The Research Of Identification Methods Of Spilled Oils Based On Distribution Of Trace Metal Elements

At present, the marine crude oil industry and marine crude oil transportation developed rapidly, the marine crude oil exploration, development, submarine pipeline and transportation have been expanding. At the same time, oil spill occurred frequently. These result in serious pollution of marine ecological environment, and attention of public. Exact identification of spilled oil has important practical significance. For example, evaluated and predicted the effect of marine ecological environment by oil pollution scientifically, settled legal disputes logically, established supervisory laws and regulations of marine environment and emergency system of oil spill.This paper established a method that the determination of the trace metal elements (V、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mo、Ba、Pb etc) in different crude oils by Inductively Coupled Plasma Mass Spectrometry(ICP-MS).And then 143 different crude oils were measured and the database of the trace metals in different crude oils was established. The distribution of the trace metals of crude oils and the changes of the trace metal elements(Ni、Fe、V、Ba)in the crude oils from Bohai Sea and Foreign Sea under comprehensive weathering condition were explored respectively. Thus developing a new method of identification of oill spill with the trace metals to improve the accuracy of identification of marine oil spill. The main conclusions are summarized as follows:Firstly, summarized the oil spill pollution status at home and abroad at this stage, briefly described the effect of oil spill on marine environment, expatiated the investigative status of fingerprint identification technology for spilled oils, briefly introduced infrared spectroscopy(IR),fluorescence spectroscopy, gas chromatography (GC-FID),gas chromatography-mass spectrometry(GC-MS), and thin layer chromatography(TLC)in the application of spilled oil fingerprint identification and their characteristics, summarized the application of chemometrics in spilled oil identification. And importantly, ICP-MS was widely accepted as an attractive tool for determining the elemental composition of oil samples.On the base of these, the innovation and significance of this paper were explicit.Secondly, established a method that the determination of V、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mo、Ba、Pb etc in different crude oil by Inductively Coupled Plasma Mass Spectrometry(ICP-MS). Firstly the oil sample was digestded by microwave using HNO3-H2O2 as oxidant. 6Li、45Sc、72Ge、89Y、115In、159Tb、209Bi were selected as the internal standard elements for the determination.The matrix effect was compensated and the MS interference was corrected by selecting the suitable isotope of the elements to be determined,then the experimental were optimized. The results showed that the detection limits of above-mentioned elements were between 0.0056 and 0.8729μg/g. RSDs were less than 5.0%,and recoveries were between 92.3% and 118.8%. This method has been extended to analyze elements in other Crude oil.Thirdly, the database of the trace metal elements (V、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Mo、Ba、Pb etc)of the Bohai Sea、the South Chin Sea、land and foreign crude oils was established. The distribution of these 12 trace metals of crude oils was explored. Data shows that the content of Fe、Ni、Zn was generally higher in crude oil samples measured. And the content of V had a larg changes from domestic oils to foreign oils. The content of V was highest of foreign oils, up to 26.25ppm. The content of Fe、Ni was significantly higher than the content of V of the majority domestic crude oils as Ni/V、Fe/V values greater than 1.But in some foreign oils the content of V was higher than the content of Fe、Ni. In addition the average content of Ba of the domestic continental oil was prominent, as 8.17ppm, and can be used as determination for land-based sources of oil. The ratio of Ni/V and Fe/V were different in different crude oils, besides, the oil samples can be divided by cluster analysis.At last, this paper presents the changes of the trace metal elements(Ni、Fe、V、Ba)in the crude oil from Bohai Sea and Foreign Sea under comprehensive weathering condition . The results show that the distribution patterns of Fe、Ba elements in crude oil had great change after 30 days weathering; However, Ba element was stable in 3 days weathering. So it can be used as reference for identification of terrestrial oil spills if the oil spill occurred in the three days. And then it was proved that the customary Ni、V have strong weathering-resistant capabilities under this synthetical weathering condition and the Ni/V ratio was stable. So the Ni/V ratio can be used for source identification of weathered oil. In sum, This paper established a method that the determination of the trace metal elements in different crude oils by Inductively Coupled Plasma Mass Spectrometry(ICP-MS).And an oil spill identification method was built based on the trace metals. It has application in primary and fast identification of spilled oil.