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Environmental science & technology

Long-range transported atmospheric pollutants in snowpacks accumulated at different altitudes in the Tatra Mountains (Slovakia).


PMID 21919451

Abstract

Persistent organic pollutants (POPs), including polychlorobiphenyls (PCB), endosulfans, hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polybromodiphenyl ethers (PBDEs), and polycyclic aromatic hydrocarbons (PAHs), were analyzed in snowpack samples collected along an altitudinal gradient (1683-2634 meters above sea level) in the High Tatra Mountains (Slovakia). All analyzed compounds were found at all altitudes, pointing to their global distribution. The presence of PBDEs, particularly BDE 209, in the snowpack samples is especially relevant, as it reflects the air transport capacity of this low volatile, very hydrophobic pollutant to remote mountain regions. The most abundant compounds at all altitudes were PAHs, with mean values ranging from 90 to 300 ngL(-1), 1 order of magnitude higher than concentrations of other compounds. PCBs (sum of PCB 28, 52, 101, 118, 153, 138, and 180) and BDE 209 were the dominant organohalogen pollutants, with concentrations from 550 to 1600 pg L(-1) and from 670 to 2000 pgL(-1), respectively. Low brominated PBDEs, endosulfans, HCHs and HCB were consistently found in all samples at lower concentrations. The concentrations of these compounds correlated positively with altitude (i.e., negatively with temperature), which is consistent with cold-trapping effects. The regression coefficients were positive and statistically significant (p < 0.05) for all compounds except BDE 209, endosulfan sulfate, HCB and α-HCH. Contrariwise, the concentrations of BDE 209 and endosulfan sulfate exhibited a statistically significant positive correlation with total particle amount, which agrees with long-range atmospheric transport associated to aerosols according to the physical-chemical properties of these compounds. Snow specific surface area, which determines the maximum amount of each organic compound that can be sorbed by snow, proved utile for describing the distribution of the more volatile compounds, namely α-HCB and HCB, in the snowpack.