Levels of polychlorinated biphenyls in 1,4-dichlorobenzene mothballs

Although polychlorinated biphenyls(PCBs) are globally recognized pollutant, an understanding of their resources as by-products in chemical industry is poorly investigated. This paper presents data from a study that was conducted in order to determine the extent of PCBs in 1,4-dichlorobenzene(p-DCB) mothballs. Total PCBs and dioxin-like PCBs were detected in five mothball samples. Total PCB concentrations ranged from 328 ng/g to 1798 ng/g, while the levels of WHO-TEQ were between 0.16 pg/g and 13 pg/g. Mean concentrations of total PCBs and WHO-TEQ in the samples were 724 ng/g and 3.2 pg/g, respectively. The highest level of PCB congeners was that of trichlorinated biphenyls(537 ng/g), which maybe due to the relatively low chlorination in the process of p-DCB production. A mechanism of the formation of PCBs from polychlorinated benzene in the presence of chlorine is also suggested. The results suggested that re-estimation on the risk of p-DCB products, especially the products for daily use such as mothballs, is expected.     

Simultaneous monitoring of PCB profiles in the urban air of Dalian, China with active and passive samplings

The concentration of polychlorinated biphenyls (PCBs) in the urban air of Dalian, China was monitored from November 2009 to October 2010 with active high-volume sampler and semipermeable membrane device (SPMD) passive sampler. The concentration of PCBs (particle + gas) ( ∑ PCBs) ranged from 18.6 to 91.0 pg/m 3 , with an average of 50.9 pg/m 3 , and the most abundant dioxin-like PCB (DL-PCBs) was PCB118. The WHO-TEQ values of DL-PCBs were 3.6-22.1 fg/m3 , with an average of 8.5 fg/m 3 , and PCB126 was the maximum contributor to ∑ TEQ. There was a much larger amount of PCBs in the gas phase than in the particulate phase. The dominant PCB components were lower and middle molecular weight PCBs. With increasing chlorination level, the concentration of the PCB congeners in the air decreased. The gas-particulate partitioning of PCBs was different for the four seasons. The gas- particulate partitioning coefficients (logK p ) vs. subcooled liquid vapor pressures (logP L 0 ) of PCBs had reasonable correlations for different sampling sites and seasons. The absorption mechanism contributed more to the gas-particulate partitioning process than adsorption. Correlation analysis of meteorological parameters with the concentration of PCBs was conducted using SPSS packages. The ambient temperature and atmospheric pressure were important factors influencing the concentration of PCBs in the air. The distribution pattern of the congeners of PCBs and the dominant contributors to DL-PCBs and TEQ in active samples and SPMDs passive samples were similar. SPMD mainly sequestrated gas phase PCBs.     

Hepatoprotective and antioxidant effects of dietary Glycyrrhiza polysaccharide against TCDD-induced hepatic injury and RT-PCR quantification of AHR2,ARNT2,CYPIA mRNA in Jian Carp(Cyprinus carpio var.Jian)

To evaluate the protective effects of Glycyrrhiza polysaccharide(GPS) against 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD)-induced hepatotoxicity in Jian carp,the fish were fed diets containing GPS at doses of 0.1,0.5 and 1.0 g/kg for 60 days before an intraperitoneal injection of 0.6 μg/kg TCDD at a volume of 0.05 mL/10 g body weight.At 72 hr post-injection,blood and liver samples were taken for biochemical analysis and the fish liver samples were used for the preparation of pathological slices.The results showed that increases in alanine aminotransferase(GPT),aspartate aminotransferase(GOT),lactate dehydrogenase(LDH),and alkaline phosphatase(AKP) in serum induced by TCDD were significantly inhibited by pre-treatment with 1.0 g/kg GPS.Following the 1.0 g/kg GPS pre-treatment,total protein(TP),albumin(Alb),catalase(CAT),glutathione peroxidase(GPx),total antioxidant capacity(T-AOC) and superoxide dismutase(SOD) activities in liver tissue increased significantly,malondialdehyde(MDA) formation(P 0.05 or P 0.01) was significantly inhibited,and the expression of cytochrome P4501A(CYP1A),aryl hydrocarbon receptor 2(AHR2) and aryl hydrocarbon receptor nuclear translocator 2(ARNT2) mRNA(P 0.05) was significantly enhanced.Histological observations on fish liver were obtained by preparing paraffin tissue sections via HE staining,and the results showed that histological changes were obviously reduced by 0.5 and 1.0 g/kg GPS.GPS significantly reduced liver tissue damage caused by TCDD.Overall,these results proved the hepatoprotective effect of GPS in protecting against fish liver injury induced by TCDD,and supported the use of GPS(1.0 g/kg) as a hepatoprotective and antioxidant agent in fish.     

