ABSTRACT
This chapter purposes to summarize the knowledge on the involvement of free radicals in the process of metal-induced carcinogenesis, to critically evaluate this knowledge, and to propose future directions for research in this area. It focuses on specific chromium, nickel, arsenic, beryllium, iron, and copper compounds. These specific compounds were chosen because certain compounds of the elements chromium and nickel and the metalloid arsenic are known human occupational carcinogens. Specific insoluble hexavalent chromium chompounds are the strongest carcinogens among chromium compounds. Epidemological studies have indicated that workers who mine chromium ores or work in the pigment industries where specific chromium compounds are components of the pigments, such as lead chromate, have increased frequencies of lung cancer. In the case of soluble hexavalent chromium compounds, the chromate ion containing the hexavalent chromium atom is taken up into cells by the somewhat nonspecific sulfate anion transport system.
