Determination of indicator polychlorinated biphenyls (PCBs) by gas chromatography–electron capture detector

An effective method for determination of indicator polychlorinated biphenyls (PCBs) has been validated using gas chromatography (GC) equipped with electron capture detector (ECD). The GC–ECD method was validated by determining the linear range (working range) for determination of the compounds, minimum detectable quantities (MDQ), the precision and accuracy of the method for the analysis of the compounds. MDQ obtained for the compounds ranges from 0.0005 to 0.002 ng. Indeed the method was found to be more sensitive as the number of chlorine atoms attached to the biphenyl increases. The precision and accuracy of the GC method validated ranges from 2.4% to 14.5% and −7.0% to 14.6% respectively. Coefficient of variation associated with the repeatability of the retention times and corresponding peak areas was found to be 0.0001–0.0007 for the retention times and 0.0014–0.059 for the peak areas. Percentage recoveries for the compounds were in the range of 95.7–101.0%. The validated method was then applied to determine levels of indicator PCBs in sediments sampled from eleven sampling points along the Lake Bosuntwi in Ghana and the highest PCB load of 19.17 ng g⁻¹ was recorded at Pipie No. 2. PCB 52 and PCB 101 were found to be the most ubiquitous indicator PCBs in the study area, both with 90.91% occurrence.     

溶剂调控Pd/C催化多氯联苯高效加氢脱氯

采用沉积沉淀法制备了5% Pd/C催化剂,研究了溶剂体系对其催化4-氯联苯（4-CBP）加氢脱氯的影响,建立了正丁醇-水两相溶剂体系,实现了高浓度电容器油（主要为多氯联苯（PCBs））的高效加氢脱氯降解.结果表明,相对比非质子溶剂,醇类等质子溶剂对加氢脱氯反应更加有利.水的加入对异丙醇-水均相溶剂和有机-水两相溶剂中Pd/C催化4-CBP加氢脱氯均有明显的促进作用,而且在正丁醇-水（1：3,V/V）两相溶剂体系中可以在90min内实现4-CBP加氢脱氯的完全转化,而且催化剂可以重复使用8次以上.在该溶剂体系中,10g/L的含PCBs电容器油在Pd/C催化下可以在360min内完全加氢脱氯生成联苯.     

丛枝菌根真菌及猪炭对多氯联苯污染土壤的联合修复作用

选用玉米(Zea mays L.)为供试植物,采用盆栽试验研究了接种丛枝菌根(Arbuscular mycorrhiza,AM)真菌(Funneliformis mosseae)和添加不同粒径猪炭对多氯联苯(Polychlorinated biphenyls,PCBs)污染土壤的联合修复效应及其对土壤微生物的影响.结果表明,接种AM真菌(10%接种量)及添加2.5%猪炭对土壤有效磷含量提高具有显著的协同效应,猪炭还显著提高了土壤有机碳、速效钾含量和pH值(p0.05);猪炭显著促进了菌根真菌侵染率,但对玉米根系生物量具有抑制作用.接种AM真菌的同时添加猪炭提高了细菌16S rDNA丰度,且接种AM真菌同时添加粒径0.25 mm猪炭显著促进了土壤PCBs降解率.AM真菌与猪炭改变了土壤微生物种群的相对丰度,其中,Planctomycetes与土壤三氯联苯降解显著相关(r=0.049,p0.05),而Acidobacteria与五氯联苯降解显著相关(r=0.008,p0.01).AM真菌及猪炭提高了土壤有效养分含量,促进了植物生物量和土壤PCBs降解,对PCBs污染土壤具有较好的修复潜力.     

短链脂肪酸对太湖底泥多氯联苯微生物厌氧脱氯的影响

选取二氯联苯PCB5和PCB12、四氯联苯PCB64和PCB71、类二噁英五氯联苯PCB105和PCB114、六氯联苯PCB149和PCB153、七氯联苯PCB170,考察了添加7.5mmol/L乙酸和7.5mmol/L混合酸（乙酸：丙酸：丁酸=1：1：1）条件下,9种典型商业多氯联苯单体在太湖底泥厌氧微环境中24周内的脱氯降解情况.结果表明：乙酸和混合酸的添加均在一定程度上强化了多氯联苯的降解,多氯联苯总浓度降低速率由（0.276±0.023） mg/（kg·week）分别加快至（0.383±0.033）和（0.410±0.036） mg/（kg·week）;提高了部分脱氯路径的相对反应速率,特别是单侧氯取代的对位脱氯,但未改变脱氯微生物对多氯联苯降解底物的选择性及主要脱氯路径;进一步降低了体系类二噁英多氯联苯总毒性当量（TEQ）,24周降幅均在95%以上;乙酸和混合酸所起到的促进效果并无显著性差异.     

Polychlorinated biphenyls and omega-3 fatty acid exposure from fish consumption, and thyroid cancer among New York anglers

Fish from the Great Lakes contain polychlorinated biphenyls(PCBs)which have been shown to disrupt endocrine function and mimic thyroid hormones,but they also contain beneficial omega-3 fatty acids that may offer protection against endocrine cancers.The purpose of this study was to examine the effects of Lake Ontario fish consumption and the estimated consumption of PCBs and omega-3 fatty acids on the risk of thyroid cancer in a group of sport fishermen.Anglers from the New York State Angler Cohort Study were followed for cancer incidence from 1991–2008.Twenty-seven cases of incident thyroid cancer and 108 controls were included in the analyses.Total estimated fish consumption,estimated omega-3 fatty acid consumption,and estimated PCB consumption from Lake Ontario fish were examined for an association with the incidence of thyroid cancer,while matching on sex,and controlling for age and smoking status.Results from logistic regression indicate no significant associations between fish consumption,short-term estimated omega-3 fatty acids,or estimated PCB consumption from Great Lakes fish and the development of thyroid cancer,but it was suggested that long-term omega-3 fatty acid from Great Lakes fish may be protective of the development of thyroid cancer.In conclusion,fish consumption,with the possible concomitant PCBs,from the Great Lakes does not appear to increase the risk of thyroid cancer in New York anglers.Further research is needed in order to separate the individual health effects of PCBs from omega-3 fatty acids contained within the fish.     

