2014 年 31 巻 p. 45-50
Raw cow’s milk (test milk) and feed samples were obtained from two dairy farms in the coastal area of southeast Dianchi Lake, Kunming City, Yunnan Province, China in July and September, 2013, to determine their concentrations of cadmium (Cd) and lead (Pb) by inductively coupled plasma mass spectrometry (ICP-MS). As references, the concentrations of Cd and Pb in raw milk (control milk) and feed samples of cows conventionally reared in Japan were also determined. Concentrations of Cd were not significantly different between test milk (0.39 ± 0.23 μg/l in July and 1.73 ± 2.47 μg/l in September) and control milk (0.55 ± 0.26 μg/l). However, concentrations of Pb were higher in test milk (23.37 ± 6.83 μg/l in July and 26.22 ± 10.83 μg/l in September) than in control milk (10.43 ± 5.23 μg/l) (P < 0.01). The mean concentrations of Pb in test milk in July and September exceeded the maximum recommended level established by the European Commission, and the concentrations of Pb in some feeds from the study farms (corn stem and leaf feed and broad-bean stem feed) were also above the values given in Japanese standards. These results indicate the possibility of Pb contamination in milk and feeds at dairy farms in the present study area. Hence, special attention should be paid to Pb residues in milk and feed at dairy farms in this region of China.
