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AQUATIC HUMIC SUBSTANCES AS SOURCES AND SINKS OF PHOTOCHEMICALLY PRODUCED TRANSIENT REACTIONS
Citation:
Hoigne, J., B. Faust, W. Haag, AND R. Zepp. AQUATIC HUMIC SUBSTANCES AS SOURCES AND SINKS OF PHOTOCHEMICALLY PRODUCED TRANSIENT REACTIONS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-89/040 (NTIS PB89221386), 1989.
Description:
In sunlit surface waters, aquatic humics and nitrate act as sensitizers or precursors for the production of photoreactants such as singlet oxygen, humic-derived peroxy radicals, hydrogen peroxide, and solvated electrons. ifetimes of the various reactants are controlled by their reactions with aquatic humics, by solvent quenching (singlet oxygen), by reactions with molecular oxygen (solvated electron), or by other processes (peroxy radicals). he steady-state concentration of each transient formed during solar irradiation was determined from the observed disappearance rate of added organic probe compounds. he probe compounds have selective reactivities with the individual transient species of interest. ffects of these photoreactants on the elimination of micropollutants and on chemical transformations of dissolved organic matter are discussed.