乌鲁木齐河源1号冰川雪-冰界面含氮离子迁移研究

冰川积累区雪-冰界面附近的化学物质迁移对冰芯记录的形成具有重要意义,为讨论主要含氮离子在这一界面的迁移,本研究基于2004年11月至2006年3月在天山乌鲁木齐河源1号冰川连续采集的64组雪冰样品分析了NO3与NH4+的变化情况.结果表明,雪层底部干季(11月至翌年3月)含氮离子浓度的平均值高于湿季(4-10月)的,而...     

雪冰中NO_3~-浓度记录的研究进展

NO3-是雪冰中含量最高的含氮无机离子,雪冰中NO3-浓度记录的解读已成为研究全球变化的重要内容之一.近年来国内外已经就极地与中低纬高海拔地区雪冰中NO3-浓度记录开展了大量的研究,关于NO3-所指示的环境意义形成了一系列的认识.从雪冰中NO3-的可能性来源(包括太阳活动、陆源粉尘、闪电等自然源以及其他人类源)、时空变化特征以及气-雪-冰界面转化过程等方面综述了近年来该领域的研究成果,并结合全球变化的背景对其研究前景进行了展望.     

天山东部冰川雪坑离子浓度特征的对比研究——以奎屯河哈希勒根51号冰川和哈密庙尔沟平顶冰川为例

对2004年获取的天山奎屯河哈希勒根51号冰川1个雪坑和哈密庙尔沟平顶冰川4个雪坑的离子浓度特征进行了研究,结果表明:Ca2 、NO3-和SO24-是哈密庙尔沟平顶冰川雪坑雪层和积累区雪坑底部冰中的主要离子(尤其是Ca2 ),其雪层中的主要阳离子关系可在底部冰中得以较好的反映,但雪层中各离子浓度与海拔的相关性不明显,可能与海拔的跨度较小和挖取的雪坑较疏有关;雪坑底部冰中的离子浓度与海拔间明显的相关性说明淋融作用随着海拔升高、气温降低而逐渐减弱。SO24-和Ca2 是奎屯河哈希勒根51号冰川雪坑中的主要离子(尤其是SO42-),其雪坑离子化学特征与哈密庙尔沟平顶冰川差别较大,可能与哈密庙尔沟平顶冰川处于塔克拉玛干沙漠、古尔班通古特沙漠和鄯善沙漠的下风向相关,还可能与雪层内淋融作用的强弱和沉积通量的高程效应有关。哈密庙尔沟平顶冰川积累区雪坑中NH4 、NO3-和K 的Cs/Ci较Ca2 、Mg2 和Na 要大,奎屯河哈希勒根51号冰川Na 和NH4 的"雪冰比"较Cl-、SO42-、Mg2 和Ca2 要大,说明这两条冰川雪坑中的Ca2 和Mg2 信号较其它离子可能更易于在冰芯记录中保存下来,为冰芯研究和古气候记录的恢复提供了保障。     

天山博格达峰四工河4号冰川雪坑中人类活动的NO3-、SO42-记录

2009年7月在天山博格达峰地区四工河4号冰川采集了20个雪坑样品.对所有样品(Na+、K+、Ca2+、Mg2+、NH4+、Cl-、SO42-、NO3-、HCOO-和CH3COO-)进行了分析.与天山地区其它冰川比较,博格达峰四工河4号冰川雪坑中SO24-和NO3-浓度均表现为最高值,分别达到521.4ng.g-1和760.4ng.g-1.2008年12月的多条空气后向轨迹经过了乌鲁木齐市中心;雪坑样品pH值与乌鲁木齐市平均值基本一致,并且雪坑样品[NO3-]/[SO24-]比率与乌鲁木齐市冬天[NO3-]/[SO42-]比率相符合;雪坑样品[HCOO-]/[CH3COO-]比率仅为0.79,低于1.结果表明,博格达峰四工河4号冰川雪样的SO24-和NO3-主要来自于人类污染.     

