Fate of elemental mercury in the Arctic during atmospheric mercury depletion episodes and the load of atmospheric mercury to the Arctic.
ABSTRACT Atmospheric mercury depletion episodes (AMDEs) were studied at Station Nord, Northeast Greenland, 81 degrees 36' N, 16 degrees 40' W, during the Arctic Spring. Gaseous elemental mercury (GEM) and ozone were measured starting from 1998 and 1999, respectively, until August 2002. GEM was measured with a TEKRAN 2735A automatic mercury analyzer based on preconcentration of mercury on a gold trap followed by detection using fluorescence spectroscopy. Ozone was measured by UV absorption. A scatter plot of GEM and ozone concentrations confirmed that also at Station Nord GEM and ozone are linearly correlated during AMDEs. The relationship between ozone and GEM is further investigated in this paper using basic reaction kinetics (i.e., Cl, ClO, Br, and BrO have been suggested as reactants for GEM). The analyses in this paper show that GEM in the Arctic troposphere most probably reacts with Br. On the basis of the experimental results of this paper and results from the literature, a simple parametrization for AMDE was included into the Danish Eulerian Hemispheric Model (DEHM). In the model, GEM is converted linearly to reactive gaseous mercury (RGM) over sea ice with temperature below -4 degrees C with a lifetime of 3 or 10 h. The new AMDE parametrization was used together with the general parametrization of mercury chemistry [Petersen, G.; Munthe, J.; Pleijel, K.; Bloxam, R.; Vinod Kumar, A. Atmos. Environ. 1998, 32, 829-843]. The obtained model results were compared with measurements of GEM at Station Nord. There was good agreement between the start and general features periods with AMDEs, although the model could not reproduce the fast concentration changes, and the correlation between modeled and measured values decreased from 2000 to 2001 and further in 2002. The modeled RGM concentrations over the Arctic in 2000 were found to agree well with the temporal and geographical variability of the boundary column of monthly average BrO observed by the GOME satellite. Scenario calculations were performed with and without AMDEs. For the area north of the Polar Circle, the mercury deposition increases from 89 tons/year for calculations without an AMDE to 208 tons/year with the AMDE. The 208 tons/year represent an upper limit for the mercury load to the Artic.
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ABSTRACT: Mercury (Hg) transport was studied in a river in Kobbefjord, near Nuuk in West Greenland, during the 2009 and 2010 summer periods. The river drains an area of 32 km 2 , and the Kobbefjord area is considered representative to low-Arctic West Green-land. The river water origins from both precipitation and melting of small glaciers and annual water dis-charges for 2009 and 2010 were estimated to be 29 and 26 million m 3 , respectively. Mean Hg concentra-tions (±SD) were 0.46±0.17 and 0.26±0.17 ng L −1 for 2009 and 2010. The annual Hg transport was estimat-ed to 14 and 6.4 g, corresponding to a transport rate of 0.45 and 0.20 g Hg km −2 year −1 from the river basin. The highest Hg concentrations (up to 1.0 ng L −1) and discharges were measured in spring 2009 along with melting of extensive amounts of snow deposited dur-ing the 2008–2009 winter period. In contrast, the following 2009–2010 winter period was relatively dry with less snowfall. This indicates that a major fraction of the Hg in this area is likely to come from Hg deposited along with winter precipitation (as wet deposition) released upon snowmelt. Also, the results show that while Hg concentrations were low in Kob-befjord River compared to other sub-Arctic/Arctic riv-ers, the annual Hg transport rates from the basin area were within the range reported for other sub-Arctic/ Arctic areas.Water Air and Soil Pollution 01/2012; · 1.75 Impact Factor
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ABSTRACT: Snow surface-to-air exchange of gaseous elemental mercury (GEM) was measured using a modified Teflon fluorinated ethylene propylene (FEP) dynamic flux chamber (DFC) in a remote, open site in Potsdam, New York. Sampling was conducted during the winter months of 2011. The inlet and outlet of the DFC were coupled with a Tekran Model 2537A mercury (Hg) vapor analyzer using a Tekran Model 1110 two port synchronized sampler. The surface GEM flux ranged from -4.47 ng m(-2) hr(-1) to 9.89 ng m(-2) hr(-1). For most sample periods, daytime GEM flux was strongly correlated with solar radiation. The average nighttime GEM flux was slightly negative and was not well correlated with any of the measured meteorological variables. Preliminary, empirical models were developed to estimate GEM emissions from snow surfaces in northern New York. These models suggest that most, if not all, of the Hg deposited with and to snow is reemitted to the atmosphere.PLoS ONE 01/2013; 8(7):e69342. · 3.53 Impact Factor
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ABSTRACT: Mercury is one of the most hazardous heavy metals and the mercury contamination is of serious danger for the Arctic environment. Mercury compounds are rather mobile and can easily migrate both to the water and to the air. Mercury is removed most intensively from the atmosphere during the polar springtime (so-called AMDE effect, i.e., the Atmospheric Mercury Depletion Event). This phenomenon was observed from the beginning of the polar sunrise till the end of the snowmelt, i.e., from April to early June. In 2000–2001, the depletion of atmospheric mercury was discovered in the Antarctic. In 2001, the mercury analyzer was installed at Amderma station located on the Yugor Peninsula, and AMDE cases were registered there during the measurements. The study in the Arctic region demonstrated that the effect of mercury depletion is observed at the rather limited space along the coast of the Arctic seas. The activation of AMDE is associated both with the intensive UV-radiation and with such meteorological parameters as temperature, wind speed and humidity in the surface layer that favors the mercury depletion in the atmosphere. This process is typical for the high latitudes only and is observed during about two-three months from the beginning of the polar sunrise until the end of the snowmelt.Russian Meteorology and Hydrology 06/2013; 38(6). · 0.27 Impact Factor