广州市夏季大气中多氯联苯和多溴联苯醚的含量及组成对比

用GC-ITD-MS和GC-NCI-MS分别测定了广州市区4个代表性的地点大气中多氯联苯(PCBs)和多溴联苯醚(PBDEs)的含量.∑64PCBs的含量范围为307.2～2720.8 pg·m-3,含量处于世界中等水平;除工业区两侧的黄浦和天河2个采样点外,市区∑10PBDEs和BDE-209的含量范围分别为41.5～256.8 pg·m-3和116.3～888.7 pg·m-3,∑10PBDEs的含量和世界其它地方相当,而BDE-209的含量高于其它地区.PCBs中主要以三、四和五氯代PCBs为主,它们的含量占∑64PCBs的80%以上,同系物分布与国外不同,原因可能是我国曾生产和使用不同的工业产品.PBDEs中以四、五和十溴BDEs为主,其含量占∑11 PBDEs的80%以上,BDE-209、BDE-47和BDE-99是主要成分,表明污染主要来自于五溴和十溴联苯醚工业品4个采样点∑10PBDEs和∑64PCBs含量的分布表明这两类污染物有不同的排放源,PCBs主要来自于老城区,而PBDEs主要来自于新工业区.     

Degradation and mineralization of 2-chioro-, 3-chloro- and 4-chlorobiphenyl by a newly characterized natural bacterial strain isolated from an electrical transformer fluid-contaminated soil

A bacterium classified as Achromobacter xylosoxidans strain IR08 by phenotypic typing coupled with 16S rRNA gene analysis wasisolated from a soil contaminated with electrical transformer fluid for over sixty years using Aroclor 1221 as an enrichment substrate.The substrate utilization profiles revealed that IR08 could grow on all three monochlorobiphenyls (CBs), 2,4'- and 4,4'-dichlorobiphenylas well as 2-chlorobenzoate (2-CBA), 3-CBA, 4-CBA, and 2,3-dichlorobenzoate. Unusually, growth was poorly sustained on biphenyland benzoate. In growth experiments, IR08 degraded all CBs (0.27 mmol/L) in less than 96 h with concomitant stoichiometric release ofinorganic chloride and growth yields were 2-3 times higher than those observed on biphenyl. In contrast to most of the chlorobiphenyl-degrading strains described in the literature, which are reported to form CBA, no metabolite was identified in the culture broth byHPLC analysis. When co-incubated with respective CBs and biphenyl, strain IR08 preferentially utilized the chlorinated analoguesin less than 96 h while it took another 264 h before 90% of the initially supplied biphenyl could be degraded. The promotion of co-metabolic transformation of halogenated substrates by the inclusion of their non-halogenated derivatives may not therefore, result inuniversal benefits.     

现代黄河三角洲土壤特性对多氯联苯分布的影响规律

对现代黄河三角洲22个表层土壤样品中类二嗯英类多氯联苯（PCBs）进行双毛细管柱GC．ECD结合MS测试,并使用相关数学统计学分析方法一相关性研究方法研究了现代黄河三角洲地区土壤特性对PCBs分布的影响,结果表明：土壤有机质量分数与其类二嗯英类PCBs的总质量浓度呈弱的正相关关系。土壤粒径组成中粘粒质量分数与其类二嗯英类PCBs的总质量浓度呈相关性关系,且达到极显著的水平;粉砂粒的质量分数与类二嗯英类PCBs的总质量浓度无相关关系;砂粒质量分数与类二嗯英类PCBs的质量浓度呈负相关关系,达到显著相关的水平。土壤溶解盐质量分数及pH值与类二嗯英类PCBs的总量没有明显的相关性。可见,土壤中有机质、土壤颗粒组成中粘粒和砂粒质量分数是影响现代黄河三角洲地区土壤中PCBs分布的主要因素。     

不同水源灌溉的农田表层土壤中多氯联苯和多溴联苯醚的浓度分布特征

本工作主要关注北京郊区污水河、地下水及混合水源灌溉的3块农田的表层土壤中,26种多氯联苯(PCBs)和14种多溴联苯醚(PBDEs)的浓度分布特征,并对目标污染物各单体浓度之间的相关性进行了统计学分析.结果显示,所有供试表层土壤样品中共检出26种PCBs(∑26PCBs),浓度水平范围为130—1.93×103ng.kg-1干重.检出的PCBs种类包括12种共平面多氯联苯异构体(15.6—433 ng.kg-1干重),6种指示型多氯联苯异构体(50.7—452 ng.kg-1干重)和其它8种多氯联苯同系物(52.1—1.15×103ng.kg-1干重).同时还检出14种多溴联苯醚同系物(∑14PBDEs),浓度水平范围为1.81—14.4μg.kg-1干重,其中十溴联苯醚(BDE-209)为最主要的组分,约占总组分94%以上.污水河河水和地下水混合灌溉的农田中PCBs和PBDEs的浓度大于地下水灌溉农田中的含量.此外,在所有样品中发现高氯代的多氯联苯同系物(氯原子数≥4)浓度之间存在显著的相关性,可能与灌溉水源和土壤对高氯代联苯的强保留等因素有关.     

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。