Sources of platinum group elements in the environment
Kapitel i bok, 2015
Platinum group elements (PGE, i.e. Pt, Pd, Rh, Ir, Ru, Os) are among the least abundant elements in the Earth’s continental crust. PGE concentrations in urban and roadside environments are, however, increasing as a result of anthropogenic emissions. Automobile catalysts are generally considered the main PGE source into the urban and roadside environments. We argue that most studies to date have been carried out with a presumption of potential sources, and this bias may have masked additional, yet unidentified PGE sources. Comparison of environmental records at urban locations suggests that PGE emissions reflect contributions from several sources, including automobile catalysts, industry and medical treatment centers. Coal combustion may also contribute to urban PGE fluxes. Environmental records at remote locations support contributions from such diverse sources. Estimates of PGE emissions, however uncertain, indicate that these diverse sources contribute significantly to the global PGE budget at the Earth’s surface.