Resistance to arsenic-toxicity in a population of the earthworm Lumbricus rubellus

Specimens of the earthworms Lumbricus terrestris L. and L. rubellus Hoffmei ster from an uncontaminated site rapidly deteriorated in condition when kep t in spoil rich in metal contaminants and arsenic. The site from which the spoil was collected supports several earthworm species, L. rubellus being d ominant. Native L. rubellus survived for 12 weeks in spoil in the laborator y. L. rubellus collected from the spoil site and an uncontaminated site wer e kept for 28 d in uncontaminated soil and in soil containing 2000 mg sodiu m arsenate heptahydrate kg(-1), the state of the specimens being recorded u sing a semi-quantitative assessment of earthworm condition (condition index , CI). The CI remained high for all specimens except those from the unconta minated site kept in As-rich soil, for which mortality was 100% after 28 d. Tissue As concentrations in L rubellus from uncontaminated and contaminate d sites were <1 mg kg(-1) and 230 mg kg(-1), respectively. In L. rubellus c ollected from the uncontaminated site and exposed to contaminated soil cont aining 2000 mg sodium arsenate heptahydrate kg(-1), mean tissue As concentr ation was 92 mg kg(-1). (C) 1999 Elsevier Science Ltd. All rights reserved.