Landfill is an important atmospheric mercury emission source

Due to the special physical and chemical properties,mercury is a global pollutant which could be aeriallytransported cross the borders[1,2]. Both natural processesand human activities emit mercury to the air. The majoranthropogenic mercury emission source categories arecoal combustion, waste incineration, chlorine-alkali plant,metal smelting and refining and so on[1—3] . Human activi-ties emit not only elemental mercury (Hg0), which has along lifetime in the air, but also reactive gaseous mer…     

贵州六枝煤矸石复垦土壤及农作物中汞分布规律研究

使用Lumex测汞仪,测定了贵州六枝煤矿不同风化年限的煤矸石风化土壤及农作物中总Hg含量,并对此矿区煤矸石风化土壤—农作物系统中汞的分布规律进行了研究.结果表明,煤矸石及受煤矸石淋滤液影响的土壤样中汞含量范围在0.045 -0.474 mg·kg-1之间;煤矸石汞含量随着风化年限的延长逐渐降低,风化时间较短的煤矸石及受...     

Case study of longwave contribution to dust radiative effects over East Asia

In order to evaluate the impacts of LW contribution to aerosol radiative effects over East Asia,a dust longwave radiative parameterization scheme is integrated into the online mesoscale dust forecasting model GRAPES_CUACE/dust.A case modeling study shows that about half at surface and one third at TOA of the dust negative shortwave radiative forcing are cancelled by its positive longwave forcing over the dust affected area.In the dust layer,longwave radiation emitting by dust cools the atmosphere,which counteracts about 17%of shortwave heating of atmosphere during daytime and results in cooling of atmosphere simply during nighttime.At the same time,the atmosphere beyond the dust layer is warmed because of absorbing the LW radiation emitted by dust layer.Dust longwave contribution exerts more evident impact on the air temperature in lower atmosphere and surface.The surface air temperature cooling rate resulting from the dust solar radiation is cancelled about 40%by dust longwave warming at daytime.At nighttime,dust longwave contribution warms land and sea surface.The online calculation of dust LW radiation reduces about 15%relative errors of predicted AOD based on the dust model with only SW radiative feedback.This case study result suggests that dust longwave contribution has important impacts on the earth-atmosphere energy process,especially on the surface and in the lower atmosphere and should not be neglected in the study of dust radiation effects.     

中国贵州大气汞的沉降(英文)

研究贵州省主要中心城市及自然保护区大气汞的沉降。测定大气中总汞、二价汞、甲基汞 ,用 Moss Bag、涂层KCl扩散管 (Denuder)、便携式大气测汞仪进行测定与评价。在国际上首次报道大气汞的沉降和汞沉降瞬间和相对空间变化关系以及煤汞引起的污染。     

秀山汞矿开采对当地土水环境的影响

为了解矿山开采对当地土水环境的影响,测定了秀山龙洞沟汞矿附近土壤和水样中的总汞含量.结果表明矿区水样的总汞含量为0.018 6～0.675mg/L,比全国水体平均值高2～3个数量级;土壤汞含量为1.40～19.72mg/kg,明显高于中国土壤背景值.随与汞矿的距离变远和水土的自净作用,土水样品中的汞含量逐渐变小.但是,矿山的长期开采和冶炼,加上长期的风化、水流和大气沉降作用,将矿区的大量汞迁移到周围的农田和河流,使得当地的土水环境受到汞的污染.     

