热解析气相色谱法测定土壤中苯系物

建立了用热解析气相色谱法测定土壤中苯系物的方法.采用保留时间定性,外标法定量.方法检出限分别为:苯1.8 μg·L-1、甲苯3.5 μg·L-1、乙苯7.0 μg·L-1、间二甲苯8.6 μg·L-1、对二甲苯8.6 μg·L-1、邻二甲苯9.8 μg·L-1、苯乙烯10.0 μg·L-1;加标回收率在79%～100%之间,相对标准偏差为1.5%～3.9%.方法操作简便,快速,灵敏度高,能适应现代化的应急监测.     

土壤中苯系物的吹扫捕集-气相色谱-质谱测定方法

采用吹扫捕集-气相色谱-质谱联用(PT-GC-MS)法,研究了污染土壤中苯系物(包括苯、甲苯、乙苯、对间二甲苯、邻二甲苯和异丙苯)的测定方法,优化了吹扫捕集作为北京潮土中苯系物预处理方法的参数. 结果表明,吹扫时间11 min,解吸温度190 ℃和解吸时间0.5 min为最佳的吹扫捕集方法参数. 采用PT-GC-MS法测定土壤中的苯系物的平均加标回收率为99.0%～103.9%,相对标准偏差为10.3%～17.5%(n=7);苯系物的检出限为1.6～2.8 μg/kg,定量限为5.4～9.6 μg/kg. 将研究结果与文献中的苯系物监测质量控制参数进行比较发现,由于采用有机质含量低、砂质壤土质地的北京潮土为研究对象,使该试验的回收率均高于文献中的结果;同时,相对标准偏差和检出限与文献中的结果也存在差异,主要是由于挥发性污染物所赋存的介质及实验仪器操作条件不同所致.      

顶空GC-MS快速分析油漆稀释剂中的苯系物

建立了同时测定油漆稀释剂中常见的7种苯系物的顶空气相色谱-质谱联用(HS/GC-MS)检测方法。研究了顶空条件,包括孵化温度、孵化时间和振动速度,并对色谱参数进行了优化。结果表明:孵化温度60℃、孵化时间20 min、振动速度300 r/min是顶空的最佳条件,DB-5MS UI(30 m×0.25 mm×0.25μm)的色谱柱对7种苯系物在10 min内能进行有效的分离。在优化条件下,7种苯系物的线性范围为0.25~100.0μg/m L,相关系数为0.998 5~1.000,检出限为0.15μg/m L(S/N≥3)。在3个加标水平下,稀释剂中苯系物的回收率在90%~110%之间,相对标准偏差(RSD)是0.5%~6.5%。该方法简单、灵敏,可用于油漆稀释剂中苯系物的快速检测。     

饮用水源水中痕量苯系物测定的自动顶空气相色谱法研究

建立了自动顶空气相色谱法测定水源水中痕量苯系物的实验方法,研究了不同色谱柱、无机盐加入量、顶空平衡温度和时间等因素对测定结果的影响。实验结果表明,DB-FFAP毛细管柱对苯系物分离效果较好,顶空平衡温度和平衡时间分别为80℃和15 min时为最优的实验分析条件,氯化钠加入量3g可使苯系物的响应值达到最大。在此实验条件下,7种苯系物在7～140μg/L范围内线性关系良好,相关系数在0.9997以上,检出限范围1.27～2.11μg/L。当水体中加标浓度约为21、63、106μg/L时,加标回收率分别为93.1%～95.8%、95.9%～103%、97.6%～106%,相对标准偏差为4.6%～7.5%、3.6%～6.6%、3.1%～5.2%。     

自动固相微萃取-毛细管气相色谱法检测环境水中苯系物的研究

对自动固相微萃取(SPME)-毛细管气相色谱法测定环境水中苯系物的方法进行了研究。通过对环境水中苯系物在不同SPME条件的优化、筛选实验，建立了苯系物的自动固相微萃取-气相色谱的检测方法，该方法简便、灵敏、快捷、可靠，分离度高，准确性好。在0．001mg／L～1．00mg／L范围内有良好的线性关系，最低检测浓度为0．1lμg／L～0．41μg／L。样品测定的相对标准偏差为1．8％～3．5％，回收率为88％～108％，精密度和准确度均较好。     

