Overview
The authors collected 40 raw milk samples at milking from Brown Swiss cows in a dairy area of the Mantaro River basin whose pastures are irrigated with canal water carrying mining and domestic discharges. Lead and cadmium were measured by flame atomic absorption and weekly intakes and risk quotients were estimated for people aged 2 to 85. Cadmium was reported far above the limit used for whole milk.
Key numbers
- Lead: mean 15 µg/kg, SD 2.6, range 10 to 20 µg/kg (Table 3).
- Cadmium: mean 505 µg/kg, SD 123.2, range 280 to 690 µg/kg (Table 3).
- Limits used: lead 20 µg/kg and cadmium 2.6 µg/kg for whole milk (Table 3).
Methods (brief)
Fifty grams of homogenized milk were dried, ashed at 450 °C and taken up in dilute nitric acid, then analyzed by flame atomic absorption following AOAC 973.35 at an accredited laboratory. Detection limits were 0.0045 mg/kg for lead and 0.002 mg/kg for cadmium. Standard solutions were used to check precision; no certified reference material recovery is reported.
Evidence Fitness
Forty samples from one mining-affected valley, two sampling campaigns, with full summary statistics. The cadmium values are very high for milk measured by flame atomic absorption and should be treated with caution. The milk is raw and unskimmed, so this is a proxy for reduced-fat milk and does not measure it.