Natural and anthropogenic atmospheric mercury in the European Arctic: a fractionation study

摘要

Gaseous elemental mercury (GEM) is converted to reactive gaseous mercury(RGM) during springtime Atmospheric Mercury Depletion Events (AMDE).This study reports the longest time series of GEM, RGM and particle-boundmercury (PHg) concentrations from a European Arctic site. From 27 April 2007until 31 December 2008 composite GEM, RGM and PHg measurements wereconducted in Ny-?lesund (78° 54′ N, 11° 53′ E). The averageconcentrations of the complete dataset were 1.6 ± 0.3 ng m?3,8 ± 13 pg m−3 and 8 ± 25 pg m−3 for GEM, RGM and PHg, respectively.For the complete dataset the atmospheric mercury distribution was 99 %GEM, whereas RGM and PHg constituted <1 %. The study revealed a seasonaldistribution of GEM, RGM and PHg previously undiscovered in the Arctic.Increased concentrations of RGM were observed during the insolation periodfrom March through August, while increased PHg concentrations occurred almostexclusively during the spring AMDE period in March and April. The elevatedRGM concentrations suggest that atmospheric RGM deposition also occursduring the polar summer. RGM was suggested as the precursor for the PHgexistence, but long range transportation of PHg has to be taken intoconsideration. Still there remain gaps in the knowledge of how RGM and PHgare related in the environment. RGM and PHg accounted for on average about10 % of the depleted GEM during AMDEs. Although speculative, the fairlylow RGM and PHg concentrations supported by the predominance of PHg withrespect to RGM and no clear meteorological regime associated with theseAMDEs would all suggest the events to be of non-local origin. With someexceptions, no clear meteorological regime was associated with the GEM, RGMand PHg concentrations throughout the year.