The Alps represent a significant sink and a barrier for long-range transported persistent organic pollutants (POPs). This is the most prominent finding of the project MONARPOP.
POPs are bioaccumulating, hardly degradable chemicals of problematic toxicological properties. MONARPOP gave a first time survey of alpine POP pollution with comprehensive geographical coverage. Horizontal and vertical variation was examined with a network of 40 sites in Austria, Germany, Italy, Slovenia and Switzerland, including seven altitude profiles of up to six plots, stretching from valleys to the top of alpine summits. Remote forests were chosen as an ecosystem widespread enough for such large scale screening, offering Norway spruce needles, humus and mineral soil as proven pollution indicators. In addition to the screening of environmental matrices, semi-permeable membrane devices (SPMD) were used as passive samplers at some altitude profiles. Active air samplers and bulk deposition collectors were installed at three Alpine summits (Sonnblick in AT, Weissfluhjoch in CH and Zugspitze in D) to study atmospheric POP loads. Both active air and deposition samplers are innovations of the project to allow continuous sampling of POPs under the extreme climatic conditions of high mountains. The construction of the active air samplers permits, as a novelty, a separate sampling of air from different source regions. Meanwhile, both sampler types perform in routine operation. [...]