Comparative in vitro metabolism of chloroxylenol,chlorophene, and triclosan with rat,mouse, and human hepatic microsomes

A number of studies have reported the presence of chlorinated phenols, commonly used as antiseptics, in the environment. Chloroxylenol, chlorophene, and triclosan are three such chemicals believed to have leached into water supplies through the wastewater treatment facilities. Understanding how these compounds are metabolized is important in determining the risks of chemical exposure. In this study, we compared the in vitro metabolism of these three chlorinated phenols with rat, mouse, and human liver microsomes. The structures of the metabolites formed during the microsomal reactions were identical when rat, mouse, and human liver extracts were used, but variations existed in the kinetics of the reactions.     

固相萃取/气相色谱质谱法测定灰尘中的氯代多环芳烃

建立了固相萃取(SPE)/气相色谱质谱(GC/MS)联用检测灰尘中氯代多环芳烃(ClPAHs)的方法.以正己烷和二氯甲烷混合液为提取溶剂,索氏提取灰尘样品中的20种ClPAHs,活性硅胶层析柱与活性炭混合硅胶SPE柱协同净化.净化后的提取液采用GC/MS测定,SIM模式扫描,并用质谱特征离子定量分析.结果表明,填充量为0.2 g(W(活性炭)∶W(硅胶)=1∶40)的活性炭混合硅胶SPE小柱能有效地将ClPAHs分离出来,载样后采用反向溶剂洗脱,既提高了回收率又减少了洗脱剂甲苯的用量,净化效果好.处理灰尘样品后检测分析,20种ClPAHs的平均回收率稳定在60.4%—120.1%,相关系数>0.99,检出限为0.04—0.17 ng.g-1,相对标准偏差为1.6%—10.2%.本方法前处理简单,定性、定量准确可靠,可广泛应用于环境介质中氯代多环芳烃的检测.     

Kinetics and mechanisms of reactions for hydrated electron with chlorinated benzenes in aqueous solution

The reactions between chlorinated benzenes (CBzs) and hydrated electron (eaq-) were investigated by the electron beam (EB) and laser flash photolysis (LFP) experiments. Under the EB irradiation, the effects of irradiation dose, initial concentration and the number of Cl atoms on the removal efficiencies were further examined. At 10 kGy, the removal efficiencies of mono-CB, 1,3-diCB, 1,2-diCB and 1,4-diCB were 41.2%, 87.2%, 84.0%, and 84.1%, respectively. While irradiation dose was 50 kGy, the removal efficiencies increased to 47.4%, 95.8%, 95.0%, and 95.2%, respectively. Irradiation of CBzs solutions has shown that the higher the initial concentration, the lower the percentage of CBzs removal. In addition to this, the dechlorination efficiencies of 1,2-dichlorobenzene (1,2-diCB), 1,3-dichlorobenzene (1,3-diCB) and 1,4-dichlorobenzene (1,4-diCB) were much higher than that of chlorobenzene (mono-CB). The kinetics of the reactions was achieved with nanosecond LFP. The rate constants of second-order reaction between eaq- with mono-CB, 1,2-diCB, 1,3-diCB and 1,4-diCB were (5.3±0.4) × 10⁸, (4.76±0.1) × 10⁹, (1.01±0.1) × 10¹⁰ and (3.29±0.2) × 10⁹ L·mol^-1·s^-1, respectively. Density functional theory (DFT) calculations were performed to determine the optical properties of unstable CBzs anion radicals, and the main absorption peaks lied in the range of 300–550 nm. The primary reaction pathway of CBzs with eaq- was gradual dechlorination, and the major products were Cl^- and benzene (CBzs(-Cl^-)). Furthermore, biphenyl (or chlorobiphenyl) was observed during the LFP, which was probably formed by recombination of benzene radicals.     

双介质矿岩轴向加载损伤破坏试验分析研究

为研究夹石对矿体力学变形特性的影响,选用全精炼的工业石蜡作为夹石模拟材料,并与水泥和矿粉进行配比制样。通过表壁裂纹扩展、微观成像、表壁应变值变化、整体加载压缩变形、磁感应强度变化、红外温度测量共同表征夹石试样在加载过程中的力学变形特征,厘清夹石矿岩的破坏特点。同时提出了一种数值模拟夹石的方法,进行不同夹石含量矿岩的安全系数、最大主应力及不同监测点处应变值的变化监测。试验结果表明:存在夹石的试样在加载过程中表壁出现较多裂纹条数,且以短裂纹为主,分布区域较广;表壁纵向应变变化较平稳,而横向应变存在阶梯型变化;红外温度测量并无恒定的变化幅度,存在升降的起伏变化;磁感应强度值变化存在上升下降型、下降平稳型、下降上升型的变化特点。数值模拟结果表明:夹石的存在弱化了矿岩的整体强度,这与相似模拟结果具有一致性。同时不同的夹石强度对矿岩的整体稳定性影响不一样。当试样的整体稳定性与夹石的物理性质有关,夹石强度是矿石强度50%左右时,彼此接触严丝合缝,夹石存在及含量的多少产生的影响不大;如果夹石强度只是矿石强度的2%时,相应的测点起伏变化较大;如果试样完整性不好,存在较多微观空区,空区附近的相应测点的应变值变化起伏较大。     

