title: The fate of fipronil in modular estuarine mesocosms.
abstract: The degradation and corresponding product manifold for the pesticide fipronil was determined in three replicate estuarine mesocosms. Aqueous fipronil concentrations rapidly decreased over the 672 h timescale of the experiment (95% removal). Loss was apparently first-order in fipronil, although there appeared to be a change in the removal mechanism after 96 h that corresponded to a dramatic slowdown in its disappearance. The reduction product of fipronil, fipronil sulfide, was not detected in the water column; however, it formed rapidly in sediments and was identified as the major product of fipronil degradation in the system (20% yield at 672 h, with respect to initial fipronil concentration). Fipronil sulfone is thought to form primarily via biological oxidation; and, although it was generated rapidly in the water column (10% yield), only trace amounts were detected in the sediment (1% yield). The direct photolysis product of fipronil, fipronil desulfinyl, was present in all samples; it formed rapidly in the water column (4% yield) and partitioned into the sediment phase (7% yield) over the course of the experiment. The mass balance on fipronil and associated products was 42% at 672 h.
authors.affiliation: Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 29208, USA.
authors.forename: Spencer S
authors.initials: SS
authors.lastname: Walse
authors.forename: Paul L
authors.initials: PL
authors.lastname: Pennington
authors.forename: Geoffrey I
authors.initials: GI
authors.lastname: Scott
authors.forename: John L
authors.initials: JL
authors.lastname: Ferry
mesh_terms: D017753:Ecosystem; D019015:Geologic Sediments / Q000737:chemistry; D007306:Insecticides / Q000378:metabolism*; D010084:Oxidation-Reduction; D010777:Photochemistry; D011720:Pyrazoles / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D007306:Insecticides; D011720:Pyrazoles; D014874:Water Pollutants, Chemical; C082360:fipronil