油田地表土壤中多环芳烃提取方法改进研究

研究了油田运行井周围的地表土壤中16种多环芳烃的提取和测定方法.对超声提取方法进行优化,得到了最佳超声提取条件,分析在最佳超声条件下直接超声波、微波辅助超声、微波与振荡辅助超声的提取效果,并与72h索氏提取相比较.结果表明,在温度30℃,功率120 W下超声60 min提取多环芳烃的效果最好.     

Micro-terraforming by Antarctic springtails (Hexapoda: Entognatha)

It has long been an axiom of Antarctic terrestrial ecology that interactions between terrestrial invertebrates and their abiotic environment are unidirectional: they are affected by their extreme environment in numerous ways, but they themselves do not affect their environment. Field observations in tandem with laboratory investigations of the exuvial refugia of the springtail Gomphiocephalus hodgsoni Carpenter, reported here, challenge this long-held assumption. These previously undescribed structures consist of minute lithic particulate matter that has been bound together by the accumulation of moult exuviae. Macrophotography, microscopy and manipulation assays demonstrated that the exuviae act as a kind of ‘cement’. Detachment of exuviae by emulsification indicated that this is mediated by the accumulation of cuticular hydrocarbons (retained in shed exuviae) at the lithic–exuvial interface. In addition to re-enforcing preferred microhabitat features by extending the hygrically buffered refuge phenotype, these structures contribute to primary soil formation processes through the structural cohesion of particulate matter. These by-products of moulting behaviour represent the first tangible evidence of environmental modification by terrestrial invertebrates on the Antarctic continent.     

Thermal cracking of n-octodecane and its geochemical significance

The mechanism of carbon isotopic fractionation for gaseous hydrocarbons is revealed by investigating the residual liquid hydrocarbons in laboratory pyrolysates of n-octodecane. The results indicate that cracking and polymerization in the relatively low temperatures and dispropor-tionation reactions leading to light hydrocarbons and pol-yaromatic hydrocarbons at high temperatures are probably causes for the carbon isotope reversal of gaseous hydrocarbons that is commonly observed in pyrolysis experiments. This study provides significant insight for quantitative modeling of natural gas δ13C values and aid in the identification and assessment of natural gases derived from oil cracking.     

Application of C5—C13 light hydrocarbons in depositional environment diagnosis

Based on the geological background and Gammacerane/C31H（S ＋ R） ratios, source rock depositional environments of the studied oil samples （194） from 13 oilfields were classified into three groups according to salinity： saline-lacustrine facies, fresh to brackish lacustrine facies （including limnetic facies）, and semi-saline to saline facies （including marine facies of the Tarim Basin）. C5-C13 compound groups in the crude oils were separated by GC, and about 286 compounds were qualitatively analyzed. The geochemical application of the C6- C13 compound groups and their ratios between each group with individual carbon number was investigated. Our studies show that （1） C6-C13 compound groups and their ratios in the crude oils could serve as new reliable parameters for oil-oil correlation because the C6- C13 light fractions are the major oil component, especially in light oil or condensate, in which they account for almost 90% of the whole oil; （2） the compound groups of C7 light hydrocarbons in oils derived from different depositional environments with different salinity have different characteristics; （3） C6-C13 compound groups and ratios may be affected by other factors such as maturity, but they are mainly controlled by salinity of depositional waters.     

种植黑麦草对山西工矿区多环芳烃和重金属复合污染土壤微生物群落多样性的影响

本文以山西工矿区生黄土为供试土壤,以黑麦草(Lolium perenne L.)为供试植物材料,通过室内培养实验,采用变性梯度凝胶电泳技术(DGGE),研究不同浓度PAHs和HgCl2单一及复合污染种植黑麦草对土壤微生物群落多样性的影响.结果表明:不同浓度PAHs与HgCl2处理下黑麦草土壤微生物基因条带差异明显.与对照组相比,低浓度污染处理下基因条带数稍有增加,而高浓度污染处理下部分基因条带消失.各污染水平下土壤微生物所共有的优势条带较多.在HgCl2单一污染条件下,土壤微生物多样性首先随着污染浓度的升高而增加,污染浓度大于3 mg·kg-1时,土壤微生物群落多样性指数随着浓度的升高逐渐降低,在最高浓度60 mg·kg-1时,较对照组降低5.0%;PAHs单一污染与HgCl2单一污染处理下土壤微生物群落多样性指数表现出相似的规律,污染浓度大于10 mg·kg-1时,土壤微生物群落多样性指数开始降低,在最高浓度50 mg·kg-1时,较对照组降低了2.8%.HgCl2与PAHs复合污染在中浓度A22(PAHs 5 mg·kg-1、HgCl215 mg·kg-1)时对土壤微生物群落多样性表现为协同作用,而在最高浓度A36(PAHs 50mg·kg-1、HgCl260mg·kg-1)则表现为抑制作用.     

