【作者】 赵玉丽；

【导师】 王秋泉；

【作者基本信息】 厦门大学 ， 分析化学， 2008， 博士

【摘要】 建立了一种“脉冲大体积进样-气相色谱/电子捕获负化学离子化-四级杆质谱（pLVI-GC/ECNI-qMS）”的分析方法,通过监测特征离子并利用同位素稀释法同时测定了30种卤代持久性有机污染物（POPs）;该方法避免了目前GC/qMS分析方法中的常见干扰,检出限达pg-fg/mL级与GC/HR-MS法相当。系统研究了大气POPs在树木表皮中的富集机制:气态POPs与脂质相互作用而在树表皮中富集,其富集程度取决于POPs的辛醇/空气分配系数并受树皮脂含量和环境温度的影响:颗粒态POPs被皮孔随机捕获而富集于树皮中,其富集程度取决于POPs的蒸汽压并受树皮比表面积和环境降水量的影响。提出了树木表皮富集大气POPs过程中“天然内标化合物”（NIC）的概念,发展了一种利用树皮中目标多环芳烃（PAHs）与苝（用作PAHs由空气向树表皮富集过程的NIC）的浓度比进行区域大气PAHs污染水平的评价方法,以减小由于树皮特征和环境因素差异造成的利用树表皮中PAHs浓度评价大气PAHs污染的不确定性。建立了一种POPs在树表皮/空气间的数学分配模型,为大气POPs污染监测的树皮被动采样平台提供了理论定量基础;运用模型可以由测得的树皮中POPs的浓度推算采样点空气中POPs的浓度。目标POPs包括15种多溴联苯醚（TBBPA）、1种多溴联苯（PBB）、四溴双酚A（TBBPA）、10种多氯联苯（PCBs）、5种有机氯农药（OCPs）和18种PAHs。分析采集于中国大陆68个城市的163个树表皮样品、江西德兴和福建永安“天宝岩”自然保护区采集的树木“时间隧道”样品以及“天宝岩”自然保护区的“泥炭藓”中的POPs并应用所建立的POPs在树表皮/空气间的分配模型,评价了我国大气POPs污染的空间分布状况并揭示了我国东南部地区大气POPs污染的历史演变趋势。中国大陆68个城市的∑₁₈PAHs,∑₅OCPs,∑₁₀PCBs和∑₁₇BFRs的浓度分别为4-400 ng/m³,11-460,5-130和1-470 pg/m³;且POPs浓度与城市GDP呈对数线性正相关。α/γ-HCH浓度比随着纬度由18.27°N升高到49.22°基本呈线性增大,表明残留HCHs的重新蒸馏再分配而不是当前使用HCHs的污染排放控制着目前我国HCHs的空间分布。19世纪70年代开始,到19世纪80年代、20世纪40年代中期、20世纪40年代,∑₁₈PAHs、∑₅OCPs和∑₁₀PCBs、∑₁₇BFRs分别保持在其背景浓度0.7±0.1 ng/m³、4.0+1.1和2.2±0.4 pg/m³、0.2±0.1 pg/m³:其后开始升高,到21世纪初达到其背景浓度的8、18、12和125倍;期间,∑₅OCPs和∑₁₀PCBs分别于20世纪70和80年代出现峰值,大约为其背景浓度的20和18倍。更多还原

【Abstract】 A pulsed large volume（6×20μL） injection gas chromatography coupled with electron-capture negative ionization quadrupole mass spectrometry for simultaneously determining the 30 halogenated POPs was established.The method avoided common chromatographic interferences by selected monitoring the characteristic ions of large mass-to-charge ratio but not the base peak ions,while relatively low sensitivity was compensated by increasing the sample injection volume up to 120μL.The method detection limits reached pg-fg/mL level.Besides,using perdeuterated and/or ¹³C-labeled compounds as internal standards ensured the reliability of quantification.The mechanism of persistent organic pollutants（POPs） accumulation from air into tree bark was systematically studied.The POPs of IogK_OA≤8.5 predominately existing as gas-phase are accumulated through interactions with lipid substances in bark,which is primarily controlled by their KOA and influenced by bark lipid content and ambient temperature;while the POPs of logK_OA＞8.5 predominately existing as particle-phase are accumulated through stochastic entrapment by the lenticels on the surface of the bark,which is mainly controlled by their V_p and influenced by the surface area of the bark and precipitation.A new concentration ratio of target polycyclic aromatic hydrocarbons（PAHs） to perylene（PER）,R_PAH/PER,was proposed as an alternative methodology for more objective evaluation of spatial distribution of atmospheric PAHs pollution levels on a large scale when using tree bark as passive sampling medium,in which PER was proposed to be a natural internal compound of atmospheric PAHs accumulation processes from air into tree bark.R_PAH/PER minimizes the evaluation uncertainties arising from the variations in both bark characteristics and meteorological conditions.A mathematic model describing the bark/air partitioning of POPs was established taking into consideration the accumulation processes of POPs from air into bark and compound-,species- and site-specific air-to-bark accumulation factors.It allows the assessment of the concentrations of atmospheric POPs based on those recorded in tree bark.The POPs analyzed in this study include 17 brominated flame retardants（BFRs, including 15 polybrominated diphenyl ethers,1 polybrominated biphenyl and tetrabromobisphenol A TBBPA）,10 polychlorinated biphenyls（PCBs）,5 organic chlorinated pesticides（OCPs,including 4 hexachlorocyclohexane isomers and hexachlorobenzene） and 18 PAHs.By applying the POPs’ bark/air partitioning model,we investigated the spatial distribution of atmospheric POPs across China’s mainland using 163 bark samples collected from 68 sites.The atmospheric POPs were estimated to he 0.9-624,4.5-130, 11.3-553 pg/m³ air and 4.1-399 ng/m³ air for the total concentrations of the BFRs (∑₁₇BFRs),the PCBs(∑₁₀PCBs),the OCPs（∑₅OCPs）,and the PAHs(∑₁₈PAHs), respectively.The logarithm transformed atmospheric POPs concentrations have linear relationship positively with gross domestic production of the cities,with the correlation coefficients of 0.812,0.616,0.524 and 0.618（p＜0.01,n = 68） for the∑₁₇BFRs,∑₁₀PCBs,∑₅OCPs and∑₁₈PAHs respectively.Moreover,the hexachlorocyciohexane （HCH） isomer concentration ratios ofα-HCH toγ-HCH（α/γ-HCH ratios） were fractionated with latitude（from 49.22°to 18.27°N） indicating the spatial distribution of HCHs in China is now governed by the nationwide redistillation of the HCHs residues used in the past but not by their recent use patterns.We also revealed the centurial historical evolution of atmospheric POPs pollution in Southeast China using bark pocket and peat bog samples from Jiangxi and Fujian provinces,Southeastern China. The∑₁₈PAHs,∑₅OCPs and∑₁₀PCBs,as well as∑₁₇BFRs remained at their background levels of 0.7±0.1 ng/m³,4.0±1.1 and 2.2±0.4 pg/m³,0.2±0.1 pg/m³ air,respectively, from the 1870th to the 1880th,mid-1940th and 1940^th;and then they steeply increased reaching 8,18,12 and 25 times of their respective background levels at the beginning of the 21th century;meanwhile,the∑₅OCPs and∑₁₀PCBs respectively peaked at the 1970th and 1980th with the concentrations of 20 and 18 times of their background levels.更多还原