Solubility of low-solubility chromates and their clastogenic activity in cultured cells

Low-solubility chromates, such as lead chromate, zinc chromate and calcium chromate, which are potent carcinogens, have been examined for their solubility and clastogenic effects in a cultured Chinese hamster cell line (Don) as compared with those of potassium chromate, which is a high-solubility chromate and a weak carcinogen. Lead chromate was slightly soluble in water, Tyrode's solution, protein or amino acid solution, fetal calf serum and culture medium. Zinc chromate and calcium chromate were less soluble in serum and Tyrode's solution than in water. There were good correlations between the frequencies of chromosomal aberrations in the cells treated with the above chromates and chromium concentrations dissolved from these chromates in culture medium. When the frequency of chromosomal aberration in the cells exposed to the above chromates was compared on equal amounts of dissolved chromium concentrations in culture medium, the frequency of chromosomal aberration was the most remarkable with lead chromate, followed by zinc chromate and potassium chromate and then by calcium chromate. On the column chromatographs by gel filtration on Sephadex G-200, the chromium dissolved from all the above chromates in culture medium was present with low molecular fraction. From the above results, it was assumed that the carcinogenicity of low-solubility chromates might be related to their low solubility in body fluid.