Continued scares about lead in children

A study of Detroit children blamed dust from the soil and carried by the wind during the summer months for higher seasonal lead levels in children. Parents do not need to worry about letting their children play outside! (Information below the news release.)

Childhood blood lead levels rise and fall with exposure to airborne dust in urban areas

A new nine-year study of more than 367,000 children in Detroit supports the idea that a mysterious seasonal fluctuation in blood lead levels — observed in urban areas throughout the United States and elsewhere in the northern hemisphere — results from resuspended dust contaminated with lead. The scientists, who report in the journal Environmental Science & Technology (ES&T), say the results have implications for government efforts to control childhood exposure to lead, which can have serious health consequences.

Shawn P. McElmurry and colleagues point out that average blood lead levels in the U.S. and globally have declined following the elimination of lead from gasoline, paint, water pipes and solder used to seal canned goods… Much of the current lead in major urban areas is from those “legacy” contaminants. Modern human exposure takes the form of fine particles, deposited in the soil years ago, that are swept up into the air…. The scientists set out to test a hypothesis implicating contact with lead-contaminated dust while children are outdoors and engaged in warm-weather activities — at a time when wind, humidity and other meteorological factors increase the amounts of dust in the air. Their ES&T report describes research that strongly implicates airborne dust as the reason for the seasonal trends in blood lead levels. It shows a correlation between atmospheric soil levels in Detroit and blood lead levels in children.

“Our findings suggest that the federal government’s continued emphasis on lead-based paint may be out-of step (logically) with the evidence presented and an improvement in child health is likely achievable by focusing on the resuspension of soil lead as a source of exposure,” the report states. “Given that current education has been found to be ineffective in reducing children’s exposure to Pb, we recommend that attention be focused on primary prevention of lead-contaminated soils.”

What the story didn’t disclose was that while there was some seasonal fluctuations in lead levels, none of the children in the study had levels even approaching the level the CDC uses to identify lead exposure. In fact, the levels were ten times lower than those the CDC uses for medical concern.

[Remember, last year the CDC began using 10 mcg/dl to identify children with lead exposure and for reportability. It’s the level public health officials now use to target children for government case management. It didn’t change the levels (45 mcg/dl +) recommended for medical intervention. So, while more children can now be identified as having lead exposure, it doesn’t mean these children are necessarily toxic.  In fact, according to CDC data, levels have been dropping significantly since the 1990s.] 

As the study’s graph shows, the lead levels among the 367,000 Detroit children were between about 2 and 4 mcg/dl — well below any level of concern.

leadlevels

The latest CDC data (2011) show that only 0.66% of children in Michigan had lead levels of 10mcg/dl or higher and only 17 children were found in the state with blood levels 45 mcg/dl or higher, needing medical intervention.

Parents don’t need to fear that letting their children go outside and play will put them in danger of lead poisoning.

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One response to “Continued scares about lead in children

  1. It will be interesting to see similar data from places with naturally occurring lead, such as Galena, IL or Platteville, WI. Even more interesting if compared with other particle-concentrating systems, such as bees and honey, or artificial dust collectors, in the areas with detectable lead levels.

    I knew a bunch of prospecting geologists who scored important finds by surveying local samples of honey for metal content. They used to brag that plants and bees did the tedious part of the job for them. They carried their own surveyor bees from place to place.

    Another factor that can possibly explain the elevated lead levels in urban areas, besides the residue from TEL in auto gas that had several decades to build up before it was phased out is avgas used in general aviation today. Because aviation tends to concentrate near large towns, it could be one of the sources. And it is usually more active during the summer months.

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