标定低浓度高锰酸钾溶液的方法比较

比较以高锰酸钾本身和邻菲啰啉-Fe2 作指示剂,对低浓度高锰酸钾溶液进行标定发现,以邻菲啰啉-Fe2 作指示剂的标定,结果更为准确.     

邻菲啰啉直接光度法测定水中总铁

提出了测定水中总铁的新方法-邻菲哆啉直接光度法。该方法检出限为0．03mg／L,显色络合物显色15min后可稳定6个月,精密度RSD〈4．32％,加标回收率为95．3％～103％。对地下水、地表水、工业废水和铁标准样品的比对实验表明,邻菲哆啉直接光度法与邻菲哆啉光度法（标准法）的测定结果无显著差异。     

邻菲哆啉直接光度法测定水中总铁

提出了测定水中总铁的新方法-邻菲哆啉直接光度法。该方法检出限为0．03mg／L,显色络合物显色15min后可稳定6个月,精密度RSD〈4．32％,加标回收率为95．3％～103％。对地下水、地表水、工业废水和铁标准样品的比对实验表明,邻菲哆啉直接光度法与邻菲哆啉光度法（标准法）的测定结果无显著差异。     

Influence of 1, 10-phenanthroline on adsorption behaviour of Ni （Ⅱ） onto montmorilionite

利用镍离子能与邻菲罗啉反应生成螯合物的性质,研究了加与未加邻菲罗啉条件下,蒙脱石对金属镍离子的吸附行为,考察了镍离子浓度、吸附时间、温度和溶液pH值等因素对吸附性能的影响．结果表明：加入邻菲罗啉后,蒙脱石对镍的螫合离子的吸附量明显增大;吸附平衡时间约为120min;蒙脱石对[Ni（phen）a]^2＋的吸附性基本不受pH值的影响．动力学研究表明该吸附过程符合准二级反应动力学模型,吸附量随温度升高而增大．二级动力学参数证明加入邻菲罗啉可显著提高蒙脱石对Ni^2＋的吸附性．蒙脱石对简单Ni^2＋的吸附符合Langmuir的单层吸附等温式;而蒙脱石对镍的螯合离子的吸附则符合Freundlich等温式．蒙脱石对Ni^2＋和[Ni（phen）a]^＋2的吸附均为自发、吸热和更无序的;XRD及FTIR研究表明,蒙脱石对[Ni（phen）a]^2＋的吸附以层问的物理吸附为主．     

镉与邻菲啰啉配合物吸附波的研究与应用

对镉与邻菲啰啉配合物的极谱波性质进行了研究。试验表明,在pH3.3的HCl—NaAc缓冲溶液中,镉与邻菲啰啉生成的配合物在-0.65V处产生一灵敏的吸附波,其2次导数的波高与镉浓度在0.0006～0.1mg/L范围内呈线性关系,检出下限为0.0003mg/L。此法经用于环境水样中微量镉的测定,结果与其他测定方法基本吻合。     

改进国标方法检测海岸带水体铁的研究

为了更加准确地检测海岸带水体中的铁含量,将邻菲啰啉分光光度法测定水质铁(国标法)的方法进行了改进.在邻菲啰啉分光光度法的基础上,在pH调节方式、比色皿皿差和显色剂三个方面进行改进.结果表明,改进后方法的线性、准确度和精密度都优于国标法.但改变pH调节方式和扣除比色皿皿差后检测低浓度铁的水样的精密度依然较差(RSD>5%),说明邻菲啰啉的灵敏度较低.以5-Br-PADAP为显色剂用分光光度法检测水样时,方法的准确度和精密度较好(RSD<5%,加标回收率在96.0%~106%之间),该方法可以用于海岸带水体中铁的检测.     

邻菲Luo啉分光光度法测定总铁方法的改进

本文对《水和废水监测分析方法》第3版（下称第3版）中邻菲Luo啉分光光度法测定总铁的方法提出两点改进意见。一是通过系列对比实验，确定缓冲溶液的加入量，二是水样浑浊时的前处理步骤。     

硅酸盐岩石中亚铁的流动注射分光光度分析

样品用氢氟酸-硫酸分解,根据流动注射分析原理,拟出以邻菲啰啉作试剂,流注光度测定氧化亚铁流程。19个岩石(矿物)标样的分析结果与推荐值或报道值吻合。本流程适用于测定氧化亚铁含量范围为0.51—18.91％的样品,进样速度为90个样品/小时,标准偏差为±0.04,相对标准偏差为3.23％。     

流动注射-分光光度法测定工业废水中的Fe^2＋和Fe^3＋

将Fe^2 与邻菲啰啉的显色反应引入流动注射系统，用盐酸羟胺将Fe^3 预先还原，0～6μg/ml的Fe^2符合比耳定律，检测出限0．11μg／ml。0．25μg／mlFe^2 经5次测定的标准偏差为2．2％，进样频率为120次／h，回收率98．5～104％。对工业废水中铁的测定取得了满意的效果。     

邻菲哕啉分光光度法测定水中总铁的改进

对邻菲哕啉分光光度法测定水中总铁的方法进行了改进：采用50ml比色管水浴还原水样--分光光度计比色测定水中总铁。测试结果表明,改进法精密度和准确度均优于标准方法,是测定水中总铁较为理想的方法     

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.     

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.     

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

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Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Alterations of organ histopathology and metallolhionein mRNA expression in silver barb, Puntius gonionotus during subchronic cadmium exposure

Common silver barb,Puntius gonionotus,exposed to the nominal concentration of 0.06 mg/L Cd for 60 d,were assessed for histopathological alterations(gills,liver and kidney),metal accumulation,and metallothionein(MT)mRNA expression.Fish exhibited pathological symptoms such as hypertrophy and hyperplasia of primary and secondary gill lamellae,vacuolization in hepatocytes,and prominent tubular and glomerular damage in the kidney.In addition,kidney accumulated the highest content of cadmium,more than gills and liver.Expression of MT mRNA was increased in both liver and kidney of treated fish.Hepatic MT levels remained high after fish were removed to Cd-free water.In contrast,MT expression in kidney was peaked after 28 d of treatment and drastically dropped when fish were removed to Cd-free water.The high concentrations of Cd in hepatic tissues indicated an accumulation site or permanent damage on this tissue.