|
(M/MF176) No effect of soil aging on the toxicity of pyrene and phenanthrene to a soil dwelling microarthropod. Sverdrup, Line1,2, Kelley, Axel2, Jensen, John3, Krogh, Paul-Henning3, 1 2 3 ABSTRACT- Soil samples spiked with five concentrations of pyrene and phenanthrene were aged for 0, 10, 40 and 120 days before toxicity was investigated using a standardized bioassay with the soil collembolan Folsomia fimetaria L. Toxic effects were measured as reductions in survival (LC50) and reproductive output (EC10 and EC50). Pyrene and phenanthrene were degraded in the test system during storage, phenanthrene to a higher degree than pyrene. However, when toxic effects of the tested substances were related to measured concentrations, toxicity was relatively unaffected by storage for up to 120 days. Many studies have shown a negative correlation between aging and the biodegradation of polycyclic aromatic hydrocarbons (PAHs), indicating a reduction in the bioavailability of PAHs to microorganisms with time. Our results indicate that a reduction in toxicity may not always be expected for aged soils when considering a time period of a few months. We suggest that the high test concentrations, in combination with the relatively low content of organic carbon (1.6%) in the test soil, may be a possible explanation for the observed results. Key words: ecotoxicity, aging, Folsomia fimetaria , PAH |
