An HTML version of this document is available at
http://vm.cfsan.fda.gov/~dms/lead.html
-------------------------------------------------------------------------
(FDA Consumer 8/93)
Lead Threat Lessens, But Mugs Pose Problem
Throughout history, lead in food and drink has been synonymous
with disaster. Historians suspect that some ancient empires tumbled
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 concerns still remain 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 of daily use of mugs for hot beverages.
Risk to Fetus
In February 1992 report to the Society of Toxicology, FDA
scientists Clark D. Carrington,Ph.D., Michael Bolger,Ph.D., and
Robert Scheuplein,Ph.D., said there can be a substantial
incremental risk to a developing fetus from lead leaching into food
from ceramic hollowware.
Hot acidic beverages such as coffee and tea, both caffeinated
and decaffeinated, cause 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 ia 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 quantities of lead in 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 following 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.
New Action Levels
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 1971.
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 lobbyist 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 official
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 1
percent of imported and 3 percent of domestic ceramic ware exceeded
the action levels.
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.
Lead and 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 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 cans 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 in April 1993 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 levels 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.
The upcoming FDA proposals 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 limited 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.
Foil Capsules on Wine Bottles
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 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 hazards,
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.
Crystal Ware
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 crystalware.
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.
Danger - Even at Low Levels
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.
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, bonestores 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 fetus.
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 fetus 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 intake
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.
Advice to Consumers
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.
Followed 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, 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)532-3394--where
callers may request a Spanish or English language information
package. Also, most 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.
FDA Consumer: by Judith E. Foulke, August 1993