Genetic and systemic toxicity induced in Allium cepa and Mus musculus by a tropical freshwater dam in Ibadan, Nigeria

Awba Dam reservoir is an important source of domestic water supply in the University of Ibadan, Nigeria. It receives both point and non-point sources of untreated sewage and wastewaters from student and staff residences, research laboratories and surrounding farmlands. Toxicological evidence on the pollution status of the dam are on the increase. In this study, we investigated the cytotoxic and genotoxic effects of Awba Dam water using the Allium cepa and murine sperm morphology assays. We also evaluated systemic toxicity in mice using alterations in haematological, serum hepatic biochemical and histopathological parameters. Bi-monthly composite water samples were collected from the Dam from June – September, 2017. Each sample was used in the A. cepa root growth inhibition and chromosome aberration test, and was administered as drinking water to groups of male Swiss albino mice for 35, 70 and 105 days. Tap water from underground source was used as negative control. There was significant (p<0.05) mitotic inhibition and induction of different types of chromosome aberrations in A. cepa. At the exposure periods in mice, there was significant (p<0.05) increase in frequencies of abnormal sperm cells, alterations in haematological parameters and significant (p<0.05) increase in the levels of alanine aminotransferase and aspartate aminotransferase when compared with the corresponding negative controls. Histopathological alterations, including degeneration, congestions and inflammations were observed in sections of liver and kidney. Pb, Cd, Ni and Fe in the water samples contributed to the observed toxicity. Awba Dam water contains constituents that induced genetic and systemic damage in mice and A. cepa. This is of public health importance to resident biota, and other organisms including man along the food chain.