Exposure to polycyclic aromatic hydrocarbons, arsenic and environmental tobacco smoke, nutrient intake, and oxidative stress in Japanese preschool children

The association between oxidative stress and exposure to environmental chemicals was assessed in a group of Japanese preschool children. The concentrations of 8-hydroxy-2′-deoxyguanosine (8-OHdG), 1-hydroxypyrene (1-OHP), inorganic arsenic (iAs) and monomethylarsonic acid (MMA), and cotinine in spot urine samples, collected from 134 children (3-6 yrs) from a kindergarten in Kanagawa, Japan, were measured as biomarkers of oxidative stress or exposure to environmental chemicals. For 76 subjects of the 134, intakes of anti-oxidant nutrients (vitamins A, C, and E, manganese, copper, zinc and selenium (Se)) were estimated from a food consumption survey carried out 2-4 weeks after urine sampling and by urine analysis (Se). The median (min-max) creatinine-corrected concentrations of urinary biomarkers were 4.45 (1.98-12.3), 0.127 (0.04-2.41), 4.78 (1.18-12.7), and 0.62 (< 0.6-19.0) μg/g cre for 8-OHdG, 1-OHP, iAs + MMA, and cotinine, respectively. Multiple regression analysis was carried out using 8-OHdG concentration as a dependent variable and urinary biomarkers of exposure and Se intake, intakes of vitamins and biological attributes of the subjects as independent variables. To explain 8-OHdG concentrations, intake of vitamin A and age were significant variables with negative coefficients, while 1-OHP concentration had a positive coefficient. These results indicated that oxidative stress of children is affected by chemical exposure at environmental levels, by nutrient intake and by physiological factors in a complex manner. On the other hand, unstable statistical results due to sub-grouping of subject, based on the availability of food consumption data, were found: the present results should further be validated by future studies with suitable research design.     

卷烟烟气丙烯酰胺暴露量的生物标志物分析及与滤嘴分析法的比较

为了准确评估吸烟过程中人体丙烯酰胺暴露量,建立了测定丙烯酰胺巯基尿酸(MA)代谢物N-乙酰基-S-(2-氨基甲酰乙基)-L-巯基丙氨酸(AAMA)、N-乙酰基-S-(2-氨基甲酰-2-羟基乙基)-L-巯基丙氨酸(GAMA)的固相萃取-高效液相色谱质谱联用(SPE-LC-MS/MS)方法,采用该方法对吸烟者和非吸烟者尿液中的AAMA和GAMA进行了测定,并将数据与采用滤嘴分析法得到的评价结果进行了相关分析。结果表明:1该方法准确灵敏,日内、日间精密度分别小于7%和11%,回收率94.9%~100.0%,AAMA和GAMA的检测限分别为0.6和0.1 ng/m L。2吸烟者尿液中AAMA和GAMA均值是非吸烟者的3倍左右。3尿液中丙烯酰胺主要代谢物AAMA的质量浓度与应用滤嘴分析法测得的烟气丙烯酰胺暴露量有一定相关性(R=0.567,P0.03)。     

Distinctive Lipid Composition of the Copepod Limnocalanus macrurus with a High Abundance of Polyunsaturated Fatty Acids

We studied the copepod Limnocalanus macrurus for seasonal variation in the composition of fatty acids, wax esters and sterols in large boreal lakes, where it occurs as a glacial‐relict. Vast wax ester reserves of Limnocalanus were accumulated in a period of only two months, and comprised mono‐ and polyunsaturated fatty acids (PUFA) and saturated fatty alcohols. In winter, the mobilization of wax esters was selective, and the proportion of long‐chain polyunsaturated wax esters declined first. PUFA accounted for >50 % of all fatty acids throughout the year reaching up to ca. 65 % during late summer and fall. Long‐chain PUFA 20:5n‐3 and 22:6n‐3 together comprised 17–40 % of all fatty acids. The rarely reported C24 and C26 very‐long‐chain PUFA (VLC‐PUFA) comprised 6.2 ± 3.4 % of all fatty acids in August and 2.1 ± 1.7 % in September. The VLC‐PUFA are presumably synthesized by Limnocalanus from shorter chain‐length precursors because they were not found in the potential food sources. We hypothesize that these VLC‐PUFA help Limnocalanus to maximize lipid reserves when food is abundant. Sterol content of Limnocalanus, consisting ca. 90 % of cholesterol, did not show great seasonal variation. As a lipid‐rich copepod with high abundance of PUFA, Limnocalanus is excellent quality food for fish. The VLC‐PUFA were also detected in planktivorous fish, suggesting that these compounds can be used as a trophic marker indicating feeding on Limnocalanus.     

