Modeling zinc toxicity for terrestrial invertebrates

Acute and chronic ecotoxicity tests with zinc were performed with the earthworm Eisenia fetida, the potworm Enchytraeus albidus, and the springtail Folsomia candida. To assess the influence of the soil type on zinc toxicity for these soil invertebrates, these tests were carried out in a standard artificial soil, a sandy and a loamy field soil. Based on the results of this experimental work and data taken from literature, models were developed relating the ecotoxicity of zinc to the most important parameters controlling bioavailability: pH and cation exchange capacity. Models were developed for E. fetida and F. candida using the regression technique partial least squares projection to latent structures (PLS). Acute as well as chronic toxicity data of both organisms could be normalized on the basis of the pH and the cation exchange capacity of the test soils. For other terrestrial invertebrates, not enough data were available to develop reliable models.