Throughout history, lead in food and drink has been synonymous with disaster. Historians suspect that some ancient empires rambled when leaders became deranged or died of poisoning because they used lead to sweeten wine, drank from lead©lined aqueducts, and used utensils made with lead©based clays and paints.
These days, knowledge of the dangers of lead poisoning keeps manufacturers and governments vigilant about the amounts that get into food. Small amounts of lead leach from glazes and decorative paints on ceramic dinnerware, from lead crystal. and. less frequently, from pewter and silver-plated hollowware. Also, because lead is generally in the environment, it makes its way into food through soil and water.
The levels of lead in food and drink today are the lowest in history--90 percent lower than 12 years ago. This is mostly due to the U.S. food industry's voluntary elimination of lead solder to seal the seams of food cans and the removal of lead from automobile gasoline that settled on crops and in water
. But concern still remains about lead leaching into food from ceramic ware, especially mugs. While analyzing risks from dietary lead, FDA scientists found that about 80 percent of adult exposure to lead from food in contact with ceramic hollowware comes from frequent or daily use of mugs for hot beverages.
For pregnant women, plain glass or plastic mugs may be a safer bet than ceramic mugs when drinking hot acidic beverages on a daily basis.
In a February 1992 report to the Society of Toxicology, FDA scientists Clark D. Carrington, Ph.D., P. Michael Bolger, Ph.D., and Robert J. Scheuplein, Ph.D., said there can be a substantial incremental risk to a developing ferns from lead leaching into food from ceramic hollow-ware. (See accompanying article, "Danger-Even at Low Levels.")
Antiques and other collectibles may look attractive, but this type of dinner ware is more likely to leach lead than that made more recently.
Consumers can guard against exposure to lead in food by observing the following guidelines:
* If you are pregnant, avoid the daily use of ceramic mugs when drinking hot beverages such as coffee or tea, and avoid the daily use of lead crystal ware.
* Do not feed babies from lead crystal bottles.
* Do not store acidic foods such as fruit juices in ceramic containers.
* Do not store beverages in lead crystal containers.
* Limit the use of antique or collectible housewares for food or beverages to special occasions.
* Stop using items that show a dusty or chalky gray residue on the glaze after they are washed
* Follow I label directions on any ornamental product with a warning such as, "Not for Food Use -- Plate May Poison Food. For Decorative Purposes Only."
* If your wine is sealed with a foil capsule, wipe the rim of the bottle with a cloth dampened with water or lemon juice before removing the cork.
FDA is aware of three kits to test for lead leaching from ceramic ware that consumers can use at home. These kits are not always sensitive enough to detect lead at the new lower levels, but they can be valuable for identifying items that release larger amounts of lead. For information about these kits and other questions about lead, contact the local FDA office, listed in the blue pages of the phone directory, or call FDA headquarters at (301) 443-4667.
The National Safety Council, under a grant from the federal government, maintains a National Lead Information Center with a toll-free number -- (1-800) LEAD-FYI, or (1-800) 532-339 -- where callers may request a Spanish or English language information package. Also, most U.S. ceramic manufacturers maintain toll-free lines through which consumers may obtain information about lead levels in their products. Public affairs specialists in FDA district offices can provide consumers with these numbers.
Once lead enters the body, it is assimilated in the bloodstream in the same manner as calcium.
Hot acidic beverages such as coffee and tea, both caffeinated and decaffeinated, cause the greatest leaching. FDA toxicologists agree that pregnant women should avoid daily drinking of hot coffee or tea or other hot acidic beverages, such as tomato soup, from lead-glazed ceramic cups or mugs. However, the occasional use of these pieces is not a problem, even during pregnancy.
Consumers also need to be aware of the potential for lead to leach from ceramic plates, bowls and pitchers. Glaze, improperly formulated or fired, can leach large quantifies of lead into food. Consumers who suspect a ceramic product has been improperly glazed or fired, should avoid using it for food, or should test the piece for excessive lead leaching before using it (see accompanying article, "Advice for Consumers").
Responsible manufacturers of ceramic ware use all the proper precautions, but even with properly glazed pieces, low amounts of lead may migrate into food. FDA advises consumers to avoid storing acidic beverages, such as fruit juices and iced tea, in lead-glazed pitchers because, even cold, acidic beverages have a greater tendency than other foods to cause leaching of lead.
Recent studies on the effects of lead on the fetus, infants, toddlers, and adults in amounts well below those previously believed harmful prompted FDA to reduce its action levels (guidelines telling industry at what point FDA may take regulatory action) for lead leaching from all ceramic hollowware. The action levels specify how much lead may leach from the ceramic piece into a special test solution during a 24-hour test at room temperature. This was the third reduction since action levels for lead leaching from ceramic ware were first set in 197 1.
