Accumulation of polycyclic aromatic hydrocarbons from creosote-contaminated soil in selected plants and the oligochoete worm Enchytraeus crypticus

The accumulation of PAHs from a creosote-contaminated soil was examined in laboratory experiments using English ryegrass (Lolium perenne), white clover (Trifolium repens) and radish (Raphanus sativus), and the oligochaete worm Enchytraeus crypticus. Toxicity to the plants and the worms was assessed, and a soil sample mixed with calcined sand was used for accumulation experiments to avoid interference from toxicity in the soil. Accumulation of potentially carcinogenic PAHs varied among the plants, and there was a linear relation between concentrations of PAHs in the soil and in the plants. Correlations between values of the biota-soil accumulation factors and octanol-water partition coefficients, or water solubility varied among the plants and were rather weak, so that lipophilic character or water solubility of the PAHs alone cannot explain PAH accumulation. Accumulation of carcinogenic PAHs from the soil, in the presence of the other PAHs was greatest for Trifolium repens. PAHs were accumulated in the oligochaete worm (Enchytraeus crypticus), and biota-soil accumulation factors exceeded those for the plants. It is suggested that site-specific evaluation of contaminated sites should include not only chemical analysis and evaluation of toxicity but also accumulation of contaminants into biota such as plants and worms.