短链氯化石蜡对褐牙鲆胚胎发育的毒性效应

氯化石蜡(chlorinated paraffins, CPs)是一系列多氯正构烷烃的复杂混合物,其中短链氯化石蜡(short chain chlorinated paraffins, SCCPs)因具有持久性有机污染物(persistent organic pollutants, POPs)的诸多特性而被国内外学者广泛关注,但目前关于SCCPs毒性效应的报道仍然较少。因此本研究基于SCCPs的海洋污染现状,以褐牙鲆胚胎为实验对象,通过132 h的暴露实验探究了SCCPs的毒性效应。结果表明,SCCPs具有显著的胚胎发育毒性,能够导致胚胎-仔鱼存活率降低,且具有时间效应-剂量效应;能够导致胚胎孵化延迟,高浓度(≥1 000 μg·L^-1)还会导致孵化率降低;能够引起胚胎-仔鱼发育畸形,如脊柱弯曲、心包水肿等;能够抑制仔鱼生长等。此外,SCCPs还能诱导胚-仔鱼发生氧化应激反应,实验组仔鱼的超氧化物歧化酶活性、过氧化氢酶活性及丙二醛的含量均显著高于对照组(P＜0.05),抗氧化酶基因sod、cat的相对表达量也要高于对照组。随着SCCPs浓度增加,实验组仔鱼超氧化物歧化酶、过氧化氢酶活性呈下降趋势,清除活性氧自由基的能力逐渐下降,导致机体发生严重的脂质过氧化作用,10 000 μg·L^-1实验组仔鱼中观察到丙二醛含量接近于对照组的3倍。研究结果揭示了SCCPs对海洋生物早期发育阶段的生态毒性,将为SCCPs的环境风险评估提供理论依据。     

A History of the Production and Use of Carbon Tetrachloride,Tetrachloroethylene, Trichloroethylene and 1,1,1-Trichloroethane in the United States: Part 1--Historical Background; Carbon Tetrachloride and Tetrachloroethylene

Carbon tetrachloride (CTC), tetrachloroethylene (PCE), trichloroethylene (TCE) and 1,1,1-trichloroethane (TCA) were four of the most widely used cleaning and degreasing solvents in the United States. These compounds were also used in a wide variety of other applications. The history of the production and use of these four compounds is linked to the development and growth of the United States' synthetic organic chemical industry, and historical events that affected the development and use of chlorinated solvents in general. Part 1 of this article includes a discussion of the historical background common to each of the four solvents, followed by discussion on the history of CTC and PCE. In the early years of the 20th century, CTC became the first of the four solvents to come into widespread use. CTC was used as a replacement for petroleum distillates in the dry-cleaning industry, but was later replaced by PCE. In the 1990s, CTC was phased out under the Montreal Protocol due to its role in stratospheric ozone depletion.     

大连市海产品中短链氯化石蜡的含量与分布研究

氯化石蜡（chlorinated paraffins,CPs）是一类广泛使用的工业化学品,常用作阻燃剂、增塑剂等添加到塑料及其制品中。其中,短链氯化石蜡（short-chain CPs, SCCPs）和中链氯化石蜡（medium-chain CPs, MCCPs）因其环境持久性、生物累积性和水生生物毒性受到全球关注。我国是氯化石蜡生产和使用的大国,SCCPs和MCCPs在海洋环境的赋存和生态风险尤其值得关注。本研究采集了北黄海12种海洋生物,采用稳定氮/碳同位素分析方法确定其营养级。基于气相色谱−静电场轨道阱高分辨质谱（gas chromatography-electrostatic field orbitrap high resolution mass spectrometry,GC-Orbitrap-HRMS）对SCCPs和MCCPs进行定量分析,探究中国北黄海海域海洋生物体内SCCPs和MCCPs的分布特征,并对其暴露风险进行评估。结果表明,SCCPs和MCCPs在所有采集样本中普遍存在,SCCPs浓度为29.2～2450.4 ng/g dw,略高于MCCPs（12.1～1362.8 ng/g dw）。生物体内SCCPs和MCCPs干重浓度与脂质含量具有较强的相关性（r²=0.61,p<0.05）。SCCPs同系物分布以C₁₀-CPs和C₁₁-CPs为主,MCCPs以C₁₄-CPs为主。SCCPs和MCCPs中均为Cl_7-8同系物丰度最高。SCCPs及MCCPs同系物的生物放大因子（biomagnification factors,BMF） 随着辛醇−水分配系数（octanol-water partition coefficient,log Kow ）的增加呈下降趋势。SCCPs（BMF=0.23）和MCCPs（BMF=0.14）在许氏平鲉（Sebastes schlegelii）与小黄鱼 （Larimichthys polyactis）之间表现出生物稀释作用。此外,还对食用鱼类中SCCPs和MCCPs的潜在暴露风险进行了评估,其风险熵（hazard quotient,HQ）最大值分别为0.04 和0.06,均无风险。对于农村和城镇居民而言,通过食用这些鱼类而摄入的SCCPs和MCCPs水平不会对人体健康造成显著影响。

     

Improved xenobiotic-degrading activity of Rhodococcus opacus strain 1cp after dormancy

