三峡水库库首地区大气降水化学特征

2009年6月~2010年7月对三峡水库库首地区大气降水的水化学特征进行了连续1年的研究.结果表明:三峡库首地区大气降水酸化严重,超过1/3的降水pH值低于4.5.SO42-和NO3-为降水中的最主要阴离子,雨量加权平均值分别为161.90,65.24μeq/L,二者分别占无机阴离子总量的66%、27%.Ca2+是最主要的阳离子,离子含量在8.89~932.90μeq/L之间,雨量加权平均浓度为108.34μeq/L,占无机阳离子总量的43%.季节变化分析表明,夏秋季节降水酸化严重,而冬春季节降水酸化不明显.不同季节相对酸度(FA)和中和因子(ＮＦ)分析表明,冬春季节的降水酸度主要受Ca2+离子的中和作用控制.主要离子来源分析表明,SO42-和NO3-主要来源于化石燃料燃烧,Na+、Cl-主要为海源输入的贡献,而Ca2+、Mg2+主要来源于陆壳颗粒物质.     

贵阳大气降水化学特征及来源分析

对贵阳地区2008年10月1日~2009年9月30日降水样品的pH值和主要阴阳离子组成的进行测定,并运用TrajStat软件模拟后向气团轨迹,分析了贵阳地区降水中离子来源以及影响离子浓度的因素.结果表明,2008~2009全年降水pH值加权平均值为4.23;SO42-是主要阴离子,加权平均值为265.63μeq/L,占总阴离子的69.29%.Ca2+和NH4+是主要的阳离子,加权平均值分别为182.90和112.79μeq/L,分别占总离子的47.10%和29.05%.并且NH4+、Ca2+与SO42-之间存在明显的相关性,说明贵阳大气中可能主要存着(NH4)2SO4、NH4HSO4、CaSO4等物质.总离子浓度季节差异性大,冬季高、夏季低,主要受到降水量、污染物来源等多方面的影响.海相和土壤富集系数表明,Ca2+、Mg2+、K+主要来自地壳源,而SO42-、NO3-主要来自人为源.贵阳后向轨迹表明春季气团轨迹较为杂乱,夏季气团主要来自沿海,秋冬季则主要受中国内陆的影响.     

典型污染城市9d连续大气降水化学特征:以贵阳市为例

对贵阳地区2008年10月30日～11月7日的一场连续降水进行研究.通过对降水样品的pH值和主要阴阳离子组成的测定,分析了贵阳地区酸雨的主要离子来源以及离子浓度随降水过程的变化规律等.结果表明,此次降水的pH值范围为3.65～7.20,平均值为4.24;SO42-是主要的阴离子,浓度加权平均值为119.06μeq.L-1,占阴离子总量的80.63%;NH4+(38.38μeq.L-1)和Ca2+(48.87μeq.L-1)是主要的阳离子,分别占阳离子总量的37.82%和48.16%.Mg2+、Ca2+、NH4+与SO42-的相关系数分别为0.96、0.91、0.91,说明贵阳地区降水中可能存在以MgSO4、CaSO4、(NH4)2SO4为主的化学物质.大气中不同离子在降水过程被去除的方式和速率有较大的差别,在降水初始阶段,主要富存在粗颗粒中的Mg2+等离子,因粗颗粒迅速被冲刷而较快从大气中去除;而主要富存在细颗粒中的NH4+、SO42-等离子,因细颗粒冲刷速率较慢,而能够在大气中保存较长的时间.     

泰山降水化学及大气传输的研究

为了解泰山降水的化学组成特征及其来源,于2004年7月至12月间在泰山上采集了23场降水样品,进行了pH值、电导率的测定、主要水溶性阴阳离子的分析以及每场降水的后推气流轨迹分析.结果表明,降水pH的雨量加权均值为4.74,电导率的雨量加权均值为2.26mS·m-1,泰山降水已受到酸性污染;降水中浓度较高的阳离子是NH4 和Ca2 ,雨量加权均值浓度分别为50.62和29.04μeq·L-1,浓度较高的阴离子是SO42-和NO3-,雨量加权均值浓度分别为70.32和23.44μeq·L-1;SO42-/NO3-、NH4 /Ca2 当量浓度比的平均值依次为3.41、2.13.对降水的化学组成作了相关性分析,发现NH4 、Ca2 、SO42-、NO3-浓度之间具有很好的相关性;通过气流轨迹分析发现酸性最强的降水气团来自于我国的南部地区或沿途经过华东地区,离子浓度最高的降水气团来自于我国的北部地区或欧洲大陆,来自东亚地区的降水气团的离子浓度最低.     

