Use of Daphnia magna for the Microbioassay of Pesticides. II. Comparison of Microbioassay with Gas Chromatography for Analysis of Pesticide Residues in Plant Extracts1

Abstract

Specimens of Daphnia magna Straus, which were killed by extremely small quantities of pesticides, were killed also by small amounts of extracts of common plants, such as lettuce, radishes, and beets. Even following rigorous cleanup, these plant extracts were toxic enough to the test organism to mask any mortality caused by pesticide residues. Using purified extracts of carrot tops, which had low toxicity to daphnids, the microbioassay procedure for measuring DDT, ethion, and lindane residues was compared with gas-liquid chromatography (GLC). GLC was found to give much more consistent and accurate results than microbioassay with D. magna.