Evidence for the growing importance of Eurasian local source to PAHs in the Arctic central basin

Yan Lin; Minggang Cai; Min Chen; Peng Huang; Ruibo Lei; Meng Chen; Dawei Gui; Hongwei Ke

doi:10.1016/j.scitotenv.2022.158373

Evidence for the growing importance of Eurasian local source to PAHs in the Arctic central basin

Sci Total Environ. 2022 Dec 10;851(Pt 2):158373. doi: 10.1016/j.scitotenv.2022.158373. Epub 2022 Aug 28.

Authors

Yan Lin¹, Minggang Cai², Min Chen³, Peng Huang⁴, Ruibo Lei⁵, Meng Chen⁶, Dawei Gui⁷, Hongwei Ke³

Affiliations

¹ 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.
² State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361002, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361002, China. Electronic address: mgcai@xmu.edu.cn.
³ College of Ocean and Earth Sciences, Xiamen University, Xiamen 361002, China.
⁴ College of Ocean and Earth Sciences, Xiamen University, Xiamen 361002, China; College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang 524088, China.
⁵ Polar Research Institute of China, Shanghai 200136, China.
⁶ College of the Environment and Ecology, Xiamen University, Xiamen 361102, China.
⁷ Polar Research Institute of China, Shanghai 200136, China; Chinese Antarctic Center of Surveying and Mapping, Wuhan University, Wuhan 430079, China.

PMID: 36041604
DOI: 10.1016/j.scitotenv.2022.158373

Abstract

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 (Σ₁₅PAHs) 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 Σ₁₅PAHs was significantly higher in the marginal ice zone than those in the Chukchi Sea shelf, and the dissolved Σ₁₅PAHs 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.

Keywords: Arctic Ocean; Climate change; Fresh water; Margin source; Mass balance.

MeSH terms

Arctic Regions
Environmental Monitoring
Oxygen Isotopes
Polycyclic Aromatic Hydrocarbons* / analysis
Seawater
Water

Substances

Polycyclic Aromatic Hydrocarbons
Oxygen Isotopes
Water