Speciation of PM sub(10) Sources of Airborne Nonferrous Metals within the 3-km Zone of Lead/Zinc Smelters

The purpose of this study was to estimate the speciation of PM sub(10) sources of airborne Pb, Zn, and Cd metals (PM sub(10) is an aerosol standard of aerodynamic diameter less than 10 mu m.) in the atmosphere of a 3 km zone surrounding lead/zinc facilities in operation for a century. Many powdered samples were collected in stacks of working units (grilling, furnace, and refinery), outdoor storages (ores, recycled materials), surrounding waste slag (4 Mt), and polluted topsoils (3 km). PM sub(10) samples were generated from the raw powders by using artificial resuspension and collection devices. The bulk PM sub(10) multielemental analyses were determined by inductively coupled plasma-atomic emission spectrometry (ICP-AES). The proportions in mass of Pb (50%), Zn (40%), and Cd (1%) contents and associated metals (traces) reach the proportions of corresponding raw powdered samples of ores, recycled materials, and fume-size emissions of plants without specific enrichment. In contrast, Pb (8%) and Zn (15%) contents of PM sub(10) of slag deposit were found to be markedly higher than those of raw dust, Pb (4%), and Zn (9%), respectively. In the same way, Pb (0.18%), Zn (0.20%), and Cd (0.004%) were enriched by 1.7, 2.1, and 2.3 times, respectively, in PM sub(10) as compared with raw top-soil corresponding values. X-ray wavelength dispersive electron-microprobe (EM-WDS) microanalysis did not indicate well-defined phases or simple stoichiometries of all the PM sub(10) samples at the level of the spatial resolution (1 mu m super(3)). X-ray photoelectron spectroscopy (XPS) indicated that minor elements such as Cd, Hg, and C are more concentrated on the particle surface than in the bulk of PM sub(10) generated by the smelting processes. (XPS) provided also the average speciation of the surface of PM sub(10); Pb is mainly represented as PbSO sub(4), Zn as ZnS, and Cd as CdS or CdSO sub(4), and small amounts of coke were also detected. The speciation of bulk PM sub(10) crystallized compounds was deduced from XRD diffractograms with a raw estimation of the relative quantities. PbS and ZnS were found to be the major phases in PM sub(10) generated by the smelting facilities with PbSO sub(4), PbSO sub(4) times PbO, PbSO sub(4) times 4PbO, Pb metal, and ZnO as minor phases. The slag waste PM sub(10) was found to contain some amounts of PbCO sub(3), PbSO sub(4) times PbO, and ZnFe sub(2)O sub(4) phases. The large heterogeneity at the level of the individual particle generate