Open AccessFate of inorganic mercury and methyl mercury within the snow cover in the low arctic tundra on the shore of Hudson Bay (Québec, Canada)
Author(s) -
Constant Philippe,
Poissant Laurier,
Villemur Richard,
Yumvihoze Emmanuel,
Lean David
Publication year - 2007
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2006jd007961
Subject(s) - snowmelt , snow , mercury (programming language) , tundra , environmental science , bay , arctic , environmental chemistry , methylmercury , snowpack , snow cover , atmospheric sciences , oceanography , chemistry , geology , meteorology , geography , bioaccumulation , computer science , programming language
Snow samples were collected in the seasonal snow cover of the low arctic tundra (Whapmagoostui‐Kuujjuarapik, Québec) during episodic atmospheric mercury depletion events (AMDEs) and in the snowmelt period, long after AMDEs had occurred. Total and methyl mercury analyses were done in order to investigate the critical factors influencing the fate of mercury once deposited in the snowpack. Following AMDEs, snow total mercury (THg) concentrations increased and were inversely proportional to the distance from Hudson Bay. The correlations between MeHg, sulfate (SO 4 2− ), and chlorine (Cl − ) snow concentrations implicated marine aerosols as a significant source of MeHg, independent of AMDEs. However, the newly deposited MeHg was unstable in the snow cover as 15–56% of the MeHg was demethylated or otherwise “lost” during the nighttime period. In contrast, during the snowmelt period, marine aerosols were not a significant source of MeHg. MeHg snow concentrations higher than 200 pg L −1 were observed when snow's heterotrophic plate counts, total suspended volatile solids, and total suspended solids were higher than 5.0 × 10 5 CFU L −1 , 25 mg L −1 , and 90 mg L −1 , respectively. During the snowmelt, although the THg snow concentrations remained at 8–9 ng L −1 , the proportion of MeHg increased from 2.7 to 7.6%. This is the first report suggestive of the presence of mercury methylation activities within the snow cover of the low arctic tundra.