College of Environmental Science and Engineering, Xiamen University of Technology, Xiamen 361002, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361002, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361002, China.
State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361002, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361002, China.
Sci Total Environ. 2022 Dec 10;851(Pt 2):158373. doi: 10.1016/j.scitotenv.2022.158373. Epub 2022 Aug 28.
Polycyclic aromatic hydrocarbons (PAHs) are traditionally considered to enter the Arctic Ocean through long-range transport. Arctic warming, especially sea ice retreat, will certainly increase the contribution from local source (such as river input and ice melting). However, this hypothesis remains poorly constrained for lack of quantitative evidence. Here PAHs in surface seawater (67°N-89°N, 152°E-177°E) and sea ice (82°N-89°N) were collected in the western Arctic in 2010. Dissolved concentrations of 15 PAHs (ΣPAHs) in surface layer ice (26.2 to 49.8 ng/L) were one order of magnitude higher than the underlying seawater. The content of dissolved ΣPAHs was significantly higher in the marginal ice zone than those in the Chukchi Sea shelf, and the dissolved ΣPAHs concentration differed by nearly an order of magnitude in two closely adjacent sections in the basin area, which both showed high fraction of river water and sea ice meltwater. This pattern could be explained by the different local inputs from Eurasia and North America. This scenario was further visualized by ice back trajectories capturing significantly higher PAH signals from the Eurasian margin than those from North America and stable oxygen isotopic data finding a positive correlation of PAH levels with the fractions of river runoff and ice-melting water coming from the Eurasia. The PAHs budget of the Arctic Ocean was also dominated by local sources (river and ice melting) as inputs (76 %) and volatilization as outputs (47 %). This study reveals the importance of Eurasian local inputs in supplying PAHs to the central Arctic Ocean. Those processes, which have not been well recognized for PAHs previously, are expected to increase and will undermine global efforts to reduce exposure by remobilizing PAHs stored in permafrost and ice.
多环芳烃（PAHs）传统上被认为是通过远距离传输进入北冰洋的。北极变暖，尤其是海冰消退，肯定会增加当地来源（如河流输入和冰融化）的贡献。然而，由于缺乏定量证据，这一假设仍然没有得到很好的限制。本研究于 2010 年在北极西部采集了北纬 67°-89°、东经 152°-177°之间的表层海水和海冰中的多环芳烃。表层冰（26.2 至 49.8ng/L）中 15 种多环芳烃（ΣPAHs）的溶解浓度比底层海水高一个数量级。边缘冰区的溶解ΣPAHs 含量明显高于楚科奇海大陆架，而在盆地内两个相邻区域，其溶解ΣPAHs 浓度相差近一个数量级，这两个区域都显示出高比例的河水和海冰融水。这种模式可以用欧亚大陆和北美的不同局部输入来解释。冰回溯轨迹进一步说明了这一点，这些轨迹从欧亚大陆边缘捕获到的 PAH 信号明显高于从北美捕获到的信号，稳定氧同位素数据也发现 PAH 水平与来自欧亚大陆的河流径流量和冰融水量的分数呈正相关。北冰洋的 PAHs 收支也主要由当地来源（河流和冰融化）作为输入（76%）和挥发作为输出（47%）。本研究揭示了欧亚大陆局部输入在向北极中部海洋输送 PAHs 方面的重要性。这些以前未被充分认识到的过程，预计会增加，并通过重新移动多年冻土和冰中储存的 PAHs，破坏全球减少暴露的努力。
