Sources and Trends of Persistent Organic Pollutants at Three Passive Monitoring Sites in South Africa

The Stockholm Convention on Persistent Organic Pollutants (SCPOPs) is an international treaty that operates under the patronage of the United Nations (UN) to control certain chemicals that are considered persistent organic pollutants (POPs). They are of great concern because of their adverse effects on human health and the environment. Exposure to POPs may lead to cancer, infertility, respiratory infections, and other health complications. It is therefore critical to study the degree of human and environmental exposure to these POPs. Passive air sampling was conducted in South Africa to evaluate the presence and trends of persistent organic pollutants at Barberspan (rural agricultural), Vanderbijl Park (urban industrial) and Molopo Nature Reserve (isolated nature reserve). Samples were collected in 2012. Passive air samplers using poly were used for sampling. The Buchi System B-811 automatic extractor was used to analyze for dichloro-diphenyl-trichlorethane (DDT), pentachlorobenzene (PeCB), hexechlorobenzene (HCB) polychlorinated biphenyls (PCBs) and hexachlorocyclohexane (HCH). Sampling was conducted for a period of one year. POPs concentrations were generally low at all sites, but Vanderbijl Park had the highest concentrations. Seasonal changes in concentrations were much the same at the three sites with temperatures and wind patterns being major factors. The presence of these chemicals in Molopo Nature Reserve and Barberspan is evidence of long range transportation over dry semi desert areas. Back-trajectories indicate possible sources, including areas where DDT is used for malaria control. The presence of POPs is areas they have never been in use poses health and environmental risks in these areas.

Levels and distribution of polychlorinated biphenyls in the atmosphere close to Chinese Great Wall Station, Antarctica: Results from XAD-resin passive air sampling

Antarctica is an important research region for assessing persistence and long-range atmospheric transport (LRAT) of persistent organic pollutants (POPs). In this study, XAD-resin passive air sampling was conducted near the Chinese Great Wall Station, Antarctica, during a one-year sampling period in 2009-2010. The air concentrations of polychlorinated biphenyls (PCBs) were at a very low level, with total PCBs in the range of 26.74-45.08 pg m 3. PCB profiles were dominated by tetra-PCBs, tri-PCBs and di-PCBs, indicating LRAT was responsible for the pollutants in the Antarctic atmosphere. The sampling site near the Chinese Great Wall Station did not show higher PCB levels than the other sites, suggesting that PCB sources associated with the Great Wall Station were negligible. PCB-11 is a non-Aroclor congener, which has specific sources compared to other Aroclor PCB congeners. PCB-11 was observed in all air samples, with an average concentration of 1.22 pg m 3. To our knowledge, this study is the first investigation of PCB levels and distribution in the atmosphere around the Chinese Great Wall Station, Antarctica.

Comparisons of indoor active and passive air sampling methods for emerging and legacy halogenated flame retardants in Beijing, China offices

One active and two passive air sampling configurations were deployed simultaneously in three offices in Beijing,China to test their comparability for sampling emerging and legacy halogenated flame retardants spanning a large range of octanoleair partition coefficients(KOA).Sampling in each office was carried out for three consecutive 28-day periods in the spring-summer of 2013.The active sampler was run for 2.5 h at different times every day for 28 days to parallel the passive samplers and sample a total volume comparable to that sampled by the passive samplers(~20 m^3).At the end of each 28-day sampling period,a separate active air sample was taken by running the sampler pump continuously for about 2.5 days.The comparability of measured concentrations varied between the air sampling configurations and for different compounds.The predominant compound measured in nearly all samples was BDE-209,a compound known to have heavy use in China.Several emerging flame retardants were also detected including DBE-DBCH,PBT,HBB,DDC-CO,and DBDPE.Very little of the tetra-hexabrominated BDEs associated with the technical PentaBDE product was observed.

