Health risk due to chronic heavy metal consumption via cow's milk produced in Puebla, Mexico, in irrigated wastewater areas.

The aim of this study was to determine the heavy metals content of milk from cows fed with forage irrigated with waste water from industrial sources and the health risk to children. Milk samples were taken from milk collection tanks of eight localities in the state of Puebla. On average, the heavy metals in the milk had the following order Zn> As> Pb > Cr> Cu > Ni. Pb (0.03 mg kg-1) exceeded the Codex limits. For As the hazard index was 8.0 ± 0.4, which is far above 1. On the other hand, the individual risk of cancer showed a descending order Cr> As > Pb, while the risk of total cancer (0.004 ± 0.002) indicated that the combined effect of heavy metals created a serious risk for girls and children.