Transfer of lead from lead-glazed ceramics to food.

Recent studies have shown a clear correlation between the use of lead-glazed ceramicware for cooking or food preparation and elevated blood lead levels. Two lots of lead-glazed ceramic bowls, each from a single manufacturing and firing lot were used to measure the sequential leaching of lead into salsa (an acidic food) and beans (a neutral food) stored or cooked in the bowls. The USFDA acetic acid extraction assay was also repeatedly performed on these bowls. The results of the USFDA extraction test were highly variable with levels ranging from 200 to more than 2,000 ppm (regulatory level for rejection is 2 ppm). The levels extracted declined rapidly but the rates were variable. Leaching of lead into salsa (pH = 4.8) was variable and ranged from 8 to greater than 500 ppm. Sequential extractions using salsa yielded variable but declining lead levels. Cooking beans with water in the bowls did not cause substantial leaching (levels between 3 and 8 ppm) and sequential cooking did not show any significant decline over 10 cycles. The results indicate substantial variability in leaching of lead into foods stored or cooked in lead-glazed ceramicware.