Risk Assessment of Lead and Cadmium Exposure Through Raw Milk Consumption from Small-Scale Dairy Systems in the...

Bovine milk is a primary dietary source of nutrients and bioactive compounds. However, its safety is increasingly under threat due to contamination from mining and intensive agriculture. In the Peruvian Andes, where small-scale dairy farming coexists with historical environmental liabilities, identifying the transfer of metals into the food chain is essential for public health. This study quantifies the concentrations of lead (Pb) and cadmium (Cd) in raw milk from small-scale producers in rural districts in the province of Huancayo. Non-carcinogenic risks for populations aged 2-85 years were assessed under three consumption scenarios. Forty-five samples were analyzed using microwave plasma atomic emission spectrometry (MP-AES). The mean concentrations of Pb and Cd were 11.30 ± 18.94 µg/kg and 7.85 ± 18.11 µg/kg, respectively, which are below the maximum permissible limits (MPL). However, spatial analysis identified critical hotspots near smelters, where Pb levels reached 103 µg/kg, which is a significant exceedance of the MPL of 20 µg/kg. Toxicological modelling showed that the Hazard Index (HI) remained below the unity threshold (HI < 1) for all scenarios, ruling out immediate systemic risks. Nevertheless, the highest HI (0.78) was observed in two-year-old children in the high-consumption scenario, highlighting a localized neurodevelopmental concern. These findings emphasize the importance of georeferenced environmental monitoring and differentiated public health policies to mitigate the chronic low-level exposure to metals in vulnerable, high-altitude populations.