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题名: 空气中氯代二恶英和溴代二恶英的分布特征研究
作者: 张宪
学位类别: 博士
答辩日期: 2016-11
授予单位: 中国科学院研究生院
授予地点: 北京
导师: 郑明辉
关键词: 氯代二恶英,溴代二恶英,大气,颗粒物,分布特征 ; PCDD/Fs, PBDD/Fs, Atmosphere, Particle, Distribution Characteristics
其他题名: Distribution characterization of polychlorinated and polybrominated dibenzo-p-dioxins and dibenzofurans in air
学位专业: 环境科学
中文摘要:     PCDD/Fs和  PBDD/Fs(简称  PXDD/Fs)具有高毒性,生物累积性,严重危害人类健康和生态环境安全。大气是  POPs物质在环境中迁移转化的重要媒介。据现有的研究报道,对于空气中 PXDD/Fs在气固相分配及不同粒径上的分布特征还没有一个比较统一的认识;而且有关空气中 PXDD/Fs的采样也不统一,造成监测数据彼此之间的可比性存在不确定性。因此,对大气中 PXDD/Fs的含量水平、气固相分配及粒径分布特征等的研究可以为更好地了解其环境行为,有效地评估和控制这类风险提供必要的科学依据。本研究系统地研究了 空气中PXDD/Fs的污染水平、气固相分配及粒径分布特征,及空气中  PCDD/Fs监测技术的差异性研究。主要开展了以下三个方面的研究:
    1.利用大流量分级采样器(KS30310/2.5/1.0)在北京城市生态系统研究站采集城区空气样品,系统地研究了北京城区空气中 PCDD/Fs和 PBDD/Fs的污染水平,气固相分配以及粒径分布特征。Σ172,3,7,8-PCDD/Fs和 Ʃ132,3,7,8-PBDD/Fs的浓度分别为 1499–2799 fg m–3(95.4–175 fg I-TEQ m−3),1171–2424 fg m–3(42.2–109fg TEQ m−3)。PXDD/Fs主要分布在颗粒物中(~90%)。空气中 PCDD/Fs以吸附在颗粒物的表面为主,而 PBDD/Fs则以结合在颗粒物的有机质中为主,且在不同粒径颗粒物上 PXDD/Fs也呈现出相似的分布规律。在动力学直径(aerodynamic diameters, dae)<1.0 µm的颗粒物中PXDD/Fs的含量最高,80%以上的PXDD/Fs都是分布在 dae <2.5 µm的颗粒物中。PXDD/Fs的浓度随着颗粒物粒径的增加而减少。低氯代 PCDD/Fs多倾向于分布在粗颗粒物上,高氯代PCDD/Fs则更多地分布在细颗粒物上。高溴代呋喃在各个粒径颗粒物上都是最主要的组分,且所占比例随着颗粒物粒径的增加而减少,而 PBDDs却没有呈现出相似的分布特征。
      对空气中低氯代二恶英(ΣCl1–3DD/Fs)分布特征的研究表明其浓度显著高于高氯代二恶英(ΣCl4–8DD/Fs),且主要分布在气相。在颗粒相中,ΣCl1–3DD/Fs浓度并未随着颗粒物粒径的增加而减小,70%的 ΣCl1–3DD/Fs分布在  dae>1.0 µm的
颗粒物中,这明显不同于 ΣCl4–8DD/Fs在不同粒径颗粒物上的分布特征(70%分布在 dae <1.0 µm颗粒物中)。
      进一步考察了雾霾天和季节对其含量水平和分布特征的影响。在本研究中,雾霾天空气中的 Ʃ172,3,7,8-PCDD/Fs和 Ʃ132,3,7,8-PBDD/Fs浓度明显高于普通天。PCDD/Fs(95%)和 PBDD/Fs(89%)主要分布在 dae<2.5 µm细颗粒上的趋势也更加明显。与普通天空气中颗粒物上 PCDD/Fs的存在形式不同,雾霾天空气中PCDD/Fs在不同粒径颗粒物上均是以结合在颗粒物的有机质中为主。空气中Σ172,3,7,8-PCDD/Fs和   Σ132,3,7,8-PBDD/Fs的含量水平和分布特征均表现出明显的季节特征,冬季空气中 PXDD/Fs的含量较高,夏季较低。PCDD/Fs在气相中的分配比例与温度呈正相关关系,与 PCDD/Fs相比,对  PBDD/Fs的气固相分配影响不显著。
    2.利用大流量分级采样器(KS30310/2.5/1.0)采集了两家不同生产规模的再生铜冶炼厂( DYFY和     LYJS)冶炼车间的空气样品,分析了冶炼车间空气中PCDD/Fs的含量水平及其粒径分布特征并评估了车间工作人员的呼吸暴露风险。结果表明,DYFY冶炼车间空气中  PCDD/Fs浓度为  203 pg m-3,是 LYJS车间空气中 PCDD/Fs浓度的22倍。与  DYFY相比,LYJS车间空气中PCDD/Fs在气固相分配上差异性明显。空气中颗粒物上 PCDD/Fs浓度均随着粒径的增加而减少。DYFY车间工作人员的每日呼吸摄入量是  LYJS的  4倍,均低于世界卫生组织规定的日容许摄入量标准。
    3.利用不同的大流量空气采样器(KS30310/2.5/1.0,TSP和PM10)在北京城市生态系统研究站连续采集一批城区空气样品,对比研究了其中 PCDD/Fs的浓度水平及分布状况。研究结果表明 KS30310/2.5/1.0和  TSP所监测到的PCDD/Fs的浓度具有可比性(R2均能较好地反映空气中 PCDD/Fs的分布。利用TSP与PM10采样器所监测到的PCDD/Fs浓度也具有较好的可比性(R2=0.98, p<0.01 k=0.98),TSP与  PM10对空=0.99, p<0.01 k=0.97),PCDD/Fs同类物具有相似的分布特征,气中 PCDD/Fs监测数据的差异受季节因素影响不明显,均能较好地反映空气中PCDD/Fs同类物的分布特征。