盐水溶液中常见阴离子团的激光拉曼光谱定量分析研究

应用RenishawinVia激光拉曼光谱仪分析研究了人工配制的钠盐溶液中CO3 2-、SO4 2-、HSO4-、HCO3-和NO3-等阴离子团及水包络峰的拉曼谱图特征,建立了拉曼光谱参数（强度面积积分）与溶液中阴离子团浓度的定量关系,提出了利用拉曼谱峰强度面积分法定量分析流体包裹体中CO3 2-、SO4 2-、HSO4-、HCO3-和NO3-等常见阴离子团浓度的方法。对HSO。一和HCO。一这样易电离的酸式阴离子团采用了净目标酸式阴离子团浓度拟合工作曲线。讨论了强度面积积分法定量分析的优越性和激光拉曼探针定量分析Cl-的难点及前景。     

南极冰盖NO－3浓度记录研究进展

综述了近年来南极冰盖雪冰中NO－ 3浓度的影响因素、NO－ 3的来源、沉积后变化及其浓度的时空变化特征的最新研究进展。尽管质子事件、超新星活动、陨石事件、火山喷发和核试验等各种突发事件都可能对南极雪冰中NO－ 3浓度产生影响,但综述和模拟结果表明中低纬度对流层闪电和极地平流层来源可能是南极雪冰中NO－ 3浓度本底的主要来源。综合研究表明,南极冰盖雪冰中记录的NO－ 3浓度可能是其来源、传输路径、沉积过程以及沉积后变化等的综合反映。     

长江口崇明东滩沉积物间隙水中营养盐剖面及其数学模拟

2005年410月,对长江口崇明东滩潮间带高潮滩站位沉积物间隙水中营养盐成分进行了每月一次的连续观测。结果表明,该站点间隙水中营养盐NH4+和S iO32-的浓度一般在200400μmol/L之间;NO2-+NO3-以及PO43-浓度一般在1μmol/L以下,但9月份后的3次采样得到的沉积柱表层（010 cm）NO2-+NO3-浓度则一般超过10μmol/L,甚至接近100μmol/L。沉积物中有机N含量以及受粘土矿物含量影响的蛋白石（BS i）的溶解度是决定间隙水中NH4+和S iO32-的浓度的主要因素。间隙水中S iO32-浓度和温度之间存在着显著的正相关关系（P<0.01）,说明其主要是受温度影响的溶解过程的控制;而NH4+浓度与温度之间没有明显的相关关系,说明与S iO32-相比,沉积物中NH4+产出的控制因素较为复杂。我们采用了经典的早期成岩方程对NH4+和S iO32-浓度剖面进行了数学模拟,在模型中考虑了扩散作用、埋藏作用以及营养盐的代谢作用等因素。模拟结果表明,通过改变扩散项系数基本可以模拟出营养盐剖面中间浓度高、上下浓度低的总体趋势。此外,沉积速率和代谢反应速率也在不同程度上对模拟结果产生影响。      

天山乌鲁木齐河源1号冰川雪坑中pH值和电导率的季节变化及淋溶过程

自2002年9月14日至2004年9月28日,在天山乌鲁木齐河源1号冰川积累区雪坑中连续观测取样,频率为1次/周。对表层雪样品和粒雪坑样品的pH值和电导率进行了分析。结果表明,表层雪的pH值和电导率具有明显的季节变化趋势,与本区域的主导山谷风风向NE和ENE密切相关。在春季,由于尘暴发生频率的增加,表层雪的pH值呈现较强碱性,电导率达到最大值;在冬季,由于原生气溶胶向次生气溶胶的转化,pH值呈现较弱碱性,电导率达到最小值。在后沉积过程中（2003年10月4日至2004年9月8日）,雪坑中不同时期的pH值和电导率呈现不同的季节变化特征和淋溶过程。电导率的峰值P1进入粒雪冰的时间比与它相对应的大粒径（直径>10 μm）微粒的浓度峰值提前40天左右;在有的雪坑中,pH值和电导率的峰值出现在污化层附近,与污化层的位置有较好的一致性,说明污化层对可溶性离子的淋溶作用可能有一定的影响。相关分析表明,Ca2+是影响表层雪中pH值和电导率变化的最主要离子。     

喜马拉雅山达索普冰芯近400a来NO_3~-浓度的变化

NOx作为化石燃料燃烧的重要产物,在大气和生物地球化学循环中扮演着重要的角色,是重要的酸雨物质,它的最终产物是NO3-.为研究亚洲地区大气中NOx的变化历史,从喜马拉雅山中部达索普冰芯中恢复了1600-1997年期间降水中NO3-的浓度变化.结果表明:工业革命以前,大气降水中NO3-浓度变化较为平缓,在1600-1870年期间年平均NO3-浓度保持在约50μL.m-3;工业革命后,NO3-浓度开始增加,特别是1930年以后,伴随着人类活动排放的NOx持续增加,NO3-平均浓度开始迅速增加,1970年以后NO3-平均浓度达到了115μL.m-3,是工业革命前降水中NO3-浓度的两倍多.表明人类活动排放的NOx已影响到喜马拉雅山高山地带.     

