Polycyclic aromatic hydrocarbons in earthworms and isopods from contaminated forest soils

Abstract

Individuals of the isopod species Porcellio scaber, Oniscus asellus and Philoscia muscorum and the earthworm species Lumbricus rubellus were collected at i0 sites with increasing distance from a blast furnace plant. PAH concentrations in the species decreased with increasing distance from the blast furnace plant. Each of the species contained a specific profile of PAHs. Animal concentrations correlated better with PAH levels in humus and fragmentation material than with levels in litter and mineral soil, which is consistent with the feeding behaviour of the animals. Biota-to-soil accumulation factors differed between the species and for the isopod species were negatively correlated with the octanol-water partition coefficient. This deviates from what is expected on the basis of the equilibrium partitioning theory. Possible non-equilibrium conditions are discussed. Cluster analysis of the PAH profiles observed in this study in conjunction with other terrestrial data from the literature, showed the presence of three main groups. One contained the profiles typical for atmospheric PAHs; the second cluster contained samples from earthworms, fragmentation, humus and mineral soil; the third contained litter and isopod profiles.