STP921: Effect of Natural Water Source on the Toxicity of Chemicals to Aquatic Microorganisms

    Cunningham, VL
    Manager, research assistant, and analytical chemist, Smith Kline & French Laboratories, PA

    Morgan, MS
    Manager, research assistant, and analytical chemist, Smith Kline & French Laboratories, PA

    Hannah, RE
    Manager, research assistant, and analytical chemist, Smith Kline & French Laboratories, PA

    Pages: 14    Published: Jan 1986


    Abstract

    A series of substituted chlorophenols was evaluated in the Beckman Microtox® Analyzer using natural water from several diverse sources. Statistically significant differences in the effect level, as measured by an ANOVA of the EC50 (the concentration of toxicant that causes a 50% reduction in the light output of the bioluminescent bioassay organism, Photobacterium phosphoreum), were observed as a function of water source for three of the four compounds tested. These differences may be attributed to differences in the nature and concentration of natural dissolved organic carbon (DOC) in the water samples. Some DOC, such as humics, are suspected of binding hydrophobic toxicants, and thus reducing the bioavailability and toxic effect of these compounds. At least one of the observed toxicity reductions can be accounted for by specific compound characteristics and the nature and concentration of the DOC as determined by fluorescence spectroscopy and fingerprinting by pyrolytic gas chromatography/mass spectrometry (GC/MS) techniques. However, for the other compounds tested, fluorescence techniques proved inadequate. Additional methodology will be necessary to elucidate the seemingly more complex mechanisms of toxicity reduction for these compounds.

    Keywords:

    aquatic toxicology, chlorophenols, humic acids, dissolved organic carbon, bioluminescent bacteria, Photobacterium phosphoreum, fluorescence spectroscopy, pyrolytic gas chromatography/mass spectrometry


    Paper ID: STP29044S

    Committee/Subcommittee: E47.10

    DOI: 10.1520/STP29044S


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