Soil to Blame for Spike in Kids’ Lead Levels

Lead-contaminated dust is behind a seasonal fluctuation in blood-lead levels observed in children living in urban communities. A nine-year study recently published in Environmental Science & Technology tracked more than 367,000 children in Detroit along with atmospheric soil levels of lead and found a correlation. The lead in the contaminated soil comes from past deposits of gasoline, plumbing and certain pesticides that have been outlawed for years but have left an environmental legacy. In addition, any soil near buildings built before 1978 (when lead-based paint was outlawed) is likely to be high in lead content as is soil near busy roadways.

While children’s exposure to lead has declined since lead was eliminated from gas, paint, water pipes and the solder on canned goods, scientists have noted a seasonal rise in blood-lead levels among urban kids. Past research has found increased blood-lead levels by more than 10% in Washington, D.C., New York, Chicago and Milwaukee during the months of July, August and September. Levels fall again during winter and spring.

Soil was the suspected culprit and research from scientists at Wayne State University in Detroit, Colorado State University, Indiana University-Purdue University, and Macquarie University in Sydney, Australia found that is likely the case—with fine particles escaping from the soil as contaminated dust carried by wind and suspended by humidity where children breathe them in as they are outdoors playing.

“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 [lead], we recommend that attention be focused on primary prevention of lead-contaminated soils.”

Lead has damaging impacts on developing brains, where it can permanently disrupt new brain connections and result in lowered intelligence, learning disabilities and behavioral problems. In Detroit, a city with some of the highest blood-lead levels in kids, a study in the American Journal of Public Health found a direct correlation between lead levels in kids and poor academic performance. Children with 2-5 micrograms per deciliter of lead in their blood had a 33% greater likelihood of poor academic performance. Those lead levels are equal or below those set by the Centers for Disease Control and Prevention.

“We controlled for all of the possible confounders — maternal education, socioeconomic, race, gender — to make sure what we thought we were seeing was lead-based rather than some other factors. It’s clearly a function of the lead poisoning,” Randy Raymond, an administrator in Detroit Public School’s Office of Research, Evaluation, Assessment and Accountability told the Detroit Free Press.