Department of Chemistry and Chemical Engineering, Chalmers University of Technology , SE-412 96 Göteborg, Sweden.
IVL Swedish Environmental Research Institute , P.O. Box 53021, SE-400 14 Göteborg, Sweden.
Environ Sci Technol. 2016 Dec 6;50(23):12705-12712. doi: 10.1021/acs.est.6b02700. Epub 2016 Nov 11.
Limited studies have been conducted on mercury concentrations in the polar cryosphere and the factors affecting the distribution of mercury within sea ice and snow are poorly understood. Here we present the first comprehensive seasonal study of elemental and total mercury concentrations in the Antarctic sea ice environment covering data from measurements in air, sea ice, seawater, snow, frost flowers, and brine. The average concentration of total mercury in sea ice decreased from winter (9.7 ng L) to spring (4.7 ng L) while the average elemental mercury concentration increased from winter (0.07 ng L) to summer (0.105 ng L). The opposite trends suggest potential photo- or dark oxidation/reduction processes within the ice and an eventual loss of mercury via brine drainage or gas evasion of elemental mercury. Our results indicate a seasonal variation of mercury species in the polar sea ice environment probably due to varying factors such as solar radiation, temperature, brine volume, and atmospheric deposition. This study shows that the sea ice environment is a significant interphase between the polar ocean and the atmosphere and should be accounted for when studying how climate change may affect the mercury cycle in polar regions.
关于极地冰冻圈中的汞浓度以及影响海冰和雪中汞分布的因素，相关研究十分有限。本研究首次全面研究了南极海冰环境中元素汞和总汞浓度的季节性变化，涵盖了空气、海冰、海水、雪、霜花和卤水等不同介质中的数据。海冰中总汞的平均浓度从冬季（9.7ng/L）降至春季（4.7ng/L），而元素汞的平均浓度则从冬季（0.07ng/L）增加到夏季（0.105ng/L）。这种相反的趋势表明，汞可能在冰内发生了光化学或暗化学反应/还原反应，并最终通过卤水排出或元素汞的气体逸出而损失。我们的结果表明，极地海冰环境中的汞形态存在季节性变化，这可能是由于太阳辐射、温度、卤水体积和大气沉降等因素的变化所致。本研究表明，海冰环境是极地海洋和大气之间的一个重要界面，在研究气候变化可能如何影响极地地区的汞循环时应予以考虑。
