title: Study of weathering effects on the distribution of aromatic steroid hydrocarbons in crude oils and oil residues.
abstract: The composition and distribution of triaromatic steroid hydrocarbons in oil residues after biodegradation and photo-oxidation processes were detected, and the diagnostic ratios for oil spill identification were developed and evaluated based on the relative standard deviation (RSD) and the repeatability limit. The preferential loss of C27 methyl triaromatic steranes (MTAS) relative to C28 MTAS and C29 MTAS was shown during the photo-oxidation process. In contrast to the photochemical degradation, the MTAS with the original 20R biological configuration was preferentially degraded during the biodegradation process. The RSD of most of the diagnostic ratios of MTAS ranged from 9 to 84% during the photo-oxidation process. However, the RSDs of such ratios derived from MTAS were all <5% even in high biodegradation, and such parameters may also provide new methods on oil spill identification. The parameters of monoaromatic sterane and monoaromatic sterane are not used well for oil spill identification after photo-oxidation. The triaromatic steroid hydrocarbons retained their molecular compositions after biodegradation and photo-oxidation and most of the diagnostic ratios derived from them could be efficiently used in oil spill identification.
authors.affiliation: Key Laboratory of Coastal Zone Environment Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China. cywang@yic.ac.cn.
authors.forename: Chuanyuan
authors.initials: C
authors.lastname: Wang
authors.forename: Bing
authors.initials: B
authors.lastname: Chen
authors.forename: Baiyu
authors.initials: B
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Guo
authors.forename: Mingming
authors.initials: M
authors.lastname: Zhao
mesh_terms: D001673:Biodegradation, Environmental; D004784:Environmental Monitoring; D006838:Hydrocarbons / Q000032:analysis / Q000737:chemistry*; D010578:Petroleum / Q000032:analysis*; D059392:Petroleum Pollution; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D006838:Hydrocarbons; D010578:Petroleum; D011084:Polycyclic Aromatic Hydrocarbons; D014874:Water Pollutants, Chemical