HELEN ATAIKIRU AND OKOLO
Abstract
The concentration levels of lead, chromium, nickel, cadmium and copper in the sea snail periwinkle and shrimps from Escravos river's creeks, Delta State, Nigeria were determined in order to assess the impact of petroleum exploration activities. Shell and tissue samples of periwinkle and shrimps were collected. Sample solutions prepared were analyzed using the atomic absorption spectrophotometric technique. The results obtained showed that the tissue of periwinkle contain as much as < 0.01 ug/g Pb, 1.26 ug/g, Cr, 0.90 ug/g Ni, 0.08 ug/g Cd, and 0.46 ug/g Cu while the shell contain 0.07 ug/g Pb, 0.28 ug/g Cr, 0.04 ug/g Ni, and 0.06 ug/g Cd and 0.14 ug/g Cu. The levels in the periwinkle tissue reported had an abundance ratio in the order Cr>Ni>Cu> Cd>Pb while the shell had an abundance ratio in the order Cr>Cu>Pb>Cd>Ni. The levels found in the shells of shrimps were 0.03 ug/g Pb, 0.16 ug/g Cr, 0.30 ug/g Ni, 0.07 ug/g Cd and 0.48 ug/g Cu, while the tissue of shrimp contain 0.03 ug/g Pb, 0.04 ug/g Cr, 0.18 ug/ g Ni, 0.04 ug/g Cd. and 0.41 ug/g Cu. The abundance ratio of the heavy metals in the shrimp shells is in the order Cu>Ni>Cr>Cd>Pb while the tissue had an abundance ratio in the order Cu>Ni> (Cd and Cr)>Pb. The concentrations of cadmium, chromium and nickel were found to be higher in the tissue of periwinkle than that of shrimp while the concentrations of copper, chromium and nickel were found to be higher in the shell of shrimp than the shell of periwinkle samples.