Historical trends of PCBs and PBDEs as reconstructed in a lake sediment from southern Tibetan Plateau

High-altitude lake sediment can be used as a natural archive to reconstruct the history of pollutants. In this work, the temporal distribution of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were determined using a high-resolution gas chromatography coupled with high-resolution mass spectrometer (HRGC/HRMS) in an alpine lake sediment core collected from the southern Tibetan Plateau (TP) to examine whether the expected decreasing trends due to the implementation of the international Conventions could be observed. The concentrations of PCBs and PBDEs in the sediment core were in the range of 11.8–142 pg/g dw and ND-457 pg/g dw, and their fluxes were in the range of 2.51–31.7 ng/(m²·yr) and ND-43.2 ng/(m²·yr), respectively. The prevalence of low-chlorinated (tri-CB) PCBs and low-brominated (tri- to tetra-) PBDEs in most sections of the sediment profiles was observed, suggesting that the light molecular weight PCBs and PBDEs have most likely reached lake sediments by long-range atmospheric transport from distant sources. Despite the restrictions on their applications, the sediment records for the concentrations and fluxes showed no corresponding decreasing trend with restrictions for PCBs, which suggested that these POPs (e.g., PCBs) were still emitted to the environment owing to the influence of primary or secondary emissions. To our knowledge, this is the first report on input history of atmospheric PCBs and PBDEs recorded in TP Lake sediment.     

Topsoil dichlorodiphenyltrichloroethane and polychlorinated biphenyl concentrations and sources along an urban-rural gradient in the Yellow River Delta

The Yellow River Delta (YRD) is a typical agricultural and petrochemical industrial area of China. To assess the current status of soil dichlorodiphenyltrichloroethane (DDT) and polychlorinated biphenyls (PCB) residues, topsoil samples (0-15 cm) (n = 82) were collected in Bincheng District, at the geographic center of the YRD. The total concentrations of six DDT homologues were within 3.3-3819 μg/kg, with a mean concentration of 191 μg/kg, showing significant increase along urban-rural gradient. Soil concentrations of seven indicator PCBs in the area ranged from non-detectable to 87.0 μg/kg, dominated by heavily chlorinated PCBs (PCB-101 and -118). Soil PCBs concentrations were significantly greater in urban than suburban and rural areas. Principal component and multiple linear regression analysis suggest that 86.4% of soil DDTs originate from past DDT usage, and 13.6% originate from dicofol application. Soil PCBs most likely originate from the petrochemical industry (77.1%), municipal solid waste disposal (16.5%), local commercial PCB homologues usage (5.2%), and long-range atmospheric deposition (1.2%). In general, soil DDTs pollution was classified as low level, and mean PCBs concentrations were below the severe contamination classification range. Because PCB-118 is a dioxin-like congener, monitoring and remediation is advised to assess and reduce negative environmental and human health effects from soil DDTs and dioxin-like congeners in the study area.     

2,3,7,8-Tetrachlorodibenzo-p-dioxin promotes migration ability of primary cultured rat astrocytes via aryl hydrocarbon receptor

Emerging evidence showed that 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) could induce expression of certain reactivation-associated genes in astrocytes, however, the consequent cellular effects and molecular mechanisms are still unclear. During the process of astrocyte reactivation, migration is a critical cellular event. In the present study, we employed wound-healing assay and Transwell® motility assay to explore the effects of TCDD on cell migration in primary cultured rat cortical astrocytes. We found that upon TCDD treatments at relative low concentrations (10^? 10 and/or 10^? 9?mol/L), the ability of primary astrocytes to migrate horizontally and vertically was promoted. In line with this cellular effect, the mRNA expression of two pro-migratory genes, including cell division cycle 42 (CDC42) and matrix metalloproteinase 2 (MMP2) was induced by TCDD treatment. Dioxin exerts its toxic effects mainly through aryl hydrocarbon receptor (AhR) pathway. So the role of AhR pathway in the pro-migratory effects of TCDD was examined using an AhR antagonist, CH223191. We found that application of CH223191 significantly reversed the pro-migratory effects of TCDD. Interestingly, the basal ability of horizontal migration as well as basal levels of CDC42 and MMP2 expression were dramatically reduced suggesting a possible physiological role of AhR in maintaining the endogenous migration ability of the primary astrocytes. These findings support the notion that dioxin promotes astrocyte reactivation at molecular and cellular levels.     

