Genetic and systemic disruption by a municipal solid waste leachate in aquatic and terrestrial models, and human cancer risk assessment of the leachate’s metallic constituents

Solid waste leachate can contaminate soil, surface, and ground waters, posing public and environmental health risks. This study intends to determine cytogenotoxicity of leachate (1–50%, v/v, leachate/tap water) from Lapite waste dumpsite in Ibadan, Nigeria, using the generation of chromosome, and root growth aberrations in Allium cepa, and evaluation of micronuclei in peripheral erythrocytes of Clarias gariepinus and bone marrow of mice. The histopathological effect of the leachate on fish and mice was also investigated. Some organic and inorganic constituents of the leachate were determined, and the toxic metal values were utilised to predict the non-carcinogenic and carcinogenic risks of human exposure to such metals in the leachate. The levels of the metals (0.004–10.69 mg/L), congeners (1.5 × 10− 4–4.32 × 10− 2 µg/L) of PAH, and phthalates were higher than the USEPA limits. Significant (p < 0.05) induction of cytological and morphological abnormalities, decrease in root growth, and mitotic index in A. cepa were detected. There was concentration-dependent, significant formation of micronucleated erythrocytes along with other nuclear anomalies in C. gariepinus, and micronucleated polychromatic erythrocytes in mice. Pathological lesions were noted in the tissues of leachate-exposed C. gariepinus and mice. The noxious constituents of the leachate could have provoked the observed genomic and histological disarrangement. The hazard quotient trend was in the order HQing > HQderm > HQinh. Hazard indices were higher for children than for adults. The lifetime cancer risk value for Pb indicates a high risk for cancer. These spotlight the likely human health risks from exposure to dumpsite leachate.