Monitoring gas-and particulate-phase short-chain polychlorinated paraffins in the urban air of Dalian by a self-developed passive sampler

The concentration of short-chain polychlorinated paraffins(SCCPs) in the urban air of Dalian,China was monitored from September 2016 to August 2017 with a self-developed passive sampler(PAS1) and an active high-volume sampler, simultaneously. PAS1 successfully collected the entire target SCCPs in the ambient air. Air SCCPs sampled by PAS1 were found be in the linear uptake stage during 181 days of sampling. Passive and active samples showed comparable congener profiles, and the dominant contributors of SCCPs in the two kinds of samples were similar. A significant linear correlation was observed between the total concentration of SCCPs sampled by PAS1 and active sampler in the four seasons. The passive sampling rates of the PAS1 for the gas and particulate phases of SCCPs were measured. The quantitative structure–property relationship of the sampling rate of PAS1(Rair) for gas-phase SCCPs was studied. From the molecular point of view, Rairwas mainly affected by the molecular weight and sub-cooled liquid vapor pressure of SCCPs. In general, SCCPs in the urban air of Dalian mainly existed in gas phase,lower molecular weight SCCPs primarily occurred in the gas phase, whereas higher molecular weight SCCPs were predominately adsorbed or absorbed on airborne particles. The air concentration of SCCPs in the four seasons were different, the correlation of the concentration of SCCPs in the air with the meteorology parameters was conducted. The exposure risk by intake air SCCPs of the residents around the sampling sites was evaluated according to the European risk assessment standards.

南极菲尔德斯半岛(Fildes Peninsula)和阿德利岛(Ardley Island)大气中六溴环十二烷(HBCDs)的分析

在2009—2010年南半球夏季,用大流量采样器(high-volume air sampler,HVAS)和聚胺酯泡沫(polyurethane foam,PUF)被动采样器采集了南极菲尔德斯半岛和阿德利岛6个点的大气样品,分析了HBCDs的浓度水平、异构体组成、气相-颗粒相分配和空间分布趋势.主动和被动采集大气样品中ΣHBCDs浓度(α-HBCD、β-HBCD、γ-HBCD的浓度)范围分别为n.d.(未检出)—2.73 pg·m^(−3)和0.41—3.39 pg·m^(−3),与北极和偏远地区浓度水平一致,远低于城市和工业区的污染水平.HBCDs在主动采集的颗粒相和气相中的平均比例分别为67%和33%,颗粒相以α-HBCD(57%)为主,气相以γ-HBCD(53%)为主;被动采集的PUF样品中γ-HBCD(64%)占优势.经过主动采样和被动采样的对比研究,对采样速率进行校正后,PUF被动采样器可以用于南极大气样品的采集.南极大气中HBCDs的检出,表明HBCDs具有持久性和潜在的长距离大气传输能力;南极长城站附近大气中HBCDs浓度水平略高,反映了有限的人类活动对南极环境产生了影响.

搅拌子吸附-热脱附-气相色谱-质谱法分析北京大气中33种多氯联苯

用包覆聚二甲基硅氧烷(PDMS)吸附层的搅拌子作被动大气采样器,建立了搅拌子吸附-热脱附-气相色谱-质谱法(SBSE-TD-GC-MS)分析大气中多氯联苯(PCBs)的方法。优化后的热脱附温度为280℃,热脱附时间为6 min,聚焦冷阱的温度为-40℃,33种PCB单体的热脱附残留比例低于7%。验证了方法的线性、精密度和重复性。标准曲线5个点线性关系良好,33种PCB单体的相关系数r>0.998。方法精密度验证的相对标准偏差(RSD)为0.79%~20.2%(n=8),日内重复性实验的RSD为0.43%~29.8%(n=10),日间重复性实验的RSD为3.20%~29.6%(n=20),方法检出限(LOD)为0.01~2.51 pg,回收率为98%±18%。将建立的方法用于北京大气中PCBs的分析。检出8种PCB单体,质量为2.94~129 pg。在32 d的采样周期内PCB-52、PCB-123、PCB-155一直处于线性吸附阶段,而PCB-1和PCB-3经过了线性吸附阶段、曲线吸附阶段和平衡阶段。研究结果表明,SBSE-TD-GC-MS可以用于大气中PCBs的样品采集和快速分析。

