综合分析包头市大气降水酸度的影响因素

本文通过 8年大气降水资料的统计分析 ,得出影响包头市大气降水酸度的主要因素是二氧化硫的排放。文中详细分析了二氧化硫排放和大气降水酸度的对应关系 ,也对影响降水酸度的其它因素作了浅析。提出了包头市二氧化硫污染控制的必要性和重要性     

利用后推气流轨迹解析丹东降水气团来源的研究

根据2007年丹东33场降水的72h后推气流轨迹,分析影响丹东降水酸度变化的主要气团方向。结果表明,来自西北方向的气团形成降水酸度不强,经过我国华东、京津冀以及山东半岛等工业发达地区的西南方向气团,形成降水酸度较强,途经朝鲜半岛的东南方向气团,100%为酸性降水,严重影响丹东降水的酸度。     

厦门市酸雨分布特征与气象条件的关系分析

厦门市是我国酸雨控制区之一。文章利用1992～2005年厦门市的探空、降水量和酸雨资料来分析厦门市不同气象条件对降水酸度、酸雨出现率的影响,分析结果表明:(1)不同等级的降水对降水酸度和酸雨出现率有明显影响,相对于夏、秋二季,冬、春二季的降水酸度更酸,酸雨出现率更高。(2)K指数、850～700hPa层的冷暖平流对酸雨污染没有明显影响。(3)酸雨出现率随着1500m高空风速的增大而增多,风向变化对降水酸度和酸雨出现机率的影响不大。(4)逆温对酸雨污染的有一定的影响。     

论北京降水的酸性

1994～1995年在北京市区安慧里进行了降水观测,分析了降水离子浓度,对夏季典型气象条件下的降水事件进行了后推气流轨迹分析?结果表明,北京市区年降水pH均值为5左右,夏季pH值最低,平均为4.88,说明北京出现了酸雨?气流轨迹分析显示,S-E扇形方向来流的降水酸度高;N-W扇形方面来流的降水酸度低?      

高山云雾水及降水pH值的初步考察

一、前言 城市降水酸度的监测,国内外已有大量报道,我们也曾对城市和山区降水酸度作过考察,但对高山云雾水和降水pH值对比观测见之不多。从高山云雾水和降水的pH与化学成分的测定,可以了解云、雨滴对大气污染物的清除能力。这里主要介绍1982年5月和1983年4—6月在福建省石塔山云雾考     

大连市酸雨污染特征及原因简析

2008年大连市酸雨频率为36．9％,酸雨污染以硫酸型污染为主,但硝酸盐对酸雨的贡献相对较高,降水中对酸雨主要起中和作用的离子为钙离子及铵根离子。2003年-2008年来大连市降水酸度和酸雨频率呈逐年上升趋势,从各季节变化看,最高酸雨频率主要发生在夏季,降水中（Ca2^＋NH4^＋）／（SO4^-2＋NO3^-）呈下降趋势,从而说明虽然大连市局地的二氧化硫和氮氧化物污染对降水酸度产生一定影响,但相比而言,空气中碱性颗粒物的减少．对大连市酸雨频率的升高影响更大;大连市酸雨污染受外来源的远距离输送影响的比例很大。     

青岛地区酸沉降现状的研究

青岛地区的降水酸化问题在我国北方具有一定的代表性。该研究在对青岛地区降水酸度的时空分布、酸性降水与气象条件的关系进行长期常规观测及集中综合观测,取得大量数据的基础上,重点分析了青岛地区酸沉降的现状及发展趋势。结果表明:青岛地区降水酸度和频率与SO₂环境浓度有关,SO₂浓度较高的市区降水酸度和频率亦高,市郊较低,远郊最低;降水酸度季节变化明显,冬、春季高,夏、秋季低;酸雨的发展趋势受SO₂排放量控制      

“九五”广州地区酸雨污染基本特征研究

根据“九五”期间广州地区酸雨污染状况及与"七五"期间的对比结果,通过分类统计和多元回归,研究探讨了"九五"酸雨污染的基本特征及其影响降水酸度的有关因素.研究表明,SO₄2-是降水化学组成中比重最大的离子,NO₃-对降水酸度影响较大,这两种阴离子的含量多少基本上决定了降水酸度的强弱.因此在减轻二氧化硫污染的同时,加强对氮氧化物污染控制对降低广州地区降水酸度意义重大.      

丹东凤凰山山上与山下降水酸度迥异原因分析

采用分段监测的方法研究了辽宁丹东凤凰山垂直高度上的降水酸度及组分特征,并利用后向气流轨迹与分段离子相关性叠加分析的方法,对山上与山下降水酸度的差异成因进行了分析。结果表明：凤凰山4次降水中,pH值山上均低于山下,总离子浓度山上均低于山下,说明近地面大气污染物对酸雨起到一定的中和作用;山上降水酸度主要受大气远距离传输影响,山下降水酸度受本地源和远距离传输的共同作用。     

四面山环境对降水酸度的贡献

四面山降水酸化,其降水酸度有80％来自云内,二氧化硫是目前四面山降水酸化的限制剂,降水中剩余过氧化氢潜在着使降水继续酸化的危险。     

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

ＲｅｍｏｖａｌｏｆｈｅａｖｙｍｅｔａｌｓｆｒｏｍｓｅｗａｇｅｓｌｕｄｇｅｂｙｌｏｗｃｏｓｔｉｎｇｃｈｅｍｉｃａｌｍｅｔｈｏｄａｎｄｒｅｃｙｃｌｉｎｇｉｎａｇｒｉｃｕｌｔｕｒｅＷｕＱｉｔａｎｇ，ＮｙｉｒａｎｄｅｇｅＰａｓｃａｓｉｅ，ＭｏＣｅｈｕｉＦ...     

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.