STP891

    Usefulness of the Lipid Index for Bioaccumulation Studies with Daphnia magna

    Published: Jan 1985


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    Abstract

    Bioaccumulation studies with Daphnia magna have become an important tool for hazard evaluation of potentially toxic materials released to aquatic environments. Despite widespread use of this test organism, little attention has been paid to influence of stored lipids on uptake of xenobiotics. We drew upon principles of zooplankton population dynamics in the limnological literature to define experimental parameters for bioconcentration testing of organic compounds.

    Adult test populations were initially starved and monitored for lipid content and brood production. Mean lipid index values declined at 72 h to less than 50% of those observed at 24 h. The number of hatched young peaked at 48 h and was inversely related to lipid storage and ovary production. In a separate experiment, uptake kinetics of 14C-labelled quinoline were compared between two daphnid test groups with mean lipid scores of 5.4 and 2.8, respectively. Total radioactivity was significantly higher for the high lipid group at 8 h, and the coefficient of variation was lower. Estimated bioconcentration factors adjusted to dry weight were similar. Our studies indicated that lipid reserves of daphnid test populations can be routinely monitored as an indicator of stress in the laboratory. Bioaccumulation tests should be limited to less than 24 h to avoid depletion of lipid stores, which may cause increased variation in tissue concentration over time.

    Keywords:

    Daphnia magna, lipids, quinoline, bioaccumulation, test protocols, lipid content


    Author Information:

    Dauble, DD
    Research scientist, Pacific Northwest Laboratory, Richland, WA

    Klopfer, DC
    Research specialist, Pacific Northwest Laboratory, Richland, WA

    Carlile, DW
    Research scientist, Pacific Northwest Laboratory, Richland, WA

    William Hanf, R
    Research specialist, Pacific Northwest Laboratory, Richland, WA


    Paper ID: STP33586S

    Committee/Subcommittee: E47.01

    DOI: 10.1520/STP33586S


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