Overview
Castro-Bedriñana and colleagues sampled raw milk from 12 cows on one dairy farm in the Mantaro Valley of central Peru, next to a mineral concentrator and a former dump and irrigated from a polluted river, in April and May 2022. Lead, cadmium and arsenic in milk were measured by flame atomic absorption and compared with soil and pasture. All three mean levels exceeded the limits the authors applied, and the hazard index exceeded 1 for young children.
Key numbers
- Lead in raw milk: mean 0.062 mg/kg (SD 0.008), range 0.047 to 0.077 mg/kg (Table 1).
- Cadmium in raw milk: mean 0.014 mg/kg (SD 0.005), range 0.008 to 0.026 mg/kg (Table 1).
- Arsenic in raw milk: mean 0.030 mg/kg (SD 0.028), range 0.009 to 0.096 mg/kg (Table 1).
- Soil lead averaged 652.35 mg/kg against a 70 mg/kg limit (Table 1).
Methods (brief)
Milk (50 g) was dried, ashed at 450 °C, taken up in nitric acid and read by flame atomic absorption (AOAC 973.35). Precision was checked against standard solutions only; no milk reference material is reported. Weekly intake, target hazard quotients and hazard index were computed for ages 2 to 85.
Evidence Fitness
Small, single-farm data set (24 samples from 12 cows) at a site chosen for its pollution sources, so it represents a contaminated mining-area farm, not typical milk. Arsenic by flame atomic absorption and the very low stated detection limits are questionable. Raw whole farm milk only, so it is at most background context for reduced-fat milk and does not measure that product.