Preliminary Study of Metal in Yak (Bos Grunniens) Milk from Qilian of the Qinghai Plateau

63 samples of yak milk were analyzed by the method of ICP-AES of metal elements for aluminum, cadmium, silver and chromium which can reveal the exposed level around yak farm. The metal elements of yak milk were compared to reference data for cow milk, sheep milk, buffalo milk and goat milk. In addition, the concentration was compared to PTWI (provisional tolerable weekly intake) established by the JECFA (WHO/FAO) for metal intake/body weight per week of cadmium, aluminum, and chromium level was compared to EVM (Expert Group on Vitamins and Minerals) guidance level, while the threshold of silver was lacking according to the authority standard. Analysis of regression correlation was calculated between Cd and Co, Cr, Cu, Ag, Al, Mn.