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.
College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, China.
Sci Total Environ. 2020 Sep 20;736:139608. doi: 10.1016/j.scitotenv.2020.139608. Epub 2020 May 23.
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.
多环芳烃（PAHs）已成为北极生态系统中的主要污染物，但它们在北极的传输途径和不同来源的相对重要性仍不清楚，而气候变化将使情况更加复杂。本研究对楚科奇海北部边缘的 34 个表层沉积物中的 27 种多环芳烃进行了解释。我们综合运用源解析方法（包括诊断比值、主成分分析、层次分析和正定矩阵因子（PMF）模型）和地球化学参数，揭示了不同来源的空间分布模式逐渐清晰。总多环芳烃浓度（50.4 至 896.0 ng/g dw）随纬度增加呈“丘陵”形，在楚科奇海东北部达到多环芳烃的最高水平。致癌化合物的总 BaP 毒性等效系数（TEQ）为 1.06 至 33.3 ng TEQ/g。大多数多环芳烃与粉砂含量、总有机碳、稳定碳同位素和黑碳呈正相关（p < 0.01 或 0.05）。总体而言，源解析方法表明，随着纬度的增加，多环芳烃的生源来源逐渐增加。PMF 模型进一步区分了两种生源（36.7%）、两种热成因（软木和化石燃料燃烧，35.5%）和一种原地生物成因（苝，27.8%）。在加拿大海盆边缘，捕获到极高的生源信号，可能来自通过浮冰与波弗特环流的马更些河，而另一个生源可能来自冰川消退时的煤矿侵蚀。软木燃烧（以 Retene 为特征）在楚科奇海东北部表现出更高的贡献，可能是由于气候变化导致阿拉斯加野火增加所致，而化石燃料燃烧在不同纬度表现出相似的贡献。本研究结果表明，自然多环芳烃是北极地区的重要“内部来源”，对全球变暖高度敏感，值得更多关注。
