Polarographic Evaluation of Lead and Cadmium in Livers of Sheep in Zanjan and Sanandaj Cities, Iran

Background: Lead and cadmium can enter the human body through consuming the liver of animals such as sheep, which may accumulate and cause adverse effects. The levels of lead and cadmium in the liver samples of slaughtered sheep in Zanjan and Sanandaj were investigated in the summer of 2014. Methods: 96 Samples were collected from both cities. Lead and cadmium levels were measured by anodic stripping voltammetry (ASV) after digestion with nitric acid and hydrogen peroxide in 3 steps by a 400-watt microwave digester. Lead and cadmium concentrations were determined in μg/L using standard solutions of lead and cadmium as standard addition in their specific potential, -0.42 and -0.58 V for lead and cadmium, respectively. Results: Mean values of cadmium in the livers of sheep in Zanjan and Sanandaj were 0.42 ± 0.13 and 0.35 ± 0.13 mg/kg, respectively, which had no significant difference (P 0.05). On the other hand, mean concentrations of lead in the livers of sheep in Zanjan and Sanandaj sheep were equal to 3.69 ± 1.43 and 2.36 ± 0.18 mg/kg, respectively, which had a significant difference (P 0.05). Conclusion: The concentrations of lead and cadmium in the livers of sheep were higher than WHO standards. However, only the lead levels were higher than the maximum residue levels (MRLs) standard lists. The obtained results can be due to the activities of lead industries and factories in both cities, which may increase pollution levels in the water, air, and animal feed.