AQUEOUS TRIVALENT CHROMIUM PHOTOPRODUCTION IN NATURAL-WATERS

Field studies indicate Cr(III) is photochemically produced at two freshwater lakes in southeastern North Carolina. Results of controlled photolysis experiments with marine and estuarine samples suggest this process may be common. to many natural water systems. This photogeneration mechanism sheds new insight into the existence of the thermodynamically unstable Cr(III) ion in oxygenated surface waters. Sixty-eight water samples from seven water bodies in the southeastern United States (fresh, estuarine, and marine) displayed a range of total aqueous inorganic chromium from <0.01 nM to 1.05 nM, with variable amounts of the trivalent and hexavalent species. These are the first Cr(III) and Cr(VI) values reported for all these aqueous systems and some of the first ever for nonmarine environments.