Influences of different standardised test methods on biochemical responsesin the earthworm Eisenia fetida andrei

Studies were carried out to determine the effects on thr metabolic activiti es of earthworms of experimental conditions used in toxicity assays. Earthw orms (Eisenia fetida andrei) were maintained under constant environmental c onditions, in the absence of toxic agents, using three standard toxicology assay procedures (the artisol, contact filter paper and artificial soil tes ts) for two periods of time. Two controls were used: (1) earthworms taken d irectly from stock cultures for analysis and (2) earthworms treated as in s oil test but exposed only to the culture medium rather than artificial soil . Biotransformation markers (methoxyresorufin-O-deethylase, NADH and NADPH cytochrome reductases and glutathione-S-transferase activities) and indicat ors of oxidative stress (catalase activity, lipid peroxides and peroxidisab le lipids) were investigated. The results demonstrated that substrates and handling can induce significant biochemical changes in worms maintained in uncontaminated media. None of the substrates were better than others in avo iding these artefacts. Hence, although the soil test is closer to the natur al conditions for the worms than the contact or the artisol tests, it still had significant effects on the worms in the absence of toxic chemical. Gre at care must therefore be taken when comparing results from different ecoto xicological assay procedures. (C) 2000 Elsevier Science Ltd. All rights res erved.