The new action levels are based primarily on how frequently a type of ceramic ware is used, the type of food it holds, the temperature of the food, and how long the food comes in contact with the ceramic ware. For example, a coffee mug is generally used every day to hold a hot acidic beverage, often several times a day, and a pitcher could be used to store fruit juice. Cups and mugs were put into a separate category, and they, along with pitchers, were given an action level of 0.5 parts per million, the lowest for all ceramic ware.
Manufacturers of materials used by ceramic hobbyists and handicrafters are aware of lead contamination problems, and label their products with special instructions. Public affairs specialists in FDA district offices work with state health officials and organizations to develop special education materials for handicraft and pottery associations to avoid potential sources of lead exposure that fall beyond FDA regulatory control.
In addition, FDA has notified embassies in Washington, D.C., of the new action levels so that foreign manufacturers and exporters will have the necessary information to meet the new levels. FDA samples and tests for lead leaching from imported and domestic ceramic ware sold in this country, but the agency cannot check it all. For example, products that enter the country through informal channels, such as those brought by travelers from abroad, are not monitored by FDA.
Because of its heightened focus on ceramic ware, in February 1992, FDA inspectors in every port in the country conducted a short-term intense surveillance of ceramic products used for food, ranging from fine bone china to inexpensive imported pottery. Assisted in many cases by state authorities, FDA inspectors examined more than 5,000 lots of ceramic ware from 29 countries. Nearly 700 lots of domestic ceramic ware from approximately 90 firms were also examined. The results were encouraging. Using the best screening methods available, FDA examiners found that only about 1 percent of imported and 3 percent of domestic ceramic ware exceeded the action levels. (See "New Initiatives for Import Safety," FDA Consumer, October 1992.)
FDA also has taken new regulatory steps to ensure that lead continues to stay at lowest possible levels in food. On Nov. 25, 1992, the agency published in the Federal Register a proposed regulation that would prohibit the use of tin-coated lead foil capsules (coverings for the cork and neck area) on wine bottles because lead from the capsule may get into the wine. Another proposal, published Jan. 5, 1993, would set a limit for lead in bottled water of no more than 5 parts per billion. And FDA intends to propose a regulation that would prohibit lead solder in food cans. The prohibition would also apply to imports-food in lead-soldered cans would not be allowed to enter the country.
On April 1, 1993, FDA published interim action levels for lead in food packaged in lead-soldered containers. Products that exceed these levels are subject to regulatory action, including recalls. The interim action levels will be in effect until FDA can permanently ban lead-soldered food cans.
Before the U.S. canning industry voluntarily eliminated the use of lead in solder to seal food cans, FDA estimates that from 14 to 45 percent of lead in food came from such seals. During the food packaging process, the can body, with its side seam mechanically crimped together, passed over a pot of molten solder, where a rotating roll transferred solder to the seam. The excess solder was then wiped from the can, and the can was cooled until the solder was set. Although solder was not applied to the inside of the can, some of it had to bleed through the ends of the side seam to make a strong, leakproof can. The minute amount of solder that bled through the seam later leached into the food inside. Sometimes, more lead would contaminate the can's inner surface from the solder dust in the vicinity of the solder pot or splashes from the wiping station.
As more information on lead toxicity became available, the canned food industry consulted with FDA on ways to make a safer product. In response, industry voluntarily switched to unseamed cans and to sealing can seams with nonlead-solder techniques, such as forge and wire welding.
The industry voluntarily stopped packaging infant formula in lead-soldered cans in 1982, according to information submitted to FDA by the Infant Formula Council. As for all of the other canned foods, the Can Manufacturers Institute informed FDA that as of November 1991, lead-soldered cans were no longer produced in the United States. But lead-soldered cans are permitted in some countries that export canned food to us.
The interim action levels published this April primarily affect imported food. FDA estimates that up to 10 percent (some 230 million pounds) of food imported each year may be packaged in lead-soldered cans. Some ethnic groups use imported canned foods as staples in their diets. Also, food in lead-soldered cans may enter the United States through individual purchases outside the United States. A 1991 San Diego County screening program for lead in children's blood led to detection by the Board of Health of a dangerously high blood-lead level in a 1-year-old child whose parents had brought back fruit juice in lead-soldered cans from a grocery store across the Mexican border. Investigators found that the same product had entered the United States through import channels. The juice products were recalled nationwide (see 'Toddler's Blood Test Leads to Juice Recall" in the Investigators' Reports section of the December 1992 FDA Consumer.
To decrease the possibility of lead leaching from coated foil capsules into wine, wipe the bottle rim and top of the cork with a cloth dampened with water or lemon juice.
The upcoming FDA proposal to prohibit the use of lead-soldered food cans would prevent such incidents. As an additional measure, FDA has sent letters to more than 65 countries to inform them of FDA's concerns and to learn about their regulations on lead-soldered food cans. Many of the countries that responded are aware of the problems with lead solder in food cans and have established their own lead limits or have adopted those set by the World Health Organization. FDA urges exporters to stop manufacturing lead-soldered food cans, and has made its concerns known through these letters and other discussions at world forums over the last few years.
