STP1443

    Synergistic Effects of a Combined Exposure to Herbicides and an Insecticide in Hyla versicolor

    Published: Jan 2003


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    Abstract

    Combinations of the herbicides atrazine and metolachlor and the insecticide chlorpyrifos were tested under both laboratory and field conditions to determine their individual and combined effects on amphibian populations. In the lab Hyla versicolor tadpoles experienced 100% mortality when exposed to a high combination of the pesticides (2.0 mg/L atrazine, 2.54 mg/L metolachlor, 1.0 mg/L chlorpyrifos) whereas low concentrations of the pesticides (0.2 mg/L atrazine, 0.25 mg/L metolachlor, 0.1 mg/L chlorpyrifos) or high concentrations of either herbicides or insecticide alone caused lethargy, reduced growth and delayed metamorphosis but no significant mortality. In the field high herbicide, low insecticide and low herbicide, low insecticide mixtures significantly reduced amphibian populations compared to controls but in the low herbicide, low insecticide wetlands amphibian populations were able to recover through recruitment by the end of the season.

    Keywords:

    chlorpyrifos, atrazine, metolachlor, Hyla versicolor, amphibians, pesticide interaction


    Author Information:

    Mazanti, L
    Research Scientist, Natural Resources Conservation Service, Wetland Science Institute, Laurel, MD

    Sparling, DW
    Research Biologist, Patuxent Wildlife Research Center, Laurel, MD

    Rice, C
    Chemist, Beltsville Agriculture Research Center, Beltsville, MD

    Bialek, K
    Chemist, Beltsville Agriculture Research Center, Beltsville, MD

    Stevenson, C
    Professor, University of Maryland Chesapeake Bay Laboratory, Solomons, MD

    Teels, B
    Director, Natural Resources Conservation Service, Wetland Science Institute, Laurel, MD


    Paper ID: STP11178S

    Committee/Subcommittee: E47.04

    DOI: 10.1520/STP11178S


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