英文摘要:     PXDD/Fs, which can refer to either PCDD/Fs or PBDD/Fs, are  highly toxic and accumulate in the  environment, and therefore pose  serious risk to human  health and environmental safety.  The atmosphere  is the  major media  through which  persistent organic pollutants (POPs) are transported. It is still difficult to describe the gas-particle partitioning  and  particle-size  distribution   of  airborne  PXDD/Fs.  Moreover,  it  is difficult   to   compare   detection   data   of   airborne   PCDD/Fs   between   different investigations because of  their differences in monitoring methods.  Therefore, it is of vital   importance   to   further   explore   the   PXDD/F   concentrations,   gas-particle partitioning  and   particle   size  distributions   in   ambient  air   to  comprehensively understand their environmental behavior and  risks, and to provide necessary data for reducing or controlling these risks.  In this study, the concentration level, gas-particle partitioning and  particle-size distribution of airborne  PXDD/Fs were investigated  in the air,  and  the determination  methods  of airborne  PCDD/Fs were  compared. The
study mainly consists of three parts as follows:
    1.  The   concentration  level,   profiles,  gas-particle   partitioning  and   particle  size distributions of PXDD/Fs  in ambient air, sampled from  Beijing urban ecosystem research   station,    were   determined   using    a   KS-30310/2.5/1.0   sampler.    The concentrations of Ʃ17 2,3,7,8-PCDD/Fs and Ʃ132,3,7,8-PBDD/Fs were 1499–2799
fg m−3 (95.4–175  fg I-TEQ m−3) and 1171–2424  fg m−3 (42.2–109 fg TEQ m−3),respectively. Most PXDD/Fs occurred in particles, accounting for approximate 90% of the total  concentration. PCDD/Fs were mainly adsorbed  to the particles while PBDD/Fs   were  primarily   absorbed  by   the   particles,  and   similar   PXDD/F distribution  characteristics  were  observed  for  each  particle size  fraction.  The highest PXDD/F concentrations were found  in particles of aerodynamic diameter (dae) <1.0 µm. More than 80% of the PXDD/Fs were found in particles of dae < 2.5
µm. The concentration  of the PXDD/Fs  increased as the particle  size decreased.The lower chlorinated PCDD/Fs were found at higher concentrations in the coarser particles, while  the higher chlorinated  PCDD/Fs were mainly  found in  the finer particles. Higher brominated dibenzofurans were the dominant PBDD/F congeners.The contributions  of the  higher brominated  dibenzofurans to  the  total PBDD/F concentrations decreased as the particle  size increased, however, that was not the case for PBDDs.