Many imported and domestic wines have lead foil capsules (coated on both sides with a thin layer of tin) covering the cork and neck of the bottle. The capsule is used to prevent insect infestation of the cork area and as an oxygen barrier. It's also used to impart an image and feel that are perceived as important to product differentiation and to the marketing of fine wines.
Data on the lead content in wine with lead foil seals were developed by the U.S. Bureau of Alcohol, Tobacco, and Firearms (ATF). Higher lead levels were found in samples of wines poured from the bottle than in unpoured samples. The ATF report concluded that "significant lead contamination" could result if the wine seeps between the cork and the wrap or capsule, causing the foil seal to corrode and leave lead salt deposits on the rim. Although the lead levels found do not pose a short-term health hazard, FDA's concern is with long-term exposure for individuals who regularly consume wine.
Based on these findings, FDA proposed a regulation to declare lead foil wraps for wines to be a food additive that is unsafe, and further to prohibit the use of such wraps on wine bottles. Many wine producers in the United States and Europe have already stopped using them.
FDA advises consumers to wipe the rim and top of the cork of wine bottles sealed with foil with a cloth dampened with water or lemon juice before removing the cork. Pregnant and lactating women have long been advised to avoid alcoholic beverages, including wine. Lead contamination is another good reason for pregnant women to refrain from drinking wine.
Even at low levels, lead not excreted through the digestive system accumulates in the body and is absorbed directly into blood and soft tissues, including the kidney, bone marrow, liver, and brain. When lead leaves the bloodstream, it is stored in bone, along with other minerals, where it continues to build over a lifetime.
In average adults, 10 to 15 percent of lead that reaches the digestive tract is absorbed. Young children and pregnant women, however, absorb as much as 50 percent. The body cannot distinguish between calcium and lead. Once lead enters the body, it is assimilated in the bloodstream in the same manner as calcium, and, because young children and pregnant women absorb calcium more readily to meet their extra needs, they also absorb more lead. Those with calcium deficiencies absorb even more. And lead, even in small amounts, may become toxic wherever it settles. (See "Getting the Lead Out of Just About Everything," FDA Consumer, August 1991.)
Lead also gets into the blood of pregnant women from their own bone stores. During a period of physiological stress, such as in pregnancy or lactation, bone-stores of minerals, including the normally inert lead, can be mobilized back into a woman's blood and increase her blood-lead level. As this blood circulates, it is picked up by the ferns.
FDA considers children and pregnant women at highest risk for lead poisoning. FDA toxicologists say that for pregnant women, lead exposure is an actual, rather than potential, problem. Besides potentially harming her own health, lead can damage the developing ferns because it crosses the placental barrier.
A 1987 report in the New England Journal of Medicine shows that as little as 10 micrograms of lead per deciliter of fetal blood could damage a fetus early in pregnancy during its most vulnerable period of nervous system development. It can also cause premature birth or lower birth weight. In adults, 30 micrograms of lead per deciliter of blood can cause high blood pressure and damage nerves and red blood cells.
FDA toxicologists have set provisional total tolerable retake levels (PTTILs) of lead from all sources at 25 micrograms per day for pregnant women, and 6 micrograms per day for infants and children up to 6 years. For every microgram per day of lead intake, blood lead levels increase 0.16 micrograms per deciliter of blood in children and 0.04 micrograms per deciliter of blood in adults.
PTTILs represent the intake level FDA believes provides a reasonable margin of protection from the measurable toxic effects of lead from all food and nonfood sources. Scientists have not found a no-effect level of toxicity from lead. If additional research shows that lower blood-lead levels cause measurable adverse health effects, the PTTILs would be reduced even further.
Recent studies have found that lead can leach into food from lead crystal hollowware. The International Crystal Federation has provided FDA a report of its research on lead leaching into food and alcoholic beverages, and the industry has started a program in which manufacturers share technological developments to reduce lead leaching. Also, FDA has initiated studies of its own on lead leaching from crystal.
Until FDA reviews all the data and determines what further actions, if any, need to be taken, the agency advises consumers not to store alcoholic beverages in lead crystal decanters, and pregnant women not to routinely drink from lead crystal glasses. Infants should not be fed with lead crystal baby bottles.
Because lead is ubiquitous, FDA recognizes that no effort will totally eliminate lead from the food supply, however desirable that may be. But FDA and many other federal, state and local governments are working together through all available means to reduce exposure to lead. The initial focus is on the sources likely to result in the greatest exposure.
FDA uses as many sources as it can to get the story of lead to consumers, both of the harm it causes, and about how to prevent poisoning. Careful attention to consumer advisories can prevent unnecessary exposure to this age-old health problem.
Judith E. Foulke is a staffwriter for FDA Consumer.
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