Genotoxicity and histopathological assessment of raw and simulated leachates exposed to mice

Abstract

Indiscriminate solid waste disposal to the environment without proper treatment poses a serious threat to the public health. This study was carried out to investigate genotoxicity of the raw and simulated leachates samples collected from Amilegbe municipal dump site located in Ilorin metropolis in Nigeria. Some of the physicochemical properties of both raw and simulated leachate samples were determined. Mice were exposed to 1%, 2.5%, 5%, 10% and 25% (raw leachate) and 1%, 5% and 10% concentrations (simulated leachate) respectively for 35 days. Distilled water and colchicine were used for negative and positive control respectively. Two standard genotoxicity tests namely abnormal sperm-head morphology and micronucleus (MN) assays were used to assess possible genotoxicity of the raw and simulated leachates samples. Sperm head morphology assay showed some abnormalities (folded, amorphous, banana shaped, two tails, pin tail among others) and the frequencies of the abnormalities increases was concentrationdependent. Congestion, necrosis, degeneration and appearance of vacuolation were observed in the histopathological analysis of the liver. The histopathological changes were also more pronounced with higher concentrations of raw and simulated leachates. MN and abnormal nuclei frequencies also showed statistically significant differences (p>0.05) such that MN and other nuclear abnormalities reached the maximum at the highest concentration (25% >10% >5% >2.5%>1%). This study shows that the raw and simulated leachates contain potentially genotoxic and cytotoxic substances capable of causing DNA damage.

Keywords: leachates; sperm head morphology assay; histopathology; blood; micronucleus