『Abstract
　Spherical particles have been sampled from soils and silica-rich rock coatings close to major smelter centers at Coppercliff, Coniston, and Falconbridge in the Sudbury area, Canada. Detailed analyses employing optical microscopy, scanning electron microscopy, transmission electron microscopy, micro-Raman spectroscopy, and Mossbauer（oの頭に¨） spectroscopy have potential alteration. The spherical particles are on the nano- to millimeter-size range and are composed principally of magnetite, hematite, Fe-silicates (olivine, pyroxenes), heazlewoodite, bornite, pyrrhotite, spinels (including trevorite and cuprospinel), delafossite, and cuprite or tenorite. The spinels present have variable Cu and Ni contents, whereas delafossite and cuprite are Ni free. Texturally, the spherical particles are composed of a Fe-oxide-Fe-silicate matrix with sulfide inclusions. The matrix displays growth features of a Fe-rich phase that commonly form during rapid cooling and transformation processes within smelter and converter facilities. Examination of weathered spherical particles indicates that some sulfide inclusions have dissolved prior to the alteration of the Fe-silicates and oxides and that the weathering of Fe-silicates occurs simultaneously with the transformation of magnetite into hematite. A higher proportion of Cu vs. Ni in the clay and organic fraction noted in the Sudbury soils is explained by (1) the formation of stronger adsorption complexes between Cu and the corresponding surface species and (2) the preferential release of Cu vs. Ni by smelter-derived particles. The latter mechanism is based on the observations that (a) cuprospinels have higher dissolution rates than Ni spinels, (b) a larger proportion of Cu occurs in the nanometer-size (and thus more soluble) fraction of the emitted particles, and (c) Ni spinels of relatively low solubility form in the alteration zone of heazlewoodite inclusions.

Keywords: Soils; Particulates; Heavy metals; Smelter』

1. Introduction
　1.1. History of environmental pollution in the greater Sudbury area
　1.2. Former studies on the Sudbury soils
　1.3. Objectives
　1.4. Mineralogical studies on Cu- and Ni-bearing particles emitted by other base-metal smelters
2. Experimental
　2.1. Scanning electron microscopy
　2.2. Focused ion beam and transmission electron microscopy
　2.3. Mossbauer（oの頭に¨） spectroscopy
　2.4. Micro-Raman spectroscopy
　2.5. X-ray diffraction
　2.6. Rietveld refinements
3. Results
　3.1. Chemical and mineralogical composition of the spherical particles
　　3.1.1. Cu- and Ni-rich spherical particles
　　3.1.2. Fe-oxide-silicates
　3.2. Size variations of the spherical particles
4. Discussion
　4.1. Overview of the ore refinement processes at Copper Cliff
　4.2. Emission and transformation of spherical particles in the smelter, converter, and atmosphere
　4.3. Internal (non-weathered) textures of the spherical particles
　4.4. Occurrence and chemical composition of the Fe-Ni-Cu-sulfides
　4.5. Occurrence and chemical composition of the Fe-Ni-Cu-oxides
　4.6. Weathering features and products
　4.7. Other potential weathering products
　4.8. Transformation of magnetite into hematite and release of Cu²⁺ and Ni²⁺
　4.9. Dissolution rates of Fe-Cu-Ni spinels
　　4.9.1. Dissolution rates controlled by surface reduction processes on Cu- and Ni-bearing spinels
　　4.9.2. Dissolution rates controlled by the grain-size distributions of the Cu and Ni spinels
　　4.9.3. Formation of trevorite during oxidation of the sulfides
　4.10. Emission of nanoparticles and the environmental consequences
5. Summary
Acknowledgments
References