Full Description

This study identifies combinations of over 60 pesticides and 8 common disinfectants (orconditions) including free chlorine, monochloramine, chlorine dioxide, permanganate, ozone,hydrogen peroxide, photo-oxidation with UV at 254 nm, and hydrolysis at pH 2, pH 7, and pH12, that exhibit the potential for pesticide degradate formation. Initial parent pesticideconcentrations were less than 25 g/L, and treatment dosages were on the order of typicalexposures used during water treatment. The reaction media was buffered Milli-Q water adjustedto pH 6.6 and 8.6. The reactivity of pesticide/oxidant pairs were categorized as "highly reactive"(50% parent removal), "moderately reactive" (20-50% parent removal), and "slightly reactive"(20% parent removal). The screening study results indicate the most reactive combinations oftransformation agents and pesticides leading to degradates formation in water utilities. Basedupon exposure (e.g., occurrence, usage), reactivity, toxicity and other criteria, several of the mostimportant systems were studied in detail. The identity and pathway of the major metaboliteswere determined using Ion Trap LC/MS, GC/MS, and other techniques. The data presentedhelps identify situations of potentially harmful pesticide degradate formation in commondrinking water treatment systems. Includes 19 references, table.

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Edition: Vol. - No. Published: 11/01/2007 Number of Pages: 8File Size: 1 file , 150 KB