Professor Says Rewatering May Help Prevent Lead Poisoning

Chronic lead poisoning, caused in part by the ingestion of contaminated dirt, affects hundreds of thousands more children in the United States than the acute lead poisoning associated with imported toys or jewelry. Could treating contaminated soil with water prevent this public health scourge?

In a study appearing in the August issue of the journal Applied Geochemistry, Gabriel M. Filippelli, Ph.D., professor of earth sciences and department chair at Indiana University-Purdue University Indianapolis, conducted a literature review of studies of urban soils as a persistent source of lead poisoning and also investigated the lead burden in the soils from a number of cities, including Indianapolis. His findings reveal that older cities like Indianapolis have a very high lead burden resulting in a lead poisoning epidemic among their youngest citizens.

Filippelli suggests two possible remedies, one of which he believes to be feasible from both the practical and monetary perspectives and doable almost immediately.

According to 2007 U.S. Census Bureau data, there are approximately 20 million children below the age of five in the United States, the age range of greatest susceptibility to the harmful affects of lead poisoning. Filippelli notes that about 2 percent of these children (approximately 400,000) have lead poisoning, many in epidemic proportions.

"These national numbers for chronic lead poisoning are staggering but the percentage of affected children in older urban areas is much much higher than in rural areas or newer cities. The blowing soil and dust young children ingest contains large amount of lead from lead paint and leaded gasoline deposited decades ago, and from industrial contamination. In Indianapolis, we found high levels of soil contamination. Many older urban centers have lead poisoning rates that are 5 to10 times the national average." said Filippelli, who is a biogeochemist studying environmental contamination of heavy metals and its effects on children's health.

Going into neighborhoods where yards are dirt rather than grass-covered and spraying clean water with high power shower systems when tests show that soil moisture is low (usually mid-July to mid-September in Indianapolis, for example), would significantly decrease the chronic lead poisoning in children, according to Filippelli. Since contaminated dirt blows from one property to another, this cannot be done on a house by house basis but must be carried out on a regional basis.

A better but less feasible remedy would be to put a layer of clean soil on top of the contaminated soil and to hydroseed the fresh dirt with grass. While preferable, it is less practical as the grass has to be maintained, more costly and probably unrealistic to expect money-strapped municipalities to attempt. The high-end remedy, removal of all contaminated dirt, perhaps two feet deep, is unattainable, except in small areas around industrial sites such as lead smelters.

This study was funded by the IUPUI School of Science.

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