The goals of the present work were as follows: to obtain the dormant forms of R. opacus 1cp; to study the phenotypic variability during their germination; to compare phenotypic variants during the growth on selective and elective media; and to reveal changes in the ability of the strain to destruct xenobiotics that had not been degradable before dormancy. It was shown that Rhodococcus opacus 1cp (the strain degrading chlorinated phenols) became able to utilize a broader spectrum of xenobiotics after storage in the dormant state. Germination of the dormant forms of R. opacus 1cp on an agarized medium was followed by emergence and development of phenotypic variants that could grow on 4-chlorophenol and 2,4,6-trichlorophenol without adaptation. The cells of R. opacus 1cp phenotypic variants also utilized all of the tested chlorinated phenols: 2,3-, 2,5-, and 2,6-dichloro-, 2,3,4- and 2,4,5-trichloro-, pentachlorophenol, and 1,2,4,5-tetrachlorobenzene in concentrations up to 60 mg/L, though at the lower rates than 4-CP and 2,4,6-TCP. The improved degradation of chlorinated phenols by R. opacus strain 1cp exposed to the growth arrest conditions demonstrates the significance of dormancy for further manifestation of the adaptive potential of populations. A new principle of selection of variants with improved biodegradative properties was proposed. It embraces introduction of the dormancy stage into the cell life cycle with subsequent direct inoculation of morphologically different colonies into the media with different toxicants, including those previously not degraded by the strain.     

广州土壤中短链氯化石蜡的含量水平和分布特征

短链氯化石蜡(SCCPs)是一类新的持久性有机污染物(POPs),目前我国相关研究较少。为了解SCCPs在土壤中的污染现状和分布特征,测定了24个广州土样(含3个剖面采样点)中SCCPs的含量,分析了其同族体分布模式。结果表明:广州表层土壤中SCCPs的含量变化范围为6.8～541.2ng/g,均值为79.6ng/g;剖面土壤中SCCPs的含量范围为7.5～115.8ng/g,均值为33.1ng/g。不同类型土壤中SCCPs各同系物组分的分布模式相似,以碳原子数为10和11的Cl6-SCCPs/Cl7-SCCPs为主。     

氯化石蜡的毒代动力学研究进展

氯化石蜡（chlorinated paraffins,CPs）是一类氯代烷烃混合物,其在不同环境基质甚至人体中被普遍检出,对生态系统和人体健康构成了潜在危害,受到人们的广泛关注。本文系统总结了国内外CPs毒代动力学的相关研究,阐述了CPs在生物体内的吸收、分布、代谢和排泄过程,以及经生物转化的代谢降解途径。重点阐明了CPs在水生、两栖和爬行生物体内的生物富集和生物放大潜能,在两栖、爬行、哺乳和鸟类动物中的母体转移过程,以及在动植物和微生物中的代谢途径及其代谢产物。最后提出了3个亟需探究的方向：开展系统的短链氯化石蜡替代品安全性评价,基于先进的分析技术全面探究CPs在生物体内的代谢过程,开展低剂量CPs暴露的母婴转移途径和健康风险评估,以期为CPs相关领域的研究者提供参考。     

Prediction of polychlorinated dibenzofuran congener distribution from gas-phase phenol condensation pathways

A model for predicting the distribution of dibenzofuran and polychlorinated dibenzofuran (PCDF) congeners from a distribution of phenols was developed. The model is based on a simplified chemical mechanism. Relative rate constants and reaction order with respect to phenol precursors were derived from experimental results using single phenols and equal molar mixtures of up to four phenols. For validation, experiments were performed at three temperatures using a distribution of phenol and 19 chlorinated phenols as measured in municipal waste incinerator exhaust gas. Comparison of experimental measurements and model predictions for PCDF isomer distributions and homologue pattern shows agreement within measurement uncertainty. The R-squared correlation coefficient exceeds 0.9 for all PCDF isomer distributions and the distribution of PCDF homologues. These results demonstrate that the distribution of dibenzofuran and the 135 PCDF congeners from gas-phase condensation of phenol and chlorinated phenols can be predicted from measurement of the distribution of phenol and the 19 chlorinated phenol congeners.     

Gas chromatographic studies of chlorinated phenols,chlorinated anisoles,and chlorinated phenylacetates

The g.l.c. retention times of all chlorinated phenols, anisoles, and phenylacetates on different capillary columns are presented. The relative retention times of the chlorinated phenols are discussed with reference to their pK_a values and their toxicities.     

土壤中短链氯化石蜡的气相色谱-电子捕获负化学电离-质谱分析方法

通过考察层析柱对测定短链氯化石蜡(SCCPs)干扰物去除效果的影响,结合实际土壤样品的净化需求,建立了一套适合分析土壤中SCCPs的前处理方法.土壤样品使用索氏抽提,采用硅胶复合柱和弗罗里硅土柱净化,运用气相色谱-质谱(ECNI源)检测SCCPs.SCCPs的仪器定量限为100—600 pg.μL-1.空白加标和基质加标中SCCPs的回收率分别为130%±8.50%和108%±17.8%(SD,n=3).利用该方法分析了采自广州市郊区的6个土壤样品,其SCCPs的含量范围为12.9—34.5 ng.g-1,平均值为26.1 ng.g-1.