<i>Hoplobatrachus occipitalis</i> and <i>Clarias anguillaris</i> as sentinels for assessment of heavy metals in irrigation water Kadawa Kano, Nigeria

Abstract

This study was carried out to evaluate the concentrations of heavy metals (Cd, Cu, Mn, Pb, and Zn) in Crowned bullfrog (Hoplobatrachus occipitalis) and African Catfish (Clarias anguillaris) in irrigation water Kadawa, Kano State, Nigeria. Muscle, liver, lung, and gill were analysed for Cd, Mn, Pb, Cu, and Zn using Atomic Absorption Spectrometer (AAS). It was revealed that Crowned bullfrog has the highest concentrations of Zn, Pb, and Cu with mean values of 35.02 mg/kg, 0.81 mg/kg, and 0.39 mg/kg, the least in African catfish with mean values of 12.85 mg/kg, 0.53 mg/kg and 0.35 mg/kg respectively. The lung of crowned bullfrog has the highest concentrations of Mn (0.68 mg/kg), Pb (1.81 mg/kg) and Zn (77.38 mg/kg) while the highest concentration of Cu (1.02 mg/kg), Mn (7.57 mg/kg), Pb (1.09 mg/kg) and Zn (21.20 mg/kg) were recorded in the liver of African catfish. Concentrations of Mn, Pb, and Zn in Crowned bullfrog, catfishes, and water samples were found to be above the permissible limits set by FEPA (2003) and NESREA (2011). More accumulation of heavy metals was recorded in Crowned bullfrog compared to African catfish, hence frogs may be considered as more sensitive bioindicators of heavy metals compared to African catfish.