title: Polychlorinated Biphenyls in a Temperate Alpine Glacier: 1. Effect of Percolating Meltwater on their Distribution in Glacier Ice.
abstract: In Alpine regions, glaciers act as environmental archives and can accumulate significant amounts of atmospherically derived pollutants. Due to the current climate-warming-induced accelerated melting, these pollutants are being released at correspondingly higher rates. To examine the effect of melting on the redistribution of legacy pollutants in Alpine glaciers, we analyzed polychlorinated biphenyls in an ice core from the temperate Silvretta glacier, located in eastern Switzerland. This glacier is affected by surface melting in summer. As a result, liquid water percolates down and particles are enriched in the current annual surface layer. Dating the ice core was a challenge because meltwater percolation also affects the traditionally used parameters. Instead, we counted annual layers of particulate black carbon in the ice core, adding the years with negative glacier mass balance, that is, years with melting and subsequent loss of the entire annual snow accumulation. The analyzed samples cover the time period 1930-2011. The concentration of indicator PCBs (iPCBs) in the Silvretta ice core follows the emission history, peaking in the 1970s (2.5 ng/L). High PCB values in the 1990s and 1930s are attributed to meltwater-induced relocation within the glacier. The total iPCB load at the Silvretta ice core site is 5 ng/cm(2). A significant amount of the total PCB burden in the Silvretta glacier has been released to the environment.
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Testing and Research , Überlandstrasse 129, 8600 Dübendorf, Switzerland.|PSI, Paul Scherrer Institut , 5232 Villigen PSI, Switzerland.|Oeschger Centre for Climate Change Research, University of Berne , Falkenplatz 16, 3012 Bern, Switzerland.|Department of Chemistry and Biochemistry, University of Berne , Freiestrasse 3, 3012 Bern, Switzerland.
authors.forename: Pavlina Aneva
authors.initials: PA
authors.lastname: Pavlova
authors.affiliation: PSI, Paul Scherrer Institut , 5232 Villigen PSI, Switzerland.|Oeschger Centre for Climate Change Research, University of Berne , Falkenplatz 16, 3012 Bern, Switzerland.
authors.forename: Theo Manuel
authors.initials: TM
authors.lastname: Jenk
authors.affiliation: Empa, Swiss Federal Laboratories for Materials Testing and Research , Überlandstrasse 129, 8600 Dübendorf, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Schmid
authors.affiliation: Institute for Chemical and Bioengineering, ETH Zurich , Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.|Agroscope, Institute for Sustainability Sciences ISS , 8046 Zürich, Switzerland.
authors.forename: Christian
authors.initials: C
authors.lastname: Bogdal
authors.affiliation: Institute for Chemical and Bioengineering, ETH Zurich , Vladimir-Prelog-Weg 1, 8093 Zürich, Switzerland.
authors.forename: Christine
authors.initials: C
authors.lastname: Steinlin
authors.affiliation: PSI, Paul Scherrer Institut , 5232 Villigen PSI, Switzerland.|Oeschger Centre for Climate Change Research, University of Berne , Falkenplatz 16, 3012 Bern, Switzerland.|Department of Chemistry and Biochemistry, University of Berne , Freiestrasse 3, 3012 Bern, Switzerland.
authors.forename: Margit
authors.initials: M
authors.lastname: Schwikowski
mesh_terms: D002980:Climate; D005843:Geography; D046448:Ice Cover; D011078:Polychlorinated Biphenyls / Q000032:analysis*; D012914:Snow; D053260:Soot / Q000032:analysis; D013557:Switzerland; D014867:Water / Q000737:chemistry*
chemical_list: D053260:Soot; D014867:Water; D011078:Polychlorinated Biphenyls