Survey of heavy metals in the catfish Synodontis clarias

Abstract

Elevated levels of heavy metals in the catfish Synodontis clarias can be a good indication of pollution of an aquatic ecosystem due to anthropogenic influence. The concentrations of Zn, Cd, Pb, Mn and Ni were determined in Synodontis clarias caught along a section of Taylor Creek and its associated tributaries. Samples were collected bimonthly between July 1999 and June 2000 in five stations. The metals: Zn, Cd, Ni, Pb and Mn were recorded in appreciable quantities, signifying their bioavailability. The levels of Zn, Cd, Ni, Pb and Mn may have obvious health implications on the rural communities that depend on fish species as fish supplement in view of its rich protein content and its bio-economic value. Generally, the sources of the metals in the catfish appear to be point and diffuse which include rural and agricultural runoff sources in the catchments area. However, the presence of an oil industry activity (Etelebou oil field and flow station) in one of its tributaries appears to be the major point source of the metal pollutants