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Friday, July 16, 2004 - Page updated at 09:29 A.M.
Seattle schools' lead danger disputed
The chances of neurological damage are "extremely, extremely low," says Dr. Catherine Karr, director of the Pediatric Environmental Health Specialty Unit at the University of Washington, who reviewed the published lead levels. Studies have shown that large groups of children who are steadily exposed to high lead levels have lower average IQs than children who aren't exposed. But the findings can't predict how any individual would be affected because of differences in age and brain development.
And many of the studies took place when the average blood lead level among U.S. children younger than 6 was about seven times higher than it is now before lead was phased out of paint, gasoline and food cans.
It can be far more dangerous to a child's well-being for a panicked parent to start treating a child who drank lead-tainted water as brain damaged.
"The mother says 'Johnny is not like everybody,' 'Johnny is not like everybody,' and eventually Johnny truly is not like everybody because you build up this expectation," said Mary Jean Brown, chief of the lead poisoning prevention branch at the federal Centers for Disease Control and Prevention in Atlanta. "We want to be very, very careful to say anybody was damaged because they drank from the drinking fountain."
According to the newspaper Education Week, schools in California, Maine, New Jersey, New York and the District of Columbia, like Seattle, are confronting the costly prospect of replacing lead plumbing materials, but it's a problem for every school district in the country.
Seattle Public Schools, which in early January began supplying bottled water in each of its schools built prior to 1997, has completed testing the drinking water in all but three buildings. It is considering testing bathroom faucets as well. So far, 66 percent of the schools have two or more fountains from which investigators drew water samples containing more than 20 parts per billion (ppb) of lead, the level at which the federal Environmental Protection Agency recommends schools take remedial action.
Some parents have expressed alarm over the findings. More than 30 at Alternative Elementary No. 2 met last week with Ron English, the district's water quality project manager.
Investigators measured 1,600 ppb lead in Room 5's fountain, although that level fell to 6 ppb after a 30-second flush. Room 5's fountain had passed the EPA guideline during system-wide sampling by the district in the early 1990s.
Former AE2 parent Sarah Westervelt blamed the water fountain for a friend's daughter's seizures, disorientation, and other neurological problems.
"These symptoms totally line up with her kindergarten and first grade year at this school," she said. "You can imagine the kind of suffering this has caused this child."
Asked about the possible health risk, the CDC's Brown said the science is too complicated to blame a child's neurological problems on a water fountain.
"They would have to ingest really large amounts of water for that to have an adverse health effect on them," she said. Moreover, other conditions could cause those health problems.
Toxicologists list a dozen factors that must be considered in assessing a child's lead exposure: Among them, how much lead was ingested, the number of times a child ingested that amount, a child's exposure to lead at home, and protective factors such as a child's consumption of calcium and iron. Good nutrition can help counter lead's effects, health experts say.
Perhaps the best example of how complicated the link is between lead exposure and adverse health effects is a recent health investigation in the nation's capital.
A public water utility in Washington, D.C., discovered that 163 homes with lead service pipes had lead levels over 300 ppb in flushed-water samples from their taps.
Health officials got consent to test the blood of 201 residents from 98 of these homes. None of the adults or children had an elevated blood lead level, even though most reported drinking tap water.
Many water sources such as the Tolt and Cedar rivers, which supply King County, are virtually lead free.
Lead enters the water supply when it is leached from lead pipes, copper pipes joined with lead solder, or lead-containing faucets and brass fixtures.
While the EPA set a goal of zero lead in drinking water, agency officials say that based on current technology and resources, the lowest lead level reasonably attainable in a water system is 15 ppb at the tap. To test water quality, suppliers take first-draw samples, also called "standing-water" samples, from the pipes after the water has been unused for at least six hours.
For schools, the standard is 20 ppb. Slightly more lead is allowed because the standing-water sample taken is only one-fourth the 1-liter sample that public water systems must obtain and it is water that has been in contact with a possibly lead-containing faucet. Thus it is more likely to have a higher concentration of lead.
According to the EPA, the standing-water sample is intended to measure lead exposure in a worse-case scenario for the child who is the first to drink from a fountain without flushing it. But a flushed-water sample, taken after a fountain has run for 30 seconds or more, is a more typical exposure. "There is an exceedingly small chance that any child would receive harmful levels," said the UW's Karr.
To assess the risk that Seattle schools' drinking water might pose to children, Karr used an EPA formula developed for public health officials. She described this worst-case scenario:
The student is 6 to 7, because the younger the child, the more likely lead could cause brain damage, with the highest risk to infants.
For six months or more, one half of the child's daily water intake has a lead level of 200 ppb. That's a higher level than the "first draw" samples at 90 percent of the Seattle schools with elevated levels, she said. The child would have to go from fountain to fountain taking the first drink of the day.
The child lives in a home with water that has a lead level of 7.9 ppb. That is the level in the highest-risk homes sampled in this area, according to Seattle Public Utilities.
Even in this worst case, the child's predicted blood-lead level would be 9.3 micrograms per deciliter (mcg/dL) of blood, Karr said. The CDC says blood levels of 10 mcg/dL or more could be harmful to children.
A recent study by Cornell University scientists found increases in low blood-lead levels over three to five years could slightly decrease IQ levels in young children age 5 and younger. The research involved children exposed to dust containing lead.
Karr said such small decreases in IQ are not detectable. A child who dropped two or three points in IQ, for example, would not be impaired in reading or math ability, she said.
Still, Karr and other physicians agree that children should be exposed to as little lead as possible. The schools should continue to reduce lead levels in water as much as is feasible, they say. "We don't need it, so let's not have it," said Karr.
Dr. Bill Robertson, director of the Washington Poison Center and UW professor emeritus of pediatrics, agrees. But he said health officials and the public also need to keep in perspective the very low risk of damage to children from area drinking water.
"On a relative basis, there are other things more deserving than the lead issue," he said.
At the same time, it's important for parents to remember that lead is most concentrated in lead-based paint and tainted soil, which remain the common sources of lead poisoning in children, public health experts say. Infants and toddlers can pick up and swallow lead-tainted paint chips, soil or windowsill dust.
Lead-based paint was banned from use in homes after 1978. Children are at greatest risk in homes built prior to the 1950s, when lead in some interior paints was 500 million ppb.
Of Seattle's 270,524 housing units, about 81 percent were built before 1980, according to the 2000 Census. Nearly 160,000 were built before 1940.
But a targeted survey between 1994 and 1997 of 109 low-income children younger than 3 living in old housing in Seattle found none with elevated blood lead levels, according to the Washington Department of Health.
Public health officials recommend that concerned parents ask their pediatrician about testing their child's blood lead level.
Sanjay Bhatt: 206-464-3103 or email@example.com
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