Multi-step sequential extraction of cadmium and lead in poultry droppings and shrimp waste meal

Shrimp waste-supplemented layer feeds (isoproteinous and isocaloric diets) and dropping samples were collected randomly from the University of Agriculture, Abeokuta, Teaching and Research Farms. The feeds and droppings were subjected to stepwise sequential extraction procedure designed to establish the speciation pattern of cadmium (Cd) and lead (Pb) in the samples using atomic absorption spec-trophotometry (AAS). The concentrations of solubilized fractions of Cd and Pb in control and the two shrimp waste-supplemented diets are ( mu g/kg): 0.76, 2.90, 4.64 for Cd, and 31.76, 11.80, 15.04 for Pb, whereas the unsolubilized fractions (jig/kg) are 0.10, 2.80 and 3.00 for Cd and 0.32, 0.80 and 1.40 for Pb, respectively. On the other hand, the solubilized and unsolubilized fractions of Cd and Pb in the droppings are ( mu g/kg): 3.34, 32.84 and 2.94 (solubilized Cd), 11.21, 28.84 and 12.54 (solubilized Pb), 3.06, 2.80 and 1.56 (unsolubilized Cd), 0.40, 1.01 and 2.20 (unsolubilized Pb), respectively. Based on this study, the human risks for Cd and Pb in the two diets containing shrimp waste meal are low for now, as the concentrations were below the recommended World Health Organization (WHO) maximum limits for Cd, 1,200 mu g/kg and Pb, 2,000 mu g/kg, respectively. The shrimp waste meal diets were statistically compared with control samples at 95 % confidence level.