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RELATIVE RATE CONSTANTS OF CONTAMINANT CANDIDATE LIST PESTICIDES WITH HYDROXYL RADICALS
Citation:
SHEMER, H., C. SHARPLESS, M. ELOVITZ, AND K. LINDEN. RELATIVE RATE CONSTANTS OF CONTAMINANT CANDIDATE LIST PESTICIDES WITH HYDROXYL RADICALS. J. Schnoor (ed.), ENVIRONMENTAL SCIENCE AND TECHNOLOGY. American Chemical Society, Washington, DC, 40(14):4460-4466, (2006).
Description:
The objective of this study was to establish the rate constants for the reactions of selected pesticides listed on the US EPA Contaminant Candidate List, with UV and hydroxyl radicals (·OH). Batch experiments were conducted in phosphate buffered solution at pH 7. All pesticides were found to be very reactive toward ·OH as indicated by rate constant values above 109M-1s-1. Using molinate as a reference compound, kOH ranged from 2.7x109 to 12.0x109M-1s-1 for the contaminants tested while slightly higher values from 2.9x109 to 14.3x109 M-1s-1 were obtained using nitrobenzene as a reference compound. A method was established that accounts for direct photolysis when calculating kOH using UV/H2O2 process for compounds which degrade significantly by a direct photolysis mechanism.