    Concentrations and distributions of lower chlorinated PCDD/Fs (ΣCl1–3DD/Fs) in ambient air were also studied. The concentration of ΣCl1–3DD/Fs was obviously higher  than  that  of  higher   chlorinated  PCDD/Fs  (ΣCl4–8DD/Fs)  and  mainly occurred in the gas phase. ΣCl1–3DD/F concentrations in particles did not increase with decreasing the particle size, and the majority (70%) occurred in dae >1.0 µm particles, which was different than that observed for ΣCl4–8DD/Fs.
    The  influence  of the  concentrations  and  distribution  of  airborne PXDD/Fs during  haze   day   weather  and   seasons   were  also   explored   in  this   study.Concentrations of airborne Ʃ17 2,3,7,8-PCDD/Fs and Ʃ132,3,7,8-PBDD/Fs during the haze days were noticeably higher than those during normal days. The amount of PCDD/Fs (95%) and PBDD/Fs (89%) that were in dae < 2.5 µm particles were also noticeably  higher during  haze days.  In contrast  to the particle  distribution during normal  days,  PCDD/Fs were  mainly  absorbed in  the  different sizes  of airborne particles. The concentration levels and distribution characteristics of the PXDD/Fs  presented obviously  seasonal differences.  A higher  concentration of PXDD/Fs was observed in winter, with a lower concentration in summer. In terms of  gas-particle  partitioning,  the   amount  of  PCDD/Fs  in  gas   was  positively correlated  with  temperature.  Compared  to  PCDD/Fs,  the  difference  was  not significant for PBDD/Fs.
    2. The concentration level, profiles, particle size distribution, and inhalation exposure were assessed from airborne PCDD/Fs from two different secondary copper plant smelting workshops of different scales (labeled  as DYFY and LYJS) using a KS-30310/2.5/1.0 sampler.  The PCDD/Fs concentrations  in DYFY workshop  were 203 pg m-3   and  were 22 times higher than those  detected in LYJS. The PCDD/F gas–particle partitioning  in  DYFY was  significantly different  than  that from  LYJS. PCDD/F concentrations increased as the particle  size decreased. The daily intake
by  inhalation of  DYFY  workers  was 4  times  that  of  those working  at  LYJS.However, the exposure via inhalation of the workers of both workshops was lower than the level recommended by World Health Organization.
    3.  A  comparative  study  on  the  concentration  levels  and  distribution  of  airborne PCDD/Fs was conducted using different samplers (KS30310/2.5/1.0,TSP, and PM10)by  continuously   sampling  urban  ambient   air  samples   at  the  Beijing   urban ecosystem research station. The results of airborne PCDD/F concentration using a KS30310/2.5/1.0 and a TSP showed were significantly comparable (R2 =0.99,p<0.01,regression coefficients k=0.97) and  the congener distribution pattern was similar,suggesting that they both can reflect PCDD/F distribution in air. Concentrations of the PCDD/Fs in  air collected by TSP  and PM10 samplers  were also significantly comparable (R2 =0.98, p<0.01) with  a good regression  coefficients (k=0.98), and the difference  in regression coefficient  was not influenced  by season, indicating they both can detect the airborne PCDD/F distribution in the atmosphere.
内容类型: 学位论文
URI标识: http://ir.rcees.ac.cn/handle/311016/37055
Appears in Collections:环境化学与生态毒理学国家重点实验室_学位论文

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Recommended Citation:
张宪. 空气中氯代二恶英和溴代二恶英的分布特征研究[D]. 北京. 中国科学院研究生院. 2016.
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