北极新奥尔松地区过去200年Hg污染记录及来源

自工业革命以来,Hg污染已经成为了全球性的问题.研究选取了采自北极新奥尔松(Ny-Alesund)地区富含苔藓植物残体的沉积剖面S2,对沉积样品进行Hg含量分析,结合210Pb-137Cs年代测定以及Hg沉降通量的计算,恢复了最近200年新奥尔松地区Hg的变化趋势,并重点探讨了工业革命以来引起S2剖面Hg沉积通量显著增加的主要因素.结果表明,工业革命以来,Hg含量明显上升,表层样品中Hg含量最高约为180 ng.g-1,人类污染Hg占总Hg的比例由30%上升至表层的90%,人为源Hg的输入已成为北极新奥尔松地区总Hg的主要来源.最近200年,Hg沉积通量为8～20μg.(m2.a)-1,并呈现3个明显峰值,分别对应于1800年、1880年和1970年左右.对比研究区煤炭生产量、全球Hg产量和S2剖面沉积通量记录的变化,表明当地Hg的输入主要来源于远距离大气污染物的传输作用,本地煤矿的开采和关闭可能对当地Hg沉积通量变化造成了一定的影响,但影响较小.新奥尔松地区的Hg污染程度与瑞典、加拿大等环北极地区相当,高于格陵兰地区,但仍明显低于美国、俄罗斯等工业化较高的国家.

Records and sources of mercury pollution over the past 200 years in Ny-Alesund, Arctic

Hg pollution has become a global problem since the industrial revolution. In this study,we collected a pond sediment core rich in moss residues from the Ny-Alesund of Svalbard, and determined the content and flux of Hg in the sediments. Combined with 210Pb and 137Cs dating,we reconstructed the changes of Hg concentration and depositional flux in the recent 200 years,and focused on the main controlling factors on the elevated inputs of Hg since the 1850s. The results show that the Hg contents increase significantly since the World Industrial Revolution. The highest value of Hg is up to 180 ng x g(-1) in the surface sediments, and the ratios of anthropogenic Hg increase from 30% to 90%, thus the input of anthropogenic Hg has become a main source of total mercury in the study area. The range of Hg deposition flux is between 8-20 microg x (m(2) x a)(-1) in past 200 years, and show three distinct peaks,corresponding to 1800 s, 1880 s and 1970 s. Compared the historical Hg deposition flux with the records of local coal combustion and globe Hg production, we suggest that the anthropogenic Hg is mainly derived from the long-range atmosphere Hg transport, whereas the influence of local coal mining is likely minor. The Ny-Alesund has similar Hg pollution degree with Sweden, Canada and other circum-arctic areas, but obviously higher than Greenland and significantly lower than America and Russia,as well as other industrialized countries.