Landscape scale variability of atmospherically derived industrial metal enrichment in surfical environments

Tuesday, 16 December 2014
Nicola Stromsoe, University of Queensland, St Lucia, QLD, Australia, Samuel K Marx, University of Wollongong, Wollongong, NSW, Australia, Hamish A McGowan, University of Queensland, St Lucia, Australia, John N Callow, University of Western Australia, Crawley, Australia and Atun Zawadzki, Australian Nuclear Science and Technology Organization, Kirrawee, Australia
Industrial metal pollutants are now ubiquitous in the global atmosphere and are a potential source of contamination to surficial environments, even in remote-from-source locations. Few studies, however, have examined the environmental fate of atmospheric industrial metals at a landscape scale. In this study patterns of atmospheric industrial metal accumulation were investigated within different surface environments of the Snowy Mountains, Australia. Atmospheric concentrations of industrial metals were compared with enrichment in peat mires, a tarn-lake, reservoirs and soils to elucidate patterns of dilution and concentration. Industrial metals (including lead, cadmium and antimony) were enriched in collected aerosols by 3.5-50 times pre-industrial concentrations. Surface enrichment was variable and depended on relative geomorphic activity (i.e. the rate of atmospheric deposition relative to surface derived sediment input), metal sensitivity and metal behaviour. Peat mires, the environments most dominated by atmospheric deposition, most closely reflected atmospheric enrichment patterns and tended to record the highest industrial metal enrichment. Even in this environment, however, metal enrichment was reduced by 5-7 times relative to atmospheric concentrations. Those metals most sensitive to enrichment (those with low natural abundance in local sediments (cadmium, silver, antimony and molybdenum)) were enriched within all sedimentary environments. In the most geomorphically active environments (the alpine tarn) no other industrial metals were enriched. In reservoirs located lower in the catchment, industrial metals displayed complex patterns related to metal behaviour. Particle reactive metals, such and lead, displayed relatively minor enrichment, suggesting that they are retained in catchment soils. In contrast, more mobile elements such as copper and cadmium were enriched relative to catchment soils, implying preferential down-catchment transport. The presence of industrial metals in all sampled environments further confirms their widespread perturbation in the environment. Overall, however, enrichment of industrial metals in surficial environments is complex and varies across the landscape as a function of metal behaviour and surface geomorphic processes.