Hydrogen bonding at the water surface revealed by isotopic dilution spectroscopy

The air-water interface is perhaps the most common liquid interface. It covers more than 70 per cent of the Earth's surface and strongly affects atmospheric, aerosol and environmental chemistry. The air-water interface has also attracted much interest as a model system that allows rigorous tests of theory, with one fundamental question being just how thin it is. Theoretical studies have suggested a surprisingly short 'healing length' of about 3??ngstr?ms (1?? = 0.1?nm), with the bulk-phase properties of water recovered within the top few monolayers. However, direct experimental evidence has been elusive owing to the difficulty of depth-profiling the liquid surface on the ?ngstr?m scale. Most physical, chemical and biological properties of water, such as viscosity, solvation, wetting and the hydrophobic effect, are determined by its hydrogen-bond network. This can be probed by observing the lineshape of the OH-stretch mode, the frequency shift of which is related to the hydrogen-bond strength. Here we report a combined experimental and theoretical study of the air-water interface using surface-selective heterodyne-detected vibrational sum frequency spectroscopy to focus on the 'free OD' transition found only in the topmost water layer. By using deuterated water and isotopic dilution to reveal the vibrational coupling mechanism, we find that the free OD stretch is affected only by intramolecular coupling to the stretching of the other OD group on the same molecule. The other OD stretch frequency indicates the strength of one of the first hydrogen bonds encountered at the surface; this is the donor hydrogen bond of the water molecule straddling the interface, which we find to be only slightly weaker than bulk-phase water hydrogen bonds. We infer from this observation a remarkably fast onset of bulk-phase behaviour on crossing from the air into the water phase.     

泥河水库夏季水–气界面甲烷通量日变化研究

为研究东北地区灌溉型水库的甲烷日排放特征,试验采用静态浮箱法于2008年7月测定了泥河水库水–气界面的甲烷通量.结果发现,泥河水库夏季甲烷平均排放通量为13.48 mg/(m2.h);夜间(21:00)甲烷排放最低,日间(5:00和9:00)最高.不同时刻的甲烷通量存在显著差异(P<0.05)2,1:00的甲烷排放通量显著低于5:00和9:00的甲烷通量.泥河水库出水口、库中心和进水口的甲烷通量差异不显著.相关分析表明,甲烷通量与总氮存在显著正相关(P<0.05),与气温、水温、水中总有机碳、水中溶解有机碳、总磷、水深、风速、溶氧等环境因子均未达到显著相关.     

尼罗罗非鱼对汞富集的研究

本文以尼罗罗非鱼（Ｔ·ｎｉｌｏｔｃａＬ）为材料，应用冷原子吸收测汞法，进行了汞（Ｈｇ＋＋）在鱼体内的积累的实验性研究；还对鱼体不同部位汞的蓄积量作了比较；此外，对鱼体汞中毒的死亡过程作了观察。     

北京昆玉河夏季水-气界面CO2通量日变化研究

以昆玉河为例,采用LGR-动态通量箱法,对城市河流夏季水-气界面CO2释放通量进行24h连续监测．结果表明,观测点处水-气界面CO2释放通量具有明显的日变化特征．24h内CO2释放通量在-27．18～12．51mg·m1·h1,平均值-7．28mg·m-2·h-1,昼间平均值为-8．81mg·m-2·h-1,夜间平均值为-4．22mg·m-2·h．24h内水-气界面CO2通量,极大值出现在21：20为12．51mg·mq·h-1,极小值出现在6：20为-27．18mg·m1·h～．在夏季城市河流水-气界面CO2通量受到气温、风速、总磷（TP）、总氮（TN）、总碱度（TA）等因素影响,使城市河流成为大气CO2的碳“汇”之一．     

3mm波段地面遥感大气水的研究

测量大气本身的微波辐射,可以推算大气要素,如大气温度、含水量、臭氧和其他一些气体的浓度。利用8mm和1.35cm波段的双通道微波辐射计可以遥感大气中汽态水和液态水的含量。本文通过对3个微波波段在大气中的辐射传输的计算和结果比较,发现可以在地面利用3mm波段遥感大气水,尤其是遥感晴空汽态水含量将具有更高的灵敏度。开展3mm波段的辐射测量,将有利于精确地监测大气水的含量和变化,这对中尺度天气预报,气候热平衡和微波通讯将起重要作用。     

