江河中有机污染物在鲤鱼体内富集与释放的模拟研究

以第二松花江重点有机污染物硝基芳烃为研究对象,用改进的双膜理论预测了７种硝基芳烃的挥发速率常数,快速测定了它们在鱼体内的富集与释放速率常数,用获得的参数及二室模型预测这７种化合物的鱼体内的迁移过程,并与模拟实验测定的结果进行比较,得到了比较满意的结果。     

The kinetics of reductive dehalogenation of a set of halogenated aliphatic hydrocarbons in anaerobic sediment slurries

Disappearance rate constants are reported for the reductive transformation of 17 halogenated aliphatic hydrocarbons in anaerobic sediment-water samples. Statistical experimental design in combination with multivariate chemical characterization of their chemical properties was used to select the compounds. Degradation followed pseudo first-order kinetics through at least two half-lives for 15 of the 17 compounds. Of all the compounds investigated, 1,2,3-trichloropropane and dichloromethane were unique in that they were dehalogenated according to zero-order kinetics. Reductive dehalogenation was the sole transformation reaction taking place.     

Measurements of peroxyacyl nitrates (PANS) in Mexico City: implications for megacity air quality impacts on regional scales

Peroxyacyl nitrates (PANs) were measured using gas chromatography with electron capture detection (GC/ECD) in north central Mexico City during February–March of 1997. Peroxyacetyl nitrate (PAN) was observed to exceed 30 ppb during five days of the study, with peroxypropionyl nitrate (PPN) and peroxybutryl nitrate (PBN) reaching 6 and 1 ppb maximum, respectively. Levels of total PANs typically exceeded 10 ppb during the period of measurement and showed a very strong diurnal variation with PANs maximum during the early afternoon and falling to less than 0.1 ppb during the evening hours. These levels of PANs are the highest reported values in North America (and the world) for an urban center, since levels of approximately 30 ppb were reported during the late 1970s in the Los Angeles area (South Coast Air Basin, Tuazon et al., 1978). Hydrocarbon measurements indicate that the levels of olefins, specifically butenes are significant in Mexico City. A time series taken of source indicator hydrocarbons taken before and during a Mexican National Holiday with reduced automobile traffic clearly show that mobile sources of butenes are as important as liquefied petroleum gas. Observations of 10–40 ppb C methyl-t-butyl ether (MTBE) are consistent with MTBE/gasoline fuel usage as a source of isobutene and formaldehyde. Both these reactive species can lead to increased oxidant and PAN formation. The strong diurnal profiles of PANs are consistent with regional clearing of the Mexico City air basin on a daily basis. Estimates are given using a simple box model calculation for a number of key primary and secondary pollutant emissions from this megacity on an annual basis. These calculations indicate that megacities can be important sources of both primary and secondary pollutants, and that PANs produced in megacity environments are likely to contribute strongly to regional scale ozone and aerosol productions during long range transport.     

不同量子化学算法在多环芳烃光解行为定量结构-性质关系(QSPR)中的应用

以采用MINDO/3、MNDO和AMI算法计算的17种多环芳烃（PAHs）的前线分子轨道能为分子结构参数,进行了这些PAHs光解速率常数的定量结构－性质相关（QSPR）的研究,并与基于PM3算法得到的QSPR模型进行了比较,研究结果表明,应用PM3算法得到的前线分子轨道能进行这些PAHs光解速率常数QSPR拟合的结果最好,其次是AMI算法,而MINDO/3和MNDO算法得到的结果较差。     

固相萃取-气相色谱/质谱法测定水中多环芳烃

建立了固相萃取-气相色谱／质谱联用测定水中多环芳烃(PAHs)的分析方法．优化了固相萃取条件。结果表明,固相萃取效率高、萃取时间短,采用MS的选择离子检测方式对实际水样中PAHs进行定性定量分析,平均回收率在80．4％～115％之间,相对标准偏差为7．03％～18．5％,方法的检出限在0．010～0．020μg／L之间。通过实际样品中PAHs的分析表明,该法快速,溶剂用量少,能满足痕量分析的要求。     

Effect of ambient polycyclic aromatic hydrocarbons and nicotine on the structure of Aβ42 protein