印度集中产粮区农业活动引起饮用地下水受到硝酸盐和氟化物污染

本文评价了印度集中产粮区农业活动引起的饮用地下水中NO3—N和氟化物（F）的潜在污染。从不同深度、不同类型水井中共采集了342个地下水样品,分析了地下水样品中NO3—N和氟化物的含量以及pH值和导电率（EC）。也收集了研究区内有关主要种植模式、肥料和杀虫剂使用情况等数据。地下水样品中NO3—N的含量较低,浓度范围为0．01-5．97mg／L,仅6．7％的样品中NO3-N的含量大于3．0mg／L。居民区地下水样品中的NO3-N含量高于农田区。但所有样品中NO3州的浓度均低于世界卫生组织规定的饮用水中NO3—N的容许浓度。地下水样品中NO3—N的含量随水井深度的增大而减小（r=-0．297,P≤0．01）,而随含氮肥料施肥率的增加而增大（r=0,931,P〈0．01）。种植浅根性作物地区地下水中NO3—N的浓度高于种植深根性作物的地区。地下水样品中氟化物的浓度也普遍较低（0．02-1．19mg／L）,仅2．4％的样品中氟化物浓度大于1．0mg／L,这对局部地区居民造成了潜在的氟中毒威胁。总的来说,研究区内地下水中氟化物浓度的空间变化和随含水层深度的变化不大,这表明,研究区的地层岩性是均质的。地下水样品中氟化物的浓度与农业磷酸盐肥料（普通过磷酸钙）的施肥量呈明显的正相关关系（r=0．237,P〈0．01）。研究结果表明,目前研究区内居民饮用的地下水是安全的,但集中产粮区有关的一些人为活动的确对地下水中NO3—N和氟化物的浓度产生了影响。     

Seasonal variations of major ions in fresh snow at Baishui Glacier No. 1, Yulong Mountain, China

This study presented a study of seasonal variations of major ion concentrations in fresh snow on Baishui Glacier No. 1, the largest glacier on Yulong Mountain, China. Fresh snow samples at Baishui Glacier No. 1 were collected from November 2008 to October 2009 for chemical data analysis. The results showed that the neutralizing effect of terrestrial source aerosols raised the pH value of fresh snow. The conductivity of fresh snow was much higher in dry season than that in rainy season. It was evident that the concentration of inorganic ions was generally higher in the dry season than that in rainy season, and the highest values occurred in the pre-monsoon period (April–May). The ions of fresh snow mainly came from terrestrial under the influence of west wind circulation and the Plateau monsoon in dry seasons, and had much complex sources in rainy season under the control of southeast and southwest monsoons. Both wind speed and precipitation had potential effects on ion concentration and composition of fresh snow as well. Moreover, principal component analysis showed that fresh snow ions were mainly from local lithology in dry season and from oceans in rainy season.     

The relative contributions of summer and cool-season precipitation to groundwater recharge, Spring Mountains, Nevada, USA

A comparison of the stable-isotope signatures of spring waters, snow, snowmelt, summer (July thru September) rain, and cool season (October thru June) rain indicates that the high-intensity, short-duration summer convective storms, which contribute approximately a third of the annual precipitation to the Spring Mountains, provide only a small fraction (perhaps 10%) of the recharge to this major upland in southern Nevada, USA. Late spring snowmelt is the principal means of recharging the fractured Paleozoic-age carbonate rocks comprising the central and highest portion of the Spring Mountains. Daily discharge measurements at Peak Spring Canyon Creek during the period 1978–94 show that snowpacks were greatly enhanced during El Niño events.     

