Predicting the Relative Retention Time (RRT) of Polybrominated Diphenyl Ethers (PBDEs)

Using the molecular electronegativity distance vector descriptors derived directly from the molecular topological structures, the relative retention time (RRT) of polybrominated diphenyl ethers (PBDEs) were predicted. A four-variable regression model (M30) with the correlation coefficient of 0.9816 and the root mean square errors of 0.061 was developed using a training set including 30 PBDEs. The correlation coefficient of 0.9841 and the root mean square errors of 0.054 between the values of RRT predicted by M30 and the RRT observed for 16 external PBDEs show a good predictive potential of M30. The descriptors included in the M30 represent four interactions between four pairs of atom types, i.e., atom ?C= and C=, C= and >C=, >C= and >C=,C= and Br.

Density Functional Theory Study of Marine Polybrominated Diphenyl Ethers in Anaerobic Degradation

Polybrominated diphenyl ethers(PBDEs)are a kind of serious pollutants in the ocean.Biodegradation is considered as an economical and safe way for PBDEs removal and reductive debromination dominates the initial pathway of anaerobic degradation.On the basis of experimental study,Octa-BDE 197,Hepta-BDE 183,Hexa-BDE 153,Penta-BDE 99 and Tetra-BDE 47 were selected as the initial degradation objects,and their debromination degradation were studied using density functional theory.The structures were optimized by Gaussian 09 program.Furthermore,the molecular orbitals and charge distribution were analyzed.All C-Br bond dissociation energies at different positions including ortho,meta and para bromine atoms were calculated and the sequence of debromination was obtained.There is a close relationship between molecular structure,charge,molecular orbital and C-Br bond.All PBDEs exhibited similar debromination pathways with preferential removal of meta and para bromines.

Ecotoxicological effects of mixed pollutants resulted from e-wastes recycling and bioaccumulation of polybrominated diphenyl ethers in Chinese loach(Misgurnus anguillicaudatus)

To understand potential ecotoxicological effects of electrical and electronic equipment waste (e-waste) recycling and polybrominated diphenyl ethers (PBDEs) bioaccumulation in loaches, a semi-field experiment using Chinese loach (Misgurnus anguillicaudatus) as experimental fish was performed. Larval loaches were kept in net-cage for three months in an e-wastes recycling site and a reference site in Southeastern China. There was significant difference of the survival rate between the loaches from the e-wastes recycling site (27%, 19/70) and from reference site (70%, 49/70). Histopathological responses were also found in all the livers examined in loaches from the e-wastes recycling site. These results showed that mixed pollutants resulted from e-wastes recycling led to ecotoxicological effects on loaches. The bioaccumulation of polybrominated diphenyl ethers (PBDEs), the main pollutants in e-waste, in loaches was also studied, the mean concentration of total PBDEs in sediment was 6726.17 ng/g wet weight and in water samples was 4.08 ng/L (dissolved phase). BDE 209 was the dominant congener in sediment and with relatively high concentration in water. Relatively low concentration of BDE 209 (less than 0.01% of total PBDEs) and high concentration of BDE47 (up to 39.34% of total PBDEs) were detected in loaches.

Occurrence of polybrominated diphenyl ethers in fish and shellfish downstream from electronic-waste recycling plants

We measured 39 polybrominated diphenyl ethers (PBDEs) in the muscle tissue of three species of fish (Sciaenops ocellatus,Sparus macrocephalus,and Lateolabrax japonicus) and four species of shellfish (Tegillarca granosa,Cyclina sinensis,Sinonovacula constricta,and Ostrea cucullata) that were collected downstream of electronic-waste recycling plants in Taizhou,China.A total of 24 PBDE congeners (PBDE 24) in the samples were detected.The PBDE 24 (total PBDE) ranged from 545.4 to 1688.7 ng/kg ww (wet weight).The mean PBDE 24 concentration was 1382.6 ng/kg ww in fish and 858.1 ng/kg ww in shellfish.The lower brominated congeners were detected at relatively high concentrations in all species.The penta-products,produced from e-waste,were found at relatively low levels.A principal component analysis suggested a significant correlation among di-,tri-,tetra-,and hepta-BDEs for the three species of fish.Similarly,we found a significant correlation between mono-and tri-BDEs in the shellfish.Our results suggested that the processes of PBDE metabolism and elimination were similar in both fish and shellfish.In addition,the primary source of PBDEs appeared to be from the debromination of high brominated PBDEs.

