title: Molecular-level evidence provided by ultrahigh resolution mass spectrometry for oil-derived doc in groundwater at Bemidji, Minnesota.
abstract: Dissolved organic matter samples extracted from ground water at the USGS Bemidji oil spill site in Minnesota were investigated by ultrahigh resolution mass spectrometry. Principle component analysis (PCA) of the elemental composition assignments of the samples showed that the score plots for the contaminated sites were well separated from those for the uncontaminated sites. Additionally, spectra obtained from the same sampling site 7 and 19 years after the spill were grouped together in the score plot, strongly suggesting a steady state of contamination within the 12year interval. The double bond equivalence (DBE) of Oxclass compounds was broader for the samples from the contaminated sites, because of the complex nature of oil and the consequent formation of compounds with saturated and/or aromatic structures from the oxygenated products of oil. In addition, Oxclass compounds with a relatively smaller number of x (x<8; x=number of oxygen) and OxS1class compounds were more abundant in the samples from the contaminated sites, because of the lower oxygen and higher sulfur contents of the oil compared to humic substances. The molecular-level signatures presented here can be a fundamental basis for in-depth analysis of oil contamination.
authors.affiliation: Kyungpook National University, Department of Chemistry, Daegu 702-701, Republic of Korea.
authors.forename: Ananna
authors.initials: A
authors.lastname: Islam
authors.affiliation: Kyungpook National University, Department of Chemistry, Daegu 702-701, Republic of Korea.
authors.forename: Arif
authors.initials: A
authors.lastname: Ahmed
authors.affiliation: Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA; Center for Metabolic Biology, Iowa State University, Ames, IA 50011, USA.
authors.forename: Manhoi
authors.initials: M
authors.lastname: Hur
authors.affiliation: Water Mission Area, U.S. Geological Survey, Denver, CO 80225, USA.
authors.forename: Kevin
authors.initials: K
authors.lastname: Thorn
authors.affiliation: Kyungpook National University, Department of Chemistry, Daegu 702-701, Republic of Korea; Green Nano Center, Department of Chemistry, Daegu 702-701, Republic of Korea. Electronic address: sunghwank@knu.ac.kr.
authors.forename: Sunghwan
authors.initials: S
authors.lastname: Kim
keywords: Double bond equivalent; High resolution mass spectrometry; Oil spill; Petroleum