Influence of temperate mixed and deciduous tree covers on Hg concentrations and photoredox transformations in snow

Mercury dynamics in snowpacks under forested canopy are currently unknown, even though these snowpacks may represent important Hg pools eventually released towards lakes at snowmelt. We followed Hg distribution and partitioning in snowpacks under different temperate canopy types over space and time, and conducted short-term experiments on Hg redox behaviour in these snowpacks. Hg concentrations were ca. two times higher in snow deposited under coniferous than deciduous canopies; the lowest concentrations were observed in snow over a frozen lake in the same watershed. In snow on the ground, up to 80% of the Hg was bound to particles between 10 and 70 μm. Incubations of snow in situ showed that (i) Hg photoreduction and evasion was significant in open areas (lake surface) but was greatly hampered by light attenuation under winter canopies and (ii) oxidation of newly produced Hg⁰ was a significant process in boreal snow, affecting Hg evasion to the atmosphere. We used a mass balance approach to compare Hg pools in snowpacks with wet deposition measured by precipitation collectors. A net gain of Hg was observed in snow under mixed canopies whereas, under a deciduous canopy, the pool of Hg stored at the end of the winter was comparable to that of wet deposition. Snow over lake acted as a winter source of Hg. Whereas most Hg deposited by snow on lakes is lost before snowmelt, Hg deposited on the forested watershed is largely retained in snowpacks, presenting a threat to systems receiving meltwaters.     

Heavy metals distribution in Jamaica Bay sediments

Ninety-two sediment samples collected at 53 stations in Jamaica Bay from November 1970 to October 1973 were analyzed for Pb, Cr, V, Cu, Cd, Zn, Ni, Co, and percent organic carbon (ORC). Selected samples were analyzed for Hg. The concentrations of all metals correlate with each other and with organic carbon. Vanadium, cobalt, and nickel stand out as a separate component and are enriched relative to other metals in areas affected by petroliferous pollution. The metal concentrations are strongly influenced by the strength of tidal currents and proximity to pollution sources. Amount of rainfall and/or season affects metal concentrations in Grassy Bay (a deep restricted body of water within Jamaica Bay).     

滹沱河冲洪积扇地下水硝酸盐的污染特征及污染源解析

为研究滹沱河冲洪积扇地区地下水硝酸盐污染机制,对滹沱河冲洪积扇地区地下水和地表水进行了采样监测,运用环境健康风险评价模型对研究区硝酸盐进行评价,采用水化学和多元统计方法研究了滹沱河冲洪积扇地区地下水硝酸盐污染问题。结果表明:研究区地表水NO-3污染较轻,NO-3均值为19.54 mg/L,所有水样均未超出我国地表水环境质量标准（45 mg/L）;但是,地下水已经受到了NO-3的严重污染,NO-3均值为75.84 mg/L,且有30.43%水样超出我国地下水质量标准（88. 6 mg/L）。研究区3个水文地质单元地下水硝酸盐的平均个人年健康风险分别为4.94×10-8、1.99×10-8和2.61×10-9,低于国际辐射防护委员会（ICRP）推荐的最大可接受风险水平（5.0×10-5/a）,因此,认为不会对人群构成严重危害。水文地质单元和地下水埋深对硝酸盐污染有显著影响,但是,土地利用类型对硝酸盐浓度的影响不显著。滹沱河冲洪积扇地区地下水硝酸盐的主要污染来源是生活污水和化肥。此外,强烈开采地下水也是该地区NO-3污染的诱因。     

The effects of Typhoon Morakot on concentration of airborne particulates derived from unvegetated riverbanks

Landslides frequently occur during large earthquakes and storms in Taiwan, supplying large volumes of sediment to downslope areas. When coupled with the intense northeast monsoon over Taiwan in the dry winter season, this can lead to high concentrations of airborne particulates that are hazardous to human health. Air quality monitoring stations near unvegetated riverbanks recorded high concentrations of particulate matter less than 10 μm (PM₁₀) after Typhoon Morakot in 2009. The objective of this study was, therefore, to analyze the effects on air quality of sediment caused by the typhoon. A deflation module was simulated, and the resulting estimates were compared with observed data from the Taitung monitoring station for 2004 and 2005. The relationship of dust flux to average atmospheric dust concentration was analyzed for October to December 2001–2010. Analysis showed that the 2001–2008 data are highly correlated (0.78) with the average concentration. The intercept of 28.07 represented the background concentration with no dust emission, from October to December of 2001–2008. Based on the dust flux potential in 2009, the average yearly PM₁₀ concentration would be 37.98 µg/m³; however, the measured concentration was 61.67 µg/m³ from October to December. This suggests the strong influence of dust re-suspended from unvegetated riverbanks by Typhoon Morakot.     

