Assessment of heavy metal pollution in muscles and internal organs of chickens raised in Rivers State, Nigeria

Abstract

The concentrations of Cd, Pb, Ni, Zn, Cr and Mn were determined in 120 meat samples comprising of broiler, cockrel layers and local chicken muscles, gizzard and liver using flame atomic absorption spectrophotometry. The mean metal contents in the different parts of chickens expressed in mgkg-1 are Cd 0.0236±0.0016; 0.0457± 0.0092 and 0.0162± 0.0008. Pb 0.2867±0.0176; 0.3012±0.0172 and 0.2151±0.0167. Mn 0.1265±0.0096; 0.4150±0.0283 and 0.2657±0.1068. Zn 1.9399±0.0376; 2.3245±0.0676 and 1.5701±0.0558. Ni 0.0615±0.0038; 0.1079±0.0220 and 0.0620±0.0074 for chicken gizzard, liver and muscle respectively. Cr was not detected in all the meat samples. There were significant differences in the mean concentrations of these metals in the different chicken parts. Several samples were spiked with known amount of metals and the mean recoveries of the metals were in the range of 92.5±3.12 -101.2±4.42%. The AAS instrument was certified by running certain samples several times in the AAS and the co-efficient of variation obtained between 0.588-1.64% indicating high precision. The mean moisture content of the various chicken parts are 72.30%±2.07 for gizzard, 72.83%±2.85 for liver and 74.20%±2.92 for muscles. The results of this study indicate that chickens raised in the oil rich Rivers State Nigeria have concentrations of Cd, Ni, Zn and Mn below the permissible FAO/WHO levels except Pb which is slightly higher than the 0.2mgkg-1 stipulated by FAO/WHO. The contributions of these metals to the body burden can therefore be considered negligible, thus the chickens may be considered safe for human consumption.