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Investigation into sources of fipronil in surface water and identification of a novel fipronil metabolite in reclaimed wastewater (Carolinas SETAC 2015 presentation)
Citation:
McMahen, R., M. Strynar, L. McMillan, AND A. Lindstrom. Investigation into sources of fipronil in surface water and identification of a novel fipronil metabolite in reclaimed wastewater (Carolinas SETAC 2015 presentation). Carolinas SETAC Meeting, Raleigh, NC, March 13, 2015.
Impact/Purpose:
The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.
Description:
Fipronil is a phenyl pyrazole insecticide used to control termites, fleas, roaches, ants, and otherpests in residential and agricultural settings. Fipronil has been found in various environmentalmedia (surface water, wastewater, indoor and outdoor dust, etc) and is known to undergodegradation to form a number of derivatives, notably fipronil sulfone, fipronil sulfide, fipronildesulfinyl, and fipronil amide. Not much is known about the environmental impacts of fipronil and its derivatives, however this class of compounds has recently been implicated as a partial causal agent for colony bee collapse. In an effort to understand more about the sources of these chemicals in the environment, fipronil and its derivatives were identified and quantified in surface water from locations up/downstream of golf courses, wastewater treatment plants (WWTP), city parks, and residential areas in central North Carolina. Fipronil and its known derivatives were present in almost all samples, with higher concentrations in wastewater effluent (125-460 ng/L) and downstream of these facilities, suggesting a domestic source as dominant. In analyses of reclaimed water samples, fipronil and its derivatives were notably absent, despite the fact that the only nominal difference from corresponding wastewater effluent is a residual chlorine content of approximately 2 ppm in reclaimed water. Further investigation of the reclaimed water via time-of-flight mass spectrometry (TOF-MS) allowed the observation of a novel fipronil sulfone chloramine species that is thought to result from oxidation and chlorination by sodium hypochlorite. A controlled laboratory experiment involving the incubation of an aqueous mixture of fipronil and sodium hypochlorite was used to confirm the formation of the hypothesized compound. The results of our study on fipronil in surface and wastewater will be presented, along with preliminary results that suggest the chloramination transformation process may not be unique to fipronil.
URLs/Downloads:
https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxjc2V0YWN8Z3g6MWMyNTAzNzU5YWRjMzk1