Overview
Pérez-Carrera and colleagues measured trace elements in raw milk from 30 dairy farms in an arsenic-affected groundwater area of Córdoba, Argentina, and compared farms watering cattle from shallow phreatic wells with farms using deep wells. Phreatic water carried far more arsenic (mean 1282 µg/L) than deep wells (56 µg/L), and milk arsenic was slightly higher on phreatic-water farms. Cadmium was not detected in any milk sample.
Key numbers
- Arsenic in raw milk: mean 4 ± 2.8 ng/g (range 0.7 to 11) on phreatic-water farms and 3.5 ± 2 ng/g (0.2 to 7.8) on deep-well farms (Table 4).
- Lead in raw milk: mean 23 ± 13 ng/g (below 5 to 51) and 24 ± 17.3 ng/g (below 5 to 64), means computed with half the detection limit for non-detects (Table 4).
- Cadmium: not detected in any milk sample, detection limit 3 ng/g (Discussion, p. 599).
- Nickel 48 ng/g and chromium 38 to 54 ng/g mean (Table 4).
Methods (brief)
Milk was dry-ashed, dissolved in hydrochloric acid and analyzed by ICP-OES with an yttrium internal standard; arsenic was measured by hydride generation ICP-OES. NIST-8435 milk powder was used for verification, but certified values for arsenic, cadmium, chromium, nickel and vanadium were unavailable, so the authors call those data preliminary. Recoveries sit in supplementary tables not filed with the PDF.
Evidence Fitness
Raw farm milk from individual cows, not retail milk; useful as background for cow milk in an arsenic-rich groundwater region. The number of milk samples per group is not printed and collection dates are not reported. Lead means include half-detection-limit substitution. This is a proxy for reduced-fat milk (whole raw milk, not a fat-reduced retail product), so the reduced-fat milk page is not linked.