Ambient air levels of organochlorine pesticides at three high alpine monitoring stations: Trends and dependencies on geographical origin.

Many persistent organic pollutants (POPs) such as organochlorine pesticides (OCPs), which are emitted into air, occur ubiquitously in different environmental compartments worldwide. OCPs are measurable in conspicuous concentrations in the air not only near emission regions but also in background areas, as in the Alps. In the present study, we analyzed OCPs in air samples between 2005 and 2013 at three high Alpine stations (Weißfluhjoch, Switzerland: 2663 m a s l.; Sonnblick, Austria: 3106 m a s l.; and Schneefernerhaus, Germany: 2650 m a s l.). The air concentrations of OCPs at these stations were lower than those in source regions but higher than those in the Arctic region. Concentration differences between sites were found to be relatively small. To distinguish the influences from different European source regions, four filters of low- volume active air samplers were operated alternately according to a trajectory prediction method. Air masses from the northeast (i.e., Bavaria and Eastern Central Europe) and the south (i.e., Mediterranean countries) were characterized by higher concentrations of OCPs (e.g., pentachlorobenzene and hexachlorobenzene) compared with those arriving from the Atlantic Ocean. Additionally, we evaluated the temporal trend of the single compounds; only a few compounds such as endosulfan exhibited a clear decreasing trend