西南喀斯特农村降水化学研究:以贵州普定为例

对我国西南喀斯特地区农村(普定)2008年的降水样品化学组成研究表明,该区降水pH值在4.6～7.1之间,加权平均值为5.7.Ca2+是主要的阳离子,雨量加权平均浓度为303.2 μeq·L-1占阳离子总数的34%～88%;SO42-和NO3-是主要的阴离子,雨量加权平均浓度分别为281.2 μeq·L-1、69.9 ...     

天津市大气降水化学组分变化趋势及来源研究

2001—2013年对天津市降水样品进行了采集,分析了p H、电导率(EC)、主要离子浓度(SO2-4、NO-3、Cl-、F-、NH+4、Ca2+、Mg2+、Na+、K+).结果表明:2001—2013年,降水的雨量加权平均p H、EC分别为5.48、87μS·cm-1.降雨的p H、EC及总离子当量浓度呈现上升趋势,酸雨频率呈现下降趋势.降水中各离子雨量加权平均当量浓度排列顺序为:SO2-4Ca2+NH+4NO-3Cl-Mg2+Na+F-K+,SO2-4、Ca2+、NH+4和NO-3是降水中的主要离子,占离子总量的84.8%.SO2-4雨量加权平均当量浓度表现为先轻微上升,后显著下降趋势.NO-3、Ca2+雨量加权平均当量浓度表现为明显上升趋势.NH+4雨量加权平均当量浓度显示为下降趋势.F-、Cl-、K+、Mg2+、Na+等雨量加权平均当量浓度变化趋势基本保持平稳.SO2-4对总阴离子的分担率、NH+4总阳离子的分担率均呈现下降趋势.NO-3对总阴离子的分担率、Ca2+对总阳离子的分担率均呈现明显上升趋势.[NO-3]/[SO2-4]、[Ca2+]/[NH+4]呈现出明显上升趋势.富集因子计算结果表明:Ca2+主要来自地壳.Mg2+和K+部分来自海源输入,但绝大部分来自地壳.大部分Cl-来自海源的输入,其余小部分来自地壳和人为排放.降水中SO2-4、NO-3主要来自人为活动.     

典型酸雨城市降水、降尘中阴阳离子分布特征及其相关性

对贵州省都匀市2013年3月—2014年2月降水和降尘样品的p H值及主要阴阳离子(NH+4、K+、Ca2+、Na+、Mg2+、F-、Cl-、NO-3、SO2-4)进行测定,分析其分布规律及相应离子之间的相关性.结果表明,降水和降尘水溶液p H的加权平均值分别是5.47、5.06.Ca2+、SO2-4是降水和降尘的主要离子,均值分别是141.29μeq·L-1、191.67μeq·L-1,52022.33 mg·kg-1、87590.52 mg·kg-1.降水和降尘中的总离子浓度、[SO2-4]/[NO-3]、[SO2-4+NO-3]/[Ca2++NH+4]以及NH+4、K+、Na+、F-、NO-3、SO2-4浓度在冬季达到最大,且其[SO2-4]/[NO-3]均都大于3,表明都匀市酸雨类型仍为燃煤型.从季节的变化上看,降水和降尘中的NH+4、K+、Na+、F-、SO2-4、Ca2+、Mg2+存在明显的相关性,相关系数|r|﹥0.70.降水和降尘中[SO2-4+NO-3]/[Ca2++NH+4]表现出相似的季节变化规律,[SO2-4+NO-3]/[Ca2++NH+4]与p H相关系数|r|﹥0.80,与降雨量、污染物来源、能源使用等有关.     

