ABSTRACT
Under environmental conditions chromium in compounds exists in the trivalent chromium Cr(III) or the hexavalent Cr(VI) state. Cr(III) is an essential trace element for mammals, including man, whereas it is presumed that Cr(VI) compounds are genotoxic and potentially carcinogenic in humans. Many Cr(III) compounds are slightly soluble in water. The hydrated sulfates, chlorides, and nitrates are water soluble. The occurrence of Cr(III) in sea water has been explained assuming that the redox equilibrium is only slowly attained once Cr(VI) has been reduced to Cr(III). An experimental approach for specific sampling of Cr(VI) in aerosols has been given by B. Neidhardt et al. The required detection limit of the analytical method depends on the type of sampling applied and the ratio Cr(VI)/Cr(III) in aerosols. The development of methods to determine very low levels of airborne Cr(VI) at unfavorable Cr(VI)/Cr(III) ratio, and the further elucidation of the kinetics of the Cr(VI)/Cr(III) transformations remain challenges to environmentalists.
