ecotoxicological assessment using clarias gariepinus and microbial characterization of leachate from municipal solid waste landfill

among the environmental problems in nigeria is the lack of proper management of municipal solid wastes (msw), which is capable of releasing hazardous chemicals via leachate to the surrounding environment. in this study, the potential toxic effects of raw leachate obtained from aba-eku landfill (aerl) on clarias gariepinus; and the microorganisms that may be present in the leachate were investigated. physico-chemical analysis showed that the leachate contained toxic constituents. the 96 h lc50 obtained was 36.6%. haematocrit %, erythrocyte number, haemoglobin concentration, leukocyte and lymphocyte number increased with increasing leachate concentration. histopathological lesions were marked in the gills, kidney and liver of exposed fishes and were concentration dependent. a total of 112 bacterial isolates belonging to 17 genera were recorded from samples of aerl. potential pathogens and toxin producing microorganism were identified. these observations are of prime health concern because there is no known containment or treatment system for the leachate generated from the study site. our findings would be of assistance in the assessment of hazardous effects of chemicals from waste landfills discharged into the aquatic environment and in making policy on environmental waste management