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.     

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.     

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.     

近3年太原市夏季降水的化学特征研究

本研究采集了2011~2013年太原市夏季66场降水样品,分析了p H值、电导率和水溶性阴阳离子,探讨了太原市夏季降水的化学组成及来源.结果表明,近3年太原市夏季降水p H值范围为4.63~8.02,加权平均值为5.19;2011~2013年酸雨频率分别为37.0%、31.2%和17.4%.太原夏季降水的化学组成以SO2-4、NO-3、Ca2+和NH+4为主,阴离子SO2-4和NO-3加权平均浓度分别占阴离子总浓度的67.2%和22.0%,阳离子Ca2+和NH+4加权平均浓度分别占阳离子总浓度的55.1%和29.0%;降水中SO2-4、NO-3、Ca2+和NH+4浓度水平随年度有明显的下降趋势.近3年SO2-4/NO-3的当量浓度比分别为2.97、3.06和3.08,平均值为3.02,说明太原市夏季酸性降雨类型为硫酸和硝酸复合型,且硝酸盐的贡献逐年增强.通过中和因子分析,表明太原市夏季降水中Ca2+和NH+4对酸性中和起主导作用,但Mg2+的作用不可忽略.太原市夏季降水中水溶性化学组分主要与燃煤排放有关;结合气团的后向轨迹分析表明太原市夏季降水主要受山西省内南部低空运行的短距离输送气团的控制;西南和东南气团是太原市夏季降水中水溶性化学组分的主要来源.为了有效改善太原市的空气质量,太原南部及本地焦化企业和燃煤电厂污染物的排放应给予关注.     

辽宁省背景地区降水化学特征及其与大气传输的关系

为了解辽宁省背景地区降水化学特征及其与大气传输的关系,于2007年2月─2008年1月在辽中县水文监测站进行了降水化学特征观测,测量项目包括降水pH,电导率和离子浓度. 观测期间降水pH为3.4～7.3,降水量加权平均值为4.6,整体呈酸性. 降水中主要阴离子为SO₄2-和NO₃-,浓度分别为154.3和53.4 μeq/L,二者占阴离子总量的76.8%; 主要阳离子为NH₄+和Ca2+,浓度分别为124.6和89.2 μeq/L,占阳离子总量的70.6%. 利用后向气流轨迹分析了降水气团来源对降水化学的影响,结果表明:在辽宁省及周边地区的局地气团影响下,降水中离子浓度最高;而在起源于东亚地区,经朝鲜半岛到达的南-东南气团影响下,降水次数虽最多,但离子浓度最低.      

丹江口水库淅川库区大气降水中无机离子特征及来源解析

大气降水中水化学组成深刻影响着地表水体水质和水生态系统的物质循环. 为探究丹江口水库降水中无机离子的化学组分和来源贡献,以丹江口水库淅川库区为研究区,通过野外调查、原位观测和室内分析,研究了降水中无机离子(F?、Cl?、NO₃?、SO₄2?、Na+、NH₄+、K+、Ca2+和Mg2+)的浓度特征. 结果表明:丹江口水库淅川库区降水中无机离子浓度大小表现为NH₄+(170.0 μeq/L)>Ca2+(115.4 μeq/L)>SO₄2?(112.9 μeq/L)>NO₃?(94.2 μeq/L)>Na+(61.1 μeq/L)>Mg2+(25.9 μeq/L)>F?(12.2 μeq/L)>K+(11.8 μeq/L)>Cl?(10.3 μeq/L),其中NH₄+、Ca2+、SO₄2?、NO₃?和Na+浓度占总离子浓度的90.2%;相关性分析表明不同无机离子浓度之间存在显著相关性(P<0.05),富集因子分析表明陆源人类活动对无机离子浓度的影响较大;正定矩阵因子分析表明,农业源、工业燃煤、土壤扬尘、化石燃料燃烧和生物质燃烧是无机离子的重要来源,其中NH₄+和SO₄2?的主要来源分别为农业源(56.3%)和化石燃料燃烧(78.7%). 研究显示,丹江口水库淅川库区降水中无机离子组分以NH₄+、Ca2+、SO₄2?、NO₃?为主,其主要受陆源人类活动(农业活动和化石燃料燃烧)的影响.      

长江源区大气降水化学特征及离子来源

基于长江源区冬克玛底流域2013年6～9月采集的64个降水样品,分析了降水的pH值、电导率及离子浓度特征,并应用因子分析、相关分析、富集因子及后向轨迹法,讨论了降水离子主要来源及其与大气环流的联系.结果表明,长江源区冬克玛底流域降水pH值变化范围为5. 26～9. 25,加权平均值为6. 70;电导率变化范围为0. 23～28. 70μS·cm-1,加权平均值为3. 45μS·cm-1,低于瓦里关全球大气本底站降水电导率;总离子浓度变化范围为7. 0～376. 9μeq·L-1,平均总浓度仅为40. 8μeq·L-1;各离子加权平均浓度大小顺序为:HCO_3~- NH_4~+ Ca~(2+) NO_3~- SO_4~(2-) Na~+ Cl~- K~+ Mg~(2+); HCO_3~-、NH_4~+、Ca~(2+)和NO_3~-是降水中的主要离子,占总离子浓度的74. 75%;相对酸度(FA)分析表明,有97. 8%的降水酸度被碱性物质中和,同时中和因子(NF)分析表明NH_4~+和Ca~(2+)对降水酸性的中和起主导作用;研究区降水离子主要来自陆源的贡献,而来自海源的输入则相对较少;结合气团的后向轨迹分析发现,不同来源的总离子浓度差异明显,其加权平均浓度大小顺序为:局地源西风源季风源,表明不同的大气环流背景和气团来源对降水化学组成具有重要影响.长江源区大气降水受人类活动影响较小,其降水化学特征一定程度上可以代表偏远地区的大气质量状况和本底值.研究结果能够为长江源区水质的保护以及为评估人类活动对该区域大气环境的影响提供科学依据.     

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。     

祁连山中段降水化学的环境意义研究

运用相关分析、趋势分析、富集因子法、海盐示踪法和HYSPLIT模型,对2012-07-23~2013-11-12祁连山中段葫芦沟流域降水常量离子的化学特征分析表明,降水中离子浓度大小顺序为Ca2+>SO2-4>Mg2+>Cl->Na+>NO-3>K+,其中SO2-4和Ca2+是高浓度离子,阳离子总浓度显著高于阴离子总浓度;降水电导率的变化范围为2.26~482μS·cm-1,平均值为41.9μS·cm-1;区域降水为SO2-4-Mg2+-Ca2+型,上述3种离子的浓度占离子总浓度的70%以上;就季节变化而言,降水离子在夏季呈最低浓度,而在冬、春季降水量小但离子浓度高,表现出典型的"碱雨"特征;中亚和我国西北干旱区随西风环流带来的区域陆源物质是化学离子的主要来源,人为污染源产生的气溶胶是次要来源;更重要的是,不同大气环流背景下降水离子浓度也呈现不同特征,主要表现为季风源降水、混合源降水(季风和西风的影响)和西风源降水,主要是由于不同大气环流条件下的降水淋溶过程及其强度所致.此外,降水离子浓度与降水量、风速之间的相关性反映了局地气候环境的影响.     

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.     

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.     

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.     

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.     

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.     

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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