Heavy Metal Contamination in Soils of Urban Highways: Comparison Between Runoff and Soil Concentrations at Cincinnati, OH

Runoff and soil samples were collected along I-75 in Cincinnati, OH, and heavy-metal concentrations were measured. Mass-balance calculations were made for zinc, copper, nickel, chromium, and lead to assess how much of the runoff of heavy metals got transferred to the soil. Heavy-metal content was found to be very high in the top 15 cm of the soil, and sequential extraction revealed that the metal amounts in the exchangeable fraction were very low. Analysis of the organically bound fraction showed that the organic matter was dominated by a component that was not extracted by conventional techniques. The analyses revealed that only small amounts of metals in the soil could be remobilized easily. Mass-balance estimates suggested that Pb in the soil was from vehicle exhaust when leaded gasoline was still used.