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(70-63) Comparative toxicity of a zinc salt, zinc powder and zinc oxide to three soil invertebrates. Janssen, Colin1, Lock, Koen*,1, 1 J. Plateaustraat 22, Ghent, Belgium ABSTRACT- Soils can be contaminated with different forms of zinc, which might have an influence on its availability and toxicity to terrestrial invertebrates. Here we found that the pore water zinc concentration and the calcium chloride extracted zinc fraction are higher in the soils spiked with a zinc salt (ZnCl2) compared to soils spiked with zinc oxide or zinc powder. Based on total concentrations, the acute toxicity of zinc salt to the compost worm Eisenia fetida, the potworm Enchytraeus albidus and the springtail Folsomia candida was lower compared to that of zinc oxide and zinc powder. However, when expressed on the basis of pore water concentrations or calcium chloride extracted fractions, acute toxicity was higher for zinc salt, which indicated that dermal uptake via the pore water is not the only route of uptake. Chronic toxicity of zinc salt, zinc oxide and zinc powder was similar when based on total concentrations in the soil which again indicates that the pore water route of uptake is not the only route of exposure but that oral uptake is also important. Key words: Eisenia fetida, Enchytraeus albidus, Folsomia candida, Zn speciation |
