The relationship between lysosomal biomarker and organismal responses in an acute toxicity test with Eisenia Fetida (Oligochaeta) exposed to the fungicide copper oxychloride

The LC50 of copper oxychloride for Eisenia fetida was determined, and its effects on biomass change and lysosomal damage using neutral red retention times (NRRT) of coelomocytes were measured. The aim was to establish whether a lysosomal subcellular response, measured as NRRT, could be linked to the LC50 and biomass changes. Further, we attempted to establish the ecological relevance of the LC50 by comparing it to studies previously carried out on the effects of copper oxychloride on field earthworm populations. The experiment was conducted over a period of 28 days, during which the earthworms were exposed to different concentrations of copper oxychloride in artificial soil. The calculated LC50 was 883 microg g(-1) for copper oxychloride and 519 microg g(-1) for copper. Results indicated that changes in coelomocyte membrane stability manifested earlier than effects on biomass. Since the NRRT assay was very sensitive and generated an early response before changes in biomass or mortality could be measured, it may have predictive value and may contribute information during acute toxicity tests, which could be of greater ecological relevance than mortality data alone.