Trace metal content and estimated daily human intake from chicken eggs in Ibadan, Nigeria

A total of 151 chicken eggs and 4 local chicken feeds purchased directly from the poultry farms, at the local markets, and along the roadsides of Ibadan, Nigeria, were analyzed for lead, cadmium, copper, iron, nickel, zinc, and cobalt by carbon graphite atomic absorption spectrophotometry. The authors found strong, positive correlations between the levels of metals in the feeds and the corresponding levels of metals in the eggs. The overall average concentrations (mg/kg) of each metal in eggs were as follows: lead, 0.59; cadmium, 0.07; copper, 0.78; iron, 23.20; nickel, 0.03; zinc, 13.75; and cobalt, 0.01. The average estimated daily intake of lead, cadmium, copper, and iron per person was 19.5 microg, 2.4 microg, 25.6 microg, and 762.3 microg, respectively, whereas daily intakes of nickel, zinc, and cobalt were 0.9 microg, 452.1 microg, and 0.2 microg per person. The concentrations of some metals in eggs from this study did not differ appreciably from levels determined in eggs from other countries; concentrations of lead and cadmium in the current study, however, were comparatively greater than levels found in other countries. Therefore, the estimated daily intakes of lead and cadmium in this region slightly exceeded the normal reported daily intakes of lead and cadmium from eggs in some other countries.