Lead levels in urban soil are declining but hotspots persist

(Duke University) Lead paint and leaded gasoline have been banned for decades, but unsafe levels of lead remain in some urban soils, a Duke University study finds. The researchers mapped soil lead concentrations along 25 miles of streets in Durham, N.C. Though contamination generally has declined since the 1970s, soil collected near houses predating 1978 still averaged 649 milligrams of lead per kilogram of soil, well above the 400 mg/kg threshold associated with health risks to children.