Lead leaching from traditional Mexican ceramics during cooking and implications for population health risk

Traditional Mexican cooking uses clay ceramic pots, mainly glazed with lead oxide, a source of lead exposure. We aimed to quantify and compare lead content in traditional lead-glazed ceramics (LGC), lead-free glazed ceramics (LFGC), and Talavera ceramics; assess lead leaching from these ceramics into cooking solutions; and model the potential impact on blood lead levels (BLLs) based on dietary intake. Thirteen ceramic pieces were analyzed. Lead detection was performed using sodium rhodizonate, Lumetallix™, and X-ray fluorescence. Lead leaching was quantified by ICP-MS using three food simulation solutions: deionized water, boiled rice, and 4% acetic acid, heated for 15 and 30 min, with samples collected at multiple time points up to 24 h. The All Ages Lead Model (AALM) was used to estimate BLLs based on average rice consumption data. LGC pots contained extremely high lead concentrations (median: 202,400 and 185,000 ppm on the internal and external surface, respectively). Net lead leaching from LGC increased substantially over time, particularly in acidic solutions, reaching 637.4185 ppm in 4% acetic acid after 24 h of storage. After 30 min of cooking, rice prepared in LGC showed net lead leaching of 1.2739 ppm, exceeding the Mexican regulatory limit of 0.5 ppm and representing a 1882% increase relative to baseline. All net lead leaching concentrations measured during heating in LGC exceeded the applicable safety limits set by the WHO or Mexican regulations for water and food, respectively. LFGC and Talavera pots showed minimal or no net lead leaching. Biokinetic modeling using AALM predicted that consuming rice prepared in LGC would result in an estimated 11-fold increase in BLLs compared with LFGC, with a theoretical median increase in BLL of 1.6 μg/dL across age groups. LGC poses significant health risks through substantial lead leaching during cooking and storage. LFGC offers a safer alternative, though not entirely lead-free.