Zinc isotope systematics in snow and ice accretions in Central European mountains

Zinc (Zn) pollution negatively affects human and ecosystem health. We quantified atmospheric Zn inputs at six remote mountain-top locations in the Czech Republic (Central Europe), and used delta Zn-66 isotope ratios to identify Zn from different pollution sources. The study sites were located at an elevation of approximately 1000 m near the state borders with Germany and Poland. During two winter seasons (2009-2010), over 400 samples of vertical deposition (snow) and horizontal deposition (ice accretions) were collected. Zinc pollution levels were generally low. Zinc concentrations in snow and ice accretions were less than twice as high in the east, compared to the west. Across the sites, over 90% of Zn was present in a weak-acid soluble form. Zinc concentrations were 5 times higher in ice accretions, which formed from small droplets originating in the basal cloud layer, rich in pollutants, than in snow. In contrast, droplets resulting in snow formation were larger and scavenged less pollution due to their smaller surface area. delta Zn-66 of Pribram sphalerite (west) and smelter-derived fly ash (west) were low, -0.23 and -0.47 parts per thousand, respectively. Olkusz sphalerite (east) had a higher delta Zn-66 of 0.02 parts per thousand delta Zn-66 of snow ranged from -0.60 to 0.68 parts per thousand Ice accretions had delta Zn-66 between -0.67 and 0.14 parts per thousand At the three eastern sites, delta Zn-66 of ice accretions was lower than delta Zn-66 of snow, suggesting the presence of volatilized smelter-derived or coal-burning derived Zn. delta Zn-66 of ice accretions at two of the three western sites was higher than delta Zn-66 of snow. Different delta Zn-66 values of snow and ice accretions from the same site reflected different pollution sources, which may have been situated at different distances from the receptor site. delta Zn-66 of the soluble Zn fraction was higher than delta Zn-66 of the insoluble Zn fraction, possibly also indicating a different origin of these two Zn fractions. Zinc isotope heterogeneity in the atmosphere of remote areas indicates that delta Zn-66 can be a useful tool in pollution provenance studies. (C) 2014 Published by Elsevier B.V.