This work describes that cytotoxicity of lead chloride and lead acetate to in vitro cultured lymphocytes from human umbilical cord blood, using four monitoring methods namely, trypan blue staining, acridine orange/ethidium bromide staining, 3-[4,5-dimethylthiazol-2-yl] 2,5-diphenyl tetrazolium bromide (MTT) and neutral red uptake assays; lead genotoxicity to lymphocytes was monitored by comet assay. The MIC value in each method was invariably 300 mg/L for PbCl2. Lethal concentration25 (LC25) values were almost in an agreeable range: 691.83 to 831.76 mg/L; LC50 values in each method were almost in the range: 1174.9 to 1348.9 mg/L; LC100 values were in the range: 3000 to 3300 mg/L, for lead chloride. Similarly, The MIC value in each method were invariably 150 mg/L; LC25 values were almost in the range: 295.12 to 371.53 mg/L; LC50 values were in the range: 501.18 to 588.84 mg/L; LC100 value was 1500 mg/L in all assays, for lead acetate. The comet assay also indicated that the LC100 values were 3300 mg/L lead chloride and 1500 mg/L lead acetate. Thus, both cytotoxicity and genotoxicity were recorded at 3300 mg/L lead chloride and 1500 mg/L lead acetate with lymphocytes.
