Essential trace and toxic element levels in Tibetan yak's milk collected from Qinghai, China

ABSTRACT

The concentrations of 17 trace and toxic elements (aluminum, boron, calcium, cadmium, chromium, copper, iron, potassium, magnesium, manganese, sodium, phosphorus, lead, sulfur, selenium, strontium, and zinc) were determined in 165 samples of Tibetan yak milk from Qinghai, China, using inductively coupled plasma optical emission spectrophotometer and graphite furnace atomic absorption spectrometer after microwave digestion. Calcium, potassium, phosphorus, and sodium were the most abundant elements, with average concentrations of 1970, 1532, 1297, and 512 mg/L, respectively. Certain spatial variability in the 17 trace elements was found among the different areas sampled in this study. The studies also indicated that aluminum, cadmium, copper, and lead levels in populated urbanized and industrialized regions were higher than in rural regions. Hierarchical cluster analysis classified samples into two groups based on the measured parameters, which in accordance with the environmental diversity. Overall, the essential elements in yak's milk were abundant, while the toxic elements (aluminum, cadmium, chromium, copper, and lead) can be considered sufficiently low.

KEYWORDS:

• Atomic spectrometry
• Qinghai
• Tibetan yak's milk
• trace elements