Polybrominated Diphenyl Ethers in Surface Sediment from Songhua River Basin,Northeast of China

Sixty sediment samples were collected from the main Songhua River in three years. Twelve polybrominated diphenyl ether( PBDE) congeners( BDE17,28,47,66,99,100,153,154,138,183,and BDE-209) were detected to state the pollution situation. The results showed that the total concentration of total PBDEs ranges from 0. 424 to 23. 0 ng / g dry weight,with the mean of 3. 02 ng / g,and the total PBDEs concentration is at relative low level compared with those worldwide. The congener profile showed that BDE-209 is the dominant congener that accounts for more than 80. 1% of total PBDEs in sediments,followed by BDE-47 and BDE-99. These profiles are consistent with a high consumption of Deca-BDEs for the brominated flame retardant market in China. The results of spatial and seasonal observations indicated that local sources,temperature variation, and hydrologic conditions are significant factors on PBDEs concentrations. Hazard quotients suggested that PBDEs pose no potential risk to benthic organisms in detected area at present.

Concentrations of Polybrominated Diphenyl Ethers in Maternal Blood,Placental Size,and Risk for Fetal Growth Restriction:A Nested Case-control Study

Objective To explore the effects of prenatal exposure to polybrominated diphenyl ethers(PBDEs)on placental size and birth outcomes.Methods Based on the perspective Wenzhou Birth Cohort,this nested case-control study included 101 fetal growth restriction(FGR)and 101 healthy newborns.Maternal serum samples were collected during the third trimester and measured for PBDEs by gas chromatography tandem mass spectrometry.The basic information of mother-newborn pairs was collected from questionnaires,whereas the placental size and birth outcomes of newborns were obtained from hospital records.Results A total of 19 brominated diphenyle ether(BDE)congeners were detected in maternal serum samples.Higher concentrations of BDE-207,-208,-209,and∑19PBDEs were detected in FGR cases than in controls.Increased BDE-207,-208,-209,and∑19PBDEs levels in maternal serum were related to decreased placental length,breadth,surface area,birth weight,birth length,gestational age,and Quetelet index of newborns.After adjusting for confounders,BDE-207 and∑19PBDE concentrations in maternal serum were significantly associated with an increased risk of FGR.Conclusion A negative association was found between PBDE levels in maternal serum and placental size and birth outcomes.Prenatal PBDE exposure may be associated with elevated risk of the incidence of FGR birth.

Bioaccumulative Characteristics of Polybrominated Diphenyl Ethers in Channel Catfish and Fish Feeds from China

PBDEs are widely used brominated flame retardant, which are increasingly reported in the environment. Concentrations of thirteen PBDEs in a large number of channel catfish and fish feeds collected from Hubei province of China were investigated in this study. A fast isotopic dilution GC-MS method was firstly developed to simultaneously determine thirteen PBDEs in channel catfish and fish feeds in this study, and especially for the first time PBDEs in fish feeds. Pressurized liquid extraction and multi-layer silica gel column chromatography cleanup were used, some important steps and crucial parameters were modified and intensified compared with other literatures, and GC and MS conditions were optimized. The limits of quantitation values of 0.25 - 5 μg·kg-1 wet weight in channel catfish were calculated for PBDEs;so did 1 - 20 μg·kg-1 wet weight in fish feeds. In addition, good repeatability and accuracy of the whole method were achieved. The established methods were therefore suitable for the simultaneous determinations of thirteen PBDEs in these samples at trace contamination levels. Using the established methods, PBDEs emerged in 10 of 180 channel catfish and 13 of 115 fish feeds, and the dominant PBDEs homologues were PBDE-28, PBDE-47, PBDE-100, PBDE-99, PBDE-154, PBDE-153 and PBDE-183. The detection rates of seven PBDEs congeners were in turn respectively 1.74%, 7.83%, 4.35%, 5.22%, 3.48%, 2.61% and 2.61% in fish feeds, and detection rates of seven PBDEs congeners were in turn respectively 1.11%, 3.89%, 2.22%, 1.67%, 1.11%, 1.11% and 1.11% in channel catfish. There was significant correlation in PBDEs between matching channel catfish and fish feeds (R2 = 0.742, P < 0.001, n = 30), suggesting that fish feeds contaminated with PBDEs possibly resulted in PBDEs residual in channel catfish through biological transfer.

