Analysis of 22 Elements in Milk, Feed, and Water of Dairy Cow, Goat, and Buffalo from Different Regions of China

Abstract

The objectives of this study were to measure the concentrations of elements in raw milk by inductively coupled plasma-mass spectrometry (ICP-MS) and evaluate differences in element concentrations among animal species and regions of China. Furthermore, drinking water and feed samples were analyzed to investigate whether the element concentrations in raw milk are correlated with those in water and feed. All samples were analyzed by ICP-MS following microwave-assisted acid digestion. The mean recovery of the elements was 98.7 % from milk, 103.7 % from water, and 93.3 % from a certified reference material (cabbage). Principal component analysis results revealed that element concentrations differed among animal species and regions. Correlation analysis showed that trace elements Mn, Fe, Ni, Ga, Se, Sr, Cs, U in water and Co, Ni, Cu, Se, U in feed were significantly correlated with those in milk (p < 0.05). Toxic and potential toxic elements Cr, As, Cd, Tl, Pb in water and Al, Cr, As, Hg, Tl in feed were significantly correlated with those in milk (p < 0.05). Results of correlation analysis revealed that elements in water and feed might contribute to the elements in milk.

Large scale study of the within and between spatial variability of lead, arsenic, and cadmium contamination of cow milk in China

“…As (μg/L) Cd (μg/L) differences observed between these results and the studies by Tang et al (2014) and Zhou et al (2016) who also conducted studies in China. As mentioned previously, the results obtained by Tang et al (2014) from Chinese regions showed similar values for Pb and higher values for Cd.…”

“…Area J showed an extremely high variability for Cd content which can relate to the higher value observed by Tang et al (2014) from a lower number of samples. Zhou et al (2016) observed a higher positive rate for As (82.5%) and a lower rate for Cd (32.5%). In Zhou et al (2016), only 40 raw cow milk samples were collected in two regions (20 samples per region instead of 100 in the present study).…”

“…Zhou et al (2016) observed a higher positive rate for As (82.5%) and a lower rate for Cd (32.5%). In Zhou et al (2016), only 40 raw cow milk samples were collected in two regions (20 samples per region instead of 100 in the present study). Significant differences in the levels of Pb, As, and Cd between the main Chinese milk producing regions were confirmed in this study.…”

“…A MARS 6 microwave sample digestion system (MARS6, CEM Corporation, USA) with a power of 1600 W was used for the digestion of milk samples. This digestion was performed according to the method by Zhou et al (2016): (1) ramp time 5 min, temperature 90°C, hold time 5 min; (2) ramp time 5 min, temperature 150°C, hold time 10 min; and (3) ramp time 5 min, temperature 180°C, hold time 20 min. Digested samples were allowed to cool to room temperature, transferred to polypropylene tubes (Corning, USA), and diluted to 50 mL with ultrapure water.…”

“…Those authors confirmed that an environmental relationship was responsible for milk contamination. More recently, from a limited number of samples (n = 40), Zhou et al (2016) showed differences in heavy metal concentrations in raw milk collected in two different Chinese provinces (Shandong and Shaanxi province). In conclusion, all of these studies suggest the existence of spatial variability in milk heavy metal contamination related to the production environment.…”