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1.
长江源区大气降水化学特征及离子来源   总被引:4,自引:2,他引:2       下载免费PDF全文
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.  相似文献   

2.
抚顺市降水污染现状分析   总被引:1,自引:0,他引:1  
在抚顺市区设置5个监测点位,监测抚顺1998年6月~1999年5月的降水状况。结果表明,抚顺市区降水pH值基本呈中性,酸雨出现频率为6.9%,酸雨主要出现在雨量大的降水中。降水中主要的阴离子是SO4^2-,阳离子是Ca^2 、NH4^ ,抚顺市区的降水酸度是由这三种离子的相互关系决定的。  相似文献   

3.
泰山降水化学及大气传输的研究   总被引:24,自引:4,他引:24  
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.  相似文献   

4.
2007年北京夏季降水分段采样酸度和化学成分分析   总被引:9,自引:1,他引:8       下载免费PDF全文
王跃思  李雪  姚利  赵亚南  潘月鹏 《环境科学》2009,30(9):2715-2721
为掌握降水酸度和污染性化学成分随降水持续时间的变化规律,对北京2007年夏季5次典型降水过程分时段采样,分别测定了pH值、电导率,并分析了其中水溶性大气污染成分SO42-、NO3-、NH4+等随时间的变化特征.结果表明,pH加权平均值在降水初期为5.70±0.73,为非酸雨;平缓期为4.35±0.56,呈酸雨特征.pH、电导率和各离子浓度随降水时间的持续而迅速下降,10~45 min后进入平缓期,各污染离子随之下降率为50%~90%.来自北京西北方向云团的降水(8月1日)pH值较高、污染物浓度较低,SO42-、NO3-和NH4+分别为65.4、23.9和117.3μeq/L;而来自偏南云团降水(8月6日)pH值较低、污染物浓度较高,SO42-、NO3-和NH4+浓度分别为310.8、95.7和249.8μeq/L.北京夏季二次粒子浓度升高,将使降水酸化加剧.  相似文献   

5.
沧州市大气降水化学特征分析   总被引:6,自引:0,他引:6  
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。  相似文献   

6.
泰山降水的离子组成特征分析   总被引:12,自引:1,他引:12       下载免费PDF全文
 为了解泰山降水的离子组成特征,于2004年8月~2005年7月对泰山降水进行了化学观测.共收集到37场降水,结果表明,降水pH值的雨量加权均值为4.73,酸性降水的出现频率达60%;电导率的雨量加权均值为2.96mS/m;降水离子的平均浓度为559.04μeq/L,主要离子SO42-111.48μeq/L、NO3-30.76μeq/L、NH4+80.92μeq/L、Ca2+49.94μeq/L,均高于我国西南、西北地区背景点的降水浓度;SO42-是该地区降水的主要致酸物质,在阴离子中的相对含量约为65%,NH4+是降水酸度的主要中和因子,在阳离子中的相对含量约为40%.因子分析表明,泰山降水的离子组成有不同的来源.  相似文献   

7.
大气颗粒物和降水化学特征的相互关系   总被引:8,自引:2,他引:6       下载免费PDF全文
分别于2007年在泰安市郊区和深圳市郊区采集了大气颗粒物并同时对降水进行了分级采样,通过降水过程中降水化学特征的变化和降水前后颗粒物浓度和化学组成的改变,讨论了云下冲刷过程中大气颗粒物对降水化学组分的贡献和降水对颗粒物的去除作用.泰安降水雨量加权pH为5.97,总可溶解离子浓度为1 187.96μeq.L-1,PM10的质量浓度为131.76μg/m3,PM2.5为103.84μg/m3.深圳降水雨量加权pH为4.72,总可溶解成分离子浓度为175.89μeq.L-1,PM10的质量浓度为56.66μg/m3,PM2.5为41.52μg/m3.泰安和深圳降水过程中pH和离子浓度都逐渐降低,冲刷过程主要是中和作用.泰安和深圳降水中Na+和Ca2+的去除效率较高,NH4+和NO3-去除效率较低.两地降水化学性质的差别取决于云水酸度、大气颗粒物性质和大气中酸碱性气体差别的共同作用.降水对大气颗粒物质量浓度、离子组分和元素组分都有显著清除作用.  相似文献   

