全二维气相色谱-飞行时间质谱法分离复杂体系中7种指示剂 多氯联苯

采用全二维气相色谱-飞行时间质谱法(GC×GC TOF-MS)分析了混标样品Aroclor 1260、Aroclor 1254、Aroclor 1242中的多氯联苯(PCBs)单体,考察了在复杂体系下对7种PCBs指示剂的分离能力。结果表明,与优化柱系统的分离效果相比,136种单体的混标样品中共分离出121种单体,7种指示剂经一维和二维的保留时间及质谱定性,在121种单体的2D斑点图中清晰可辨。全二维对于复杂体系的PCBs和指示剂的分离表明其强大的分离能力和对于检测复杂体系中指示剂的分辨能力,对该类物质的定性和定量检测具有重要意义。     

加速溶剂萃取-气相色谱-质谱法同时测定土壤中7种Aroclor系列多氯联苯

采用加速溶剂萃取,Florisil固相萃取小柱净化,GC-MS法同时测定土壤中7种多氯联苯(Aroclor 1016、1221、1232、1242、1248、1254、1260)的含量。建立了一种全新的Aroclor系列多氯联苯的定量测定方法,根据氯代联苯峰在单种Aroclor和7种Aroclor混合物中峰高比值(K)固定不变的原理,通过7种Aroclor混合物的标准曲线,计算得出各种Aroclor的标准曲线,测定样品中Aroclor的含量;采用建立多元一次方程组的方法,测定样品中多种不同浓度Aroclor的含量,大大提高了分析效率。7种Aroclor混合物和Aroclor1242、Aroclor1260的土壤加标样品回收率为90.5%~109%,RSD为0.96%~9.38%(n=5),均能满足分析准确度和精密度的要求。     

2006-2020年上海市闵行区大气降水化学特征及来源分析

为研究上海市闵行区大气降水化学特征及来源,以2006—2020年上海市闵行区大气降水监测数据为依据,对大气降水量、pH值、电导率(EC)和主要离子进行了统计分析。结果表明:2006—2020年上海市闵行区大气降水呈酸性,pH值范围为4.41~5.19,酸雨频率呈下降趋势;EC变化范围为1.26~3.67 mS/m,平均值为2.32 mS/m;夏季pH值最高,酸雨发生频率、EC和总离子浓度最低,冬季pH值最低,总离子浓度最高。大气降水中各离子组分浓度占比大小排序为:SO^(2-)_(4)>NH^(+)4>NO^(-)3>Ca^(2+)>Cl^(-)>Na^(+)>Mg^(2+)>F^(-)>K^(+),主要阴、阳离子SO^(2-)_(4)、Ca^(2+)和NH^(+)4浓度呈明显下降趋势,NO^(-)3浓度变化较平稳;SO 2-4与NO^(-)3的浓度比范围为0.94~3.59,呈波动下降趋势,降雨类型由硫酸型逐步转为混合型。因子分析及相关性分析显示,因子1中所有的离子成分都有较大的载荷,各离子在来源上可能具有一定的共性,Ca^(2+)与Mg^(2+)、K^(+)表现出显著相关,其可能来源于地壳组分;Cl^(-)与K^(+)、Mg^(2+)、Ca^(2+)的相关性显著,Mg^(2+)、K^(+)与Cl^(-)、Na^(+)有强相关性,表明海洋输送及生物质燃烧对大气降水化学组成的影响;NO_(3)^(-)、SO^(2-)_(4)和NH^(+)4在因子2中为高荷载,且有很好的相关性,它们可能有相似的来源或形成化合物共同存在。     

气相色谱法测定水体中多氯联苯Aroclor系列

采用液液萃取—气相色谱法(GC-ECD)测定水体中多氯联苯Aroclor系列Aroclor1016、Aroclor1221、Aroclor1232、Aroclor1242、Aroclor1248、Aroclor1254、Aroclor1260。样品经正己烷溶剂萃取,再经全自动样品浓缩仪(EVA)浓缩萃取液至1 mL,供气相色谱仪测定,外标法定量,加标回收率在75%~110%之间,检出限为0.1μg/L。该方法采用双塔双柱双检测器,排除了误检和其他物质的干扰,保证了分析结果的可靠性,方法简单、灵敏、准确。     