Contamination of soil, leaves and vegetables by polychlorinated biphenyls in Xiamen region, China

The paper aimed to identify the primary of polychlorinated biphenyls(PCBs) in the Jiulong River Estuary, investigate the spatial distribution of PCBs contamination in the environment, localize the atmospheric source and evaluate ongoing PCBs emissions by analyzing soil samples collected along the Jiulong River region. In addition, the accumulation of PCBs in the human food chain was quantified by analyzing leaf of orange trees and vegetable samples collected along a gradient of soil/atmospheric contamination moving away from the source. Consequently, the impact on the human health and the ecosystem was quantified, different management options were proposedto reduce this impact and to carry out research on organic contaminants along the Jiulong River and Xiamen region.     

Polychlorinated biphenyls in the atmosphere of Taizhou, a major e-waste dismantling area in China

PM2.5,total suspended particles(TSP) and gas phase samples were collected at two sites of Taizhou,a major e-waste dismantling area in China.Concentrations,seasonal variations,congener profiles,gas-particle partitioning and size distribution of the atmospheric polychlorinated biphenyls(PCBs) were studied to assess the current state of atmospheric PCBs after the phase out of massive historical dismantling of PCBs containing e-wastes.The average 38PCBs concentration in the ambient air(TSP plus gas phase) near the e-waste dismantling area was(12,407 ± 9592) pg/m3 in winter,which was substantially lower than that found one decade ago.However,the atmospheric PCBs level near the e-waste dismantling area was 54 times of the reference urban site,indicating that the impact of the historical dismantling of PCBs containing e-wastes was still significant.Tri-Penta-CBs were dominant homologues,consisting with their dominant global production.Size distribution of particle-bound PCBs showed that higher chlorinated CBs tended to partition more to the fine particles,facilitating its long range air transportation.     

Occurrence and congeners specific of poiychlorinated biphenyls in agricultural soils from Southern Jiangsu, China

A total of 198 agricultural soil samples were collected from Zhangjiagang and Changshu in Southern Jiangsu for analysis of 13 polychlorinated biphenyls (PCBs) in order to assess the levels of pollution, sources, area distribution, and potential risk for the environment. All methods were rigorously tested and an adequate quality control was ensured. Only one site had no PCBs residues, and the highest total PCBs concentration in the surface soils was 32.83 ng/g. The average concentration in all the soil samples was 4.13 ng/g, signaling low-level pollution. Tetra-, penta-, and hexa-chlorinated biphenyls were dominant species in soil samples, accounting for more than 75% ofΣPCBs in the soil samples. PCB118 was the most abundant congener in all the samples. The PCB118 was about 20% ofΣPCBs. The soil organic matter content showed only a weak correlation with the levels of all PCB congeners, in which a better correlation was noted for the more volatile lighter PCB congeners than for the heavier homologues. To a certain extent, the sources and land use seemed to influence the levels of PCBs.     

Sources and health risks of PM2.5-bound polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in a North China rural area

Polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) are typical persistent organic pollutants (POPs), which have high toxicity, bioaccumulation and long-distance transfer capability. Daily variation, sources of PCBs and OCPs in PM_2.5 are rarely explored in polluted rural area. Here, the sources and health risks of the PCBs and OCPs were evaluated for 48 PM_2.5 samples collected in winter 2017 in Wangdu, a heavy polluted rural area in the North China Plain. The average diurnal and nocturnal concentrations of Σ₁₈PCBs and Σ₁₅OCPs were 1.74-24.37 and 1.77-100.49, 11.67-408.81 and 16.89-865.60 pg/m³, respectively. Hexa-CBs and penta-CBs accounted for higher proportions (29.0% and 33.6%) of clean and polluted samples, respectively. Hexachlorobenzene (HCB) was the dominant contributor to OCPs with an average concentration of 116.17 pg/m³. Hexachlorocyclohexane (ΣHCHs) and dichlorodiphenyltrichloroethane (ΣDDTs) were the other two main classes in OCPs with the average concentrations of 4.33 and 15.89 pg/m³, respectively. β-HCH and p,p’-DDE were the main degradation products of HCHs and DDTs, respectively. The principal component analysis and characteristic ratio method indicated both waste incineration and industrial activities were the main sources of PCBs, contributing 76.8% and 12.7%, respectively. The loadings of OCPs were attributed to their application characteristics and the characteristic ratio method reflected a current or past use of OCPs. Health risk assessment showed that the respiratory exposure quantity of doxin-like PCBs (DL-PCBs) and the lifetime cancer risk from airborne OCPs exposure was negligible, while the other exposure modes may pose a risk to human bodies.     