微波遥感大气水的研究

在地面测量大气本身的微波辐射, 可以推算大气温度, 含水量, 臭氧和其他一些气体的浓度。采用大气中水汽吸收波段1.35cm和微波窗区8mm波段的辐射测量,可以遥感大气中汽态水含量和云中液态水的含量。本文通过对4个微波频段在大气中辐射传输的计算,可以看出在地面利用3mm波段遥感大气中的汽态水和云中液态水,尤其是遥感晴空汽态水含量将具有更高的灵敏度。开展3mm波段的辐射测量,将有利于连续精确地监测大气水的研究,这对中尺度天气预报和气候热平衡将起重要作用。     

南极大气环流特征探讨

本文应用日本南极昭和基地１９８２年的探空资料＾［１］，讨论了从地面至２０ｈｐａ高度之间的风、温和４００ｈｐａ以下的湿度场的月平均年变化结构及大气环流特征。对位温、相当位温和饱和相当位温与大气环流的关系也进行了分析探讨。为研究全球大气环流的变化与异常及南北半球大气环流的相互作用的时空尺度遥相关提供了参考。     

夜间废气排放加重中国雾霾污染

工业和交通废气、农业和生活烟雾等污染物排放是城市雾霾的重要来源,其污染物特别是细颗粒物质对人体健康有损害。就区域而言,我国北方的污染物PM2.5、PM10、CO、SO2的浓度较高,中西部、东南部和南部较低;中国大部分地区的季节性高污染通常出现在冬季。其原因主要是因为细颗粒物排放量大,且受不利气象条件的影响,停滞的气流不利于气溶胶扩散。夜间PM2.5的浓度通常高于白天,其原因:一是由于重型车辆通常在夜间作业,而且烧烤、非法秸秆焚烧等活动一般在夜间进行,导致夜间的污染物排放量增加;二是由于夜间地面温度低,空气湍流减少而导致垂直空气运动很少,故气流停滞现象夜间尤为明显。历史上喀麦隆尼奥斯湖和印度博帕尔灾难的加剧也是由于此类气象条件所致。本研究提出夜间废气排放加重了中国雾霾污染的设想,并通过分析北京地区54511气象观测站提供的2014年每天、每小时的地面气温数据,发现减少夜间污染排放可能是现阶段减少雾霾形成的低成本措施之一。     

功能化硒化镉量子点的制备以及作为汞离子荧光探针的研究

以L-半胱氨酸为稳定剂,水溶液中通过简易的两步合成了CdSe(硒化镉)量子点,在磷酸盐的缓冲介质中,Hg2+对量子点有显著荧光猝灭作用。实验考察了缓冲液pH值、反应时间、量子点浓度等多种因素对Hg2+分析灵敏度的影响。结果表明,在最佳实验条件下,pH=7.75的Na2HPO4-NaH2PO4缓冲溶液中,反应时间为30分钟,量子点浓度为7.5×10-6mol/L,Hg2+在5.0×10-8~2.5×10-6mol/L的浓度范围内对量子点有较强的猝灭作用,且体系的发光强度与溶液中的Hg2+的浓度符合修正的斯特恩方程,常见的共存离子响应考察结果表明:该法具有较高的选择性,同时与常见的检测汞离子的荧光方法相比,该方法具有较高的灵敏度和较宽的线性范围。     

Progress in the study of mercury methylation and demethylation in aquatic environments

Mercury(Hg) and its compounds are a class of highly toxic and pervasive pollutants.During the biogeochemical cycling of Hg,methylmercury(MeHg),a potent neurotoxin,can be produced and subsequently bioaccumulated along the food chain in aquatic ecosystems.MeHg is among the most widespread contaminants that pose severe health risks to humans and wildlife.Methylation of inorganic mercury to MeHg and demethylation of MeHg are the two most important processes in the cycling of MeHg,determining the levels of MeHg in aquatic ecosystems.This paper reviews recent progress on the study of Hg methylation and demethylation in aquatic environments,focusing on the following three areas:(1) sites and pathways of Hg methylation and demethylation,(2) bioavailability of Hg species for methylation and demethylation,and(3) application of isotope addition techniques in quantitatively estimating the net production of MeHg.     

