Elevated concentrations of mercury in mosses growing at the Arctic coast of Norway – a phenomenon caused by Arctic mercury depletion events

The Norwegian nationwide moss surveys have demonstrated elevated concentrations of mercury in moss growing at the Arctic coast. Gaseous elemental mercury (GEM) was measured during one year at the sub Arctic location Andøya, to see whether the high concentrations of mercury in moss were due to Arctic Mercury Depletion Events (AMDE). Samples of natural soil from the northern part of Norway were also analysed, too see whether natural soil have the same pattern as moss. A few half episodes of AMDE were seen at Andøya, but they were not as pronounced as at the high Arctic station Zeppelin, located at Spitsbergen. The lowest concentration measured at Andøya was 0.5 ng/m3. Air mass trajectories and BrO maps showed that AMDE episodes at Andøya mainly was related to atmospheric transport episodes. There is reason to believe that AMDE may contribute to the increased concentrations in moss at the Arctic coast. The natural soil showed a less pronounced pattern than the moss.