汾河表层沉积物PCBs和OCPs含量、来源及生态风险

利用GC-ECD方法测定了汾河太原段30个表层沉积物样品中多氯联苯(PCBs)和有机氯农药(OCPs)的含量,同时对沉积物中PCBs和OCPs的来源和生态风险进行了研究.结果表明,研究区PCBs和OCPs的含量分别为n.d.~50.95μg/kg和2.19 ~25.24μg/kg.Aroclor检出率最高为Aroclor1260和Aroclor1254,这可能与我国主要生产和使用的PCB有关.OCPs中p,p￠-DDE含量占优势,研究区HCH和DDT来源于工业和农业输入.生态风险评价结果表明,γ-HCH、DDT(total),o,p￠+p,p￠-DDT,p,p￠-DDE,七氯环氧化物,PCBs总量可能会对研究区水生生态环境造成潜在影响,但整体风险水平不高.     

珠三角电子垃圾和城市地区家庭灰尘中多氯联苯的来源及暴露风险

本研究对珠三角电子垃圾和城市地区家庭灰尘中多氯联苯(PCBs)进行了分析.结果表明,清远电子垃圾区灰尘中PCBs的含量为12.4～87765 ng·g-1,平均10167 ng·g-1.室内和庭院灰尘中PCBs的含量无显著差别.电子垃圾区灰尘中PCBs组成模式(以3、5、6、4氯代PCBs为主),与我国工业品中PCBs的组成并不相似,并且室内外灰尘中的组成没有明显的差别.采用化学质量平衡受体模型进行源解析显示,电子垃圾区灰尘中PCBs主要来自Aroclor 1262(36.7%)、Aroclor 1254(26.7%)、Aroclor 1242(21.4%)和Aroclor 1248(18.5%).电子垃圾区婴幼儿、儿童/青少年、成人通过灰尘对PCBs的平均日暴露量分别为42、17和2.9 ng·(kg·d)-1.风险评估显示,婴幼儿、儿童和青少年通过灰尘暴露PCBs的总非癌症危害商数(HQ)均高于1,可对身体健康产生危害,人群终生平均致癌风险为4.5×10-5,处于美国EPA可接受的致癌风险范围.广州地区家庭灰尘中PCBs的平均含量仅为48.7 ng·g-1,这与PCBs并未在我国大范围使用一致.广州地区人群通过家庭灰尘暴露PCBs的风险很低.     

海洋环境样品中PCBs的测定

建立了ＧＣ－ＥＣＤ测定海洋环境样品中ＰＣＢｓ的分析方法，通过毛细管ＧＣ／ＭＳ－ＳＩＭ和ＧＣ－ＥＣＤ对ＣＢｓ的分析，得出了的检出限，回收率线性范围以及Ａｍｅｌｏｒ－１２５４和环境样品中的含量。     

用多元线性回归分析法定量判别PCBs污染物类型

应用多元线性回归分析法处理多氯联苯（PCBs）标准样品和实际样品的气相色谱数据，定量判别PCBs污染物类型，该法简便易行，可以避免由主观判断引入的偏差。对于PCBs标准样品Aroclor 1248及PCBs配制样品，污染物组成计算结果与实际值吻合，绝对误差小于2％。实际土壤样品的分析计算结果表明：北京土壤样品PCBs污染物是Aroclor 1242；兰州土壤样品PCBs污染物是49．0％的Aroclor 1242和51．0％的Aroclor 1254的混合物。应用多元线性回归分析法处理气相色谱分析数据，还可以作为一种质量控制的手段来识别干扰物。     

二噁英对非洲爪蛙细胞色素P450表达的影响

二噁英(代DD)是一类毒性较强的环境污染物质.试验使用印记法定量检测了非洲爪蛙芳烃基受体(从R)及其核内的转录因子(Amt),细胞色素P450(CYP)中的CYP1A6 mRNA及CYP1A7 mRNA;用免疫反应检测了CYP1A蛋白质的表达.结果表明:TCDD的染毒没有引起AhR和Arnt表达量的增加,但引起CYP1A6 mRNA及CYP1A7 mRNA表达的极显著增加,以及CYP1A蛋白质的强烈表达;TCDD强烈诱发非洲爪蛙CYP1A,且存在质量浓度依存性,使用CYP1A作为环境危险性评价具有一定的可探讨性.     

