Enhanced Sorption of PAHs in Natural-Fire-Impacted Sediments from Oriole Lake, California

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• 作者：Julia Sullivan ; Kevyn Bollinger ; Anthony Caprio ; Mark Cantwell ; Peter Appleby ; John King ; Bertrand Ligouis ; Rainer Lohmann
• 刊名：Environmental Science & Technology
• 出版年：2011
• 出版时间：April 1, 2011
• 年：2011
• 卷：45
• 期：7
• 页码：2626-2633
• 全文大小：941K
• 年卷期：v.45,no.7(April 1, 2011)
• ISSN：1520-5851

文摘

Surface sediment cores from Oriole Lake (CA) were analyzed for organic carbon (OC), black carbon (BC), and their 未¹³C isotope ratios. Sediments displayed high OC (20鈭?5%) and increasing BC concentrations from 0.40% (in 1800 C.E.) to 0.60% dry weight (in 2000 C.E.). Petrographic analysis confirmed the presence of fire-derived carbonaceous particles/BC at 2% of total OC. Natural fires were the most likely cause of both elevated polycyclic aromatic hydrocarbon (PAH) concentrations and enhanced sorption in Oriole Lake sediments prior to 1850, consistent with their tree-ring-based fire history. In contrast to other PAHs, retene and perylene displayed decreasing concentrations during periods with natural fires, questioning their use as fire tracers. The occurrence of natural fires, however, did not result in elevated concentrations of black carbon or chars in the sediments. Only the 1912鈭?007 sediment layer contained anthropogenic particles, such as soot BC. In this layer, combining OC absorption with adsorption to soot BC (using a Freundlich coefficient n = 0.7) explained the observed sorption well. In the older layers, n needed to be 0.3 and 0.5 to explain the enhanced sorption to the sediments, indicating the importance of natural chars/inertinites in sorbing PAHs. For phenanthrene, values of n differed significantly between sorption to natural chars (0.1鈭?.4) and sorption to anthropogenic black carbon (>0.5), suggesting it could serve as an in situ probe of sorbents.