Cu-Zn isotope constraints on the provenance of air pollution in Central Europe: Using soluble and insoluble particles in snow and rime

摘要

Copper (Cu) and zinc (Zn) isotope ratios can be used to fingerprint sources and dispersion pathways of pollutants in the environment. Little is known, however, about the potential of delta Cu-65 and delta Zn-66 values in liquid and solid forms of atmospheric deposition to distinguish between geogenic, industrial, local and remote sources of these potentially toxic base metals. Here we present Cu-Zn deposition fluxes at 10 mountain-top sites in the Czech Republic, a region affected by extremely high industrial emission rates 25 years ago. Additionally, we monitored isotope composition of Cu and Zn in vertical and horizontal atmospheric deposition at two sites. We compared delta Cu-65 and delta Zn-66 values in snow and rime, extracted by diluted HNO3 and concentrated HF. Cu and Zn isotope signatures of industrial pollution sources were also determined. Cu and Zn deposition fluxes at all study sites were minute. The mean delta Cu-65 value of atmospheric deposition (-0.07 parts per thousand) was higher than the mean delta Cu-65 value of pollution sources (-1.17 parts per thousand). The variability in delta Cu-65 values of atmospheric deposition was lower, compared to the pollution sources. The mean delta Zn-66 value of atmospheric deposition (-0.09 parts per thousand) was slightly higher than the mean delta Zn-66 value of pollution sources (-0.23 parts per thousand). The variability in delta Zn-66 values of atmospheric deposition was indistinguishable from that of pollution sources. The largest isotope differences (0.35 parts per thousand) were observed between the insoluble and soluble fractions of atmospheric deposition. These differences may result from different sources of Cu/Zn for each fraction. The difference in isotope composition of soluble and insoluble particles appears to be a promising tool for pollution provenance studies in Central Europe. (C) 2016 Elsevier Ltd. All rights reserved.