混合发酵法降解多氯联苯的试验研究

利用混合发酵法可有效地降解多氯联苯。模拟实验表明,Aroclor 1016和Aroclor 1254在木屑与活性污泥或餐厅残渣的混合物中,经七周发酵均有一定程度的降解,最高可达60％。     

Determination of polychlorinated biphenyl congeners in environmental samples

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太湖表层沉积物中PAHs和PCBs的分布及风险评价

采用GC-EI-MS联用技术分析了太湖18个表层沉积物样品中多环芳烃(PAHs)和多氯联苯(PCBs)的含量.共检出28种PAHs,其总浓度范围为90.6~1.04×103ng/g,其中16种优控PAHs的浓度范围为63.1~885ng/g,最高浓度出现在竺山湖;56种PCBs的浓度范围为1.35~13.8ng/g,最高浓度出现在新塘港.利用分子比和因子分析/多元线性回归模型分析PAHs的来源,结果显示,太湖PAHs主要来源于燃烧,其中木柴、煤炭燃烧和油料燃烧的贡献率分别为45%和50%.PCBs同族体组成分析结果表明,PCBs的同系物组成呈现Aroclor 1242和Aroclor 1254的混合来源特征.太湖表层沉积物中PAHs和PCBs的二 毒性当量(以TCDD计)范围为0.64~3.35pg/g,风险评价结果表明,太湖沉积物中的PAHs和PCBs尚未对周围环境造成不利影响.     

现代黄河三角洲土壤中多氯联苯来源解析研究

对现代黄河三角洲22个表层土壤样品中类二英类多氯联苯（PCBs）进行双毛细管柱GC-ECD结合MS测试,并对所得数据进行主成分分析,在同系物水平上解析了现代黄河三角洲土壤中PCBs污染的类型、来源、贡献率和同系物组成.结果表明,现代黄河三角洲土壤中PCBs污染存在4类污染源：第1类污染是由地表径流带来的非点源污染,来自黄河沿岸企业的工业生产和使用,其贡献率为49.6％,同系物组成与国产PCBs相似,且与Aroclor1221相对应;第2和第3类同属点源污染,来自沿海地区的油田开采活动,贡献率分别为15.0％和10.1％,第2类同系物组成与Aroclor1221和Aroclor1242叠加的结果类似,第3类与Aroclor1260相似;第4类污染是由大气污染导致的非点源污染,来自大气的干、湿沉降,其贡献率为8.4％,同系物组成与Aroclor1242、Aroclor1248和Aroclor1260叠加的结果类似.     

Relation of hepatic EROD activity and CYP1A level in Sebastiscus marmoratus exposed to benzo[a]pyrene

This study was designed to investigate the in vivo effects of benzo[a]pyrene (BaP) on hepatic ethoxyresorufin-O-deethylase (EROD) activity and its correlation with cytochrome P450 1A (CYP1A) protein levels in Sebastiscus marmoratus, which were exposed through a water column to BaP (10, 100, 1000 ng/L, respectively) or were treated with intraperitoneal injections of BaP (0.5, 1, 5, 10 mg/kg, respectively) every 7 d. The results showed that after 25 d of waterborne exposure to 1000 ng/L BaP, fish hepatic CYP1A levels and EROD activity were significantly induced. In contrast, EROD activity was not altered 7 d after second ip injections, whereas, CYP1A protein levels were increased. Dose-dependent increase of biliary BaP metabolites demonstrated that the catalytic activity of CYP1A was induced by treatment with BaP. The lowest observable effect concentration with regard to biliary BaP metabolites (100 ng/L) was much lower than that with reference to EROD activity (1000 ng/L). The results suggest that biliary polycyclic aromatic hydrocarbon (PAH) metabolites were shown to better reflect the contamination gradients of PAHs than EROD activity. It appeared to be necessary to measure CYP1A protein levels to complement the EROD activity in relevant toxicological assessments.