Five pieces of ceramic kitchenware purchased in Chinatown contained levels of lead many times higher than the legal limit, according to an analysis by Thomas Jefferson University doctors who have tested dozens of items sold by Philadelphia merchants.
They reported the results to the Food and Drug Administration, and a spokesman said Monday night that the agency would be following up with its own tests.
Although the two spoons and three plates appear to be clearly out of compliance - the lead standard for plates is 3 parts per million, and these contained 52, 130, and 145 ppm - it is unclear whether they caused any problems for infants, who are most at risk.
How often a plate is used, the temperature and acidity of the food and the amount of time it sat on the plate all affect the leaching of lead into food. (Guidance for consumers is posted here.)
"I would hate for young children to be eating off that plate repeatedly," said toxicologist Fred M. Henretig, speaking about the item with the highest reading. Henretig, of Children's Hospital of Philadelphia, was not involved with the report.
Checking blood-lead levels of people at a free Chinatown clinic is next, said Gerald F. O'Malley, a Jefferson ER doctor who led the testing. No pattern of elevated lead levels has been seen in tests routinely reported to the Philadelphia Department of Public Health's Childhood Lead Poisoning Prevention program.
O'Malley, who had seen cases of lead poisoning in Denver a decade ago that he suspected originated with traditional Mexican pottery, embarked on the Chinatown project last summer after noticing brightly colored items on sale here.
A group of medical students used LeadCheck, a home-screening product, to test more than 130 plates, cups, bowls, teapots, and spoons that were made in China and bought in and out of Chinatown.
The swab indicated that lead was present in 25 percent of the items from Chinatown and 10 percent of those purchased elsewhere. But it could not determine amounts - or how much could leach into food, which is the key safety issue and the measure used by the FDA.
The more sophisticated atomic leachate tests were recently done at a University of Pennsylvania lab. Most items flagged by the original screening were in compliance, including every one from outside Chinatown.
Overall, 6 percent of all the items purchased were out of compliance. Still, the exceptions were extreme, and they raised additional questions.
For example, FDA regulations set different lead limits according to the type of item, from 0.5 ppm for cups and pitchers, which are likely to hold hot liquids for a period of time, to 3 ppm for flatware.
But there is no standard for ceramic soup spoons. The Jefferson doctors measured 13 and 31 ppm in the two spoons they tested.
"FDA would assess leachable lead findings for spoons on a case by case basis," spokesman Douglas Karas said Monday.
And the Jefferson physicians suspect that their findings underreported the problem because they were unable to do what is known as a "lip and rim" test on the cups, which made up the majority of initial positives.
The leachate test that they did - filling the cups near the top with an acidic solution, waiting 24 hours and then analyzing it - followed FDA protocol but catches lead only on the inside.
The insides of these cups were all white ceramic, which is unlikely to contain lead. The outsides and some of the rims, which had been swabbed for the first tests, were brightly painted and more likely to contain lead.
Thomas Gilmore, a Jefferson ER resident who did the leachate testing at Penn, said he expected the FDA followup would include the rim tests. The FDA spokesman could not immediately confirm that.
The dangers of lead are largely limited to very young children. Lead poisoning was common several decades ago, but it is rare now - and almost always attributed to lead paint in old houses.
Experts say parents may want to avoid serving young children food on brightly colored ceramics, particularly if they are old, worn or cracked. The FDA posts a Q&A about lead in traditional pottery, based on cases from Mexico.
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