舰船舱室环境空气中VOC轴向被动采样速率研究

快速获取有效、可靠的被动采样速率对被动采样器在舰船环境监测领域的应用十分重要。传统被动采样器的模型要求得到吸附管的物性参数,获取参数困难且难以推广。本文通过建立理论模型及实验舱测定等2种方式提供被动采样速率的标定方法及参考值。基于集总参数简化吸附传质模型,并搭建实验舱测定代表性VOC污染物的被动采样速率,通过回归拟合得到了模型中的关键表观参数。

基于新型被动采样校正技术的塑化剂大气垂直浓度梯度研究

改进了垂直浓度梯度被动采样器和采样速率校正方法,并利用其考察有机磷酸酯(OPEs)和邻苯二甲酸酯(PAEs)两种塑化剂在土壤垂直方向上的采样速率、浓度分布及土-气交换趋势.为了更准确地获得采样速率,利用主动采样和添加效能参考物质(DCs)联合校正被动采样速率;得到OPEs和PAEs经主动-DCs联合校正的采样速率分别为0.27—3.16 m^(3)·d^(−1)和0.23—3.25 m^(3)·d^(−1).基于主动-DCs联合校正得到的污染物浓度相比单独主动校正的结果差异显著,进而导致化合物土-气扩散趋势发生显著变化.部分物质如TIBP、TCEP、TCIPP、TPHP、TPPO、DMP、DEP等甚至出现从沉降到挥发的趋势反转.由于引入DCs校正了环境因素的影响,因此主动-DCs联合校正的被动采样速率能够获得更准确的污染物环境浓度和交换趋势.

室内空气有机磷酸酯的聚二甲基硅氧烷(PDMS)、低密度聚乙烯(LDPE)和聚氨酯海绵(PUF)被动采样对比

室内有机磷酸酯(OPEs)阻燃剂的污染日益严重,但目前OPEs室内被动采样方法和采样速率研究缺乏.本研究通过室内空气被动采样动力学实验,对比了低密度聚乙烯(LDPE)、聚二甲基硅氧烷(PDMS)、硅胶手环(WB)和聚氨酯海绵(PUF)的4种被动采样方法对室内空气9种典型OPEs的气态采样速率和采样效果.4种被动采样对OPEs的平均采样速率为:WB((5.4±4.3)m^(3)·d^(−1)·dm^(−2))>PDMS((2.0±1.6)m^(3)·d^(−1)·dm^(−2))>PUF((1.5±1.1)m^(3)·d^(−1)·dm^(−2))≈LDPE((1.3±1.5)m^(3)·d^(−1)·dm^(−2)).4种被动采样OPEs组成与主动采样气态和颗粒态OPEs的组成均存在明显差异,说明被动采样受空气中细颗粒物的影响.LDPE的采样速率最小,但达到平衡时间较快,约20 d,可用于短期采样;而WB,PDMS,PUF达到平衡时间较长,更适合中、长期采样.

北京冬季大气中多溴联苯醚的污染水平和分布特征

2010年11月至2011年2月利用聚氨酯泡沫（PUF）大气被动采样技术采集了北京市海淀、朝阳、丰台、石景山、昌平、大兴、通州等区域的大气样品,采用高分辨气相色谱/高分辨质谱联用法（HRGC/HRMS）分析了其中13种多溴联苯醚（PBDEs）同族体的污染浓度和分布特征.结果表明,北京大气中PBDEs总含量（Σ13PBDEs）为0.97~41.1pg/m3,平均值为7.85pg/m3.在区域分布规律方面呈现东南地区的采样点污染物浓度明显高于西北地区,工业地区和人口密集的商业地区明显高于郊区和背景对照区的分布特征.

