不同垃圾焚烧炉产生的PCDD/Fs和PCBs同类物的分布

要应用高分辨气相色谱一质谱联用技术，测定了3种垃圾焚烧炉产生的飞灰中17种PCDD／Fs和12种共平面PCBs的浓度及毒性当量，比较了PCDD／Fs和PCBs同类物分布的差异．结果表明，流化床焚烧炉和炉排焚烧炉产生的PCDD／Fs多于PCBs，而气化熔融焚烧炉产生的PCBs多于PCDD／Fs；产生的PCBs对总毒性当量的贡献都比较小；3种焚烧炉产生的PCDD／Fs同类物具有相似的浓度分布；流化床焚烧炉和炉排焚烧炉产生的PCBs同类物具有相似的浓度分布，而气化熔融焚烧炉产生的PCBs同类物分布与其他两种焚烧炉差别较大．     

多氯苯生产中有机氯化物的分析

在气相色谱和色谱-质谱分析的基础上,对以六六六为原料生产多氯苯的两种工艺的产品及废渣进行了分析。结果表明:伴随多氯苯的生成,尚有多种氯化物产生。在水解生产工艺中,产品和废渣中有微量PCDDs和PCDFs,但产品中还有少量PCBs。在热解工艺中,废渣内发现大量的PCBs,PCDDs和PCDFs,最毒的异构体,2,3,7,8-TCDD含量高达24ppm。     

表面活性剂洗脱污染土壤中多氯联苯(PCBs)的研究与应用

多氯联苯(PCBs)为一类在环境中广泛分布且难以降解的持久性有机污染物。利用表面活性剂亲油和亲水的两亲特性．将多氯联苯从土壤中洗脱出来，从而修复受污染土壤是当前环境研究的热点之一。文章综述了近年来国内外使用表面活性剂溶液修复多氯联苯污染土壤的研究进展。表面活性剂对土壤中多氯联苯的洗脱作用主要是：(1)表面活性剂通过减小液一固之间的表面张力，将阻塞在土壤孔隙中的多氯联苯分散到溶液中来；(2)表面活性剂通过形成胶束，促使多氯联苯从土壤中重新分配到疏水的胶束核中。洗脱效果与表面活性剂种类、性质、质量浓度及土壤成份有关，通常非离子型表面活性剂效果较好，对多氯联苯的洗脱可达86％。含多氯联苯洗脱液可利用生物降解、紫外光照射及焚烧等方法进行后续处理。     

Chemical dechlorination of polychlorinated biphenyls (PCBs) from dielectric oils

We studied the chemical dechlorination of the polychlorinated biphenyls (PCBs) in some dielectric oils via nucleophilic substitution of the chloro atoms by polyethylene alkoxide. The influence of temperature, ultrasounds, polyethylene glycol (PEG) and base type was investigated. Our findings show that dechlorination of PCBs by chemical treatment is effective at moderate temperature (90–100°C) and is strongly dependent on the nature of matrix oil. Stirring affects the process yield by influencing the homogeneity of the oil/glycol two-phase system. Ultrasounds can improve the process efficiency by making operating conditions less severe. Selected article from the 6th European Meeting on Environmental Chemistry, University of Belgrade, Serbia and Montenegro organized by Prof. Dr. Branimir Jovancicevic ().     

厦门港表层水体中有机氯农药和多氯联苯的研究

利用ＧＣ－ＥＣＤ对厦门西港１９９８年７月取得上位表层水体中的１８种有机氯农药（ＨＣＨｓ，ＤＤＴｓ等）和１２种多氯联苯（ＰＣＢｓ）进行分析。其中有机氯农药的浓度范围６．６０～３２．６ｎｇ／Ｌ（其中ＨＣＨｓ：３．５１～２７．８ｎｇ／Ｌ），ｎｇ／Ｌ，ＤＤＴｓ，０．９５～２．２５ｎｇ／Ｌ均值１．４５ｎｇ／Ｌ），多氯联苯的浓度为０．０８～１．６９ｎｇ／Ｌ，同国内外其他港口海区相比较，其污染和蔼相对较低。同时     