● B[a]P, nicotine and phenanthrene molecules altered the secondary structure of Aβ₄₂. ● β-content of the peptide was significantly enhanced in the presence of the PAHs. ● Nicotine made stable cluster with Aβ₄₂ peptide via hydrogen bonds. ● Phenanthrene due to its small size, interfered with the Aβ₄₂ monomer more strongly. Recent studies have correlated the chronic impact of ambient environmental pollutants like polycyclic aromatic hydrocarbons (PAHs) with the progression of neurodegenerative disorders, either by using statistical data from various cities, or via tracking biomarkers during in-vivo experiments. Among different neurodegenerative disorders, PAHs are known to cause increased risk for Alzheimer’s disease, related to the development of amyloid beta (Aβ) peptide oligomers. However, the complex molecular interactions between peptide monomers and organic pollutants remains obscured. In this work, we performed an atomistic molecular dynamics study via GROMACS to investigate the structure of Aβ₄₂ peptide monomer in the presence of benzo[a]pyrene, nicotine, and phenanthrene. Interestingly the results revealed strong hydrophobic, and hydrogen-bond based interactions between Aβ peptides and these environmental pollutants that resulted in the formation of stable intermolecular clusters. The strong interactions affected the secondary structure of the Aβ₄₂ peptide in the presence of the organic pollutants, with almost 50 % decrease in the α-helix and 2 %–10 % increase in the β-sheets of the peptide. Overall, the undergoing changes in the secondary structure of the peptide monomer in the presence of the pollutants under the study indicates an enhanced formation of Aβ peptide oligomers, and consequent progression of Alzheimer’s disease.     

有机溶剂浸取石油污染土壤中的多环芳烃

采用索氏提取法和气相色谱分析了某炼油厂周边土壤中的多环芳烃的种类及含量,考察了6种有机溶剂对土壤中多环芳烃的浸取效果,探讨了溶剂与溶质溶解度参数差异对浸取效果的影响。结果表明：土壤试样中含有蒽、荧蒽、芘、 、苯并[a]蒽、苯并[b]荧蒽、苯并[k]荧蒽和苯并[a]芘8种多环芳烃,其含量分别为4.20,22.05,10.62,4.26,5.54,0.80,0.94,4.18 mg/kg;筛选出二氯甲烷作为土壤中多环芳烃的浸取溶剂;最佳浸取条件为浸取时间10 min、浸取温度30 ℃、溶剂与土壤的液固比5:1（mL/g）、土壤含水量8%,在此条件下,总多环芳烃浸出率为83.0%,各种多环芳烃的浸出率分别为蒽97.8%、荧蒽78.2%、芘99.9%、 98.5%、苯并[a]蒽81.1%、苯并[b]荧蒽47.6%、苯并[k]荧蒽14.8%、苯并[a]芘58.7%。     

澳门大气气溶胶中多环芳烃研究

通过1995年和1998年澳门大气气溶胶中多环芳烃分析表明,1998年的有机污染程度是1995年的1.36～4.36倍,大气气溶胶中多环芳烃白天高于夜间,说明主要污染物为居民的工作、生活、商业、交通所排放。澳门商业交通功能区有机毒害污染较为严重,苯并(a)芘和苯并(a)蒽分别为1.56～8.10ng/m3和0.85～4.68ng/m3。      

环境中多环芳烃前处理和分析方法

多环芳烃(PAHa)是一类广泛存在于大气、水体、土壤、沉积物中的持久性有机污染物,对环境和生物体存在较大危害.介绍了国内外部分水体中PAHs的污染状况,对液态和固体PAHs的主要前处理方法和分析方法进行了比较和归纳,展望了环境样品中PAHs的前处理和分析方法的发展方向.     

江汉平原四湖流域上区地下水中多环芳烃分布特征与源解析

初次对江汉平原四湖流域上区地下水中多环芳烃(PAHs)的分布特征和来源进行研究,选择湖北潜江长湖-汉江一带9个典型地下水采样点分枯水期和丰水期进行采样,并利用气相色谱与质谱联用仪对16种优控PAHs进行定量分析.结果表明,研究区枯水期和丰水期地下水中PAHs的浓度变化范围分别为62.74~224.63 ng·L-1和55.86~115.15 ng·L-1,总体水平表现出枯水期高于丰水期,且分布于滨湖区域和近岸带的地下水中PAHs浓度较高.这些PAHs输入途径比较复杂,经用主成分分析法分析其来源,大致可归结为燃烧源,部分采样点有石油或石油燃烧的污染.研究区域地下水中PAHs浓度与国内某些地区相比,显示出较低的污染水平,但就致癌性PAHs来看,枯水期具有致癌性PAHs的浓度范围在19.32~153.39 ng·L-1之间,丰水期在16.30~64.22 ng·L-1之间,均已远远超出地下水中PAHs所允许的致癌浓度范围,这必然会对当地人类身体健康构成威胁.