Isolating different natural and anthropogenic PAHs in the sediments from the northern Bering-Chukchi margin: Implications for transport processes in a warming Arctic

Yan Lin; Lin Liu; Minggang Cai; Lisa A Rodenburg; Mahdi Chitsaz; Yanguang Liu; Mian Chen; Hengxiang Deng; Hongwei Ke

doi:10.1016/j.scitotenv.2020.139608

Isolating different natural and anthropogenic PAHs in the sediments from the northern Bering-Chukchi margin: Implications for transport processes in a warming Arctic

Sci Total Environ. 2020 Sep 20:736:139608. doi: 10.1016/j.scitotenv.2020.139608. Epub 2020 May 23.

Authors

Yan Lin¹, Lin Liu², Minggang Cai³, Lisa A Rodenburg⁴, Mahdi Chitsaz⁴, Yanguang Liu⁵, Mian Chen², Hengxiang Deng², Hongwei Ke²

Affiliations

¹ State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen 361102, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
² College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
³ State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory for Coastal Ecology and Environmental Studies, Xiamen University, Xiamen 361102, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China. Electronic address: mgcai@xmu.edu.cn.
⁴ Department of Environmental Sciences, Rutgers University, New Brunswick 08901, USA.
⁵ Key Laboratory of Marine Geology and Metallogeny, First Institute of Oceanography, Ministry of Natural Resources, Qingdao 266061, China.

PMID: 32485380
DOI: 10.1016/j.scitotenv.2020.139608

Abstract

Polycyclic aromatic hydrocarbons (PAHs) have become the dominating burden in the Arctic ecosystems, but their transport pathways and relative importance of different sources in the Arctic remained unclear, and this would be further complicated by climate change. Here we interpreted 27 PAHs in 34 surface sediments from the northern Bering-Chukchi margin. We integrated source apportionment methods (including diagnostic ratios, principal component analysis, hierarchical analysis, and positive matrix factorization (PMF) model) together with geochemistry parameters, which reveal a gradually clear picture of the spatial patterns of different sources. The total PAH concentrations (50.4 to 896.0 ng/g dw) exhibited a "hilly" shape with the increase of latitude, showing the highest level of PAHs in the northeast Chukchi Sea. The total BaP toxic equivalent quotient (TEQ) for carcinogenic compounds was from 1.06 to 33.3 ng TEQ/g. Most PAHs showed positive correlations with silt content, total organic carbon, stable carbon isotopes and black carbon (p < 0.01 or 0.05). Generally, source apportionment methods revealed an increasing petrogenic source of PAHs with latitudes. The PMF model further differentiated two petrogenic (36.7%), two pyrogenic (softwood and fossil fuel combustion, 35.5%) and one in-situ biogenic source (Perylene, 27.8%). An extremely high petrogenic signal was captured in the Canada Basin margin, possibly originating from the Mackenzie River via ice drifting with Beaufort Gyre, while another petrogenic source may come from coal deposit erosion by deglaciation. Softwood combustion (characterized by Retene) exhibited exclusively higher contribution in the northeast Chukchi Sea and might result from the increasing wildfire in Alaska due to climate change, whereas fossil fuel combustion exhibited similar contributions across different latitudes. Our results revealed natural PAHs as important "inside sources" in the Arctic, which are highly sensitive to global warming and deserves more attention.

Keywords: Arctic; Climate change; PMF; Petrogenic source; Quantification; Source apportionment.