Organic geochemistry investigations of crude oils from Bayoot oilfield in the Masila Basin,east Yemen and their implication for origin of organic matter and source-related type

Thirteen crude oil samples from fractured basement reservoir rocks in the Bayoot oilfield, Masila Basin were studied to describe oil characteristics and to provide information on the source of organic matter input and the genetic link between oils and their potential source rock in the basin. The bulk geochemical results of whole oil and gasoline hydrocarbons indicate that the Bayoot oils are normal crude oil, with high hydrocarbons of more than 60%. The hydrocarbons are dominated by normal, branched and cyclic alkanes a substantial of the light aromatic compounds, suggesting aliphatic oil-prone kerogen. The high abundant of normal, branched and cyclic alkanes also indicate that the Bayoot oils are not biodegradation oils.The biomarker distributions of isoprenoid, hopane, aromatic and sterane and their cross and triangular plots suggest that the Bayoot oils are grouped into one genetic family and were generated from marine clay-rich source rock that received mixed organic matter and deposited under suboxic conditions. The biomarker distributions of the Bayoot oils are consistent with those of the Late Jurassic Madbi source rock in the basin. Biomarker maturity and oil compositions data also indicate that the Bayoot oils were generated from mature source rock with peak oil-window maturity.     

渤海海域深层潜山油气地球化学特征及油气来源

渤海湾盆地渤海海域渤中19-6深层潜山构造带周缘发育多个富烃深次洼,油气聚集条件复杂,对其油气的有机地球化学特征及主要来源认识尚不明确。为此,利用饱和烃及轻烃色谱、色谱—质谱、天然气组分及碳同位素组分检测等地球化学测试技术对该潜山构造带的原油、天然气与其周缘富烃深次洼烃源岩的地球化学特征进行对比分析,运用油—源生物标志化合物分析技术,系统研究了渤中19-6潜山构造带油气的来源与特征。结果表明:(1)渤中19-6深层潜山构造带周缘凹陷主要发育古近系东营组二段下亚段、东营组三段、沙河街组一段及沙河街组三段上亚段等4套烃源岩,其中东三段和沙三上亚段烃源岩为其主力烃源灶,有机质丰度较高,为偏腐泥混合型有机质类型,已进入生烃高峰期;(2)深层太古界潜山及上覆古近系孔店组天然气为典型的油型气,具有不同成熟度天然气混合特征,成藏过程具有多阶段性;(3)浅层与深层油气来源都具有3套烃源岩混源输入的特征,但仍存在着差异性,其中浅层油气来源以东三段烃源岩的输入为主,并且可能存在着东二下亚段烃源岩的输入,而深层油气来源则以沙三上亚段烃源岩的输入为主。结论认为,该区油气源条件复杂,油气源主要以周缘富烃深次洼内沙三上亚段烃源岩为主,其深层凝析气藏表现出多期次油型气输入的特征。     

Correlation of source rocks and crude oils in Kupal and its near oil fields,SW of Iran

