辣子草对3种农作物的化感作用

采用生物测定法,研究了入侵植物辣子草(Galinsoga parviflora Cav.)不同器官、不同浓度水浸提液对水稻(Oryza sativa L.)、小麦(Triticum aestivum L.)、油菜(Brassica napus L)种子萌发和幼苗生长的化感效应。结果表明辣子草存在一定的化感作用。各器官水浸提液对3种作物的影响依种类有差异,辣子草水浸提液在高浓度下对水稻、小麦作物种子萌发、根长和苗高均有明显的抑制作用,对油菜的种子萌发、根长和苗高则是在低浓度下促进高浓度下抑制。辣子草的化感效应为花序>叶>茎>根,表明辣子草的化感物质主要存在于地上部分。     

海水烟气脱硫初探

分析了金山卫，定海，北仑港和台州等地的海水成份，测定了它们的缓冲能力，在鼓泡反应器中进行了海水吸收ＳＯ２的静态试验和使吸收液中ＳＯ３＾２－转变为ＳＯ４＾２－的氧化试验，试验结果表明海水具有用作烟气脱硫吸收液的可能性和吸收液经曝气后直接排海的可能性。     

单柱离子色谱法测定水中微量阴离子及其在测定水中吸附有机氯…

本文介绍用一般高效液相色谱仪，不用抑制柱：分析柱为ＩＣ－ＰＡＫ阴离子交换柱，用电导检测器检测，测定水中Ｃｌ＾－，ＮＯ２＾－，Ｂｒ＾－，ＮＯ３＾－，ＳＯ４＾－离子。试验了淋洗液不同浓度和ＰＨ对阴离子分离的影响，并与另一组淋洗液比较各阴离子的最低检测浓度，及测定自来水中阴离子含量。检测限在０．１ｍｇ／Ｌ－０．８３ｍｇ／Ｌ间。用邻苯二甲酸氢钾淋洗液测定的变异系数＜５．１０％。单柱离子色谱法用于水中吸附有     

吡草醚水解动力学的研究

研究了吡草醚在不同pH和温度条件下的降解动力学情况,以及在三种生态水样和土悬液中的水解情况。结果表明,吡草醚在酸性水环境中比较稳定,在中性和碱性环境中易降解;水解反应速率随反应温度的升高而增大;吡草醚在三种生态水中的降解速率较快,降解半衰期分别为：水库水4．56d,河水3．96d,池塘水1．35d;吡草醚在土悬液中降解较快,这与其碱性条件和含量较高的可溶性碳有关。     

吡草醚水解动力学的研究

研究了吡草醚在不同pH和温度条件下的降解动力学情况,以及在三种生态水样和土悬液中的水解情况。结果表明,吡草醚在酸性水环境中比较稳定,在中性和碱性环境中易降解;水解反应速率随反应温度的升高而增大;吡草醚在三种生态水中的降解速率较快,降解半衰期分别为：水库水4．56d,河水3．96d,池塘水1．35d;吡草醚在土悬液中降解较快,这与其碱性条件和含量较高的可溶性碳有关。     

新银盐分光光度法测定地表不中痕量砷

在酒石酸介质中，以硼氢化钾为还原剂，使砷离子转变为砷化氢，以乙醇－－硝酸银－聚乙烯醇为吸收液进行显色，在４００纳米处以原吸收液为参比进行测定。方法的检出限为０．２０微克／升，对含砷为０．６５－１．２７μｇ／ｌ的天然水进行测定，回收率为９２－１１６％，相对标准偏差７．４－１２．２％。     

喜旱莲子草对钉螺脂酶同工酶影响的初步研究

用不同浓度的喜旱莲子草水浸液处理钉螺24h,观察其灭螺效果,并用聚丙酰胺凝胶电泳技术比较研究了水浸液对钉螺酯酶同工酶的影响,结果表明:钉螺头足部肌肉的酯酶同工酶在低浓度(0.01g/L)时,活性较强,随水浸液处理浓度升高,活性迅速降低;而肝脏的酯酶同工酶在中等浓度(0.1g/L)时,活性最强,高浓度时(1g/L)有些酶带发生分解、消失。钉螺的死亡率则随着处理浓度的提高,急剧增大。喜旱莲子草干粉水浸液对钉螺酯酶同工酶影响明显,是引起钉螺中毒死亡的原因之一。这为喜旱莲子草作为新型植物灭螺剂的开发打下基础。     

从烟草废弃物中提取天然烟碱技术的研究

利用均价廉易得的某化合物溶液作浸取液及另一有机溶剂作萃取剂,减压蒸馏分离,可方便地从烟草废弃物中提取纯度在90％以上的天然烟碱。浸取液浓度为8％、萃取4次（草取剂用量与浸取液相等）时,烟碱得率为 60.l％。     

应用HACH仪器测定水中COD方法的探讨

本文研究了消解液的制备，用HACH－COD测定仪分析测定了不同来源的水样，加标回收率在93－102％之间，相对标准偏差在0．9－12％之间。该方法的准确度和精密度均能满足环境监测分析方法的要求。     

单柱离子色谱法测定水中微量阴离子及其在测定水中吸附有机氯中的应用

本文介绍用一般高效液相色谱仪，不用抑制柱：分析柱为ＩＣ—ＰＡＫ阴离子交换柱，用电导检测器检测，测定水中Ｃｌ一、ＮＯ、Ｂｒ－、ＮＯ和ＳＯ４离子。试验了淋洗液（邻苯二甲酸氢钾）不同浓度和ｐＨ对阴离子分离的影响，并与另一组淋洗液比较各阴离子的最低检测浓度，及测定自来水中阴离子含量。检测限在０．１ｍｇ／Ｌ－０．８３ｍｇ／Ｌ间。用邻苯二甲酸氢钾淋洗液测定的变异系数＜５．１０％。单柱离子色谱法用于水中吸附有机氯测定的Ｃｌ－离子检测，检测限接近μｇ／Ｌ水平。     

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.     

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.     

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.     

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.     

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.     

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.