大气中持久性有机污染物的采样技术进展

大气是全球持久性有机污染物(persistent organic polutants,POPs)监测的重要环境介质,大气中POPs的采样技术是准确表征大气中POPs赋存水平的关键所在。近年来大气中POPs的采样技术发展很快。本文介绍了大气中POPs的两类采样方法:主动采样法(active air sampling,AAS)和被动采样法(passive air sampling,PAS),总结了新型吸附材料和新型采样器研发的成果,讨论了不同类型的采样方法的特点,对比分析了不同采样方法获得的POPs监测数据,并提出今后应用不同POPs大气采样技术在监测数据可对比性研究方面值得关注的问题。

持久性有机污染物的环境大气被动采样技术

当今用于监测环境大气中持久性有机污染物共有5种大气被动采样器(PAS):半透膜仪被动采样器、聚氨酯泡沫碟片被动采样器、XAD-2树脂被动采样器、膜封闭吸收涂料被动采样器包括搅拌棒和硅化人造橡皮棒两种类型,以及最新的XAD-4树脂浸渍的PUF碟片被动采样器.介绍了大气PAS采样技术的基本原理,及采样的关键参数和PAS采样速度(R s)的计算方法.重点论述了世界各国学者关于R s的测定方法和影响R s环境因素的最新研究成果,并指出了今后PAS技术发展需关注的问题.

北京市民居室内气态多环芳烃呼吸暴露评价

采用被动采样装置采集并测定北京地区38个家庭采暖期和非采暖期室内空气中的7种气态多环芳烃(PAHs)的含量.结果表明,室内气态PAHs以2、3环组分为主,7种气态PAHs的总平均浓度为100 ng/m3左右.根据实测的PAHs浓度、不同年龄段人群室内平均停留时间及其相应的呼吸速率,计算得到室内成年人(包括老人)对7种气态PAHs的潜在总暴露速率在采暖期和非采暖期分别为66 ng/h和58 ng/h;而未成年人的潜在总暴露速率则分别为56 ng/h和50 ng/h.

中国典型城市和地区大气颗粒物中全氟烷基酸的污染分布特征

近年来,全氟烷基酸(perfluoroalkyl acids,PFAAs)在我国的各种环境介质中被广泛检出,对生态环境和人体健康构成了潜在威胁.本研究利用大流量主动采样器收集广州、太古、昆明、厦门、南昌、绵阳、南京、青岛、北京和天津等10个城市及五指山地区的大气颗粒物,利用被动采样技术收集除南京和天津外9个城市和地区的大气颗粒物,调查颗粒物中的全氟辛烷羧酸(perfluorooctanoic acid,PFOA)和全氟辛烷磺酸(perfluorooctane sulfonate acid,PFOS)的污染特征和来源.主动采样方法揭示了PFAAs的时空分布特征.空间分布上,10个典型城市中,PFOA浓度范围为0.08—25 pg·m^(-3),0.11—36 ng·g^(-1);PFOS浓度范围为(0.12—14 pg·m^(-3),0.19—9.4 ng·g^(-1)),五指山PFOA(0.23—1.2 pg·m^(-3),0.16—0.83 ng·g^(-1))和PFOS(0.31—0.93 pg·m^(-3),0.31—1.1 ng·g^(-1))的浓度低于10个典型城市.PFOA和PFOS浓度整体上呈现东部>中部>西部>背景点的趋势.时间变化上,广州市大气颗粒物中PFOA浓度没有呈现显著的随时间的变化趋势,PFOS浓度在秋冬季(4.2±4.7 pg·m^(-3),2.1±1.9 ng·g^(-1))低于春夏季(6.3±3.9 pg·m^(-3),4.7±1.6 ng·g^(-1)).五指山PFOS浓度在旱季(0.48±0.23 pg·m^(-3),0.57±0.22 ng·g^(-1))和雨季(0.52±0.24 pg·m^(-3),0.56±0.27 ng·g^(-1))处于同一水平.其他9城市PFAAs的浓度随时间变化趋势具有显著差异.10个典型城市PFAAs的来源主要与排放源的分布有关,背景点五指山主要受长距离迁移的影响.大气被动采样获得的PFAAs浓度与主动采样具有显著差异,较长的采样时间可能造成PFAAs的积累.在一定的时间和空间范围内,被动与主动采样获得的浓度变化趋势呈现一致规律,揭示了被动采样方法的适用性.PFOA的采样速率为18±16 m^3·d^(-1),PFOS的采样速率为3.1±2.4 m^3·d^(-1).针对PFAAs的被动采样捕集理论和适用范围还有待进一步研究.

