BIOACCUMULATION OF COMMONLY DETECTED METALS IN THE SILVER CATFISH (CHRYSICHTHYS NIGRODIGITATUS) COLLECTED FROM MAKOKO RIVER, LAGOS NIGERIA

Abstract

This study investigated the bioaccumulation of selected essential and non essentialmetals in the silver catfish (Chrysichthys nigrodigitatus) collected from Makoko River,dead end of the Lagos Lagoon. Concentrations of Iron (Fe), Lead (Pb) and Calcium(Ca) were found to be higher in liver of Chrysichthys nigrodigitatus with mean valuesof 34.52± 6.52 mg kg-1, 1.02± 0.16 mg kg-1and 63.45± 8.62 mg kg-1respectivelycompared to concentrations detected in its gills with mean values of 32.64± 5.71 mgkg-1, 0.10± 0.01 mg kg-1 and 41.58± 6.56 mg kg-1 respectively. While concentrationsof Copper (Cu), Manganese (Mn) and Magnesium (Mg) were found to be higher in itsgills with mean values of 2.09±1.61 mg kg-1, 1.79±1.84 mg kg-1, and 12.84±11.90 mgkg-1respectively compared to concentrations detected in its liver with mean values of0.74±0.53 mg kg-1, 1.79±0.94 mg kg-1 and 8.36± 4.67 mg kg-1 respectively. Theconcentrations of the metals in the tissues were found to be higher than respectiveconcentrations detected in water or sediments of the fish habitat indicative ofbioaccumulation. Concentrations of light metals Ca and Mg were also observed to behigher than concentrations of heavy metals Fe, Pb, Cu and Mn in the tissues of thefish species. Bioaccumulation of metals in tissue of edible fish species can havedeleterious effects on nutritional values of the fish and also pose a public healththreat to final consumers. The need for continuous monitoring of levels of harmfulpollutants in water bodies and edible aquatic species supported.