Identification of the metabolites of polybrominated diphenyl ether 99 and its related cytochrome P450s

Objective:To investigate the metabolites of polybrominated diphenyl ether 99(BDE-99)and its related cytochrome P450s in an in vitro system.Methods:Rat primary hepatocytes were isolated and treated with BDE-99 for 24-72 h.Metabolites were then extracted from the hepatocytes and media,and detected by GC/MS.Several mRNAs of metabolic enzymes were also extracted from the same cells and the gene expression levels were determined using quantitative real-time PCR.In addition,selected recombinant cytochrome P450s(CYPs) were expressed in a bacurovirus/sf9 system,and these were further used to explore the metabolism of BDE-99 in vitro.The parent depletion approach was used for screening the ability of CYPs to eliminate BDE-99.Results: A reductively debrominated metabolite,BDE-47,and three oxidative metabolites,2,4,5-tribromophenol,5-OH-BDE-47,and 5'-OH-BDE-99,were identified from the BDE-99-treated rat hepatocytes,whereas no MeO metabolite was detected in the system.RT-PCR analysis showed that CYP 3A23/3A1,1A2,and 2B1/2 were induced by BDE-99.Furthermore,using the heterological expressed CYP proteins in in vitro BDE-99 metabolism experiments we found that CYP1A2 and CYP3A4 showed the highest metabolic efficiency for BDE-99,with the metabolic clearance rates of CYP1A2 and CYP3A4 being 30.3%and 27.7%,respectively.CYP1A1 and CYP2A6 displayed relatively low clearance rates,while CYP2E1 seemed not to be associated with the BDE-99 metabolism.Conclusions:In our in vitro rat primary hepatocyte metabolism system,four metabolites of BDE-99 were identified,and CYP3A4 and CYP1A2 were demonstrated to be involved in the BDE-99 metabolism.

Colloid-facilitated release of polybrominated diphenyl ethers at an e-waste recycling site: evidence from undisturbed soil core leaching experiments

Polybrominated diphenyl ethers (PBDEs), a class of persistent organic pollutants, have been frequently detected in soil at e-waste recycling sites. However, the key factors controlling the transport of PBDEs from surface soil to the vadose zone and groundwater are unclear. Here, colloid-enhanced leaching of PBDEs from undisturbed soil cores collected at an e-waste recycling site in Tianjin, China, is reported. Spatially heterogeneous release of colloids and PBDEs was observed in all the tested soil cores under chemical and hydrodynamic perturbations, indicating the presence of preferential flow paths. Colloid concentration in the effluent significantly increased as ionic strength decreased (from 10 to 0.01 mmol/L), probably due to the stronger electrostatic repulsion between colloidal particles and the soil matrix at lower ionic strength. In contrast, colloid mobilization was not significantly affected by the changes in pH of the influent (from 4.0 to 10.0) and flow rate (from a Darcy velocity of 1.5 to 6.0 cm/h). The concentrations of 2,2′,3,3′,4,4′,5,5′,6,6′-decabromodiphenyl ether (BDE-209), the predominant PBDE congener at the site, detected in the leachate (ranging from 1.09 to 3.43 ng/L) were much lower than previously reported results from packed column leaching tests, and were positively correlated with colloid concentrations. This indicates that remobilization of colloids at e-waste recycling sites can promote the leaching and downward migration of PBDEs from surface soil. The findings highlight the potential risk of surface soil PBDE contamination to groundwater quality and call for further understanding of colloid-facilitated transport for predicting the fate of PBDEs at e-waste recycling sites.

