Sublethal effects of phenanthrene, nicotine, and pinane on Daphnia pulex.

Abstract

Nearly 500 compounds were detected in the tissues of Great Lakes fish as compared to 8 in tissues of hatchery-reared fish. Lethal concentrations for many representative compounds were determined by testing their acute toxicity (48-hr EC50) to Daphnia pulex. However, the population growth and survival of aquatic organisms over longer time intervals are usually affected at concentrations much lower than the EC50 for a specific chemical. To develop a general relationship between acute and chronic concentrations for representative compounds detected in Great Lakes fish, the authors initiated full-life-cycle testing on D. pulex with phenanthrene, nicotine, and pinane. Growth and fecundity of daphnids was measured in 16-d tests in the laboratory. Phenanthrene and nicotine were highly toxic and pinane was moderately toxic to D. pulex in acute studies. For phenanthrene, a compound of the polycyclic aromatic hydrocarbons (PAHs) that has been associated with incomplete combustion of organic matter. For nicotine, a compound in the heterocyclic nitrogen class of chemicals that has been used as an insecticide, the EC50 was 0.24 mg/L. Cyclic alkanes, many of which are constituents of crude oil were represented by pinane for which the EC50 was 3.35 mg/L.