Genotoxicity Evaluation of Landfill Solid Waste Leachates from a Waste Dumpsite in Lagos State, Nigeria using the Allium cepa Assay

Abstract

The management of municipal landfill’s leachate is considered one of the most significant environmental issues. Potential mutagenic and genotoxic effects of solid waste leachates (SWL) were investigated using the Allium cepa root meristematic cells assay technique. In Allium root growth inhibition test, experimental onion bulbs were cultivated in various concentrations of the SWL and distilled water was used as a negative control. The root tips from the treated bulb were processedby orcein squash technique after 72 h. The mean lengths of root bundles were obtained andeffective concentration (EC) values calculated. Some of the physicochemical properties of the WL were also determined. The A. cepa assay was carried out at concentrations of 0.05, 0.1, 2.0, 5, 10, 20, 50 and 100% of the WL. There was a statistically different (p < 0.05), concentrationdependent inhibition of onion root growth and mitotic index, and induction of chromosomal aberrations in the onion test. The results of the physicochemical analysis revealed that the concentrations of some parameters were above the maximum permissible limit set by the world health organization (WHO) and could partly be correlated with the toxicity of wastewater. The landfill leachates pose a risk to human health and the environment in general. Hence, ecotoxicity/genotoxicity assays would be useful in leachate risk assessment when coupled with physicochemical analysis.