土壤中多氯联苯简化计算定量方法研究

针对含有两种或两种以上Aroclor多氯联苯混合物的样品,研究其简便易行的定性、定量方法。将复杂样品中的多氯联苯分别折算成Aroclor 1016、1242、1260含量,在定性的同时予以定量。3种不同组分混合样品的加标回收率分别为68.2%～80.6%、67.9%～74.2%、67.1%～76.8%,实际土壤样品的测定结果与已有研究结果相吻合。方法缺点为无法识别和计算各Aroclor之间的准确比例,可用于应急监测复杂组分样品中多氯联苯的测定。     

东南沿海典型岛屿大气降水化学特征及来源分析

于2020年6月—2021年5月,应用相关分析、富集因子(EF)以及正定矩阵因子分解模型(PMF)和气团来源分析对东南沿海岛屿平潭大气降水化学特征及来源进行了综合评价与分析。结果表明,平潭大气降水pH值为3.96~7.49,平均值为4.78;电导率(EC)为4.9~342.0μs/cm,平均值为24.4μs/cm,高于我国降水背景点值;大气降水中各离子组分当量浓度排序为:Cl->Na+>SO_(4)^(2)>NO-3>Ca 2+>NH+4>Mg 2+>K+>F->NO-2,Cl-和Na+是降水中占比最大的阴、阳离子,其当量浓度占总离子当量浓度的51.4%;NO-3对平潭大气降水酸化的贡献较高(55.9%),且有77%的大气降水酸度被碱性物质中和,其中铵根离子(NH+4)和钙离子(Ca 2+)有着较强的中和能力。富集因子分析结果表明,除海洋源外,地壳源和人为源也是平潭大气降水离子的主要来源;PMF模型结果显示,海洋源、人为源、地壳源和燃烧源分别贡献了平潭大气降水离子的61.1%,23.8%,10.0%和5.1%;气团来源分析结果表明,区域传输对平潭大气降水离子分布及空气质量影响显著,京津冀和长三角地区排放的人为污染物可以经海上传输通道由北至南影响我国下风向地区,给沿海地区大气细颗粒物(PM_(2.5))与臭氧(O_(3))协同控制带来挑战。     

某典型交通路口大气颗粒物(PM10和PM2.5)中多氯联苯季节变化特征

应用同位素稀释高分辨率气相色谱-高分辨质谱 (HRGC-HRMS) 联用技术对北京市北四环典型交通路口大气颗粒物PM₁₀和PM_2.5中多氯联苯(PCBs)进行了监测,分析了PCBs浓度水平、单体组成特征、粒径分布规律和季节变化趋势。结果表明:大气颗粒物PM₁₀和PM_2.5样品中19种PCBs浓度和毒性浓度(TEQ,以世界卫生组织毒性当量因子WHO-TEF计)分别为1.05～13.83 pg/m³(平均值为6.66 pg/m³)和1.24～15.18 fg/m³ (平均值为6.84 fg/m³)、0.80～8.51 pg/m³(平均值为4.32 pg/m³)和0.88～13.40 fg/m³ (平均值为5.90 fg/m³),PM₁₀和PM_2.5中PCBs的单体分布模式相似,浓度丰度最大的是PCB-28和PCB-209,而对毒性当量贡献最大的是PCB-126。PCBs浓度季节变化明显,冬、春季明显高于夏、秋季。 PCBs浓度季节变化特征表明,不同季节采样点PCBs来源不同,除历史使用外,采暖季节可能主要来自机动车排放和化石燃料的燃烧,而非采暖季节主要来自机动车排放。粒径分布表现为PCBs倾向于富集在PM_2.5中,占PM₁₀总浓度的61%～87%(平均值为72%)。     