造纸厂土壤中短链和中链氯化石蜡的污染特征和风险评估

短链氯化石蜡是一类新型持久性有机污染物,氯化石蜡在造纸工业中常用作施胶剂,为了评估造纸厂区土壤中短链及中链氯化石蜡（SCCPs及MCCPs）的污染状况及其潜在风险,采集厂区表层和不同深度的土壤,利用全二维气相色谱-电子捕获负化学离子源-质谱（GC×GC-ECNI-MS）测定土壤中短链及中链氯化石蜡（SCCPs及MCCPs）的含量及同类物分布特征.结果表明,SCCPs和MCCPs在厂区土壤中均有检出,其含量分别为42~3853 ng·g^-1和34~2091 ng·g^-1,氯含量分别为59.9%~61.9%和48.7%~52.8%.不同采样点土壤样品中CPs（ΣSCCPs+ΣMCCPs）含量差异较大,污水处理区及施胶区土壤中SCCPs及MCCPs含量较高.与其他地区相比,厂区土壤中SCCPs及MCCPs处于较高水平.C₁₀Cl_6-7及C_14-15Cl₅是大部分土壤样品的主要同类物.主成分分析表明,厂区土壤中SCCPs及MCCPs可能主要来自于CP52产品的生产和使用.运用风险商值模型（RQ）评价SCCPs及MCCPs在造纸厂区土壤中的潜在风险,发现厂区土壤中SCCPs风险商范围为0.01~0.73,处于中等风险范围,MCCPs风险商范围为0~0.07,处于低等风险范围.儿童和成人人体暴露值低于TDI［10 μg·（kg·d）^-1］,造纸厂区非饮食暴露导致的健康风险较低.     

The significance of PCBs in the atmosphere of the southern hemisphere

Air monitoring stations were set up at 2 sites in the southern hemisphere--Moody Brook, Falkland Island (51 degrees 25' S, 57 degrees 56' W) and Halley, Research Station, Antarctica (75 degrees 35' S, 26 degrees 30' W). PCBs were monitored at the stations throughout 1999. Highest concentrations were observed when temperatures were greater. In general, concentrations were greater at Moody Brook than at Halley, although the difference in concentrations between sites was less for more chlorinated congeners. Air concentrations at both sites were compared with samples collected nearby over-water. Over water air concentrations were found to be greater than over land air concentrations. Concentrations were also compared with literature data for air concentrations at a remote site in the Canadian Arctic. Atmospheric concentrations of tri-chlorinated biphenyls were found to be approximately double those reported for Ellesmere Island in the Canadian Arctic, whilst concentrations in samples from Antarctica were very similar to those found in the high Arctic. Most other PCBs were a factor of 2-4 greater in the Canadian Arctic.     

Electrochemical oxidation of polyethylene glycol in electroplating solution using paraffin composite copper hexacyanoferrate modified (PCCHM) anode

Electrochemical oxidation of polyethylene glycol (PEG) in an acidic(pH 0.18 to 0.42) and high ionic strength electroplating solution was investigated. The electroplating solution is a major source of wastewater in the printing wiring board industry. A paraffin composite copper hexacyanoferrate modified(PCCHM) electrode was used as the anode and a bare graphite electrode was used as the cathode. The changes in PEG and total organic carbon (TOC) concentrations during the course of the reaction were monitored. The efficiency of the PCCHM anode was compared with bare graphite anode and it was found that the former showed significant electrocatalytic property for PEG and TOC removal. Chlorides present in the solution were found to contribute significantly in the overall organic removal process. Short chain organic compounds like acetic acid, oxalic acid, formic acid and ethylene glycol formed during electrolysis were identified by HPLC method. Anode surface area and applied current density were found to influence the electro-oxidation process, in which the former was found to be dominating. Investigations of the kinetics for the present electrochemical reaction suggested that the two stage first-order kinetic model provides a much better representation of the overall mechanism of the process if compared to the generalized kinetic model.     

生物处理含氯代脂肪烃废水的研究进展

从降解菌种及涉及的酶体系,降解过程机理,降解动力学和所用反应器等４方面对氯代脂肪烃的生物降解的研究作了综述,文献表明：通过驯化,某些菌种能在特写条件下降解氯代脂肪族物质。还介绍了降解菌种的特征,降解的可能途径和动力学模型,并比较了各种氯代脂肪族组分的可生物降解性。同时对降解所用的反应器进行了评价。     

Dioxins in the Venice lagoon

Venice is famous around the world for its uniqueness and architectural splendours, arts and the history of the “Serenissima Repubblica”, as it was known in the past, but few are aware that Venice economy is strongly dependent on the industrial activities based mainly on the adjacent Porto Marghera area. For many years, the lagoon that physically separates the city from the dry land has avoided association between the concern connected with the pollution derived from these industrial activities and the public perception of Venice. Since 1995, dioxins have appeared as a lagoon contaminant, and their presence, at such a level requiring immediate “in depth” studies and interventions, has been fully realized for decades.     

氯代芳香化合物生物降解性能与其化学结构的相关性

应用结构－活性定量关系研究方法,对氯代芳香化合物的好氧生物降解性能与其化学结构间的关系进行了研究,并建立了受试物的好物降解速率常数与４个高阶分子连接性指标及取代基电子效应数为结构参数的定量关系,分析表明,有机物取代基的电性能数和空间构型是影响受试物好氧生物降解性能的２个重要因素。