title: The effects of naturally occurring acids on the surface properties of chrysotile asbestos.
abstract: Chrysotile asbestos is considered an environmental health hazard. It is postulated that the surface of chrysotile, with its inherent positive charge and chemical content of trace transition metals within the mineral is a causative factor of the concern. Weathering may reduce the negative health effects of chrysotile asbestos, by alteration of the outer brucite layer of the chrysotile. To assess the changes in the surface properties of chrysotile asbestos by simulated weathering, chrysotile was treated with oxalic, hydrochloric, and carbonic acids. Naturally occurring chrysotile, from a mine site and serpentinitic stream sediments from the Sumas River were analyzed and compared. Oxalic acid, a chelating acid, was the most effective at extracting the majority of the trace elements present in the chrysotile, reducing their positive surface charge and producing visible changes at the surface of the fibers as shown by Field Emission Scanning Electron Microsopy (FESEM). Carbonic acid had little effect on the surface properties. Stream environments had minor detectable effects on the surface properties on the chrysotile stream sediments.
authors: a Faculty of Land and Food Systems , The University of British Columbia , Vancouver , Canada.
authors: Emma P
authors: EP
authors: Holmes
authors: L M Les
authors: LM
authors: Lavkulich
mesh_terms: D017632:Asbestos, Serpentine / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry*; D019015:Geologic Sediments / Q000737:chemistry; D008906:Mining; D019815:Oxalic Acid / Q000737:chemistry*; D045483:Rivers / Q000737:chemistry; D014131:Trace Elements / Q000737:chemistry; D014887:Weather
chemical_list: D017632:Asbestos, Serpentine; D002614:Chelating Agents; D014131:Trace Elements; D019815:Oxalic Acid
keywords: Serpentinitic sediments; asbestos; chrysotile; electron microscopy; surface chemistry; surface composition; weathering