Lead Poisoning—Its Devastating Effects
‘THE most common serious childhood disease.’ “The No. 1 environmental threat to children.” As you may have guessed, the threats described here are one and the same: lead poisoning.
According to the CDC (U.S. Centers for Disease Control), “children are particularly susceptible to lead’s toxic effects. Lead poisoning, for the most part, is silent: most poisoned children have no symptoms. The vast majority of cases, therefore, go undiagnosed and untreated. . . . It is not solely a problem of inner city or minority children. No socioeconomic group, geographic area, or racial or ethnic population is spared.” The report adds: “Childhood lead poisoning is a problem worldwide.”
How Lead Affects Children
It is estimated that from three million to four million children under six years of age in the United States alone have levels of lead in their blood high enough to impair normal development. This may mean anything from slightly diminished reading skills to full mental retardation. And if that is the case in one country, the global figures must be staggering.
In Africa, Asia, Mexico, and the Middle East, lead is still sometimes used as a medicine by those unaware of its dangers. It is used to relieve constipation, to prevent infections of the umbilical cord, and even as a teething substance for babies.
The danger is not so much that children are falling over and dying from lead poisoning. As is indicated by a 1991 issue of FDA Consumer, childhood deaths from lead poisoning have become very rare. But the effects are still devastating. Lead has aptly been called “a killer of intelligence.” Newsweek magazine quoted one health official as saying: “There’s a very large number of kids who find it difficult to do analytical work or even line up in the cafeteria because their brains are laden with lead.”
Some other symptoms of lead-poisoned children include irritability, insomnia, colic, anemia, and impaired growth. A damaged nervous system, accompanied by chronic restlessness—like that of a caged animal, as one doctor described it—may also characterize such a child. In more severe cases, some children may suffer comas and seizures, and even after reaching adulthood, they may continue to suffer from emotional problems. Some of these effects may be permanent, says the head of the Lead Poisoning Prevention Branch of the CDC. Until a proper diagnosis is made, parents are often beside themselves as to the cause of this insidious malady.
Why Are Children So Vulnerable?
Lead is especially dangerous to children for two reasons. First, children are affected by much lower levels of lead than those that affect adults. Since their brain and nervous system are still developing, they are particularly sensitive to the effects of lead. Second, children, because of their behavior and activity, are more likely to pick up lead from their environment.
Consider lead-based paint for example, still an important source of contamination. In countries where it is legal to use such paint in houses, the cases of lead poisoning are sure to go on mounting. And while many countries have banned some uses of lead-based paint in recent years, the paint still exists in older houses. Walls, windowsills, toys, cribs, and furniture all may still have layers of it. In the United States, for example, high levels of lead remain in about 57 million homes. In the mid-1980’s, some 13.6 million American children under seven years of age were living in homes with lead-based paint. Over a million of these probably had dangerously high lead levels in their blood.
A smooth painted surface may not pose any danger. But as paint ages, it begins to crack and peel. Since lead has a sweet taste, children are likely to eat the paint chips. Babies have ingested lead from flaking windowsills. And when the paint eventually turns to dust, children pick it up on their fingers from toys, floors, and carpeting—inevitably it goes from there into their mouth, gastrointestinal tract, and bloodstream. Particularly are children between the ages of six months and six years susceptible.
“It takes strikingly little lead to cause lead poisoning,” writes Newsweek magazine. “A child can become severely lead poisoned (60-80 microgram/dl) by eating one milligram of lead-paint dust—equivalent to about three granules of sugar—each day during childhood.” For the child to be merely at risk, his intake of paint dust would be the equivalent of just one granule of sugar a day. “That’s why a child can become ill merely by regularly touching a windowsill and then sucking his thumb,” reports Newsweek, adding that many parents “simply don’t realize—or can’t believe—that the dust on their windowsill might be quietly stealing part of their child’s potential.”
Lead and the Fetus
The problem extends even into the wombs of pregnant women, where the developing brains and nervous systems of unborn children may suffer harm as well. When an expectant mother takes lead into her body, whether by eating or by breathing, it works its way into her bloodstream. Then it is passed on to the fetus through the umbilical cord. The child may suffer neurological damage or a reduced IQ. “If a pregnant woman ingests even a small amount of lead,” says one health writer, “it can pass through her placenta to the fetus.” And Science News reported: “Studies have documented that women who work with lead in factories suffer higher rates of sterility, miscarriage, premature birth and birth defects.”
Fathers too may contribute to such dangers. Lead in the bloodstream of men may cause sperm to be malformed and sluggish, which could prevent conception or cause deformed fetuses. An estimated 400,000 fetuses in American women are so contaminated by lead that they will suffer developmental impairment. Since lead poisoning is a worldwide epidemic, the number of affected unborn children must indeed be monumental.
Not Just Children
Clearly, adults are at risk too. To protect their children, they must protect themselves. How are they exposed to lead? Experts agree that besides house paint, the most common sources of exposure today are the lead in water due to plumbing (as even copper pipes may have been joined by lead solder) and leaded gasoline. In schools and offices, the water fountains have water tanks with lead-soldered seams. One EPA (U.S. Environmental Protection Agency) official estimates: “About 20 percent of exposure to lead comes from drinking water.” The federal Agency for Toxic Substances and Disease Registry reported that the level of lead “from electric water coolers can be very high, and can pose quite high toxicity risk for all individuals, not just children.”
To add to the dilemma, parents may bring lead home on the clothes they wear in the workplace and further expose their children. It has been estimated that nearly eight million workers in the United States alone are exposed to lead in their working environment. A large percentage of these are women.
