Photochemical reactions contribute to the abiotic transformation of pesticides in prairie pothole lakes (PPLs), which contain a variety of photosensitizers. Despite the fact that triplet excited state dissolved organic matter (DOM) can enhance phototransformation of pesticides by acting as a photosensitizer, it may also decrease the overall phototransformation rate through various mechanisms. In this study, the effect of DOM on the phototransformation of four commonly applied pesticides in four different PPL waters was investigated under simulated sunlight using photoexcited benzophenone-4-carboxylate as the oxidant. For atrazine, isoproturon and mesotrione, a decrease in phototransformation rates was observed, while metolachlor phototransformation was enhanced in the presence of DOM. Phototransformation rates and the extent of inhibition/enhancement by DOM varied spatially and temporally across the sites. Characterization of DOM from the sites and different seasons suggested that DOM type and seasonal variations are important factors controlling phototransformation rates of pesticides in PPLs.

Phototransformation of pesticides in prairie potholes: Effect of dissolved organic matter in triplet-induced oxidation

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.