Thesis (M. Eng. in Ocean Engineering)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and the Woods Hole Oceanographic Institution), 1999. / Includes bibliographical references (leaves 97-103). / by Rachel H. Levine. / M.Eng.in Ocean Engineering

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20398号 / 工博第4335号 / 新制||工||1672(附属図書館) / 京都大学大学院工学研究科分子工学専攻 / (主査)教授 関 修平, 教授 今堀 博, 准教授 伊藤 彰浩, 教授 白川 昌宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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Polycyclic aromatic hydrocarbons (PAH) are a class of environmental pollutants consisting of a minimum of two fused aromatics rings originating from the incomplete combustion of organic matter and/or anthropogenic sources. Numerous possible anthropogenic and natural sources make the presence of PAH ubiquitous in the environment. The carcinogenic nature of some PAH and their ubiquitous presence makes their chemical analysis a topic of environmental and toxicological importance. Although environmental monitoring of PAH is an important step to prevent exposure to contaminated sites, it provides little information on the actual uptake and subsequent risks. Parent PAH are relatively inert and need metabolic activation to express their carcinogenicity. Covalent binding to DNA appears to be the first critical step in the initiation of the tumor formation process. To this end, the determination of short term biomarkers – such as monohydroxy-PAH metabolites (OH-PAH) - fills an important niche to interpret actual PAH exposure levels, prevent extreme body burdens and minimize cancer risk. One would certainly prefer an early warning parameter over a toxicological endpoint – such as DNA-adducts – indicating that extensive damage has already been done. Several methods have been developed to determine OH-PAH in specific tissue or excreta and food samples. The general trend for the analysis of OH-PAH follows the pattern of sample collection, sample clean-up and pre-concentration, chromatographic separation and quantification. Popular approaches for sample clean-up and preconcentration include liquid-liquid extraction (LLE) and solid-phase extraction (SPE). Chromatographic separation and quantification has been based on high-performance liquid iv chromatography-room temperature fluorescence detection (HPLC) and gas chromatographymass spectrometry (GC-MS). Although chromatographic techniques provide reliable results in the analysis of OHPAH, their experimental procedures are time consuming and expensive. Elution times of 30-60 minutes are typical and standards must be run periodically to verify retention times. If the concentrations of target species are found to lie outside the detector’s response range, the sample must be diluted and the process repeated. On the other end of the concentration range, many samples are “zeroes,” i.e. the concentrations are below detection limits. Additional problems arise when laboratory procedures are scaled up to handle thousands of samples under mass screening conditions. Under the prospective of a sustainable environment, the large usage of organic solvents is one of the main limitations of the current chromatographic methodology. This dissertation focuses on the development of a screening methodology for the analysis of OH-PAH in urine and milk samples. Screening techniques capable of providing a “yes or no” answer to OH-PAH contamination prevent unnecessary scrutiny of un-contaminated samples via conventional methods, reduce analysis cost and expedite the turnaround time for decision making purposes. The proposed methodology is based on capillary zone electrophoresis (CZE) and synchronous fluorescence spectroscopy (SFS). Metabolites extraction and pre-concentration is achieved with optimized SPE, LLE and/or QuEChERS (quick, easy, cheap, effective, rugged and safe) procedures. The small sample and extracting solvent volumes facilitate the simultaneous extraction of numerous samples via an environmentally friendly procedure, which is well-suited for routine monitoring of numerous samples. Sample stacking is successfully implemented to improve CZE limits of detection by two orders of magnitude. The unique electrophoretic pattern of positional isomers of OH-PAH demonstrates the potential of CZE for v the unambiguous determination of metabolites with similar chromatographic behaviors and virtually similar fragmentation patterns. The direct determination of OH-PAH without chromatographic separation is demonstrated via SFS. The non-destructive nature of SFS provides ample opportunity for further metabolite confirmation via chromatographic techniques

In the search for the conformation of extant or extinct life in an extraterrestrial setting the detection of organic molecular species which may be considered diagnostic of life is a key objective. These molecular targets comprise a range of distinct chemical species, with recognisable spectroscopic features. This project aims to use these features to develop an in-situ molecular specific Raman spectroscopic methodology which can provide structural information about the organic–inorganic interface. The development of this methodology identified a surface enhanced Raman spectroscopic technique, that required minimal sample preparation, allowed for the detection of selected organic species immobilised on an inorganic matrix and was effective for quantities below those which conventional dispersive Raman spectroscopy would detect. For the first time spectral information was gained which allowed analysis of the organic–inorganic interface to be carried out, this gave an insight into the orientation with which molecules arrange on the surfaces of the matrices. Additionally a method for the detection of organic residues intercalated into the interlamellar space of smectite type clays was developed. An evaluation of the effectiveness of uni and multivariate methods for the analysis of large datasets containing a small number of organic features was also carried out, with a view to develop an unsupervised methodology capable of performing with minimal user interaction. It has been shown that a novel use of the Hotellings T2 test when applied to the principal component analysis of the datasets combined with SERS allows identification of a small number of organic features in an otherwise inorganic dominated dataset. Both the SERS and PCA methods hold relevance for the detection of organic residues within interplanetary exploration but may also be applied to terrestrial environmental chemistry.

