RESUMEN
This survey of soil lead in the vicinity of old industrial sites examines how the stable isotope patterns vary among the sites according to the sources of the lead ore processed at each site. Lead smelters and refineries, which closed down decades ago, are the basis of this investigation. Samples were taken from near five old factory sites in Collinsville and Alton (Illinois), Ponderay (Idaho), East Chicago (Indiana) and Omaha (Nebraska). Historical records were searched for accounts of the sources of the lead. Lead concentrations were measured by atomic absorption flame spectrophotometry, and stable isotopic analysis was done by plasma ionization mass spectrometry. At every site visited, remnants of the old factories, in terms of soil lead pollution, could be found. In spite of potential complications of varying smelter feedstock sourced from mines of different geological age, it was possible to match the isotopic patterns in the soils with the documented sources of the ores. The Collinsville and Alton sites resembled Missouri lead. The Ponderay value was higher than major Bunker Hill, Idaho deposits, but closer to the minor, nearby Oreille County, Washington ores. Mostly Utah ore was used in East Chicago. The Omaha soil reflects lead from Mexico, Colorado and Montana.
RESUMEN
Twelve suspected former secondary lead smelting sites were investigated. Ten of the sites were confirmed to be former secondary lead smelters or lead works by historical fire insurance maps and contemporaneous metal industry trade directories. At eight sites sampled, the ratio Sb:Pb was closer to ratios from 10 known lead smelting sites than were the As:Pb and Cd:Pb ratios. Data from the 10 known lead smelting sites showed that the Sb:Pb ratio is most characteristic of secondary lead smelting sites. This is because the primary alloy smelted at such sites is antimonial lead. Lead contamination at the eight sites investigated here can be attributed At least in part to the former smelters because of the association between Sb and Pb.