上海地区留鸟麻雀中多溴联苯醚(PBDEs)空间分布特征研究

为了探明上海地区留鸟麻雀中多溴联苯醚(PBDEs)污染水平、分布模式及其区域性地理分布特征,本研究以上海为典型研究区域,检测了不同功能区域内麻雀肌肉中PBDEs的含量。结果发现,上海麻雀肌肉样品中Σ_(7)PBDEs含量(BDE 28、BDE 47、BDE 99、BDE 100、BDE 153、BDE 154和BDE 183含量之和,以脂质质量计)范围为9.0~83.6 ng·g^(-1),BDE 209最高含量达292.0 ng·g^(-1),BDE 209平均含量是Σ_(7)PBDEs平均含量的2倍左右,表明十溴联苯醚(Deca)商业品是上海地区麻雀中PBDEs的主要污染源。上海工业园区和城市中心地区样品中Σ8PBDEs含量(Σ_(7)PBDEs和BDE 209含量之和)显著高于农村地区的麻雀样品,Σ_(8)PBDEs地理空间分布遵从填埋场>工业园区>城市中心地区>城郊结合部>农村的规律,垃圾填埋场、工业园区是上海区域潜在的PBDEs的释放源。与全国其他地区相比,上海市麻雀中PBDEs含量处于较低水平,上海地区PBDEs的生态风险较小,但垃圾填埋场、工业园区和中心城区的个别麻雀样品PBDEs含量水平较高,其潜在环境风险不容忽视。

大鼠肝微粒体体外代谢多溴联苯醚(PBDEs)类污染物的研究

多溴联苯醚(PBDEs)是一类在工业上被广泛使用的阻燃剂,具有环境持久性、生物可富集性、生物毒害性等持久性有机污染物(POPs)的特点。PBDEs具有众多不同的单体,其在不同生物体内表现出不同的单体组成特征。为了调查主要PBDEs在大鼠(哺乳动物模式生物)中的差异性代谢模式及探究原因,本文研究了大鼠肝微粒体对BDE-47和BDE-99的代谢产物和途径,对其差异性代谢特点进行比较,并就参与反应的酶种类和活性对该现象的原因进行了初步讨论。

Distribution and partition of polybrominated diphenyl ethers(PBDEs) in water of the Zhujiang River Estuary

The spatial,temporal,and vertical distributions of polybrominated diphenyl ethers(PBDEs) in water columns from the Zhujiang River Estuary were examined,and the partition behavior of PBDEs between particle and dissolved phases was investigated in the present study.The results show that the distributions of PBDEs concentrations in the water varied with the sampling seasons.The PBDEs concentrations in water samples were lower in May 2005,when the brackish water was dominant in the estuary,than in October 2005,when fresh water from river runoff dominated the estuary.The spatial distribution of PBDEs in October 2005 indicated that the river runoff was the major mode to input PBDEs to the estuary,and the concentration of PBDEs in water might be dissolved organic carbon(DOC) dependence.The spatial and vertical distributions of PBDEs in May 2005 were relatively homogeneous,and SPM was the major factor on controlling the levels of PBDEs in this sampling time.Both DOC and POC could play certain roles in determining the distribution and partition of PBDEs between particle and dissolved phases,but their effects varied with the water properties.

Efficient removal of polybrominated diphenyl ethers from soil washing effluent by dummy molecular imprinted adsorbents: Selectivity and mechanisms

Surfactant enhanced elution is an effective method for removing hydrophobic organic pollutants from soils.The key to the development of leaching technology is selective removal of targeted pollutants in soil washing effluent and recycling of surfactant solutions.In this study,a molecular imprinting technique was applied to selectively sorb polybrominated diphenyl ethers(PBDEs)in soil washing effluent.The novel molecular imprinted polymers(MIPs)using different template molecules were synthesized by precipitation polymerization.Adsorption behaviors andmechanisms ofMIPs were studied through experiments and theoretical calculations.The results show that 4-bromo-4'-hydroxybiphenyl and toluene can be effective imprinting molecule for MIPs synthesis.The maximal adsorption capacity of selected dummy molecular imprinted polymer(D1-MIP)was 1032.36μmol/g,and that of part molecular imprinted polymer(P-MIP)was 981.13μmol/g.Their imprinting factors in 5 PBDEs adsorption ranged from 2.13 to 5.88,the recovery percentage of Triton X-100 can reach 99.09%,confirming the feasibility of reusing surfactant.Various PBDEs could be removed by MIPs,and Quantitative Structure Property Relationship analysis revealed that PBDEs’molecular volume,planarity,polarity,and hydrophobicity have major influences on their adsorption performance.DFT calculation revealed that Van derWaals force and hydrogen bonding played important roles during selective adsorption.These results can provide effective theoretical guidance for surfactant enhanced soil elution in practical engineering applications.

