微波萃取在环境样品分析测试中的应用

综述了微波萃取技术以及在环境样品前处理方面的应用,简述了微波萃取法的原理、特点及其在环境样品中提取多环芳烃（PAHs）、有机氯农药、多氯联苯（PCBs）和重金属等方面的应用.     

GC-NCI-MS法测定底泥中类二(噁)英多氯联苯

建立了气相色谱/负化学负离源/质谱(G-NCI-MS)法测定底泥样品中世界卫生组织(WHO)推荐的12种类二(噁)英多氯联苯.底泥样品采用索氏提取,酸碱复合硅胶柱净化,选择离子扫描监测,同位素稀释内标法定量.比较PCBs各单体在负化学负离源(NCI)和电子轰击电离源(EI)条件下的灵敏度,发现PCBs各单体在NCI条件...     

典型污染地区底泥和土壤中残留多氯联苯（PCBs）的情况调查

为了解PCBs在生态系统中的分布,利用毛细管气相色谱对受PCBs污染地区的土壤、底泥进行实际环境样品的调查。在底泥和土壤样品中测定近50个同属物的含量,并对其分市规律进行了探讨。指出在实际环境样品中PCBs的同属物分布和工业产品有明显不同。通过不同深度底泥样品测定,证明PCBs在底泥中的渗透作用较弱。     

白洋淀底泥重金属形态及竖向分布

为了解白洋淀底泥沉积物中重金属含量及其潜在生态危害程度,选取白洋淀淀区具有代表性的7个样点,通过无扰动重力采样器采集0～14 cm表层底泥,用优化的BCR连续萃取法对底泥中重金属进行不同形态提取,对不同形态以及不同深度的重金属含量进行测定,分析不同形态重金属与底泥中总有机碳(TOC)之间的关系,并通过地累积指数(Igeo)法对底泥重金属污染程度进行评价.结果表明,Co、Fe、Mn、Pb、Zn的形态分别以残渣态、酸可溶态、铁锰氧化态以及有机结合态为主;有机结合态重金属与底泥TOC结合的趋势大于其他形态;Co、Pb、Zn含量随着深度增加总体呈降低的趋势,它们在0～2 cm底泥的含量最高,Mn的含量在6～8 cm达到最小,14 cm时含量达到最大;白洋淀淀区底泥中Co、Mn污染程度主要为无污染或轻度污染,Pb、Zn除府河入口外主要为轻度污染,府河入口处的Pb、Zn为中度污染.     

环境样品中多环芳烃的前处理技术

系统地综述了大气、水体、土壤和底泥以及其它环境样品中多环芳烃的前处理技术,对索氏提取、超声波提取、超临界流萃取、固相萃取、固相微萃取、微波辅助萃取、快速溶剂萃取等前处理技术在环境样品中的应用进行了概述和比较,并对环境样品中多环芳烃前处理技术的发展进行展望．     

微波萃取-紫外分光光度法测定土壤中PCBs的研究

采用微波萃取和紫外分光光度法联用的手段,研究了土壤中多氯联苯(PCBs)的分析方法。包括微波提取多氯联苯的最佳操作条件,以及在此条件下紫外分光光度法检测提取土壤中的多氯联苯。结果表明,该方法不仅简便快捷,而且有较好的精密度和广泛的适用性。     

微波萃取土壤中重金属Cr的形态分析研究

运用Tessier法和微波萃取法研究了长沙铬渣场铬渣堆集区土壤中重金属铬的形态分布,并研究了铬的生物可利用性。结果表明,微波萃取法和传统的Tessier法得出的Cr的形态分布规律相同,即:残渣态有机结合态铁锰氧化物结合态碳酸盐结合态可交换离子态,并且整个实验所需时间仅为传统方法的1/76。但微波萃取法的可交换离子态和碳酸盐结合态的萃取效率较低,需要进一步优化实验条件以获得理想的实验结果。两种提取方法对土壤中重金属的生物利用性的分析结果均为:不可利用态潜在利用态有效态,表明该区域内土壤中金属Cr的生物可利用态含量较少。     

多氯联苯在多介质环境中的污染状况

多氯联苯(PCBs)是一类持久性有机污染物,在环境中广泛存在。综述了国内外对多氯联苯在水、大气、土壤、底泥等环境介质中污染状况的研究进展。     

羟基氧化铁对太湖底泥中多氯联苯微生物厌氧脱氯的影响

多氯联苯（PCBs）的微生物厌氧脱氯过程与底泥的理化性质密切相关.三价铁是底泥中常见的竞争性电子受体,在太湖底泥微环境中添加羟基氧化铁（FeOOH）,探究其对PCBs厌氧脱氯的影响.结果表明:①两种微环境（未添加FeOOH的对照组和添加了FeOOH的试验组）中的脱氯启动均存在滞后期,对照组的脱氯滞后期为21~42 d,而添加了40 mmol/kg（以泥浆计）FeOOH的试验组中,脱氯于42~63 d启动.脱氯启动后,对照组和FeOOH试验组的脱氯速率分别为0.035和0.014 mg/（kg·d）.第210天时,对照组内54.09%的PCBs母体被降解,而FeOOH试验组中仅去除了20.81%.因此,FeOOH对PCBs的还原脱氯具有显著的抑制作用,不仅延长了脱氯滞后期,还降低了脱氯程度和脱氯速率.②FeOOH显著抑制了间位（meta-）和对位（para-）氯的脱除（P < 0.05）.第210天时,对照组和FeOOH试验组中间位（meta-）氯原子的降解率分别为27.2%和8.9%,对位（para-）氯原子的降解率分别为17.9%和4.9%.但无论在三价铁〔Fe（Ⅲ）〕还原条件下还是无FeOOH添加的对照条件下,脱氯偏好均显示为间位（meta-）>对位（para-）>邻位（ortho-）.邻位脱氯路径仅存在于对照组中,说明FeOOH还原完全抑制了邻位脱氯进程.③脱氯过程中,对照组和FeOOH试验组的生物多样性（Shannon-Wiener指数和Simpson指数）从0天到210天逐渐降低,且Fe（Ⅲ）还原条件下的生物多样性低于对照组.随着脱氯反应的进行,厚壁菌门（Firmicutes）在两个体系中占比最高,而变形菌门（Proteobacteria）的优势地位下降,绿弯菌门（Chloroflexi）的占比有一定程度的提高.对照组和FeOOH试验组中脱氯菌Dehalococcoides均出现富集,Dehalococcoides可能对太湖底泥微环境中PCBs的厌氧脱氯具有重要作用.研究显示,FeOOH对太湖底泥中PCBs的厌氧脱氯具有抑制作用,并使微环境中的微生物群落发生了一定变化.      

微波消解、ICP-AES法快速测定水底底泥中的微量元素

采用微波消解样品,电感耦合等离子体发射光谱法(ICP-AES),在射频功率:1.1KW,等离子气流量:15.0L/min,辅助气流量:1.50L/min,雾化气流量:0.5 L/min,蠕动泵转速20r./min下,快速测定底泥中微量元素Cu、Pb、Zn、Cr、Cd、Ni、Mn含量的方法,方法快速简便、准确度高、精密度好,可用于各类底泥中微量元素的测定.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

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.     

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.     

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.     

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.     

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.     

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.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

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.