Tolerance to zinc in populations of the earthworms Lumbricus rubellus from uncontaminated and metal-contaminated ecosystems. Environmental Contamination and Toxicology

Abstract. Zinc tolerance in Lumbricus rubellus populations from two metal-polluted (smelter and mine) sites was studied by comparing the effects of zinc with responses in a reference site strain. For the study, adult worms were collected directly from the field. Thus, no attempt was made to differentiate between tolerance resulting from population-level genetic adap-tation or phenotypic plasticity in metal physiology. To compare relative sensitivity for zinc, worms from the three populations were exposed in laboratory tests. Effects on survival, weight change, cocoon production, and internal zinc levels were measured. Prior to exposure, it was anticipated that worms from the metal-contaminated sites would show substantially in-creased tolerance to zinc. This was not the case for all measured parameters. Thus, although differences in the shape of the dose-response relationships for survival and cocoon productio