<p> Coal tar is a rich source of polycyclic aromatic compounds (PAC) which include hydrocarbons (PAH), sulfur-containing aromatics (PASH), nitrogen-containing aromatics and high molecular mass PAH. The separation of coal tar into four fractions was carried out on activated (170°C, 48 hrs) neutral alumina. Low mass aromatics and aliphatics were eluted with hexane in fraction A1 (2.2% recovery), while PAH/PASH were eluted by benzene in fraction A2 (25%). High molecular mass PAH were eluted by dichloromethane in fraction A3 (5.5%) and nitrogen-containing aromatics were eluted by methanol in fraction A4 (21%). These fractions were characterized by normal phase liquid chromatography, GCMS, probe mass spectrometry (for fractions A3 and A4) and LC-MS (for fraction A3).</p> <p> While ratio of PASH to PAH in fraction A2 was rather unfavorable (25:1), the separation of PASH from PAH was attempted using two methods: an oxidation/reduction method and a ligand exchange method. The oxidation/reduction method of Lee was a complete failure. The PdCl2-silica method of Nishioka was partially successful. Of the 25 thia-arenes identified in fraction A2, 12 eluted with the PAH while the other 13 were either partially (5) or fully (8) retained by the PdCl2-silica gel column and then eluted later to give a sulfur-enriched fraction. This fraction was further separated using normal phase HPLC to afford sulfur-containing compounds with molecular masses between 184 amu and 258 amu which exhibited almost no contamination due to PAH. Thus, it would be possible to purify about one-half of the PASH from a complex mixture such as coal tar.</p> <p> Fraction A3 which contained high mass PAH was subjected to semi-preparative normal phase HPLC to afford several high molecular mass PAH fractions. The 326 amu PAH fraction was selected because it contributed to 10% of the genotoxic of the mixture. This fraction was further separated by normal phase HPLC and the subfractions were analyzed by reversed-phase HPLC with diode-array detection. Thirty-five peaks were collected from the reversed-phase HPLC analysis and were characterized by probe mass spectrometry and fluorescence spectroscopy (in part). Of the 35 peaks, 8 peaks were eluted in the mutagenic active range; these eight compounds will be evaluated using the Ames assay to determine which are active mutagens.</p> / Thesis / Master of Science (MSc)

Sites contaminated with polycyclic aromatic hydrocarbons can be simultaneously contaminated with trace elements. Co-contaminated soil is considered a complex problem since inorganic and organic contaminants behave differently and thereby often require different remediation strategies. Despite the fact that co-contaminated soils are a common problem, existing research on remediation of contaminated soil mostly focuses on either organic or inorganic contaminants. In the present study, the possibilities of electrokinetic remediation as an alternative to commonly used remediation technologies was investigated. An experiment was setup to evaluate the effects of electrokinetic remediation on both polycyclic aromatic hydrocarbons and trace elements, such as arsenic, cadmium, chromium, copper, lead and zinc, simultaneously. The experiment was performed in 12 litre large plexiglass cells. Two cells with electrokinetic treatment, equipped with iron electrodes, to amend the soil with iron via intentional corrosion of the electrodes, and one control. The cells were filled with contaminated soil and deionized water was pumped through the cells to simulate a groundwater flow. The experiment ran for two months, during which pore water was sampled weekly and simulated groundwater monthly, to monitor changes in contaminant concentrations. Soil samples were taken at the start and at the end of the experiment. Results showed that the concentration of polycyclic aromatic hydrocarbons in the simulated groundwater decreased from 0.39 ± 0.15 μg L-1 to 0.12 ± 0.064 μg L-1 during the experiment. However, at the point of writing, samples of soil at the end of the experiment has not yet been analysed for concentration of polycyclic aromatic hydrocarbons, something that needs to be done to validate previously described results. In terms of the trace elements, the applied method did not increase their mobility, nor did it decrease it. Moreover, the trace elements behaved similarly in the control cell as in the treatment cells. This was observed for all the tested trace elements, indicating that electrokinetic remediation in this particulate case may be a suitable remediation technology for organic, but not that successful for inorganic contaminants. In regard to this, further research is required to establish whether electrokinetic remediation is a promising remediation technology for co- contaminated soil and how it can be optimized to ensure remediation success for both organic and inorganic contaminants.

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