Chirinos-Peinado et al. 2023 — Lead, cadmium, and arsenic in raw milk near mineral concentrator, Peru
This study measured lead, cadmium, and total arsenic concentrations in 19 raw bovine milk samples collected from cows raised on a farm immediately adjacent to a mini mineral concentrator in the Mantaro Valley, Central Andes, Peru. Paired soil and pasture samples were collected to trace the soil-pasture-milk transfer pathway. Health risks were assessed for the Peruvian population across age groups (2–85 years) using weekly intake, dietary risk quotient, and hazard quotient calculations at three consumption scenarios (minimum, average, maximum).
Key numbers
n=19 raw milk samples (individual cows, same herd). Mean concentrations in milk: Pb 0.029 ± 0.022 mg/kg; Cd 0.007 ± 0.006 mg/kg; As 0.010 ± 0.004 mg/kg (wet weight). Pb and Cd exceeded Codex Alimentarius maximum permissible limits (MPL: Pb 0.020, Cd 0.0025 mg/kg). As was below its MPL (0.014 mg/kg). Soil: Pb 292 ± 60.90, Cd 3.54 ± 1.58, As 5.60 ± 2.20 mg/kg. Soil Pb was 4.2× the MPL; Cd was 2.5× the MPL. Pasture: Pb 23.17 ± 10.02, Cd 0.25 ± 0.57, As 0.063 ± 0.09 mg/kg. Weekly intake for As in children under 19 years exceeded the tolerable weekly intake (TWI). Hazard index (HI) exceeded 1 for children under 11 years. Transfer from pasture to milk was particularly notable for As (5.7× higher transfer factor than Cd; 122× higher than Pb). Method: FAAS (flame atomic absorption spectrometry), AOAC 973.35 for Pb and Cd, AOAC method for As.
Methods (brief)
FAAS using NAMBEI AA320N spectrometer. Wavelengths: Pb 283.3 nm, Cd 228.8 nm, As 193.7 nm. Samples acid-digested by dry and acid mineralization at 450°C. Soil digested by EPA 3050B. Duplicate samples; CV <5%; precision >95%. Laboratory accredited by INACAL (Peru). Sampling per Peruvian Technical Standard 202.112:1998 revised 2013. Study period: March 2022.
Implications
Certification: Direct cow milk contamination data with Pb and Cd exceeding Codex MPLs in a mining-adjacent context. Supports the need for geographic sourcing screening in dairy supply chains. Most relevant to dairy ingredient pages (raw milk, milk powder precursor) and supplier QA framing. Courses: Illustrates soil-pasture-milk pathway and how legacy mining contamination enters the dairy food chain. Useful for supplier risk assessment and geographic sourcing modules. App: Provides contamination reference values for raw cow milk in high-risk geographic contexts; not typical global values but illustrates maximum-range plausibility. Microbiome: Not addressed.