PARENT SESSION
WP8b The Terrestrial Environment: Exposure Routes and Risk Assessment
4:30 PM to 6:30 PM, Wednesday, 09 May 2001
Session Chair: J.P. Sousa
Room 8

(416) Ecotoxicity of zinc in spiked artificial soils versus contaminated field soils.

Lock, Koen¹, Janssen, Colin¹, ¹

ABSTRACT- The chronic toxicity of zinc to Folsomia candida in spiked artificial soils could be predicted based on pH, cation exchange capacity and total zinc concentration. However, this model could not adequately predict chronic zinc toxicity in historically contaminated field soils. Pore water concentration, water extractable as well as calciumchloride extractable zinc fractions of the contaminated field soils were lower than predicted on the basis of models developed for spiked artificial soils, indicating that the effect of aging on metal bioavailability should be taken into account. The reproduction of F. candida in contaminated field soils was lower than predicted with models based on the pore water concentration, the water extractable as well as the calciumchloride extractable zinc fraction in spiked artificial soils. This suggests that the latter fractions are not the only bioavailable zinc fractions and that dietary metal exposure might also be an important route of uptake under environmentally relevant conditions. The effect of aging and the importance of dietary uptake need to be studied urgently in order to be able to perform effect-based risk assessments of metal contaminated soils.

Key words: bioavailability, Zn, Folsomia candida, terrestrial ecotoxicity