Structural influences of low-molecular-weight dissolved organic carbon mimics on the photolytic fate of atrazine
1998
Hapeman, C.J. | Bilboulian, S. | Anderson, B.G. | Torrents, A.
The fate of atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) was examined in the presence of dissolved organic carbon (DOC) mimics to discern the effect of the various structural characteristics of DOC with respect to direct photolysis and transformation via a photoinitiated nitrate-mediated hydroxy radical process (indirect photolysis). Experiments were conducted with coniferyl alcohol, 2-octanol, oxalic acid, pyrogallol, quinone, and salicylic acid. All mimics except octanol and coniferyl alcohol caused an increase in the atrazine degradation rate when no nitrate was present. A decrease in atrazine degradation in indirect photolysis was observed for coniferyl alcohol, octanol, pyrogallol, and salicylic acid, whereas the rate increased with oxalic acid and quinone. Examination of the product ratios showed a dependence of the chemical activity (photosensitizer, OH. radical scavenger or OH. generator) on structure. Results revealed that structural aspects of DOC, in addition to concentration, must be considered when predicting the photolytic fate of pesticides.
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