Toxicity and bioaccumulation of phenanthrene in Enchytraeus albidus (Oligochaeta: Enchytraeidae)

Polycyclic aromatic compounds, such as phenanthrene (PHE), tend to accumulate in the soil compartment, where they may be retained for many years because of their persistency and hydrophobicity. The toxicity and bioaccumulation of these chemicals in soil biota and potential biomagnification along the food chain is an issue of concern. The main goal of this study was to determine the toxicity and bioaccumulation of PHE in Enchytraeus albidus (Oligochaeta: Enchytraeidae) in a natural standard soil (LUFA 2.2) following standard test guidelines. Phenanthrene dose-relatedly affected the survival and reproduction of E. albidus with median lethal concentration and median effective concentration (EC50) values of 135 and 33 mg/kg dry soil, respectively. A toxicokinetics study, performed at a nontoxic soil concentration of 8 mg/kg, showed uptake and elimination rate constants of 4.91 kg soil per kilogram fresh weight animal per day and 0.236 per day, respectively and a bioaccumulation factor (BAF) of 20.8 kg soil per kilogram fresh weight animal. These results show that the three-week exposure in the toxicity test with E. albidus is sufficiently long to reach equilibrium, but also that PHE may accumulate to considerable levels, possibly causing a risk for predators.