8.
通过对重庆市黔江区"十二五"期间320个降水样品的pH值和化学组成成分等特征进行了研究,结果表明,五年间黔江区降水pH范围为4.71~7.81,电导率范围为21.8~42.5 μS/cm-1,平均值33.4 μS/cm-1.降水pH和电导率的Spearman秩相关系数法检验表明,pH的rs为正值,电导率的rs为负值,五年期间大气降水中总离子当量浓度有所下降,降水酸雨环境得到有效控制.SO2-4是降水中主要阴离子,占阴离子总量的74.3%,Ca2+是降水中主要阳离子,占阳离子总量的31.4%.黔江区酸雨为硫酸型或燃煤型酸雨,SO2-4/NO-3浓度比均值为7.13,SO2-4/NO-3比值在2013年达最大值,之后呈现减小趋势,黔江区汽车尾气和工业排放的NOx对降水的影响在变大.在99.0%的置信水平下,降水离子浓度总和与电导率线性相关显著.相关性研究表明:降水中SO2-4、NH+4、Ca2+、Mg2+、F-主要来自煤燃烧.Mg2+、Na+与Cl-即来源于地壳源又来自于海洋远源传输,人类活动对黔江区降水影响较大.  相似文献   

9.
基于2019~2020年在南京北郊收集的大气降水进行降水pH、电导率和化学组分分析,研究南京北郊大气降水pH值和电导率的季节变化规律,分析了降水中水溶性无机氮(WSIN)和水溶性有机氮(WSON)的污染水平和沉降特征.结果表明,观测期间南京北郊大气降水发生酸雨(pH<5.6)的频率达到37.18%,降水酸化在秋冬季节较严重,pH值随季节表现出春季>夏季>秋季>冬季的变化趋势.降水电导率平均值为29.49μS·cm-1,春季出现高pH和电导率与该季节大气中含量较高的扬尘有关.降水中WSIN和WSON的季节差异较大,最高和最低NO-3-N和NH+4-N浓度分别出现在春季和夏季;WSON浓度则表现为秋季(2.63 mg·L-1)最高.降水中WSON与水溶性总氮(WSTN)浓度平均比值约为0.47,说明WSON对总氮研究具有重要意义.WSIN和WSON湿沉降通量的平均值分别为12.10 kg·(hm2·a)-...  相似文献   

10.
湖北省环境监测中心站大气组对本地区一年内历次降水进行了监测,获得了大量的监测数据。本文以实际监测数据为依据进行综合分析得到了降水样品中各化学成分——离子的平均当量浓度及其相互关系;降水pH值与电导率的关系;降水中阴、阳离子当量浓度之比值与pH值的关系及本地区降雨pH值的频数分布。同时,还对连续降水过程进行了分段采样和测定,得到了在连续降水过程中各种离子浓度及pH值的变化以及降水对各种离子的清除效果。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
Earthworm toxicity tests are useful tools for terrestrial risk assessment but require a hierarchy of test designs that differ in effect levels (behavior, sublethal, lethal). In this study, the toxicity of chlorpyrifos contaminated soil on earthworms was assessed. In addition to the acute and chronic tests, an avoidance response test was applied. Earthworms were exposed to sublethal and lethal concentration of chlorpyrifos, and evaluated for acute toxicity, growth, fecundity and avoidance response after a certain exposure period. The test methods covered all important ecological relevant endpoints (acute, chronic, behavioral). Concentration of 78.91 mg/kg, chlorpyrifos caused significant toxic effects in all test methods, but at lower test concentrations, only significant chronic toxic effects could be observed. In the present study, chlorpyrifos had adverse effect on growth and fecundity in earthworm exposed to 5 mg/kg chlorpyrifos after eight weeks. The avoidance response test, however, showed significant repellent effects concentration of 40 mg/kg chlorpyrifos. For chlorpyrifos, concentration affecting avoidance response was far greater than growth and fecundity, it seemed likely that earthworms were not able to escape from pesticide-contaminated soil into the clean soil in field and hence were exposed continuously to elevated concentrations of pesticides.  相似文献   

16.
Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene (PS) bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as "purge and trap" and analysed by gas chromatograph-mass spectrometer (GC/MS). Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks.  相似文献   

17.
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.  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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.  相似文献   

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