Most of these children are not living next to Superfund sites, but in our inner cities. Auto exhaust from leaded gasoline and lead paint from older buildings have contaminated the soil in many cases exceeding the EPA threshold value of 400 parts per million. Children are exposed to the lead when they play outside, get dust on their hands, and track soil into their homes.
Unlike homes that fall under the jurisdiction of the Superfund program, there are not any resources available to remove and replace this contaminated soil. Researches at the University of Washington may have identified a cost-effective approach to the problem of high lead in inner city soils. The results of their study are published in the January/February 2003 issue of the Journal of Environmental Quality.
The study, funded by the Water Environment Federation and conducted from 1997-1999, looked at reducing lead contaminated soil from a home garden in Baltimore with different types of municipal biosolids including compost. Biosolids are the nutrient-rich material produced during wastewater treatment. Use of biosolids as a fertilizer for agriculture and for soil reclamation is common. Results from this study suggest biosolids may have another important use in inner cities.
The study added these biosolids and composts to the lead contaminated soil and then used both lab tests and an animal feeding study to evaluate changes in lead levels. The biosolids compost addition to the soil was the most effective of all the biosolids tested with lead reductions ranging from 20-38%. This compost had high iron and manganese concentrations, which were important factors in reducing lead.
According to Rufus Chaney, co-author of the study and a metals specialist for the USDA research service, "Since we've found the extensive urban soil lead problem in the middle '80s, we've been seeking a lower cost option to soil removal. This new finding appears to be the answer."
As a result of this initial study, a pilot program has begun adding composts to home gardens in Baltimore. Compost in combination with phosphorus was also used to treat a site in East St. Louis. Initial results from these programs confirm the results of the lab study.
"Using compost generated by cities to help remediate soils in the cities is a beneficial solution all around," said Sally Brown, University of Washington, co-author of the study.
The Journal of Environmental Quality, http://jeq.scijournals.org is a peer-reviewed, international journal of environmental quality in natural and agricultural ecosystems published six times a year by the American Society of Agronomy (ASA), Crop Science Society of America (CSSA), and the Soil Science Society of America (SSSA). The Journal of Environmental Quality covers various aspects of anthropogenic impacts on the environment, including terrestrial, atmospheric, and aquatic systems.
The American Society of Agronomy (ASA) www.agronomy.org, the Crop Science Society of America (CSSA) www.crops.org and the Soil Science Society of America (SSSA) www.soils.org are educational organizations helping their 10,000+ members advance the disciplines and practices of agronomy, crop, and soil sciences by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services.
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Journal of Environmental Quality