ORCID Profile
0000-0002-0891-2712
Current Organisation
US Geological Survey
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Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.SCITOTENV.2017.06.156
Abstract: Aquatic organisms in streams are exposed to pesticide mixtures that vary in composition over time in response to changes in flow conditions, pesticide inputs to the stream, and pesticide fate and degradation within the stream. To characterize mixtures of dissolved-phase pesticides and degradates in Midwestern streams, a synoptic study was conducted at 100 streams during May-August 2013. In weekly water s les, 94 pesticides and 89 degradates were detected, with a median of 25 compounds detected per s le and 54 detected per site. In a screening-level assessment using aquatic-life benchmarks and the Pesticide Toxicity Index (PTI), potential effects on fish were unlikely in most streams. For invertebrates, potential chronic toxicity was predicted in 53% of streams, punctuated in 12% of streams by acutely toxic exposures. For aquatic plants, acute but likely reversible effects on biomass were predicted in 75% of streams, with potential longer-term effects on plant communities in 9% of streams. Relatively few pesticides in water-atrazine, acetochlor, metolachlor, imidacloprid, fipronil, organophosphate insecticides, and carbendazim-were predicted to be major contributors to potential toxicity. Agricultural streams had the highest potential for effects on plants, especially in May-June, corresponding to high spring-flush herbicide concentrations. Urban streams had higher detection frequencies and concentrations of insecticides and most fungicides than in agricultural streams, and higher potential for invertebrate toxicity, which peaked during July-August. Toxicity-screening predictions for invertebrates were supported by quantile regressions showing significant associations for the Benthic Invertebrate-PTI and imidacloprid concentrations with invertebrate community metrics for MSQA streams, and by mesocosm toxicity testing with imidacloprid showing effects on invertebrate communities at environmentally relevant concentrations. This study documents the most complex pesticide mixtures yet reported in discrete water s les in the U.S. and, using multiple lines of evidence, predicts that pesticides were potentially toxic to nontarget aquatic life in about half of the s led streams.
Publisher: Wiley
Date: 27-02-2018
Publisher: US Geological Survey
Date: 2014
DOI: 10.3133/DS811
Publisher: Springer Science and Business Media LLC
Date: 03-07-2018
DOI: 10.1038/S41598-018-28132-3
Abstract: This is the first field study of its kind to combine radio telemetry, passive s lers, and pesticide accumulation in tissues to characterize the hibian exposome as it relates to pesticides. Understanding how habitat drives exposure in in iduals ( i . e ., their exposome), and how that relates to in idual health is critical to managing species in an agricultural landscape where pesticide exposure is likely. We followed 72 northern leopard frogs ( Lithobates pipiens ) in two agricultural wetlands for insight into where and when in iduals are at high risk of pesticide exposure. Novel passive s ling devices (PSDs) were deployed at sites where telemetered frogs were located, then moved to subsequent locations as frogs were radio-tracked. Pesticide concentration in PSDs varied by habitat and was greatest in agricultural fields where frogs were rarely found. Pesticide concentrations in frogs were greatest in spring when frogs were occupying wetlands compared to late summer when frogs occupied terrestrial habitats. Our results indicate that habitat and time of year influence exposure and accumulation of pesticides in hibians. Our study illustrates the feasibility of quantifying the hibian exposome to interpret the role of habitat use in pesticide accumulation in frogs to better manage hibians in agricultural landscapes.
No related grants have been discovered for Michelle Hladik.