Stephan Kraemer from EDGE together with the former PhD student Martin Walter and university assistant Walter Schenkeveld, and colleagues from the University of Veterinary Medicine Vienna, investigated the weathering kinetics and hydroxyl radical yield of toxic chrysotile asbestos fibers in suspensions of (cement-amended) soils with different pH and organic carbon properties.
Soil solution pH proved to be the major determinant of asbestos weathering in soil suspensions (with fiber weathering and soil solution pH being inversely related). Addition of cement to soils inhibited asbestos weathering because of its alkalinity. The hydroxyl radical yield of asbestos in soil suspensions decreased by maximally ≈75%, and fully decreased to background levels in soils to which cement has been added (due to precipitation of Fenton-inactive minerals on fibers). In low pH podzol suspensions, also increases in the fibers’ hydroxyl radical yield were observed, presumably because of an association of soil solution Fe with the asbestos fiber surface.