气象要素影响下雪冰离子淋溶过程研究——以乌鲁木齐河源1号冰川为例

为了更好地理解化学离子在雪坑中的迁移和保存,进一步解释冰芯记录,基于乌鲁木齐河源1号冰川海拔4130 m处的雪冰化学资料,研究了气温和降水与离子淋溶过程的关系.结果表明：气温与离子浓度呈负相关关系,夏季的雪坑离子浓度波动剧烈,冬季的雪坑离子浓度相对稳定.离子浓度随正积温的升高呈指数衰减趋势,当正积温至0℃以上时,离子浓度急剧降低;当正积温升至60℃左右时,离子浓度呈缓慢降低.不同离子的淋溶过程对正积温的响应有所不同,随着正积温的增加,SO₄^2-,NO₃^-,Na⁺,Cl^-,NH₄⁺和Ca²⁺的衰减趋势非常显著,而Mg²⁺和K⁺则呈现无规律性的变化.淋溶因子指出,融水渗浸作用导致雪坑中大部分离子被淋溶;不同离子的淋溶因子也有明显差异,Mg²⁺淋溶因子最小（0.43）,SO₄^2-淋溶因子最大（0.84）,说明Mg²⁺最为稳定,而SO₄^2-最易淋溶.降水对雪坑离子浓度的影响较为微弱,主要通过增加表层雪离子浓度而提升整个雪坑的离子浓度.     

反硝化菌的耐砷驯化及其对水铁矿吸附态砷迁移转化的影响

采集缺氧活性污泥进行室内微生物驯化,培养耐砷反硝化菌。把耐砷反硝化菌、营养液和吸附As(V)的水铁矿在厌氧条件下培养,研究反硝化菌代谢作用下,系统中Fe、Mn、NO3-和As形态的动态变化。结果表明,缺氧活性污泥中的反硝化菌具有一定的耐砷能力。在砷含量500μg/L以内,其反硝化强度基本不受砷的影响。在吸附有砷的水铁矿体系中,反硝化菌所产生的反硝化作用可导致溶液中NO3-含量的降低、Fe含量的升高、As含量降低,且As(III)所占比例增加。这说明,体系中水铁矿的还原性溶解和As(V)的还原性解吸已经发生。As含量降低的原因是,在培养体系中水铁矿的含量高,Fe的释放量只占很小比例,表层水铁矿被还原后,在次表层形成新的水铁矿吸附位,这种新吸附位不仅可以吸附溶液中已经存在的As,而且能够再吸附由于还原性溶解和解吸所释放出的As。     

Source apportionment and distribution of atmospheric mercury in urban Beijing,China

The concentration of gaseous elemental mercury (GEM) in the atmosphere of urban Beijing was measured from October 2003 to September 2004 to investigate the origins and spatial-temporal variations of atmospheric Hg. The mean value of Hg concentration is 17.1 ng·m-3 (n=653). The atmospheric Hg data showed spatial-temporal variations throughout the duration of our observation. The maximum GEM concentration (53.7 ng·m-3) was observed at Gucheng in the western area of urban Beijing. The GEM concentrations increased from the north to the south of the studied area, and were higher in winter than in summer. The highest and lowest monthly averages of GEM concentrations were measured to be 23.3 and 4.1 ng·m-3 in January and July, respectively. In addition, GEM concentrations are higher in the daytime than at night in Autumn and from 14 March to 15 April, but daily GEM variation showed an inverse pattern from 22 April to 22 May. In winter, two peak values of GEM concentrations occurred at 13:30 and 21:30. Daily variation of GEM concentrations in summer was the lowest in the four seasons. Mercury from coal combustion was estimated to be the main source of anthropogenic emissions in Beijing from October 2003 to September 2004. Additionally, Hg emission from natural gas burning was estimated to be another dominant source of atmospheric Hg in Beijing.