大气中挥发性有机酸的采样和分析方法

一、大气中有机弱酸的行为及其来源:大气中存在着许多对人的眼睛、皮肤及粘膜等有刺激作用和在低浓度下会产生恶臭的有机酸。最近Keene等及其他学者研究表明在大气的酸性降水及云水里存在着许多有机弱酸,Keene等在边远地区的湿沉降中发现有机酸是主要致酸物质,其对降水中自由酸的最大贡献为25％到98％。Kawamura等在洛衫机的雨水中测到来自于天然源即生物源的高级脂肪酸(C_(12)—C_(30)和人为源的有机酸(如苯甲酸和苯酚)以及短链的脂肪酸(C_5—C_(11))。又如Likens等在美国东北部的降水中测到多种有机弱酸:柠檬酸、甲、乙、丙、     

基于标准雨量计的降水采样方法比较

对太原市2013年7—11月的大气降水使用标准雨量计、国产A型和进口B型自动降水采样设备进行同步记录,分析国产A型和进口B型设备采集降水样品的p H、电导率和无机阴阳离子。结果表明,进口B型设备采集降水样品的降雨量(155.35 mm)比标准雨量计记录值(117.50 mm)高32.21%,而国产A型设备采集降水样品的降雨量(107.12mm)比标准雨量计记录值低8.83%。7—9月的15场降水,国产A型设备采集大多数降水样品的电导率和离子加权浓度均值基本上低于进口B型设备,差异程度分别达65.51%和62.52%;而p H则基本上高于进口B型,酸雨比例差异程度为61.53%。     

上海市“十一五”期间酸雨状况与成因分析

分析“十一五”期间上海市酸雨污染变化趋势和特征,简析酸雨污染形成的原因。结果表明,“十一五”期间,降水pH低值区和酸雨频率高值区范围明显扩大。降水中化学组分的变化印证了上海市脱硫措施和扬尘防治措施的成效。但是,全市降水的酸化仍在持续,主要原因在于大气中强碱钙离子和人类活动产生的弱碱铵离子的相对变化,导致现有的碱性离子无法完全中和降水中比例最高的硫酸根和贡献日益显著的硝酸根。     

PCB levels in European eel (Anguilla anguilla) from two coastal lagoons of the Mediterranean

Eels are exposed to pollutants due to their unusual life cycle and are vulnerable to contamination associated with sediment due to their diet, feeding habits and territoriality. Since the 1980s, a decline in American and European eel populations has been recorded. The causes of this decline still are unknown but pollution from domestic and industrial effluents is known to be involved. Since little data is available on PCB contamination in eels from Italian waters, PCBs were measured in muscle of Anguilla anguilla captured in 2001 in two brackish ecosystems of the Mediterranean: the lagoons of Orbetello and Santa Giusta (Italy). PCBs were higher in samples from Orbetello lagoon than in those detected from Santa Giusta lagoon (P < 0.05). Congener and isomer analyses indicated Aroclor 1260 as a likely source of PCBs in the Orbetello and Santa Giusta samples. Only the toxic equivalents (TEQs) of mono-ortho PCBs were calculated.     

Source and risk assessment of PCBs in sediments of Fenhe reservoir and watershed, China

The concentrations of polychlorinated biphenyls (PCBs) in sediments from the Fenhe reservoir and watershed were detected at 28 sites in wet and dry seasons. The ∑(123)PCBs ranged from n.d. to 126.49 ng g(-1) dw. The dominated congeners were tri-PCBs (34.29%) and tetra-PCBs (24.05%). In the Fenhe reservoir, ∑(123)PCBs presented a decreasing trend, while percentages of low chlorinated congeners showed an increasing trend. For the temporal variations, PCBs homologues profiles of sediment samples and spatial distribution of ∑(123)PCBs for the two periods were similar (with CD = 0.021 and r(2) = 0.999 respectively), although PCBs concentrations in the wet season were significantly higher than in the dry season. PCA was applied to analyze the possible sources for PCBs, suggesting that PCBs might be mainly influenced by Aroclor 1016 and 1242. Compared with 3 established sediment quality guidelines, levels of PCBs in sediments of the investigated watershed might have a potential biological impact, especially in the wet season.     