被动采样技术在监测大气有机氯污染物中的应用

为了研究大气被动采样技术的可行性,评价其技术性能、特色和应用价值,采用以XAD-2树脂为吸附介质的被动采样器,对北京市和四川卧龙自然保护区大气中的典型持久性有机氯污染物分别进行了为期5个月和半年的样品采集,利用气相色谱-高分辨质谱方法对HCB,HCHs,DDTs和PCBs等进行了测定.结果表明：数据重现性良好,检测下限的范围为0.2～8.0pg/m^3;北京市有机氯污染物检出质量浓度相对较高,其中ρ（HCB）最高,为1910 pg/m3,ρ（p,p′-DDT）最低,为21 pg/m^3;卧龙自然保护区有机氯污染物检出质量浓度相对较低,其中ρ（HCB）最高,为254 pg/m3,ρ（PCB52）最低,为1.3 pg/m^3.初步表征、比较了北京市和四川卧龙自然保护区大气中HCB,HCHs,DDTs和PCBs等化学组成特征.以XAD-2树脂为吸附介质的大气被动采样器,可以应用于城市和边远地区持久性有机氯污染物的长期采样和监测.

被动采样法测定环境空气中的二氧化氮

用被动采样方法吸收空气中的NO_2,经实验室和野外实验证明,该方法测得的NO_2浓度对渗透管发生的NO_2浓度的相关系数为0.9995.用七个相同的采样器在相同时间、相同地点测得的NO_2浓度的相对标准偏差为3.6%.当NO_2浓度为50μg/m^3左右时.采样周期可长达一个月.该方法可用于大气环境中10μg/m^3NO_2日平均浓度的测定.

四川西部山区土壤和大气有机氯污染物的区域分布

为研究持久性有机污染物(POPs)的长距离传输和边远山区POPs的区域分布与来源,于2005年10月—2008年4月在四川西部山区的卧龙自然保护区内沿巴朗山迎风坡1个海拔梯度(1242～4475m)采集表层土壤和大气被动采样样品.对色谱-高分辨质谱(GC-HRMS)的数据分析表明,在卧龙山区2800m以上的高海拔地区,土壤和大气中HCB,HCHs和DDTs具有浓度低、分布均匀的特点,这可归因于大气长距离传输的贡献;在有人居住和活动的地区,也观测到HCHs和DDTs的浓度异常和污染情况.通过对有机氯污染物浓度水平、相对化学组成、浓度空间分布特征和季节变化等情况的综合分析,可以区分大气长距离传输和局地污染源排放2种源贡献.大气被动采样技术能够提供边远山区有机氯污染物大气浓度水平和时空分布的信息.结合大气和土壤的现场数据,可以综合观测和表征山区环境有机氯污染物的浓度异常现象.

美国密闭环境大气长期监测被动采样技术研究综述

针对用于美国密闭舱室长期、低浓度大气污染监测的被动采样技术,概述其所开展的一系列研究工作。并结合被动采样器设计的最新研究进展,指出被动采样在各类密闭环境监测中的应用前景和发展方向。相关研究对我国开展船舶等各类密闭环境的大气污染长期监测研究具有指导意义。

有机氯农药土-气交换的研究进展

土-气交换是控制有机氯农药(OCPs)在地区和全球尺度上迁移传输和环境归宿的关键过程。本文对OCPs土-气交换的研究方法、交换现状以及影响因素进行了综述。研究方法主要有土-气分配系数(KSA)、逸度商(fS/fA)及逸度比率(ff)、土-气交换通量、农药手性分析以及环境模型等;OCPs土-气交换现状表明,土壤仍是OCPs主要储存地;而影响OCPs土-气交换的主要因素是温度、土壤有机质以及化合物的辛醇-空气分配系数(KOA)。最后,针对目前OCPs土-气交换研究中存在的不足,为深入开展该研究提出了思路和研究方向。