The Biochemical Effects of Waters from Awba Dam and Rivers Around Ewekoro Cement Factory, Ogun State, Nigeria on Selected Organs of the African Catfish (Clarias gariepinus)

Abstract

The environment is polluted by indiscriminate disposal of sewage, industrial waste, toxic heavy metals and human activities. The settlements around Ewokoro cement factory depend on surrounding rivers for their domestic purposes. Thus, the study was designed to evaluate the biochemical effects of waters from Awba dam (located in University of Ibadan, Nigeria), rivers (Itori, Alaguntan, Elebute), and groundwater around Ewekoro cement factory, Ogun state, Nigeria on selected tissues of African catfish (Clarias gariepinus). Sixty juvenile African catfish were randomly assigned into six groups of 10 fish and cultivated in waters from Awba dam, and Ewekoro area while tapwater served as control for 12 weeks. Results showed that the turbidity, taste and colour of water samples were objectionable according to the NESREA standard. The concentrations of heavy metals; Co, Mn, Ni, Pb, Fe and Cr in water samples from Itori, Alaguntan and Elebute rivers, groundwater and Awba dam exceeded the permissible NESREA and WHO standards. The heavy metals; Fe, Pb, Co and Mn accumulated in the gills, kidneys and brain of C. gariepinus grown in waters from Awba dam, Ewekoro area rivers and groundwater. The levels of urea, nitric oxide, micronuclei (MN) and lipid peroxidation as well as activities of myeloperoxidase and lactate dehydrogenase were significantly high in C. gariepinus cultivated in these waters. The levels of antioxidant parameters (SOD, CAT and GSH) were significantly low in brain and kidney of C. gariepinus. More so, the level of caspase-9 decreased, while insignificant differences were observed in the levels of creatinine and caspase-3 in the C. gariepinus. Histology showed severe distortions in the cyto-architecture of kidneys, gills and brain of fish cultivated in these waters. Waters from Awba dam and Ewekoro area rivers have high metallic contents resulting in bioaccumulation of metals in kidneys, gills and brain of C. gariepinus leading to oxidative stress and inflammation, thereby creating a public health concern for the settlements in these areas.