吹扫-捕集气相色谱法测定水中有机化合物

研究建立了吹扫 捕集法富集样品 ,利用HP 1大口径厚液膜通用型熔融石英毛细管柱 ( 30m× 0 .53mm× 2 .6 5μm) ,ECD检测器 ,同时测定水中 8种挥发性卤代烃及氯代苯的方法 ,确定了最佳吹扫 捕集条件。结果表明 :水样体积为 5mL时 ,标准偏差 <0 .0 5μg/L ,变异系数 <3.0 % ,加标回收率为 97.0 %～ 10 5% ,8种物质的最低检测限在 0 .0 3～ 0 .13μg/L之间     

沈阳地区地表水、浅层地下水及沿岸土壤中苯

对沈阳地区主要地表水(浑河、细河、蒲河、沈抚灌渠)及其沿岸地下水和土壤中苯系物(BTEX)的污染特点和分布特征进行了研究.结果表明:细河和沈抚灌渠地表水中BTEX检出率较高(33%～67%),苯和甲苯是该区域的主要污染物,ρ(苯)和ρ(甲苯)分别为<0.30～24.90和<0.30～354.00 μg/L;地表水检出的BTEX均未超过《生活饮用水卫生标准》(GB5749—2006)的限值(1 510 μg/L). 细河两岸的浅层地下水在一定程度上受到BTEX的污染,苯和甲苯的检出率分别为25%～33%和13%～25%,二甲苯和乙苯检出率较低(0～20%). 彰驿镇19个监测井中有2个浅层地下水监测井中的ρ(苯)超过GB5749—2006限值(10 μg/L),夏季ρ(苯)最大值为236.00 μg/L. 沿岸附近土壤中5种BTEX全部被检出,检出率均高于相应的河水. 研究区包气带土壤层虽具有良好的防污性能,但也具有储存和阻碍BTEX挥发和降解的负面效应,对当地的生态系统和人类健康构成了潜在的威胁.      

银-氨络合物的吸附催化波及应用

介绍了在氨 (4mol L) 氯化铵 (1 2mol L) 无水亚硫酸钠 (2 % ) 亚硝酸钠 (0 2mol L)底液条件下,银氨络合物在- 0 0 5V处产生一灵敏的吸附催化波,银线性范围为 0 5～ 2 0 μg mL,检出限为 0 2 5 μg mL。本研究还作了催化波性质初探、干扰试验,并成功地应用于水质分析     

环境空气中苯系物污染物的快速定量研究

本文采用便携式GC/MS仪器对大气中痕量苯系物污染物的快速定量分析进行研究。对比实验结果表明,全扫描和选择离子扫描两种扫描方式下苯系物测定结果的相对标准偏差分别在5.1%²8.4%和13%28.4%和13%¹9%之间,回收率范围分别为46%19%之间,回收率范围分别为46%¹86%和60%186%和60%¹10%,方法检出限范围分别为2.504110%,方法检出限范围分别为2.504¹0.63 ug/m3和0.49410.63 ug/m3和0.494².399 ug/m3。总体而言,选择离子扫描方式在测定结果的精密度与准确度上均优于全扫描方式。     

气相色谱质谱-内标法检测油漆中苯系物

以氯苯为内标物,采用气相色谱-质谱联用仪对油漆中苯系物的检测技术进行了研究,考察了主要苯系物的线性、回收率和精密度情况,开发出一种同时检测油漆中六种苯系物的高灵敏度方法。对样品的色谱分离条件、提取溶剂、定量方法及内标物选择等进行了优化,实现了一次进样同时定性定量检测油漆中6种苯系物。六种苯系物在1.0~500.0μg/mL范围内线性良好,各种苯系物的标准工作曲线线性相关系数0.995 4~0.999 8;在100.0~500.0μg/mL浓度范围内,加标回收率在85.01%~107.44%之间,精密度在2.58%~12.43%之间;5种苯系物组分中苯、甲苯、乙苯、间(对)二甲苯、邻二甲苯的最小检测浓度(按三倍信噪比)分别为0.01、0.002、0.05、0.05、0.05μg/mL。该方法灵敏度较高,所得数据准确,是一种检测油漆等化工品中苯及同系物含量的有效方法。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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