The use of semipermeable membrane devices as passive samplers to determine persistent organic compounds in indoor air

In the study reported here semipermeable membrane devices (SPMDs) were used to sample 28 PAHs and 19 PCBs in the gas phase in 15 single-family houses located in an area where domestic wood burning is widespread. Eight of the households used wood burning appliances whereas the others used other systems for residential heating. Most of the studied compounds were found in the houses: the PAHs at levels that were similar to or slightly higher than published SPMD-sampled levels for background or urban sites in Sweden, and the PCBs at levels that were somewhat lower than those recently found in both indoor and outdoor urban locations. A principal component analysis revealed that wood-burning heating systems may contribute to PAHs in indoor air. The sources may be emissions indoors or penetration from outdoors. The convenience of SPMD technology facilitates its use for semi-quantitative screening and monitoring of various persistent organic compounds indoors in dwellings and working environments.     

Occurrence of PAHs and PCBs in the Alna River, Oslo (Norway)

Thirty two polychlorinated biphenyl congeners (PCBs), hexachlorobenzene (HCB) and pentachlorobenzene (PeCB) were analysed in passive sampler extracts from surface water-exposed semipermeable membrane devices (SPMDs) and in bed sediment samples from a small urban watercourse, the River Alna (Oslo, Norway). Performance reference compound-corrected data from the passive samplers deployed at three sites along the river were used to track PCB contamination in the overlying water. SPMDs were able to detect an increase in dissolved PCB concentrations at the site furthest downstream that was corroborated by bed sediment concentrations. In comparison, no major increase in concentration of HCB, PeCB or PAHs could be observed. Comparison of passive sampling-based overlying water concentrations with total concentrations measured in bed sediments supports the possibility of further PCB sources upstream of the study area. Diagnostic PAH ratios (from SPMDs) and PCB congener pattern (from sediments) were used in an attempt to identify possible contaminant sources to the Alna River. Selected PAH diagnostic ratios support a multiple emission source scenario and demonstrate the complexity of identifying specific sources of these compounds to surface waters. PCB congener patterns in sediments from all three sites tend to indicate a source of highly chlorinated PCBs (of the Archlor 1260 type) and either a source of lower chlorinated PCBs or the less-likely occurrence of dechlorination in sediment. Information collected during the present screening study also confirms the Alna River as a continuous source of PCBs to the Oslofjord.     

Human plasma levels of POPs,and diet among native people from Uelen,Chukotka

Some of the people living in the Chukotka Peninsula of Russia depend heavily on marine mammals, but little is known of the exact dietary patterns and plasma levels of POPs among these populations. In this study, POPs levels in plasma from 50 participants from the isolated community of Uelen (Bering Strait) were determined and related to dietary information obtained through a food frequency questionnaire. The intake of marine mammals was high and the combined intake of blubber from walrus, seal and whale was a significant predictor (p < 0.01) of plasma concentrations of sum PCBs and borderline for sum CDs (p = 0.02) and sum DDTs (p = 0.04). There was a significant gender difference in the levels of POPs, and among women there was a significant increase with age. Extensive breastfeeding and lower blubber intake among women could be possible explanations for this gender difference. Despite the high intake of blubber the plasma levels of PCBs and DDTs were lower than some of those reported for the East Coast of Greenland. The geometric mean values for sum PCBs (17 congeners) and sum DDTs were 1316 ng g(-1) lipids and 563 ng g(-1) lipids, respectively. PCB 163, which partly co-eluted with PCB 138, was found in high concentrations (40% of PCB 138). This raises questions regarding the validity of using PCB 138 and PCB 153 to calculate the level of Arochlor 1260. The geometric mean of sum CDs was 518 ng g(-1) lipids. Concentrations of beta-HCH (geometric mean; 410 ng g(-1) lipids) were higher than observed for other native populations depending on marine mammals. Transportation of beta-HCH by ocean currents through the Bering Strait into the Arctic Ocean or regional point sources might explain these elevated levels.     

