Landfill use: A potential source of toxicant to aquatic life

Regardless of the beneficial aspect of landfill use, its environmental impact becomes subject of concern to sustainability and development. Landfilling among other things lead to generation of leachate. Therefore this study was undertaken with a view to analyzing the detailed physicalchemical components of leachate from closed sanitary landfill and its associated impact on fish (Clarias batrachus). Whole effluent toxicity (WET) approach was used to evaluate the toxicological effect of leachate on fish. Five different concentrations of the leachate (3.13 – 5.63 % v/v) as observed during the range finding test were applied definitively to obtain the effluent’s lethal concentration (LC50) on the named fish. BOD5, COD, heavy metals and other components which included aromatic hydrocarbons were analyzed via standard methods (APHA, EPA, and AOAC). About 880 mg/L of ammonical nitrogen was a reflection of the leachate’s stench ammoniac odour. The BOD5 and COD analysis were recorded at 3,500 mg/L and 10, 234 mg/L respectively, whereas, benzene, toluene and ethyl benzene concentrations were 0.22 mg/L, 1.2 mg/L and 0.86 mg/L respectively, and above allowable/permissible discharge limit according to EPA standards. The acute toxicity test via static use of the leachate revealed an LC50 of 5.88% on C.batrachus as calculated using Finney’s probit analysis from EPA. The study concluded that fish mortality observed in the research can be attributed to the physical-chemical constituents of the landfill leachate. Therefore it can be inferred that despite the use of landfills as waste management option, yet its negative impact on the immediate environment need to be investigated more