title: Integrated methodology for forensic oil spill identification.
abstract: A new integrated methodology for forensic oil spill identification is presented. It consists of GC-MS analysis, chromatographic data processing, variable-outlier detection, multivariate data analysis, estimation of uncertainties, and statistical evaluation. The methodology was tested on four groups of diagnostic ratios composed of petroleum biomarkers and ratios within homologous PAH categories. Principal component analysis (PCA) was employed and enabled the simultaneous analysis of many diagnostic ratios. Weathering was taken into account by considering the sampling uncertainties estimated from replicate spill samples. Statistical evaluation ensured an objective matching of oil spill samples with suspected source oils as well as classification into positive match, probable match, and nonmatch. The data analysis is further refined if two or more source oils are classified as probable match by using weighted least squares fitting of the principal components, local PCA models, and additional information relevant to the spill case. The methodology correctly identified the source of two spill samples (i.e., crude oils from Oseberg East and Oseberg Field Centre) and distinguished them from closely related source oils.
authors.affiliation: Department of Environmental Chemistry and Microbiology, National Environmental Research Institute, Frederiksborgvej 399, PO Box 358, 4000 Roskilde, Denmark. jch@dmu.dk
authors.forename: Jan H
authors.initials: JH
authors.lastname: Christensen
authors.forename: Asger B
authors.initials: AB
authors.lastname: Hansen
authors.forename: Giorgio
authors.initials: G
authors.lastname: Tomasi
authors.forename: John
authors.initials: J
authors.lastname: Mortensen
authors.forename: Ole
authors.initials: O
authors.lastname: Andersen
mesh_terms: D003718:Denmark; D044707:Forensic Sciences / Q000379:methods*; D005618:Fresh Water; D008401:Gas Chromatography-Mass Spectrometry; D015999:Multivariate Analysis; D010578:Petroleum / Q000032:analysis* / Q000633:toxicity; D025341:Principal Component Analysis; D012623:Seawater; D012985:Software Design; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity
chemical_list: D010578:Petroleum; D014874:Water Pollutants, Chemical