination. Cytotoxicity was a linear function of Cd2+ concentration 0.1-1.5 mM and Cu2+ concentration between 10 and 100 microM. Nickel was not cytotoxic at concentrations as high as 10 mM. The presence of Cu2+ lessened the cytotoxic effect of Cd2+. Ni2+ did not affect cytotoxicity in combination with either Cu2+ or Cd2+.Ni2+ inflated estimates of cell survival by the neutral red assay in this study. Cells exposed to Ni2+ yielded measured quantities of neutral red dye in excess of those measured in cells from control treatments.