中国表层土壤汞和硒分布空间异质性的因素分析

在大尺度(中国)范围内,季风和降水等因素可能对土壤中挥发性元素汞和硒的含量具有显著影响,但影响表层土壤中汞和硒差异的关键因子及其贡献率仍未知.分析了干、湿沉降,微生物挥发作用对土壤中汞和硒积累的贡献,结果显示表层土壤汞和硒的积累是一个动态的过程.在全国尺度上,湿沉降对表层土壤中硒的贡献率达到91.5％,对汞的贡献率为4...     

重金属汞对植物生理活动的影响和钙离子的拮抗作用

汞对植物各方面的生理活动均有严重影响。植物吸收的汞大都积累在根部,这是由于汞与植物根部蛋白质相结合的结果。汞也可诱发生物的染色体突变。富集在作物体内的汞进而通过食物链危害人体。人类的轻度汞中毒可通过摄入含钙食品来缓解。探讨了汞对植物体细胞和生殖细胞的影响,并研究了钙离子对植物汞伤害的缓解作用。发现汞对植物体细胞和生殖细胞均有严重影响,钙离子对植物叶细胞和生殖细胞的汞伤害均有较高程度的拮抗作用,但对根细胞的汞伤害没有明显的缓解作用。     

气压脉动仪及湍流大气中的气压脉动频谱特征研究

基于自制气压脉动仪在内蒙古科尔沁地区大气边界层与大气环境综合实验站2019年夏季的观测资料,计算气压脉动特征参数,分析气压频谱及气压标准差特征.结果表明,自制气压脉动仪能够反映气压的快速变化,频率响应接近1 Hz;气压脉动方差谱曲线在0.0006～0.5 Hz的频率范围内满足n?2标度率,峰值频率低于风速和温度;不同稳...     

Heavy metals contents in soil profiles of typical agricultural lands in Yixing,Jiangsu Province,China

The effect of land use pattern on the heavy metals(HMs)distribution in soil profiles was investigated in Yixing City,China,for the four typical types of land utilization,i.e.vegetable fields on the plain,paddy fields,tea gardens on hilly lands and bamboo groves.The variance of HMs concentration in the depth of 0-15 cm,15-30 cm,30-60 cm of soil profiles was compared among the different tillage ages. Results showed there was a notable accumulation of Cd,Hg,Cu,Pb,Zn and Cr in the soil profiles of vegetable fields and paddy fields causing a pollution of Cu,Hg and Cd in some profiles,while no remarkable accumulation of HMs in the soil profiles of the tea gardens and bamboo groves was found. The accumulation extent of HMs in the soil profiles of the four kinds of land use followed a sequence of vegetable fields>paddy fields>tea gardens>bamboo groves.The accumulation of HMs was mainly due to the industry,transportation,other urban human activities,and intensive use of fertilizers and pesticides.The downward leaching of HMs was relatively remarkable in the soil profiles of vegetable fields. There was an accumulation in surface and subsurface layers for Cd,Hg,Pb,Zn in the soil profiles of paddy fields and tea gardens,and for Cd,Hg in those of bamboo groves.Serious pollution effects of Hg, Pb,and Zn have been shown in the soil of vegetable fields.All the four kinds of agricultural land are basically free from the pollution of the external sources of As and Ni.With the increase of tillage time, the soil of vegetable and paddy fields will face the potential risk of HMs pollution,which mainly comes from Hg,Cd and Cu,whereas that of tea gardens and bamboo groves faces a relatively small risk.     

法国Carrier喷水室冷却去湿过程热工性能的研究和分析

本文在理论分析及实验的基础上,分析研究了最近我国引进的法国Carrier喷水室中,空气被冷却去湿处理时,喷排间距、喷水方向、水气比、空气流速、喷水压力、喷水初温等因素对热二性能的影响,从而提出了提高喷水室热湿交换效率和减少能耗的途径。可供在空调运行及设计时参考。