环境中多氯联苯来源、结构关系与处理方法

多氯联苯（PCBs）是一类重要的持久性环境污染物,在环境中广泛存在,由此引起的生态效应日益受到各界广泛关注。PCBs对皮肤、肝脏、生殖及免疫系统的病变甚至癌变都有诱导效应,且通过食物链在生物体内累积,对人类健康产生深远影响。有关该污染物的生态行为、毒理效应及其处理技术的研究成为环境科学及污染生态学学科等相关领域的焦点内容和热点问题。简要介绍了PCBs的结构特征、性质、污染现状及国内外的处理技术。     

多氯联苯（PCBs）污染现状分析

文章分别从水体、大气和土壤三个层次阐述了我国环境介质中氯联苯（PCBs）的污染水平,对PCBs的来源、污染途径及控制方法等进行了总结,结果表明,我国环境介质中PCBs污染暂时处于轻度污染,但随着经济发展呈加重趋势,应加强对PCBs污染调查和控制研究,并提出PCBs污染控制对策。     

SPME-GC联用测定沉积物中PCBs的影响因素

建立了固相微萃取-气相色谱联用测定沉积物中多氯联苯(PCBs)的分析方法,分析了实验过程中的各种条件因素对萃取效果的影响。结果表明,对于100μm PDMS萃取纤维头,在80℃条件下搅拌速率为450 r/min时萃取50 min后于280℃进样口解析6 min萃取效果最佳。该方法快捷、操作简单,7次平行测定的RSD为4.6%~11.4%,相对回收率为84.6%~107.4%,满足分析要求,可用于沉积物中PCBs的测定。     

多氯联苯(PCBs)的DFT计算

本文采用B3LYP/6-31G*方法对多种多氯联苯(PCBs)分子进行结构优化,并对几种特征构型的PCBs进行了自然键轨道(NBO)分析。结果表明,PCBs的稳定性随其结构的微小变化而变化,其降解的难易与构型的稳定性有很大的关系,理论计算结果与实验结果基本一致。     

多氯联苯污染土壤修复技术研究进展

多氯联苯是环境中广泛存在的一种持久性有机化合物,具有三致作用。多氯联苯具有疏水性和亲脂性,土壤是其在环境中的最终归宿,因此,多氯联苯污染土壤的修复越来越受到重视。简介了多氯联苯的基本性质、土壤环境中多氯联苯的污染现状,综述了国内外多氯联苯污染土壤修复技术的研究进展,并对其发展前景进行了展望。     

多氯联苯热力学性质的预测

文章采用分子电性距离矢量（MEDV）表征209个多氯联苯类化合物（PCBs）的分子结构,运用多元线性回归技术,同时采用逐步回归结合统计检测筛选模型变量,建立了多氯联苯类化合物的自由能（G^o）、焓（H^o）、嫡（S^o）、分子总能量（ET）、零点振动能（EZPV）、恒容热容（CV）和热能校正值（Eth）与MEDV矢量的定量结构性质关系（QSPR）模型。模型的线性相关系数均在0．97-1.000之间。继用留一法和外部样本对模型稳定性能进行检验。结果表明：所建QSPR模型有良好的稳定性和预测能力,为多氯联苯类化合物热力学性质研究提供了理论依据。     

头发样品中痕量多氯联苯的分析方法研究

头发样品用6 moL/L盐酸酸解、经正己烷/二氯甲烷(4:1)萃取、层析柱净化和分离,利用气相色谱一质谱联机(GC-MS)检测,分析了32种多氯联苯(PCBs),并优化了头发消解所用盐酸的浓度以及层析柱净化分离多氯联苯的条件.头发中32种PCBs同类物的平均加标回收率为85.3%～104.9%,RSD为5.3%～9.2...     

