Dangerous lead is in ground beneath your feet

Still, awareness has lowered exposure for children

December 20, 2007|By Greg Burns

Once parents have finished vetting toys for the holiday season, they should take at least one more precaution to safeguard their children from exposure to lead: Remove their shoes.

The lead in toys amounts to a mere speck compared with the tons of dust spoiling the environment because of lead-based paints and leaded gasoline of generations past. Merely leaving your shoes at the door can notably reduce the risk of exposure, because tracking in the substance remains a surprisingly common route of contamination even today.

Thanks to public-awareness campaigns, most parents have at least some idea of the danger posed by lead paint in older buildings. Childhood lead exposure has declined sharply.

Still, the familiar assumption that decades-old paint is the biggest culprit in lead poisoning needs to be re-examined. Where it still exists, poorly maintained paint is indeed a genuine menace. But the most abundant and accessible source of lead isn't a big chunk of paint or, for that matter, a toy.

It's dust.

Recent research suggests that city kids may face their greatest risk from tiny particles of lead in the yards around their homes or the open spaces where they play.

Tainted soil

"We've completely missed the boat in recognizing how big a problem soil lead is," says Howard Mielke, a Tulane University researcher who has devoted his career to the subject. "Lead dust is subtle and hidden, but it is probably making the biggest impact on the child in an urban environment."

Mielke, 66, became a lead-dust evangelist through personal experience.

A routine checkup in 1983 uncovered elevated levels of the poison in Mielke's then-2-year-old daughter, Beverly. For several days, Beverly's chemist father tracked her doings, including her playtime at a licensed home day-care center several hundred yards from a major freeway. Finally, his suspicions settled on an outdoor sandbox.

Sure enough, the sand had been mixed with tainted soil, and the bare dirt around it had a lead content approximating the levels of industrial toxic-waste sites. That is not uncommon near busy interstates.

In addition, the play area bumped up against an exterior wall of the house, a problem because the dense particles of lead floating in the wind tend to hit such a surface, drift down and accumulate at the base -- right where his daughter was puttering around for hours a week.

The day-care center replaced the sandbox and its contents, while also covering the surrounding dirt with indoor-outdoor carpeting. Within weeks, Beverly's blood-lead levels dropped by half, and she suffered no identifiable ill effects.

In the years since, Mielke has learned more than he ever dared suspect about lead's insidious presence.

On balance, the news about lead poisoning is good, with blood-lead levels down and homes less contaminated than in the past. Society is better off: One recent report attributes a drop in violent crime to the curbing of impulsive behavior associated with lead poisoning.

A little bit hurts, too

But the drop in lead levels also coincides with new research showing that even a small amount in a child's bloodstream can undermine the ability to think, concentrate and behave.

No question, a lot of lead is bad. But a little is no good either. And eliminating it from the environment may be impossible.

The latest efforts focus on covering the soil where children play. Mielke is supervising a project that involves spreading 6-inch layers of fresh dirt over 25 properties in New Orleans. In Norway, a government-funded effort is systematically correcting the grounds of playgrounds, schoolyards and day-care centers, Mielke said.

Turns out, simple landscaping can help considerably, as long as the grass and shrubbery keep the dirt from blowing. Wood chips, artificial turf and pavement all have the same positive effect.

Hygiene makes a difference as well, including taking off shoes at the door, which can reduce the amount of dirt tracked into a home by an estimated one-third. Regular hand-washing, especially when children return from playing outside, also has a measurable impact.

Trouble is, dust tends to flow freely, and relatively clean areas can get dirty in a snap.

"There's no escaping it," said Dr. Helen Binns, a lead expert and professor at Northwestern University's Feinberg School of Medicine in Chicago. "You can't dig up the city. Where are you going to dump it? We don't really know what to do with it."

Greg Burns writes for the Chicago Tribune.

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