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(M/EH084) Bioavailability of PAH in organic rich soil - Earthworm vs. SPMD uptake. Hartnik, Thomas1, Andersen, Sjur2, Amundsen, Carl-Einar1, 1 2 ABSTRACT- PAH-compounds are thought to be unavailable for biota at low contamination levels when there is a high organic content in the soil. This is also thought to be further true when the contamination is aged. We conducted an experiment where bioavailabilty of PAH compounds was studied in an aged organic rich soil (>40 years, organic C>15%) contaminated with creosote. In the experiment PAH concentrations in soil, soil solu-tion and earthworm (eisenia fetida) were determined as well as toxicological effects (reproduction, survival). In order to investigate if semipermeable membrane devices (SPMD) can be used to study bioavailability of lipophil organic pollutants in soil, uptake of PAHs in earthworm is compared with uptake in SPMD. Toxic effects are determined using standardised earthworm reproduction test with eisenia fetida. The results show that earthworm predominantly takes up high molecular PAHs, soil solution on the other hand low molecular PAHs. This indicates that PAH-concentrations in soil solution do not reflect the bioavailable fraction in organic rich soils. The results also indicate that semipermable membrane device (SPMD) is a promising tool to mimic bioavailabilility of lipophilic organic contaminantes in field investigations. In contrary to other potential accumulators for the terrestric environment (e.g. earthworms), SPMD do not show avoid- or escape-reactions. In order to use SPMD to assess bioavailability they have to be calibrated with biological uptake. The system we have designed calibrates uptake in SPMD with uptake of contaminan-tes in earthworm as well as ecotoxicological parameters (survival,cocoon production, growth and offspring). Key words: PAH, bioavailability, SPMD, earthworm toxicity |