环境样品中多环芳烃的分析方法

多环芳烃(PAHs)是一种广泛存在于环境中的污染物。PAHs通过分配、沉降、迁移等过程,影响其在环境中的分布特征,从而对人类健康存在很大的潜在危害。文章主要从气相色谱,高效液相色谱及酶联免疫吸附法对PAHs的分析方法进行了概述。     

复杂环境样品中三氟乙酸分析方法的研究进展

三氟乙酸的生物累积效应和持久污染性已经成为关注的热点,对其进行监测至关重要。本文综述了环境样品中三氟乙酸分析方法,讨论了样品的预处理技术和检测方法。     

环境样品中有机氯和有机磷农药分析方法研究进展

随着农药使用越来越广泛,农药在环境中的残留状况日益受到人们的关注,其中分析技术是该领域研究的基础,通过不断的研究改进,农药分析方法已取得了很大进展。文章综述了近年来水、土壤、生物体和食品等环境样品中有机氯以及有机磷农药的前处理和仪器分析方法,并对各种方法进行了评价,对农药残留分析方法的发展趋势做出了展望。     

Gas Chromatographic Enantiomer Separation of Polychlorinated Biphenyls (PCBs): Methods,Metabolisms, Enantiomeric Composition in Environmental Samples and their Interpretation

The year 2016 not only marks the 50^th anniversary of the first successful discovery of gas chromatographic (GC) enantiomer separations in 1966 by Gil-Av, but also the less appraised 50^th anniversary of the discovery of polychlorinated biphenyls (PCBs) in the environment. This article reports on GC enantiomer separations of axially stable, chiral PCBs (PCB atropisomers) with modified cyclodextrins. Nineteen atropisomeric PCBs exist, but most data exists for four PCB atropisomers (PCB 95, PCB 132, PCB 149, and PCB 136), which can be resolved without significant coelutions on three columns coated with modified cyclodextrins. Nonracemic compositions of PCB atropisomers and their hydroxylated metabolites have been documented in various studies. However, the measured enantiomer fractions are currently difficult to interpret und understand. The most plausible reasons for these difficulties are discussed and interpreted with the help of selected examples from the literature.     

超声波辅助分散液液微萃取测定水样中的多氯联苯

将超声波辅助分散液液微萃取（USADLLME）与气相色谱-大新技术公司电子捕获检测器（GC-ECD）联合,建立了一种高灵敏度检测水样中多氯联苯的新方法。对影响微萃取的因素进行了优化。在优化的条件下,该方法的线性范围为0.05～50μg/L（r^2〉0.999 5）,相对标准偏差在1.4%～6.9%之间。相对检出限为7.24～16.3 ng/L（S/N=3）。在自来水、塘水、江水中分别加入0.1、0.5、1μg/L多氯联苯溶液,加标回收率为81.1%～100.6%、88.1%～95.6%和85.0%～101.8%。本方法可以对水环境中的痕量多氯联苯进行检测,具有操作简便、快速等优点。     

无机盐离子对鼠李糖脂增溶多氯联苯的影响研究

探讨了几种具代表性的无机盐离子对鼠李糖脂(RL)增溶2,2’,4,4’-四氯联苯的影响。结果表明,适当增加Na+、Mg2+、Ca2+的浓度对RL增溶2,2’,4,4’CB有显著的促进作用,且Mg2+的促进作用比Na+的大,但当Mg2+浓度大于0.8 mmol/L时,促进作用减弱。当Ca2+浓度超过0.2mmol/L时,RL开始产生沉淀,导致RL对2,2’,4,4’CB的增溶作用逐渐降低。无机阴离子对RL增溶2,2’,4,4’CB的影响很小。     

Levels,Sources, and Risk Assessment of Polychlorinated Biphenyls (PCBs) in Soils from Industrial Areas: A Case Study from Saudi Arabia

ABSTRACT

The objective of this study was to assess the pollution levels, sources, and human health risk of polychlorinated biphenyls (PCBs) in soils of industrial areas of the central and eastern regions of Saudi Arabia. Therefore, the surface soil samples from industrial areas (cement kiln, oil refinery, electric power plant, steel industry, and desalination plant) were collected and analyzed by High-Resolution Gas Chromatography-Mass Spectrometry/Mass Spectrometry-Time of Flight (HRGC-MS/MS-TOF) to quantify the levels of 26 PCBs (including 12 dioxin-like PCBs and 14 indicator-PCBs). The investigated 26 PCBs were detected in all soil samples. The total PCBs concentration (from tri-CBs to hepta-CBs) ranged from 171 to 4892 pg g^?1 with an average of 1369 pg g^?1 in soils of the central region and of 142–1231 pg g^?1 with an average of 302 in soils of the eastern region, showing higher values at cement factory and/or oil refinery sites. Overall, the indicator-PCBs were the main congeners and contributed dominantly to the total mass of PCBs in comparison with the dioxin-like PCB congeners, with the most abundant for PCB-180 in the soil samples of the central region. Among individual dioxin-like PCBs, PCB-126 had the highest average value of the toxicity equivalence (TEQ). The TEQ values of ∑12dioxin-like PCBs did not exceed the Canadian soil quality guidelines of dioxin (4 pg TEQ g^?1). Based on human health risk assessment via ingestion, dermal contact, and inhalation, low adverse effects of PCBs could be expected as indicated by lower values of cancer risk (≤10^?6). The principal component analysis indicated that there is a different source of PCBs with similar or different PCB profiles.     