Those who store alcoholic beverages or other liquids in lead-crystal decanters are also taking some risk, since lead from the crystal may leech into the beverage. Similarly, ceramicware that has not been fired at high enough temperatures may diffuse lead particles from the glaze into food. One couple, for instance, bought a set of coffee mugs while traveling in a foreign country. It turned out that the mugs released 300 times more lead than health standards in their own country permit. The couple became severely ill after using the mugs for a short time. Additionally, solder in food cans, still used in some countries, accounts for a percentage of low-level lead poisoning.
Gun buffs also are at risk of lead poisoning. Why? Well, recent studies have shown that those who frequent indoor firing ranges have high levels of lead from inhaling leaded dust. The explosion and the microscopic shearing of lead bullets as they travel down gun barrels send lead particles into the air, and the shooter draws them into his lungs, reports Science News magazine. Some of the symptoms listed are chronic metallic taste and neurological hand twitching. Other studies indicated that family members may also risk high lead exposure from handgun users who bring home lead dust on their clothes.
With lead poisoning so common and so dangerous to children and adults alike, the next question is obvious: What can be done to prevent it?
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How Much Lead Can the Body Take?
HOW much lead is too much? How much can the body safely absorb? While scientists still debate such questions, many countries have enacted laws to prevent lead poisoning, at least from lead paint. Australia put such a law on the books back in the early 1920’s. Great Britain, Greece, Poland, and Sweden enacted similar laws later in that decade. The United States did not enact its Lead Paint Poisoning Prevention Act until 1971.
However, the United States has made increasingly stringent laws in this field since then. In 1985 the CDC (U.S. Centers for Disease Control) lowered the acceptable level of lead in blood to 25 micrograms (25 millionths of a gram) of lead per deciliter (about a fifth of a pint) of blood. That was half the amount of lead the surgeon general had pointed to back in 1970, which was 60 micrograms per deciliter. But as the years passed, more studies suggested that children may be harmed by even lower levels of lead. So in 1991 the CDC again cut the acceptable level to less than half, lowering it to 10 micrograms per deciliter.
Although there is bitter dispute over one of the key studies that prompted this change, other studies have come up with similar results. Two studies in Scotland, for instance, linked blood lead levels as low as 11 micrograms per deciliter with reduced intelligence and behavior problems in children. And as the Bangkok Post noted early in 1992, laws such as the one in Thailand that protects adults from lead may not protect children—in particular the unborn.
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Lead Poisoning—An Ancient Problem
LEAD may have been in use as early as 3000 B.C.E. The ancient Egyptians used it for sculpture and pottery, the Phoenicians and Chaldeans trafficked in it, and the Greeks of Athens mined it for some seven centuries. But it was the Romans, during the reign of the Caesars, who first discovered the industrial potential of lead—and they paid a high price for that discovery.
The Romans called it plumbum. (The English word “plumbing” is derived from that Latin word.) Skilled workers rolled large sheets of lead into 15 standard lengths of pipe for use in their extensive water conveyance systems. Both the Romans and the Greeks set the pattern for modern-day plumbers by fitting lead pipes one into the other. Thus miles of pipes could be joined together to carry water long distances. The Romans also formed lead into drinking vessels, containers for wine, and cooking utensils. Weatherproof membrane made of lead sheets was developed for roofing.
But just as the use of lead is not new, the fact that it makes people sick is hardly a recent discovery either. “For at least 2,000 years,” writes Science News magazine, “societies have recognized lead as a potent toxicant while remaining mystified as to how it poisons.” Be that as it may, the ancient Romans seemed fairly oblivious to the real dangers of lead. According to Jerome Nriagu of the Canadian National Water Research Institute, they commonly added to their wine a grape syrup that had been boiled in lead containers. Newsweek magazine quotes Nriagu as saying: “One teaspoon of such syrup would have been more than enough to cause chronic lead poisoning.” And Roman leaders were big wine drinkers. Nriagu estimates that the Roman elite drank anywhere from one to five quarts [1-5 L] of it every day!
“It’s postulated that one of the reasons the Romans went the way they did,” reports The Medical Post of Canada, “was their penchant for sweetening their wines with lead.” One report says: “Poisoning from extensive use of the metal in utensils, weapons, cosmetics, wine vessels, and water pipes may have been responsible for [Rome’s] imperial madness and for infertility and miscarriage rates that kept the ruling classes from replacing themselves.”
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Lead in the Wild
IF YOU are a lover of wildlife, it may disturb you to know that up to three million waterfowl die each year from lead poisoning. Here, too, lead poisoning is called an “invisible disease” since it often takes place unnoticed. The U.S. Department of the Interior reports that for every bird that hunters manage to kill, a half pound [0.23 kilograms] of lead pellets from shotguns ends up in the environment. Biologists sampling the top few inches of the bottoms of wetlands, ponds, and lakes have found in some areas more than 100,000 lead pellets per acre [250,000 lead pellets per ha]! Lost lead fishing weights also litter the bottom.
After the hunting season is over, ducks and other waterfowl in search of food swallow these pellets. Three to ten days later, poison reaches the bloodstream and is carried to major organs—the heart, the liver, and the kidneys. By days 17 to 21, the bird falls into a coma and dies. Bald eagles can get lead poisoning from swallowing the lead shot that lurks in the bodies of the waterfowl they eat. Since 1966, more than 120 of these rare birds of prey have been found dead from lead contamination—over half of these since 1980. Of course, this number represents only those eagles whose bodies were examined and the cause of death determined; it is probably a mere fraction of the actual total.