Dry summer months linked to increased lead levels
Posted March 11, 2013
DETROIT — Old paint isn’t the only culprit behind increased levels of lead in children.
A study out of Wayne State University linked airborne dust to higher concentrations of lead in children during summer months in urban areas.
Assistant WSU professor Shawn McElmurry’s recently completed study confirmed the presence of lead in airborne dust and dirt and solved an anomaly long recognized in lead-exposure research.
“There has been a lot of work done to reduce the exposure to lead found in old paint, but everybody has long recognized that lead levels in kids’ blood vary throughout the year and increase drastically during the hot, dry months of late summer and early fall,” McElmurry said.
“But that’s never added up — an increase in levels at a time when kids are traditionally spending more time outside and less time exposed to lead-based paints.”
As a civil and environmental engineer, McElmurry has long known that lead was used in a slew of products before information about its harmful effects became known, and it was eventually phased out of regular use in the 1970s and ’80s.
“A second major source of lead was emitted into the air from gasoline up until the 1980s,” McElmurry said. “And that lead was deposited into the soil along roadways.”
Since lead levels are known to increase in hot, dry months and are highest in longtime urban areas, McElmurry came up with a theory that fuel-based lead particles that were deposited into the soil more than 30 years ago might be the culprits behind the seasonal increase in lead levels.
With the help of colleagues from Colorado State University, Macquarie University and Indiana University-Purdue University Indianapolis, and funding from the Robert Wood Johnson Foundation Health & Society Scholars program, McElmurry embarked on a study that spanned nine years and included 367,000 subjects to see if his theory held.
Turns out, it did. The study concluded, with only a .05-percent margin of error, that the soil in urban areas with a history of heavy automobile use contained a highly increased presence of lead, while soil located farther from the roadway had less, and the lead content continued to drop in soil as the distance from urban areas and historically well-traveled roadways increased.
“Higher concentrations of lead were found in the center or urban areas, and it decreases as you go out, but even in a city, soil from alongside a roadway has increased levels than soil taken from the middle of a park, and those findings were consistent everywhere, in urban areas around the world,” he said.
“And what that tells us is we need to be spending much more time and energy looking into contaminated soil.”
While the study proved a major source of lead contamination in urban areas, more research and information is needed before a solution can be found.
One of the things the study didn’t look at it is how the lead was being ingested or absorbed into the body.
“There are a lot of bio-kinetics involved with the absorption of lead in the human body,” McElmurry said.
“We were unable to look at how the lead was being absorbed — whether it was being breathed in from dry dust particles in the area, or whether particles came in contact with the hands and were ingested through the mouth when eating, or in some different way altogether.”
What the study did conclude is that lead contamination in soil, especially in urban areas, is not all that uncommon, and kids exposed to contaminated soil have higher concentrations of lead in their blood.
The dangers of lead contamination are well-known to include learning and behavioral disorders, health problems and even seizures.
The Center for Drug Control and Prevention recently lowered the level at which medical help is recommended from 10 micrograms per deciliter to 5 micrograms per deciliter.
A representative from the CDC commented on the dangers of lead.
“Lead exposure can affect nearly every system in the body,” said Jay Dempsey, a health communications specialist at the CDC.
“(The) CDC emphasizes the importance of eliminating or safely controlling all sources of lead in a child’s environment. Lead can be found in a variety of sources, including lead-based paint, found in older homes built before 1978, and the dust produced as it deteriorates, soil, certain consumer products and more.”
The CDC website goes on to say that, “even low levels of lead in blood have been shown to affect IQ, ability to pay attention and academic achievement,” and that such effects are usually irreversible.
McElmurry said parents shouldn’t worry, though.
“There are some pretty simple steps you can take to reduce lead contaminates and reduce exposure,” he said. “Remove chipping paint and paint over or replace old paint; reduce play in bare soil — especially near roadways and alongside the home where outdoor paint could have contaminated the soil — and lawn maintenance to reduce the presence of bare soil.”
The CDC website recommends staying informed and getting children tested, and it has a variety of tools aimed at preventing and treating lead exposure, including a downloadable lead-exposure prevention coloring book. To check it out, visit www.cdc.gov.
For more information on the study findings, email McElmurry at firstname.lastname@example.org.
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