Porcellio scaber als Testorganismus für Bioakkumulationsstudien

The terrestrial bioaccumulation assessment is mainly based on the established test systemaccording to OECD 317 with terrestrial oligochaetes. The parameters which characterisethe bioaccumulation of a substance include the bioaccumulation factor (BAF),the uptake rate constant (ks) and the elimination rate constant (ke). Therefore, theterrestrial isopod Porcellio scaber, which allows the estimation of biomagnification factors(BMF) by considering the food uptake pathway only, has been tested for its applicabilityin bioaccumulation studies. However, regarding the very low bioaccumulation of thedifferent substances tested the regulatory use of the test system might be limited. For thehydrophobic fully chlorinated hydrocarbon chemical hexachlorobenzene (HCB), biomagnificationfactors between 0.047 and 0.057 were achieved. An influence of coprophagia onthe accumulation of HCB could not be detected. The hepatopancreas turned out to be thetissue compartment in which HCB accumulates most effectively. The use of perfluorinatedsurfactants as further test substances led to similar results. Biomagnification factors between0.048 (perfluorooctanesulfonate) and 0.0097 (perfluorooctanoic acid) were achieved.The uptake of the test substances with hydrophobic and surfactant properties in P. scaberwas generally low, which can be explained by the low uptake of the substances in thetest organism. A cross-species comparison with aquatic and terrestrial species (fish andearthworm) showed significant differences in the biomagnification behavior of the testsubstances. In further studies with P. scaber the bioaccumulation of silver nanoparticleswas investigated, which were applied via contaminated sewage sludge. The studies showedthe bioavailability and bioaccumulation of silver from silver nanoparticles which weresulphonated in the sewage treatment process. The experimental animals ingested thesilver nanoparticles into the digestive tract which were incorporated in the soil substratevia contaminated sewage sludge. The bioaccumulation factors (BAF) for silver determinedin the bioaccumulation studies were 1.349 and 0.948 and showed a correlationwith the test substance concentration in the soil. The hepatopancreas turned out tobe the organ with the highest silver accumulation and presumably led to the stagnantsilver elimination observed during the elimination phase. No toxic effects were observedduring application of the silver nanoparticles s (NOEC>13.70 mg/kg). Since significantlylower silver nanoparticle concentrations are to be expected in the environment, acutedamage to P. scaber, through exposure to silver nanoparticles via sewage sludge, canpractically be ruled out. The developed test system can be used for the estimation ofbioaccumulation factors for substances that enter the environment via sewage sludge