中国水生生态系统中多环芳烃的生态毒性与生态风险研究进展

多环芳烃是我国环境中的主要污染物之一,对生态系统和人体健康具有严重危害。对中国水生生态系统中多环芳烃的生态毒性与生态风险研究进展进行了综述。从基因、细胞、个体、种群和群落等不同层次概括了多环芳烃的水生态毒性研究进展,介绍了水生生态系统多环芳烃生态风险的主要评价方法,综述了这些评价方法在中国的应用情况,分析了中国水生生态系统中多环芳烃的生态毒性与生态风险研究的存在问题与发展方向。多环芳烃的水生态毒性研究主要集中在水生生物种群与群落水平,基因与细胞水平的研究较少,而生态系统水平的研究基本为空白。在多环芳烃的水生生态风险方面,主要利用国外提出的一些评价方法,缺少自主创新的评价方法,探讨系统水平生态风险评价方法是中国研究人员可能的突破方向。     

长春市大气环境PM2.5中多环芳烃的来源解析及健康风险评价

为研究长春市采暖期与非采暖期PM2.5中多环芳烃(polycyclic aromatic hydrocarbons,PAHs)的浓度和来源,于2017年10月25日—11月30日和2018年3月19日—4月30日共采集80个样品,监测PM2.5的质量浓度的同时利用气相色谱-质谱联用仪(gas chromatography-mass spectrometry,GC-MS)进行16种多环芳烃的检测分析,结合比值法进行PAHs来源解析,并通过美国国家环境保护局健康风险评价模型进行健康风险评估.结果表明,采暖期和非采暖期PM2.5的平均质量浓度分别为283.37μg/m3和195.81μg/m3,是《环境空气质量标准》(GB 3095—2012)的二级日标准限值的3.78倍和2.61倍.其中,16种PAHs均以中高环为主,芘(PYR)的浓度最高,采暖期和非采暖期所占比分别为76.03％、77.41％.特征比值法分析显示采暖期污染主要来自煤燃烧和汽车尾气排放的混合源,非采暖期主要来自汽油和柴油燃烧源.通过健康风险评价可知,在采样期间儿童与成年男性的三种暴露途径(呼吸吸入、皮肤暴露、口服摄入)致癌风险从大到小均为:皮肤暴露>呼吸吸入>口服摄入;而成年女性的三种途径的终生致癌风险(incremental lifetime cancer risk,ILCR)值从大到小为:口服摄入>皮肤暴露>呼吸吸入,其中采暖期的致癌风险值均高于非采暖期.在所有人群中,ILCR值均低于10-6,其致癌风险水平处于可接受状态.研究结果为长春市大气污染综合防治和环境管理提供科学依据.     

高效液相色谱法测定土壤中的多环芳烃

采用高效液相色谱-荧光检测器快速测定土壤中15种多环芳烃。通过对液相色谱柱、梯度洗脱程序、检测波长程序及柱温等液相色谱条件的选择和优化,使土壤样品中15种多环芳烃在32min内得到完全分离,方法的最低检出限为0.0002～0.0045 mg/kg,回收率为71.20%～95.07%,RSD为5%～10%。该优化方法的精密度高、检出限低、重复性好,是一种能够快速、准确测定土壤中多环芳烃的检测方法。     

大气颗粒物中多环芳香烃快速萃取方法的研究

大气颗粒物中多环芳香烃(PAHs)的标准提取方法有索氏萃取法和超声波萃取法。本研究在使用两种标准方法的基础上,利用快速溶剂萃取方法(ASE)对公路大气、隧道大气和汽车尾气等大气颗粒物样品提取PAHs,并探讨了颗粒物中提取PAHs时合适的萃取方法和萃取溶剂。实验结果表明,公路大气样品中PAHs提取可以选用乙腈为溶剂的ASE方法;隧道空气样品PAHs提取中索氏提取法优于其他方法;而汽车尾气样品中大部分PAHs的提取,以二氯甲烷为萃取溶剂的ASE的效果与其他方法相同。     

同多酸催化下几种含氧芳香烃溴代反应的研究

分别以4种酚类化合物:2-甲基苯酚、邻苯二酚、间苯二酚、对苯二酚为反应物,首先将反应底物的羟基进行甲基或者甲氧基甲基保护,然后将所得到的产物在醋酸溶剂中,以溴化钾和过氧化氢为试剂,钼酸铵为催化剂的条件下,研究了在苯环骨架上引入了溴原子的方法.研究结果表明,实验方法操作简单易行,反应时间较短,产物专一性好,后处理简单,并且收率较高,活化溴原子对苯环的进攻位置主要受到催化剂钼酸大分子结构的控制.产物经红外光谱和核磁共振谱进行了结构表征,证实成功合成了目标化合物.