沧州市大气降水化学特征分析

为了解沧州大气降水化学特征,于2009年4-11月采集了沧州大气降水样品,测定了pH值、电导率和主要离子(Na+、NH4+、K+、Mg2+、Ca2+、F-、Cl-、NO3-和SO42-)浓度。结果表明,观测期间降水pH值为4.18~7.30,降水量加权平均pH值为5.23,降水酸化频率为34%;电导率值为18.5~245.0μS/cm,降水量加权平均电导率值为39.2μS/cm;降水主要离子加权平均浓度为641.36μeq/L;降水中主要阳离子成分是NH4+和Ca2+,降水量加权平均浓度分别为191.06和96.81μeq/L,分别占到阳离子总量的53%和27%;阴离子主要成分是SO42-和NO3-,降水量加权平均浓度分别为175.05和58.19μeq/L,分别占到阳离子总量的63%和21%。降水中[SO42-]/[NO3-]值为3.01,仍属于硫酸型降水,但酸雨类型逐渐由硫酸型向硫酸-硝酸混合型过渡;[NH4+]/[Ca2+]值为1.97,NH4+对降水酸度的中和作用要大于Ca2+;NH4+、SO42-和NO3-等二次组分占到降水中主要离子总量的66%,表明二次污染比较严重。降水离子相关分析表明,SO42-、NO3-、Ca2+、NH4+的相关性较好,SO42-和NO3-的相关系数为0.732,NH4+与SO42-(R=0.540)、NO3-(R=0.628)的相关系数分别大于Ca2+与SO42-(R=0.532)、NO3-(R=0.410)相关系数。气流轨迹分析表明,研究区降水主要受到5类气团影响,不同气团影响下,降水pH值、电导率和离子组成存在差异。     

中国南海大气降水化学特征

利用中国科学院南海海洋研究所"实验3"号船南海海洋断面科学考察2012年夏季航次进行大气降水采样,测定样品pH值和主要阴阳离子浓度,结合TrajStat软件模拟后向气团轨迹,分析南海夏季大气降水离子化学特征及来源.结果表明,夏季降水pH平均值为6.3,最小值为5.6.阴阳离子浓度顺序均分别表现为Cl->SO2-4>NO-3和Na+>Mg2+>Ca2+>K+,Cl-和Na+是主要的阴离子和阳离子,浓度平均值分别为2 637.5μeq·L-1和2 095.5μeq·L-1,表现出了海洋性大气降水的特征.7种离子间均表现出良好的线性相关关系,相关系数在0.9以上,说明它们可能具有统一来源;NO-3与其他离子的相关系数相对较低,可能NO-3具有相对复杂的来源;Ca2+和K+还可能跟南海珊瑚环境有关.本研究的6个站位后向轨迹显示,水汽气团来源于正南或西南方向,未经过大陆上空,因此本研究中南海夏季大气降水的离子来源受人为影响可以忽略.     

浙江宁波天童地区酸性降水化学特征研究

为了解浙江宁波天童地区降水的化学特征、离子来源及酸性降水的成因,于2010年3月—2011年2月在该地区采集了90个降水样品,并运用离子色谱法分析其化学组分.结果显示,天童地区降水的酸化频率和酸化程度非常高,酸雨频率为97%,雨量加权pH平均值为4.37,离子浓度的大小顺序为SO24->NH4+>NO3->Ca2+>Cl->Na+>Mg2+>K+>F-,降水较清洁;降水pH值和各离子含量存在明显的季节变化,总体表现为冬、春季污染程度高于夏、秋季;SO24-/NO3-的浓度比值为1.9,表明该地区酸雨类型为硫酸和硝酸复合型;SO24-、NO3-、NH4+和部分Ca2+主要来自人为污染源,Na+、Cl-和大部分Mg2+主要来自海洋源,K+和大部分Ca2+则主要来自地壳源,海洋对天童地区降水离子组分影响较大,但对降水酸度影响并不显著;NH4+与SO42-(r=0.90)、NO3-(r=0.88)的相关性分别大于Ca2+与SO24-(r=0.67)、NO3-(r=0.73)的相关性,且NH4+/Ca2+的浓度比值为1.47,说明NH4+对降水酸性的中和作用大于Ca2+,与我国其他城市降水相比,天童地区降水中的碱性离子,尤其是Ca2+浓度较低,从而导致降水酸度高于北方地区和西南其他地区.     

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.     

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.