PCB congener distribution in estuarine water,sediment and fish samples: implications for monitoring programs

Traditional analyses for PCBs in environmental matrices havefocused on commercial Aroclor mixtures with detection limits inthe 100 to 1000 part per trillion range. This approach hasrecently been supplanted by analyses for specific PCB compoundscalled congeners with detection limits less than 0.5 ppt. At thenational level, total PCB determinations based upon selected PCBcongeners typically characterize analyses of surface water,sediment and tissue. These federal efforts rely on a suite of 18to 20 congeners out of a total of 209 congeners to characterizetotal PCB. The present study compares total PCB estimates basedupon this subset of congeners with estimates based upon anexpanded list of 81 congeners from water, sediment and fishtissue collected from the Delaware Estuary.Analytical data from monitoring programs conducted in theDelaware Estuary by the Delaware River Basin Commission, NOAANational Ocean Service, U.S. Army Corps of Engineers and the U.S.Environmental Protection Agency from 1996 to 1998 were evaluated. Total PCB estimates derived from the different sets of congeners,including the adjustment factor of 2.0 used by NOAA, werecompared. This evaluation indicated that differences existbetween total PCB determinations based upon these approaches, andthat these differences vary depending on the matrix analyzed. The bias associated with using a smaller set of PCB congeners,and the implications for risk assessment are discussed.     

The Mid-Canada Radar Line and First Nations' people of the James Bay region, Canada: an evaluation using log-linear contingency modelling to analyze organochlorine frequency data

Abandoned radar line stations in the North American arctic and sub-arctic regions are point sources of contamination, especially for PCBs. Few data exist with respect to human body burden of organochlorines (OCs) in residents of communities located in close proximity to these radar line sites. We compared plasma OC concentration (unadjusted for total lipids) frequency distribution data using log-linear contingency modelling for Fort Albany First Nation, the site of an abandoned Mid-Canada Radar Line station, and two comparison populations (the neighbouring community of Kashechewan First Nation without such a radar installation, and Hamilton, a city in southern Ontario, Canada). This type of analysis is important as it allows for an initial investigation of contaminant data without imputing any values. The two-state log-linear model (employing both non-detectable and detectable concentration frequencies and applicable to PCB congeners 28 and 105 and cis-nonachlor) and the four-state log-linear model (using quartile concentration frequencies for Aroclor 1260, PCB congeners [99,118,138,153,156,170,180,183,187], beta-HCH, p,p'-DDT +p,p'-DDE, HCB, mirex, oxychlordane, and trans-nonachlor) revealed that the effects of subject gender were inconsequential. Significant differences (p < 0.05) between the groups examined were attributable to the effect of location on the frequency of detection of OCs or on their differential distribution among the concentration quartiles. In general, people from Hamilton had higher frequencies of non-detections and of concentrations in the first quartile (p < 0.05) for most OCs compared to people from Fort Albany and Kashechewan (who consume a traditional diet of wild meats that does not include marine mammals). An unexpected finding was that, for Kashechewan males, the frequency of many OCs was significantly higher (p < 0.05) in the 4th concentration quartile than that predicted by the four-state log-linear model, but significantly lower than expected in the 1st quartile for beta-HCH. The levels of PCBs found for women in Fort Albany and Kashechewan were greater than those reported for Dene (First Nation people) and Métis (mixed heritage) of the western Northwest Territories (NWT) who did not consume marine mammals, and for Inuit living in the central NWT (occasional consumers of marine mammals). Moreover, the levels of total p,p'-DDT were greater for Fort Albany and Kashechewan women compared to these same aboriginal groups.