STP891

    The Sensitivity of Chronic Endpoints Used in Daphnia magna Straus Life-Cycle Tests

    Published: Jan 1985


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    Abstract

    The sensitivity of three endpoints used to evaluate the chronic toxicity of boric acid, un-ionized ammonia, and triclopyr triethylamine salt (TEA salt) to Daphnia magna was examined. The endpoints examined during these studies were reproduction, growth, and survival. A 21-day static renewal toxicity test was conducted with Daphnia magna for all three test materials. The maximum acceptable toxicant concentrations (MATCs) derived from these studies were boric acid 6.4 < MATC < 13.6 mg B/L, unionized ammonia 0.42 < MATC < 0.87 mg NH3-N/L, and triclopyr TEA salt 80.7 < MATC < 149.0 mg/L. Reproduction was consistently the most sensitive endpoint in all three studies. An examination of the literature indicates that the utility and relative sensitivity of reproduction and survival as chronic endpoints have been questionable because of erratic adult survival and large amounts of reproductive variation. The data from this study show that use of well nourished and healthy test organisms reduces variability in both reproduction and survival and enhances the reliability of the daphnid chronic test.

    Keywords:

    Daphnia magna, boric acids, zooplankton, chronic toxicity, un-ionized ammonia, chronic toxicity, triclopyr


    Author Information:

    Gersich, FM
    Project leader, biologist, and research chemist, Mammalian and Environmental Toxicology, The Dow Chemical Company, Midland, MI

    Hopkins, DL
    Research chemist and research leader, Analytical and Environmental Chemistry, The Dow Chemical Company, Midland, MI

    Applegath, SL
    Project leader, biologist, and research chemist, Mammalian and Environmental Toxicology, The Dow Chemical Company, Midland, MI

    Mendoza, CG
    Research chemist and research leader, Analytical and Environmental Chemistry, The Dow Chemical Company, Midland, MI

    Milazzo, DP
    Project leader, biologist, and research chemist, Mammalian and Environmental Toxicology, The Dow Chemical Company, Midland, MI


    Paper ID: STP33576S

    Committee/Subcommittee: E47.01

    DOI: 10.1520/STP33576S


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