Levels of Some Trace Metals (Zn, Cr, and Ni) in the Muscle and Internal Organs of Cattle in Nigeria

This scoping study assessed the concentrations of zinc, chromium, and nickel in the muscle and internal organs of a sample of commercially available meat from Nigerian-bred cattle. The dried samples were digested with a 3:2 HNO3/HClO4 mixture and analyzed for these three metals with an atomic absorption spectrophotometer (AAS). The ranges of detectable values (mgkg(1)) were Zn (433.82529.36) Cr (5.3919.85), and Ni (0.801.72). Liver and muscle showed the highest concentrations of Zn while the highest concentrations of Cr occurred in the tripe. Nickel's concentration in the liver was the lowest. All samples showed Zn concentrations greater than the Codex Alimentarium limits of 50mg/kg (muscle) and 80mg/kg (edible offal), and 147 samples exceeded the 150mg/kg limit set by the Australia New Zealand Food Authority. One hundred and twenty of the 150 samples showed Cd concentration above the U.S. Environmental Protection Agency's limit of 8mg/kg, while 93% (muscle), 77% (liver), 97%(tripe), and 100% (kidney and intestine) showed concentrations of Ni higher than 0.5mg/kg set as a guideline limit by Council of Mutual Economic Assistance. These high concentrations in the tested commercial sample of Nigerian beef may reflect the general pollution levels of these metals in the Nigerian environment.