上海市典型家庭室内空气中PCBs与PBDEs初步研究

于2008年12月─2009年3月用PUF被动采样器采集了上海市6个典型家庭室内的空气样本,利用GC-EI-MS和GC-NCI-MS法分别测定了样本中14种多氯联苯(PCBs)和7种多溴联苯醚(PBDEs)的质量浓度,采用GC-ECD法测定了ρ(BDE-209).结果表明:ρ(ΣPCBs)为313.84～753.79 pg m3,平均值为442.09 pg m3;ρ(ΣPBDEs)为0.62～83.35 pg m3,平均值为21.83 pg m3;ρ(BDE-209)为114.9～221.19 pgm3,平均值为185.58 pg m3.与文献报道相比,上海市家庭室内空气中ρ(ΣPCBs)处于中等水平,ρ(ΣPBDEs)略低,但ρ(BDE-209)明显高于其他地区.儿童和成人对PCBs的日均暴露量达到1 980和4 772 pg d,对PBDEs的日均暴露量达到930和2 241 pg d.PCBs和PBDEs能够引起人体生物毒性效应,因此,作为在室内空气中普遍存在的有机污染物,其持续低剂量的暴露应引起重视.

多溴二苯醚(PBDEs)对环境的污染及其生态化学行为

作为一种良好的防火溴代阻燃剂(brominnted flamt retardants,BFRS),多溴二苯醚(polybrominated diphenyl ethers,PBDEs)主要应用于各种家用和工业产品中,包括各种电子产品和家庭装饰产品。近年来,环境中PBDEs的浓度在不断上升。PBDEs具有很高的亲脂性和持久性,使得其在环境中易于富集和生物放大;同时,PBDEs又具有一定的挥发性,能够长途迁移至偏远地区;PBDEs具有一定的生物致毒作用和内分泌干扰作用。本文从生态化学行为和生态毒性两个方面综合论述了PBDEs在环境中的分布及存在水平、一般毒性效应和内分泌干扰行为,分析了当前研究中存在的问题,展望了PBDEs污染的研究方向。

珠江三角洲流域土壤多溴联苯醚(PBDEs)的分布及环境行为

用索式抽提、复合硅胶/氧化铝层析柱分离纯化、GC-MS分析方法分析了珠江三角洲流域土壤中10种多溴联苯醚(BDE-28、-47、-66、-99、-100、-153、-154、-138、-183、-209)在土壤中的质量分数和组成分布。∑9PBDEs(不包括BDE209)的质量分数从0.133ng·g-1干物质量到3.81ng·g-1干物质量,平均质量分数为1.02ng·g-1干物质量,BDE-209的质量分数从2.38ng·g-1干物质量到66.6ng·g-1干物质量,平均质量分数为13.8ng·g-1干物质量,与欧洲背景土壤中PBDEs的质量分数水平相当。同系物的组成分布说明珠江三角洲土壤中多溴联苯醚的污染来源主要是五溴、八溴及十溴产品的使用。土壤中∑9PBDEs和各同系物的含量与土壤总有机碳(TOC)的含量呈现显著的正相关。有机碳均一化后BDEs单体含量的对数与其logKow正相关(除-47,r2=0.89),表明土壤有机质的吸附决定着PBDEs在环境中的分布和迁移。

