Accelerated release of persistent organic pollutants (POPs) from Alpine glaciers

 Recent studies performed by our research consortium revealed that melting Alpine glaciers represent a secondary source of persistent organic pollutants (POPs), which were previously deposited to and incorporated into glaciers are now released to the environment due to the rapid melting induced by climate warming^{(a, b, c, d)}. POPs are “legacy” pollutants regulated for many years due to their particularly hazardous properties to persist in the environment, accumulate along food chains, and exhibit serious toxic effects^(e). In order to investigate the underlying processes, we performed a series of preliminary investigations, which provided coherent findings. After all our first studies revealed the complexity of the transport processes of chemicals within glaciers, particularly for temperate Alpine glaciers, which embody appreciable amounts of water, and for POPs, which are particularly challenging to analyze.

In this project the transport of water within temperate ice and processes affecting the fate of POPs, including deposition on, incorporation into, transport within, and release from glaciers, is investigated and quantified.

The project consists of three closely linked work packages: (i) compilation of an inventory of POPs in temperate glaciers and proglacial lakes, based on analyses of POPs in dated ice cores, meltwater, surface snow, and lake sediment cores; (ii) investigation of the distribution and temporal variation of percolating meltwater within temperate ice, by means of field studies and glacier modeling; (iii) qualitative and quantitative description of the flow and storage of ice, water, and chemicals in Swiss glaciers, by combining the results from the two previous work packages in a multicompartmental chemical fate model.

Our preliminary investigations about the release of POPs from melting glaciers (first detected in a core drilled at the bottom of Oberaar reservoir, foto enclosed) gained considerable attention among the scientific community, the general public, and in the political environment. Recently a parliamentary interpellation was addressed to the Swiss Federal Council to inquire about its intention regarding the issue of release of hazardous pollutants from melting Alpine glaciers^(f). Percolation of meltwater and processes affecting chemical species within Alpine glaciers have never been considered with such an interdisciplinary approach, which represents a major strength of this project. In glaciology, understanding of temperate glacier ice is a fundamental – although poorly known – issue. Further, the hazardous nature of POPs and the dramatic melting of glaciers worldwide, suggest the relevance of this project, particularly for countries largely relying on glacial resources, such as Switzerland.

References:

^(a) Blüthgen, N., Reconstruction of historical inputs of persistent organic pollutants (POPs) in remote Alpine lakes in Switzerland. Universisty Zurich 2009, Master Thesis;

^(b) Bogdal, C.; Nikolic, D.; Lüthi, M.; Schenker, U.; Scheringer, M.; Hungerbühler, K., Release of legacy pollutants from melting glaciers: model evidence and conceptual understanding. Environ. Sci. Technol. 2010, 44, 4063-4069;

^(c) Bogdal, C.; Schmid, P.; Zennegg, M.; Anselmetti, F. S.; Scheringer, M.; Hungerbühler, K., Blast from the past: Melting glaciers as a relevant source for persistent organic pollutants. Environ. Sci. Technol. 2009a, 43, 8173–8177;

^(d) Bogdal, C.; Schmid, P.; Zennegg, M.; Sturm, M.; Scheringer, M.; Hungerbühler, K., The haunting legacy: Sediment record of persistent organic pollutants in the glacier-fed Lake Tscheppa, Switzerland. Organohalogen Compounds 2009b, 71, 321-325;

^(e) UNEP, United Nations Environment Programme, Stockholm Convention on Persistent Organic Pollutants. 2001, http://chm.pops.int.

^(f) Recordon, L., Eindämmung der durch die Gletscherschmelze freigesetzten persistenten organischen Schadstoffe, Interpellation, eingereicht im Ständerat, 02.12.2009, http://www.parlament.ch/D/Suche/Seiten/geschaefte.aspx?gesch_id=20094042.)

Collaboration:

Dr. Christian Bogdal, Prof. Dr. Konrad Hungerbühler, Safety & Environmental Technology Group (S&E), ETH Zurich;

Dr. Martin Lüthi, Prof. Dr. Martin Funk, Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich;

Dr. Margit Schwikowski, Laboratory for Radiochemistry & Environmental Chemistry, PSI;

Dr. Peter Schmid, Laboratory for Analytical Chemistry, Empa;

Prof. Dr. Flavio Anselmetti, Sedimentology Group, Eawag.