Overview
Chirinos-Peinado and colleagues measured lead and cadmium by microwave plasma atomic emission in 45 raw milk samples from smallholder farms across 12 districts of Huancayo province in 2025 and modelled weekly intake and hazard quotients for ages 2 to 85. Overall means were below the limits, but El Tambo district, near smelters and urban activity, had much higher levels.
Key numbers
- All samples: lead 11.30 ± 18.94 µg/kg (max 103.0); cadmium 7.85 ± 18.11 µg/kg (max 75.0) (Table 2).
- El Tambo: lead mean 30.63 µg/kg (max 103.00); cadmium mean 33.58 µg/kg (max 75.00) (Table 3).
- 13.33% of samples exceeded the 20 µg/kg lead limit and 8.89% the 10 µg/kg cadmium limit (Results 3.1).
Methods (brief)
Twenty-five millilitres of milk were digested with nitric acid and hydrogen peroxide at 85 °C and read by MP-AES at an accredited laboratory. Calibration used NIST-traceable standards with blanks and replicates; no matrix reference material recovery is reported. The detection limit was 1 µg/kg for both metals.
Evidence Fitness
A moderate farm sample with district breakdown and a stated LOD. Values of 0.90 µg/kg sit below the LOD and appear to be substitutions, and one district SD is inconsistent with its range. Farm raw whole milk is a proxy for half-and-half, skim milk and semi-skimmed milk, none of which were measured. The dataset is separate from the same group’s 2022 El Tambo single-farm study.