Heavy Metals in Raw Milk and Dietary Exposure Assessment in the Vicinity of Leather-Processing Plants

The objective of this study was to assess the contamination levels of arsenic (As), lead (Pb), chromium (Cr), and cadmium (Cd) in raw milk and the subsequent potential health risk to local consumers close to leather-processing plants in China. The As and Pb concentrations in milk from contaminated areas were 0.43 ± 0.21 and 2.86 ± 0.96 μg/L, respectively, which were significantly higher than in milk from unpolluted farm, with values of 0.20 ± 0.05 and 2.32 ± 0.78 μg/L, respectively. The Cr and Cd levels in milk from contaminated areas were 1.21 ± 1.57 and 0.15 ± 0.04 μg/L, respectively, which were slightly higher than in milk from unpolluted farm, with values of 0.87 ± 0.61 and 0.13 ± 0.04 μg/L, respectively, (P > 0.05). Target hazard quotient (THQ) and hazard index (HI) values for As, Pb, Cr, and Cd from milk consumption were calculated for individuals aged 3 to 69. The THQ followed a descending order of As > Pb > Cr > Cd, with values of 0.0066-0.0441, 0.0033-0.0220, 0.0019-0.0124, and 0.0007-0.0046, respectively. The HI values (0.0124-0.0832) were far below the threshold of 1.