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October 18, 2000
Centers for Disease Control to report on chemical exposure in U.S.From: Ronda Mosley-Rovi
Director - Environmental Programs Public Technology, Inc.
1301 Pennsylvania Ave., N.W.
Washington, D.C. 20004-1793
Phone: 202.626.2455; fax: 202.626.2498
e-mail: mosley-rovi@pti.nw.dc.usBy Maggie Fox, health and science correspondent
Are chemicals leaching from toys and causing dangerous hormonal changes in American children? Are tiny traces of dioxins threatening the virility of American men? Will spraying pesticides to kill mosquitoes lead to an epidemic of cancer in future decades?
A report from the U.S. Centers for Disease Control and Prevention (CDC), due out in a few months, aims to start answering some of these questions. The National Exposure Report Card will tell scientists and the public how many Americans and which ones have unusually high levels of lead, pesticides and other undesirable substances in their blood.
"We don't have anything remotely like this," Dr. James Pirkle, who is helping direct the study, told reporters. "It's like going from tricycles to Hondas."
For the National Exposure Report Card, CDC scientists are traveling around the country, taking blood and urine samples from 5,000 people considered representative of the race, gender, ethnic and economic makeup of the nation.
"We ask them 5,000 questions, literally 5,000 questions," Pirkle said. These include checks into where they have worked, what fertilizers or pesticides they have used on their lawns, how long ago their homes were painted and what they eat.
But since thinking you may have been exposed to a chemical does not necessarily mean it got into your body, the tests will also confirm who has a heavy load of dioxins, lead or PCBs. This information will be correlated and compared with CDC's data on rates of cancer and other disease.
The report, due out in December or January, will be the most extensive look at what chemicals Americans have actually been exposed to. It will be available on the Internet, along with information on what is known about how much of a particular toxic substance it takes to cause disease.
Report checks on 25 chemicals and compounds
It will look at 25 substances, including heavy metals such as lead, cadmium and mercury, tobacco products, organophosphate pesticides such as chlorpyrifos and malathion and phthalates, used to soften plastic and the recent subject of attacks by groups that say they leach out of children's plastic toys, bottles and even pacifiers.
It will look for dioxins the chemicals that cleared out Times Beach, Missouri, in 1983 and the Love Canal site in Niagara Falls, New York, in 1978 and for PCBs (polychlorinated biphenyls) by-products of electrical manufacturing that are now known to cause cancer.
Some dioxins have hormone-like effects on the human body, causing changes that can lead not only to cancer but to infertility and other sexual changes.
The U.S. government has declared certain dioxins to be cancer-causing agents.
Each year, the report will be reissued with 5,000 new people tested to keep an eye on changes in patterns. The scientists will look first and hardest at substances known to cause cancer, birth defects and neurologic diseases--notably the dioxins, PCBs, pesticides and volatile organic compounds such as the gasoline additive MTBE. Then they will look at substances whose role in causing disease is more open to question: chemicals such as phthalates.
"All of this stuff is controversial," Pirkle said. "That is why we are in the middle of it."
This past summer, the European Parliament toughened a draft law that would ban toys including pacifiers suspected of leaking phthalates into babies' mouths when sucked. Eight EU countries have decided to impose unilateral bans on phthalates and two more are considering it.
Consumer campaigners say the chemicals are linked to liver, kidney and testicular problems, but the plastics and toy industries deny a risk, arguing that not enough of the chemicals leach into babies' mouths to pose a problem.
The chemical industry demands tests that show how much of the substances actually do leach out into people's bodies. Pirkle, father of four children, said he hopes the report exonerates phthalates. "You can't live without pacifiers," he said. "Pacifiers are full of phthalates."
He worries the United States will follow European moves to take pacifiers and teething rings off shelves. "That is something you cannot do because of the mental health issues involved," he joked.
We all have dioxin contamination
Pirkle said people are likely to be surprised by the findings because chemical exposure is extremely widespread.
"If you gave a sample of blood or urine to us, we could find all sorts of things you didn't think you had. We are regularly, every day, exposed to 50,000 chemicals."
Leaning casually against a $450,000 gas mass spectrometer used to measure heavy metals, Pirkle told of finding higher-than-expected amounts of lead in people living in the remote Himalayas.
Lead usually gets into people's bodies when they breathe in fumes from fuel containing lead, which is why leaded gasoline in banned in the United States, or when they eat a lead-containing substance such as paint chips. It can cause brain damage and death.
"Almost everyone has some amount of every toxin in the world in their bodies," Pirkle said. "Everybody in this room has dioxin in their bodies," he added, though that does not necessarily mean disease.
For this reason, Pirkle said it is vital to find out just how much of each chemical may cause harm to people. "We have good data on animals and we are very good at treating rats and mice. (But) how do you extrapolate from a mouse to a person? We are trying to jump past a lot of this and are trying to get direct measurements in people."
CDC can measure 230 toxic substances in blood or urine. Of these, Pirkle said, 50 can be measured only equipment at the CDC. They can look for chemicals likely to be used in terrorist attacks such as nerve agents, sulfur mustards like the mustard gas that killed 70,000 in World War I, heavy metals and ricin.
The lab should be able to use its resources to defuse panic after a possible terrorist attack, he said. Not only should its screens be able to quickly tell who has been exposed to a deadly gas they can tell who has not.
A quick screening test can help public health officials decide quickly how much of an emergency they have on their hands, he said. "It's considered bad form in public health to evacuate a city when you don't have to."