多溴联苯醚(PBDEs)在海洋环境中的行为研究进展

多溴联苯醚(PBDEs)被称作"二十一世纪的多氯联苯",是一类具有生态风险性的新型持久性有机污染物。本文在介绍PBDEs物理化学性质的基础上,分析了PBDEs在海洋中的时空分布变化趋势,重点总结了PBDEs在海洋中的生物积累、生物放大、生物转化行为及其对海洋生物的毒性,探讨了海洋环境中PBDEs未来的研究方向。

日用塑料制品中PBDEs的污染特征及其人体健康暴露风险

采用气相色谱/质谱联用仪和健康风险评价模型,研究了北京居民日常接触的典型日用塑料制品中PBDEs（多溴二苯醚）的赋存特征及其人体健康暴露风险.结果表明：1塑料盆、垃圾桶、塑料垫、塑料板凳、拖把、热水壶壳、给水管、采暖管、排水管、拖鞋、收纳箱、文件框等12种日用塑料制品中w（∑21PBDEs）为0.45-21.30 mg/kg,平均值为5.98 mg/kg.2日用塑料制品中十溴二苯醚是主要的PBDEs同系物,w（十溴二苯醚）平均占w（∑21PBDEs）的82.51%;九溴二苯醚是次要PBDEs同系物,平均占9.76%;三溴-六溴二苯醚质量分数较低,平均占1.77%,日用塑料制品生产过程中添加含十溴二苯醚的废弃阻燃塑料是引起PBDEs污染的主要原因.3成人通过呼吸吸入、皮肤接触和手-口3种途径摄入的PBDEs暴露量分别为295.77、44.29、0.00pg/（kg·d）,儿童通过3种途径的PBDEs暴露量分别为769.55、40.83、1.91 pg/（kg·d）表明呼吸吸入是主要暴露途径.4日用塑料制品中PBDEs对成人和儿童的释放暴露非致癌危害熵分别为2.28×10-4和5.46×10-4,低于美国标准中可接受风险熵（1.0）,表明日用塑料制品中PBDEs对人体的健康风险影响很小.

行政办公室内PBDEs污染特征及人体暴露量

为研究普通行政办公场所内多溴联苯醚（PBDEs）的污染现状、同类物分布特征及办公人群吸入暴露量,于2013年3月～8月期间在杭州市行政办公场所采集20个空气样品,用GC-ECD分析样品中14种PBDEs同类物.结果发现：杭州市办公场所空气中PBDEs总平均浓度达9.57×102pg/m3,与欧洲国家相比处于较高污染水平,其中BDE-209是主要污染成分,占总含量的57.4%,说明杭州市办公场所PBDEs的主要工业品来源是十溴联苯醚.与家庭住宅空气样品对照发现,办公场所PBDEs平均浓度是家庭住宅的1.26倍,并且这一浓度差异主要体现在BDE-209单体上.办公场所各采样点同类物气固相对百分含量在50.0%左右,说明空气中PBDEs一半以气态形式存在,一半则吸附在空气颗粒物中,这可能是PBDEs气固分配还未平衡所致.此外,杭州市普通行政办公人群BDE-99的总摄入量为2.03×102pg/（kg？d）,比国际标准BDE-99每日允许摄入量低21.7%.

厦门近海沉积物中PBDEs与PBBs残留的GC-NCI／MS和GC-ECD分析

将气相色谱．负离子化学源．质谱法（GC—NCI／MS）和气相色谱-电子捕获检测法（GC-ECD）应用于分析沉积物中6种多溴联苯醚（PBDEs）和5种多溴联苯（PBBs）残留。沉积物样品以V（正己烷）：V（丙酮）=1：1作为提取剂，采用索式提取法，提取液经酸性硅胶和中性硅胶层析柱净化和正己烷洗脱后，以PCB-103为内标物和GC-NCI—MS的选择离子监测方式（SIM）进行定性与定量分析，PBDE-209则采用GC．ECD法分析。平均加标回收率为93．3％～110．8％，相对标准偏差为1．2％-8．6％，方法检测限均小于0．20μg／kg（PBDE-209的方法检测限是7．74μg／kg），相关系数都大于0．9990。所分析沉积物样品中均含有微量的PBDE-99、PBB-49和PBDE-209。