The Kupal oil field is located in the north of Dezful Embayment in southwest of Iran. The purposes of this study were correlations between the Sarvak and Asmari reservoirs oils in the Kupal oil field and determining the source of oil in this field. In order to achieve these objectives, different geochemical methods, including Rock Eval, gas chromatography, gas chromatography-mass spectrometry, and carbon isotope analyses of asphalthene in oils and source rocks, were used. The results of pyrolyzed possible source rocks of the Kupal and its near fields by the Rock Eval apparatus indicated good source rock potential for the Kazhdumi and Pabdeh formations. In addition, Kazhdumi formation in the Haft-Kel oil field indicated gas production potential while the samples of the Gurpi formation were in a non-source rock zone. The Asmari and Bangestan reservoir oils had the same components and geochemical characteristics, except the Sarvak (Bangestan) reservoir oil in the Kupal field contained Oleanane biomarkers, whereas Asmari reservoir oil had no Oleanane biomarker. This fact was attributed to the fault in the southwestern part of the Kupal oil field, which moved the Pabdeh formation (in which its oil contains Oleanane biomarkers) to more depths and near the Sarvak formation. This movement caused the maturation of Pabdeh formation and migration of the produced oil to the Sarvak reservoir.     

地球化学参数在沉积古盐度中的应用

在对沉积物进行沉积古盐度分析时,微量元素分析能够起到很好的作用,它们对沉积盐度的变化具有很高的灵敏度,此外稀土元素具有很好的稳定性,能够保存沉积时的古盐度信息,生物标志化合物是生物的化学化石,具有稳定的结构,不易受成岩作用影响,能够记录生物沉积时的古盐度。通过阅读大量的文献,系统的总结了主微量元素、稀土元素和生物标志化合物在不同沉积盐度中的特征及其地质应用。对于沉积相分析不明确的地层,利用地球化学参数能够更直观地分析出沉积盐度。但沉积物在沉积过程中很容易受其他因素影响,因此在利用地化参数对沉积盐度判别时还应与地质背景、岩性岩相等相结合,以便能最大限度反映出沉积时的古盐度。     

柴达木盆地西部七个泉与咸水泉油田原油地球化学特征对比研究

通过对取自七个泉油田和咸水泉油田原油样品中各类生物标志物的分布与组成特征的对比,发现七个泉油田原油中正构烷烃系列比较完整且丰度较高,而咸水泉油田原油中正构烷烃因轻微生物降解而被部分消耗,导致咸水泉油田原油的Pr/nC₁₇值和Ph/nC₁₈值明显高于七个泉油田原油。2个油田原油均呈现较强烈的植烷优势,七个泉油田原油的姥/植比更低,表明它们都来源于强还原环境下形成的烃源岩。在生物标志物分布与组成特征上,七个泉油田原油甾烷的C₂₇/C₂₉>1,而咸水泉[JP2]油田原油甾烷的C₂₇/C₂₉值均为0.8,意味着七个泉油田原油中浮游植物贡献高于咸水泉油田。咸水泉油田原油的C₂₉甾烷ααα20S/（ααα20S＋ααα20R）值和重排补身烷含量高于七个泉油田原油,暗示咸水泉油田原油成熟度比七个泉油田原油成熟度高。2个油田的长链藿烷序列均比较完整,伽马蜡烷含量也较高,对比长链藿烷和伽马蜡烷的丰度发现咸水泉油田原油的长链藿烷和伽马蜡烷丰度都比七个泉油田原油低,说明咸水泉油田原油形成的环境的盐度和还原性比七个泉油田原油弱。     

储层有机地球化学及油气运移特征

根据储层岩石热解色谱、储层沥青中的正烷烃、碳同位素和生物标志化合物分析资料，探讨了塔里木盆地油Ⅱ区块储层特征和油气运移特征。实验表明，应用热解烃和储层沥青含量可以判别源岩层、储层以及储层相对优劣。研究结果认为，垂向上从石炭系到三叠系储层，油气由石炭系运移到二叠系，但三叠系储层油气并非源于二叠系；横向上二叠系储层油气运移范围小，石炭系储层油气从凹陷向隆起发生了侧向运移，志留系储层油气有侧向运移迹象，方向和石炭系相反，奥陶系储层油气以自生自储为主。     

分子有机地球化学在石油勘探中的应用

分子有机地球化学是二十世纪 70年代以来迅速发展的分支学科。它通过分析生物标志化合物 (又称分子化石 )的化学组成及构型转化来研究沉积有机质的演化以及沉积矿产特别是石油的成因。本文简要地介绍了分子有机地球化学方法在为油气勘探提供关于有机质来源、沉积环境、成熟度、油气运移及生物降解等多方面信息中的应用。