水和废水中多氯联苯(PCBs)的测定方法及进展

本文引用了七十余篇近几年国内外的有关著文,对水和废水中的多氯联苯(PCBs)的测定方法进行了评述,全面系统地介绍了水样的采集、富集、净化和分析测定等操作程序,着重于样品的前处理和气相色谱分析,并提出了这一领域今后的发展趋势。     

Soil contamination at abandoned sawmill areas

Contamination of soil by technical chlorophenol formulation at wood preserving sites was studied. The examined soils contained 50 to 1000 mg of polychlorinated phenols (CPs), 1 to 50 mg of polychlorinated phenoxyphenols (“pre-dioxins”, PCPPs) and 0.1 to 5 mg of polychlorinated dibenzofurans (PCDFs) per kg of dry soil. CPs were found to be mobile, leaching deep into the soil, while PCPPs and PCDFs accumulated in the top soil. All three classes of contaminants were stable in soil.     

Examination of dioxin fluxes recorded in dated aquatic-sediment cores in the Kanto region of Japan using multivariate data analysis

Past dioxin (coplanar polychlorinated biphenyl (Co-PCB), 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin (PCDD) and 2,3,7,8-substituted polychlorinated dibenzofuran (PCDF)) fluxes recorded in dated aquatic-sediment cores were analyzed using principal component analysis (PCA). The data set consisted of samples from four cores collected from the Kanto region of Japan. Time trends and spatial differences in the dioxin flux were examined, and the potential relationship to emission sources was investigated. Twenty-five compounds and 58 core slices, corresponding to the later half of the 20th century, were subjected to the analysis. The PCA of both log-transformed and maximum-value-standardized data successfully divided the dioxin compounds into a small number of groups, and three similar clusters of Co-PCBs, PCDDs and penta- to hepta-CDFs were identified. PCB formulations used in the past are judged to have been responsible for the major part of the Co-PCB flux recorded in the sediment cores. However, the relationship to emission sources needs further investigation. It is suggested that most 2,3,7,8-substituted PCDDs and PCDFs are different from Co-PCBs in their emission sources or movements in the environment. The subcore clusters obtained from the PCA of log-transformed data show that the cores from different sampling areas exhibited distinct dioxin fluxes and compositions. Common time trends among the cores were more effectively summarized by the PCA of maximum-value-standardized data focusing on relative time trends. PC scores show that recently the flux of each dioxin compound in the four cores has been generally declining after having reached a peak.     

Trace elements, organochlorines, polycyclic aromatic hydrocarbons, dioxins, and furans in lesser scaup wintering on the Indiana Harbor Canal

During the winter of 1993-94, male lesser scaup (Aythya affinis) were collected on the heavily polluted Indiana Harbor Canal (IHC), East Chicago, IN, USA, and examined for tissue contaminant levels. Lesser scaup collected on the IHC had higher concentrations of cadmium (Cd), mercury (Hg), selenium (Se), polychlorinated biphenyls (PCBs), selected organchlorine pesticides, polychlorinated dibenzodioxins, polychlorinated dibenzofurans, polycyclic aromatic hydrocarbons, and aliphatic hydrocarbons than reference birds. Of the scaup collected on the IHC, 44% had Cd concentrations in the liver considered above background for freshwater waterfowl (>3 microg/g dry wt.), 50% had Se concentrations in the liver above a level possibly harmful to the health of young and adult birds (>33 microg/g dry wt.), and 88% of the scaup carcasses exceeded the PCB human consumption guidelines for edible poultry in the USA (>3.0 microg/g lipid wt.). The ratio of pristane:n-heptadecane concentrations in 47% of lesser scaup collected on IHC was elevated above 1.0, which is indicative of chronic exposure to petroleum hydrocarbons.     

Reductive dechlorination of non-ortho substituted polychlorinated biphenyls by ultraviolet irradiation in alkaline 2-propanol

The photodechlorination pathways of 3,3′,4,5,5′-pentachlorobiphenyl (3,3′,4,5,5′-PentaCB) and the related lower polychlorinated biphenyl congeners irradiated at 254 nm in alkaline 2-propanol were elucidated. Steric effect is the most important factor for controlling the dechlorination pattern of these substrates. Electronic effect also influences the photoreactivity of chlorine substituents.