The Study Of The Apply Of Bicyclic Sesquiterpenes In Marine Oil Spill Identification

Oil transportation mostly depends on sea carriage and the leakage of oil duringshipping seems inevitable. The leaked oil would a disastrous event to the localenvironment and pose great threat to people’s health. So the only way to minimize thedamage of the leakage is to locate the spot where the pollution happened. Biologicalmarker compounds have pronounced features of geochemistry as well asdegradation-resistance. So those compounds, e.g. hopance gonane and rearrangedsterane, could be used as marker to determine when and where the leakage happened.But in some refined light petroleum products，hopance and gonane with high boilingpoint was diminished and the concentration of bicyclic sesquiterpenes increasedsignificantly.Bicyclic Sesquiterpenes (for BS) are important biological marker compounds.Those compounds with functional groups and bicyclic structure originated fromhopances which were degraded and fractured by microorganism. The degradedproducts went through defunctionalization and rearrangement to form the differentisomers which have the carbon skeleton of decalin. They are widely dispersed invarious organisms and the oil sediment. So they existed in refined oil product likepetrol and diesel. Because of their degradation-resistance and low boiling point, theycan be used as marker compounds in geochemistry. In this thesis, the crude oil ofBohai drilling platform or those from Weizhou island as well as some foreign oilsamples were analyzed by GC-MS to determine BS both qualitatively andquantitatively. According to the the fingerpirnt characteristic of oil sample, this paperhas carried on the principal component analysis and the then some biodegradationexperiments were adopted to discusses the degradation-resistance of bicyclicsesquiterpenes.The main research and conclusion of this paper summarized as follows:1. The fingerprint distribution of bicyclic sesquiterpenes and the semi-quantitativeanalysis of internal standard method.The semi-quantitative analysis of internal standard method of bicyclicsesquiterpenes in oil was established by using GC-MS. And10kinds of BS wereanalyzed both qualitatively and quantitatively. And then the fingerprint distribution ofBS in oil samples which came from different oil platforms in different geographical positions were analyzed.The results show that the the total content of BS in crude oildifferent platforms in different areas are very different. The fingerprint of BS of oil inthe different oil platforms of same areas is similary as well as it has significantdifferences in vary sources. By this method, the sources of oil can be identificatedaccuratly.2.To identify oil spill with principal component analysis (PCA) of diagnosticratio about BS.In this thesis,8Bohai samples,7Weizhou Island samples, and9overseas oilsamples were analyzed both qualitatively and quantitatively by GC-MS insemi-quantitative analysis; combining with the reference redefined the diagnosis ratioof BS, and calculating each diagnosis ratio of10BSs in each oil sample. According tothe multivariate statistical method, taking principal component analysis by SPSS17.0software database for diagnosis ratio of bicyclic sesquiterpenes. The results show thatthe sample in one area can be divided into one category, i.e., the Bohai Sea oil sampleswere divided into the same class, Weizhou Island samples were divided into the samecategory, and the distribution of BSs in foreign oils were scattered and irregularbecause of the regional variations. Therefore, PCA of BSs can be used to divide the oilsource area, so as to achieve the source preliminary judging of the oil-spilling.3.Changing pattern of bicyclic sesquiterpenes in crude oils in simulating soastaloil spill biodegradationUsing the middle crude oil of the Bohai Sea，coastal oil spill biodegradation wassimulated for2Id. And the distribution pattern of BSs duirng short-termbiodegradation was investigated and the change and stability of the diagnosis ratios ofthese compounds were evaluated. The results showed that the patterns of bicyclicsesquiterpene in the crude oils changed little after21days biodegradation and thediagnosis ratios had no apparent change nearly. Therefore, bicyclic sesquiterpenes arestability during the first21days biodegradation and could be used as a diagnostic toolfor oil spill source identification.