Unresolved Complex Mixture (UCM) in Coastal Environments Is Derived from Fossil Sources

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• 作者：Helen K. White ; Li Xu ; Paul Hartmann ; James G. Quinn ; Christopher M. Reddy
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：January 15, 2013
• 年：2013
• 卷：47
• 期：2
• 页码：726-731
• 全文大小：225K
• 年卷期：v.47,no.2(January 15, 2013)
• ISSN：1520-5851

文摘

The unresolved complex mixture (UCM) frequently dominates organic extracts isolated from estuarine and coastal sediments in the vicinity of industrial centers. Despite an obvious link to a petroleum source, speculation exists that biogenic sources also contribute to the UCM. To determine the source of the UCM to these environments, natural abundance radiocarbon (螖¹⁴C) and stable carbon (未¹³C) isotopic composition of the UCM solvent-extracted from coastal sediments, road dust, and urban atmospheric particulate in the United States was measured. Extracts of UCM and separate saturate and aromatic fractions from all samples are predominantly (>90%) fossil-derived and hence have a petroleum source. Even the polar fraction of the UCM, which has a 螖¹⁴C composition reflecting contributions from recently photosynthesized carbon (鈭?65鈥?, is composed of 66% fossil carbon indicating the presence of petroleum residues that have been transformed into more polar derivatives. The 未¹³C of the UCM had consistent values (鈭?7.65 卤 0.51鈥? n = 16) for all but one sample, indicating a common origin of the UCM. We conclude that in coastal areas dominated by human activities whole fractions of the UCM, as well as separate saturate, aromatic, and polar fractions, are principally derived from petroleum sources.