Photodegradation Of Some Naturally Occurring Organic Compounds And Their Metal Complexes

Photodegradation of naturally occurring organic compounds in Atibaia River water, sewage, and Aldrich humic acid was investigated under both solar and artificial near-UV irradiation. The influence of cadmium, copper and iron on the degradation rates of the Atibaia River water samples was also investigated. It is shown that at concentration of 1 × 10-6 M, copper strongly inhibited the photodegradation, whereas cadmium and iron did not affect this process. Ecological implications of such behaviour are discussed. © 1988.752-3243248Araki, Shiraishi, Catalytic action of iron and manganese ions in the photochemically-induced oxidation of D-fructose with atmospheric oxygen (1986) Bulletin of the Chemical Society of Japan, 59, pp. 229-234Aust, Morehouse, Thomas, Role of metals in oxygen radical reactions (1985) J. Free Rad. Biol. Med., 1, pp. 3-25Baxter, Carey, Evidence for photochemical generation of superoxide ion in humic waters (1983) Nature, 306, pp. 575-576Borkman, Hibbard, Dillon, The photolysis of tryptophan with 337.1 nm laser radiation (1986) Photochem. Photobiol., 43, pp. 13-19Copper, Herr, Introduction and overview (1987) Photochemistry of Environmental Aquatic Systems, pp. 1-8. , R.G. Zika, W.J. Copper, ACS symp. Ser. 327De Paoli, Rodrigues, Aparelhagen para fotolise (1978) Quim. Nova, 1, pp. 16-17Hanaki, Kamide, The copper catalysed autooxidation of cysteine (1983) Bull. Chem. Soc. Jpn, 56, pp. 2065-2068Hoffman, Trace metal catalysis in aquatic environments (1980) Environmental Science & Technology, 14, pp. 1061-1066Jardim, Soldá, Gimenez, The role of cupric ions in the generation of superoxide in natural waters (1986) Sci. Total Environ., 58, pp. 47-54McCormick, Thomason, Near UV photooxidation of tryptophan. Proof of superoxide formation (1978) J. Am. Chem. Soc., 100, pp. 312-313Miles, Brezonik, Oxygen consumption in humic-colored waters by a photochemical ferrous-ferric catalytic cycle (1981) Environ. Sci. Technol., 15, pp. 1089-1094Mopper, Zika, Natural photosensitizers in sea water: riboflavin and its breakdown products (1987) Photochemistry of Environmental Aquatic Systems, pp. 174-190. , R.G. Zika, W.J. Copper, ACS Symp. Ser. 327Norwitz, Keliher, Spectrophotometric determination of nitrite (1984) The Analyst, 109, pp. 1281-1285Power, Sharma, Langford, Bonneau, Joussot-Dubien, Laser flash photolytic studies of well characterized soil humic substances (1987) Photochemistry of Environmental Aquatic Systems, pp. 157-173. , R.G. Zika, W.J. Cooper, ACS Symp. Ser. 327Zafirou, Joussot-Dubien, Zepp, Zika, Photochemistry of natural water (1984) Environmental Science & Technology, 18, pp. 358A-371AZepp, Braun, Hoigne, Leenher, Photoproduction of hydrated electrons from natural organic solutes in aquatic environments (1987) Environ. Sci. Technol., 21, pp. 485-49

The dissolved iodate and iodide distribution in the South Atlantic from the Weddell Sea to Brazil

Iodide and iodate concentrations are reported and discussed for the WOCE A23 transect from the Weddell Sea north to about 25°S. Iodide concentrations are very low in the surface waters of the Weddell Sea (20 nM) and increase steadily northwards to about 100 nM in the surface waters of the south Atlantic gyre. In deep waters iodide concentrations are low but detectable at 0.5–2 nM. There is no detectable total iodine depletion in the surface waters south of the polar front although there is a small depletion evident north of the front. The results are discussed in terms of the hydrography, nutrient concentrations and phytoplankton activity along the transect. In particular, a systematic change in the relationship between iodide and nitrate along the transect is discussed