索氏提取-固相萃取-高效液相色谱法测定土壤中异丙隆

用索氏提取-固相萃取-HPLC方法测定土壤中异丙隆。利用正交实验分析影响索氏提取回收率的4种因素,其显著性顺序:提取溶剂的类型提取溶剂的比例提取温度提取时间。最佳索氏提取条件:温度80℃,提取时间8h,提取溶剂及比例V正己烷∶V丙酮=1∶3。方法检测限0.18μg/kg,定量检测下限0.90μg/kg,回收率73.0%~89.0%,相对标准偏差5%。     

吹脱捕集气相色谱法分析水中挥发性卤代烃

建立了吹脱捕集气相色谱法测定水中7种挥发性卤代烃的分析方法。对色谱条件、吹脱时间、实验用水等进行了探讨,同时对分析参数如线性相关性、相对标准偏差、最低检出限及加标回收率进行了评价。结果表明,采用吹脱捕集气相色谱法,在1.0μg/L～20.0μg/L范围内,7种卤代烃的质量浓度和峰面积呈良好的线性关系;10.0μg/L的7种挥发性卤代烃标准溶液经重复7次测定,其相对标准偏差为1.30%～8.71%;水样的加标回收率在86.3%～110%之间;最低检出限在0.17μg/L～0.96μg/L之间,该方法已成功地应用于饮用水和地表水中挥发性卤代烃的定性定量测定,结果令人满意。     

吹扫捕集——GC/MS测定韶关地表水中VOCs方法探讨

采用吹扫捕集-GC/MS对地表水中39种的VOCs进行了测定。各组分的检出限为0.1μg/L～25.2μg/L,回收率在85%～117%之间,精密度在0.5%～14.5%之间。其结果令人满意,适用于韶关市地表水中VOCs的测定。     

反乳化分散液液微萃取-HPLC测定水中二氯酚

建立了一种快速、简便、灵敏的反乳化分散液液微萃取新方法,并与高效液相色谱联用成功用于环境水样中2,4-二氯酚与2,6-二氯酚的测定。对萃取条件(如萃取剂、分散剂/反乳化剂的种类和体积、盐浓度、p H等)进行了优化,得到了最佳的反乳化分散液液微萃取条件。对2,4-二氯酚与2,6-二氯酚测定的线性范围分别为5~600μg/L(r=0.999 8)和5~600μg/L(r=0.999 7),检出限(3σ)为2.06μg/L和2.88μg/L。对200μg/L的标准溶液测定得到的相对标准偏差(RSD)分别为1.71%和2.67%(n=6)。该方法已成功用于3种实际环境水样中痕量2,4-二氯酚与2,6-二氯酚的测定,加标回收率为83.2%~118.2%,RSD为0.56%~17.81%(n=3)。     

全自动固相萃取-串联四级杆质谱测定水中16种多环芳烃

建立了采用全自动固相萃取(SPE)净化,浓缩,气相色谱-串联四级杆质谱二级质谱监测(GC-QQQ-MS/MS)同时测定水中16种多环芳烃的方法。通过优化样品前处理条件和仪器分析条件,取样体积为1.0L时多环芳烃的最低检出限为0.06~0.27μg/L,最低定量限为0.21~0.91μg/L。针对三组加标浓度为10μg/L、100μg/L、500μg/L的样品,平行测定6次,平均回收率在79.84%~108.43%,相对标准偏差在3.17%~9.27%。     

静态顶空-气相色谱法测定水中二硫化碳

采用气相色谱法静态顶空进样,HP-1柱分离,FPD检测器检测,测定水中CS2,并对测定条件进行了探讨。实验表明,当取样量为10.0 mL,气液比为12.3,在40℃平衡25 min时,能获得满意的灵敏度,且稳定性很好。二硫化碳在0.63μg/L～502μg/L之间呈线性,相关系数为0.999 2,相对标准偏差为1.3%～5.7%、加标回收率为88%～105%,检出限可达0.3μg/L。干扰试验表明硫化氢、甲硫醇、甲硫醚不干扰二硫化碳的测定。本方法操作简便,测定快速,完全能够满足快速分析水中二硫化碳的要求。     

改进离子色谱法测定水样中高氯酸盐、氯酸盐和亚氯酸盐

建立一种快速准确的离子色谱法同时测定环境水样中痕量的ClO_4~-、ClO_3~-和ClO_2~-。该方法基于Dionex ICS2100离子色谱仪,采用亲水性强的Ion Pac AS20阴离子分析柱,选用KOH淋洗液,以1.0 mL/min流速梯度淋洗。研究结果表明,待测样品中ClO_4~-、ClO_3~-、ClO_2~-含量低于100μg/L时,进样量为300μL,在1~100μg/L范围内线性关系良好,相关系数0.999 8,检出限为1μg/L,加标回收率为94.15%~96.91%,相对标准偏差≤3.43%。待测样品中ClO_4~-、ClO_3~-、ClO_2~-含量高于100μg/L时,进样量为25μL,在100~1 000μg/L范围内线性关系良好,相关系数0.999 1,检出限为10μg/L,加标回收率为91.30%~96.28%,相对标准偏差≤0.59%。该方法简单快速,可满足EPA推荐的饮用水中高氯酸盐限量质量浓度(1μg/L)检出要求,同时重现性好、回收率和准确性高,具有重要的应用价值。     

异丙隆降解菌Y57的分离鉴定及其降解特性

从农药厂的活性污泥中分离出1株能高效降解异丙隆的细菌Y57,通过生理生化鉴定和16SrDNA同源性序列分析,鉴定为鞘氨醇单胞菌属(Sphingomonassp.).接种量为1%的Y57可以在48h之内将30mg/L的异丙隆完全降解,降解率达到99%以上,降解最适pH值为7.0,降解效率与接种量呈正相关,在通气良好状况下降解速率较高.1mmol/L的Li⁺、Ca²⁺、Mg²⁺可以提高Y57降解异丙隆速率;1mmol/L的Ni²⁺、Zn²⁺对降解有明显的抑制作用;1000mg/L的酵母粉、葡萄糖、牛肉膏或蛋白胨对降解具有抑制作用.降解谱实验表明,Y57还可以降解绿麦隆、敌草隆、敌稗等除草剂.     

氢化物发生—原子荧光光谱法测定地表水中的痕量锡

利用AFS-9330双道原子荧光光度计测定水中的锡,以1.0%的盐酸作为载流液、1.0%的硼氢化钾为还原剂,荧光强度与其质量浓度在0⁴0μg/L范围内,线性良好,相关系数为0.9992,方法检出限为0.06μg/L,相对标准偏差在1.79%40μg/L范围内,线性良好,相关系数为0.9992,方法检出限为0.06μg/L,相对标准偏差在1.79%².83%之间,加标回收率为91.0%2.83%之间,加标回收率为91.0%¹03%。     

石墨炉原子吸收光谱法测定水环境中的铍含量分析

本文阐述了使用石墨炉原子吸收光谱法测定江水中铍含量的方法与步骤。选用原子吸收分光光度计和铍元素空心阴极灯进行样品测定,试验结果显示,该方法的检出限为0.00223μg/L,回收率为95%~98%之间,线性范围分别为0~2μg/L,是一种简单、快速、准确测定水质中铍含量的较好的检测方法。     

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.     

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.     

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.     

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.     

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.