Lead in Surface Soil, Copperbelt Environment Project Soil Sampling Results, 2006. This map, produced by the Kabwe Scoping and Design Study (KSDS) of the Copperbelt Environment Project, is an interpolated distribution of lead in soil based on a district and township survey. This means that soil samples were taken at individual points throughout Kabwe, and the surveyors used a mathematical model to estimate lead concentrations across the whole district. The United States Environmental Protection Agency (EPA) considers lead a hazard in children’s play areas at or above 400 mg/kg.