Polychlorinated Biphenyls in Sediments from Sicilian Coastal Area (Scoglitti) using Automated Soxhlet,GC-MS,and Principal Component Analysis

A methodology for the PAHs and PCBs congener determination in sediment samples has been revised. We determined the distributions of PAHs and PCBs in the superficial sediments of the Scoglitti (Italy) coastal area to provide data for comparison with other marine systems and to hypothesize the sources. Extraction yield, for PCB, was never less than 60% in most cases, while for PAHs, utilizing perdeuterated surrogate standard (benz[a]anthracene-d₁₂ and anthracene-d₁₀) was never less than 72%. The total concentration of the 16 PAHs investigated, expressed as the sum of concentrations, ∑PAHs, varied from 1–5087 μg/kg of dry matrix, while the ∑ PCBs ranged from detection limit to 36 μg/kg of dry matrix. Linear relationships were found between PAHs concentration and organic matter percentages (R² = 0.60) and water content and organic matter percentages (R² = 0.87). Isomeric ratios were used for discriminating between pyrolitic and petroleum origin. The principal component analysis (PCA) has been conduced to discriminate the different sampling sites in internal or external harbor area.     

环境样品中钒的检测方法

综述了近年来环境样品中钒的检测方法,其中包括常规分光光度法、催化动力学光度法、催化荧光法、导数分光光度法、原子发射光谱法、原子吸收光谱法等,并分别列举了各检测方法的应用.经对比发现,水样中的钒宜采用催化褪色光度法检测,人发中的钒应采用催化阻抑褪色法检测.此外,原子光谱法的应用范围最广,可用于检测多种环境样品中的钒,检测效果满意.     

工业企业棕地土壤中84种多氯联苯的测定

由于多氯联苯易被土壤有机质吸附,工业企业棕地土壤可能成为多氯联苯的新排放源,因此建立该类土壤中多氯联苯适用的分析方法尤为重要。本文将US EPA8082方法与3665方法相结合,将高锰酸钾加入到提取体系,建立了正己烷-丙酮-高锰酸钾体系提取,硅胶净化,GC/ECD分析,GC/MS验证的方法测定工业企业棕地土壤中84种多氯联苯。研究发现,高锰酸钾的加入可以祛除部分元素硫,同时将部分共萃物氧化为盐类,使得硅胶净化基线噪声大大降低。通过对不同类型工业企业棕地土壤样品的加标回收、精密度试验等对方法进行评价,84种多氯联苯的方法检出限为5.0~65.0 ng/kg,加标回收率为62.19%~117.96%,相对标准偏差(RSD,n=6)为0.24%~24.67%。该方法抗基体干扰强、成本低,可用于工业企业棕地土壤中84种多氯联苯的分析测定。     

Solid Phase Enhanced Direct Spectrofluorometric Determination of Polychlorinated Biphenyls (PCBs) in Natural Waters

A method of detection of PCBs in water, based on extraction/concentration with chips cut from an SPE disk-shaped C18 inverse phase coupled with a fluorescence detection and quantification directly on the phase has been evaluated. Experiments were performed with PCBs congeners IUPAC N° 3, 35, 67 and 169. Within the experimental conditions used : Hitachi F-4500 fluorometer, band-paths: 2.5 nm and extraction time: 60 min. the limits of detection were estimated to be respectively : 0.07, 0.4, 0.3 and 0.2 ppb. These values are within the range of PCB concentrations found in highly polluted waters and thus confer some interest to the method. However its sensitivity is not sufficient for application to moderately polluted natural water and the method needs some further improvements. Moreover, fluorescence quenching by humic substances was shown to substantially affect PCB's fluorescence intensity and must be taken into consideration for quantitative analysis.