西藏阿里地表面太阳光谱观测

阿里位于青藏高原西部,是太阳能资源极其丰富的地区.本次在西藏阿里噶尔县(海拔4280 m,32°30′02″?N,80°06′01″?E)夏至日前后,对波长在280?—?1200 nm的太阳光谱进行了短期观测.结果显示:阿里2020年6月21日12:34,在482 nm波长处出现了太阳光谱辐射强度的最大值2.33 W·?m?2·?nm?1,对比观测点拉萨的最高太阳光谱强度出现在2020年6月27日13:56,波长482 nm处光谱强度为2.80 W·?m?2·?nm?1,在太阳直接辐射、大气中云层及微粒的散射辐射、地表面反射辐射的叠加下,这两地的最高太阳光谱强度都超过了AM0最高光谱强度;将阿里2020年6月22日日中时刻的太阳光谱与AM0、AM1.5标准光谱进行对比,可以看出:阿里的紫外、可见光谱的强度明显高于AM1.5,且接近AM0;阿里2020年6月21日出现了"日食"现象,太阳光谱也随着日食的初亏?—?食甚?—?复圆变化.此次观测为青藏高原西部地区提供了稀有的太阳光谱数据支撑,有利于整个西藏太阳能利用的发展.     

西藏日太阳总辐射估算模型的优化与时间尺度效应

根据2012～2014年拉萨站点的日太阳辐射观测数据,对3种日太阳总辐射估算模型(左大康、Prescoff和王炳忠等提出的估算模型)的估算结果和实际观测结果进行误差检验分析,结果表明:3种模型都通过了显著性检验,其平均绝对误差(MAE)分别为6.17 MJ/(m~2·d)、6.42 MJ/(m~2·d)和12.31 MJ/(m~2·d),均方根误差(RMSE)分别为1.60 MJ/(m~2·d)、1.65 MJ/(m~2·d)和2.78 MJ/(m~2·d),表明利用地理位置信息和日照时数的左大康估算模型对拉萨日太阳总辐射的估算效果优于Prescoff和王炳忠估算模型。利用左大康估算模型分别估算得到2015年拉萨、那曲和葛尔地区的日太阳总辐射值,并进行模型验证。通过分析拉萨1971～2015年的太阳总辐射变化和周期性特征,研究日太阳总辐射估算模型的时间尺度效应。按照11年和四季两种不同的时间尺度,利用线性回归法对日太阳总辐射估算结果和实际观测结果进行误差和相关性分析,得到经验参数a和b的值与时间尺度有一定关系。11年和四季两种时间尺度除夏季以外,其他时间拟合模型的精度均得到了提高。通过线性回归法得出45年的西藏日太阳总辐射优化估算模型,该模型估算日太阳总辐射的误差小于左大康模型,估算精度较高。     

不同地域的阳光光谱分布特性

目的研究阳光的光谱能量分布特性。方法对高原、西北沙漠、热带海洋等3个地域200~800 nm波段的阳光进行光谱测量,分析不同地区、不同天气状况、不同扫描速度下的阳光光谱能量分布特性。结果高原地区阳光光谱中的紫外-可见波段的辐照强度明显比西北沙漠和热带海洋地区高,多云时200~800 nm波段的辐射总量与晴天相比降低1/4,200~400 nm的紫外波段的辐射总量仅为晴天时的54%。光谱测量仪的扫描速度对光谱测定结果基本无影响。结论研究获得的阳光紫外截止点、340 nm处的辐照强度、不同波段的辐照量,可为实验室光源暴露试验中的光源选择、光谱能量控制提供参考。     

西藏的环境氟水平与砖茶型氟中毒

为探讨西藏儿童与砖茶型氟中毒的关系,以拉萨为中点,藏北那曲为北部点,定日县为南部点,对这3个地区的土壤、燃料、水源和主要食物进行了氟含量测定.采用世界卫生组织(WHO)和世界粮农组织(FAO)提出的<化学污染物的膳食摄入量研究指南>,进行了食物结构、饮茶习惯、儿童食物摄入量以及儿童每日总摄氟量的调查按美国国家牙科研究所Horowitz提出的标准进行了儿童氟斑牙检查.结果表明,3个调查点均属传统的低氟区,而儿童每日摄氟量高,那曲8.03mg,拉萨6.93mg,定日7.68mg.其原因来自含砖茶的食品酥油茶和糌粑(青稞粉拌砖茶水的食物).这2种食物占日总摄氟量的99.74%(那曲),98.70%(拉萨),99.60%(定日),砖茶氟摄入导致西藏儿童砖茶型氟中毒的流行.氟斑牙患病率分别达到82.66%(那曲),52.89%(拉萨),75.93%(定日),氟斑牙指数表明,那曲、定日属氟中毒重度流行区,拉萨属中度流行区.砖茶型氟中毒是我国近年来发现的氟病新类型,与饮水型、燃煤污染型比较,它具有覆盖面大、隐蔽性强、难以防治的特点,降低砖茶氟含量可能是防治砖茶型氟中毒的最好方式.     

北京地区大气气溶胶光学厚度的观测和分析

利用中国科学院大气物理研究所研制的中分辨率太阳-天光光谱自动观测系统(MORSAS)于北京对太阳直射光谱和天空散射光谱进行准连续观测,其中无云情况(包括晴天和浑浊天气)下的观测资料用于获取大气气溶胶光学厚度.该仪器与一台美国NASA主持的国际气溶胶观测网仪器CIMEL CE-318太阳光度计进行对比观测,二者所得结果一致性较好.作者给出了近3年北京地区大气气溶胶光学厚度和表征粒子谱宽度的Angstrom指数(a)的变化情况.与20世纪90年代中期相比,近3年北京秋冬季气溶胶光学厚度有所减小,表明北京的环境治理有一定成效;而春季气溶胶光学厚度则在近2年有明显增加,源自沙尘天气,且Angstrom指数亦变小,表明大粒子比例增加,因此需要加强对沙尘源的治理.     

基于多波长激光雷达探测雾和霾的应用研究

该文利用355 nm&532 nm的双波长大气颗粒物监测激光雷达和910 nm的激光云高仪3个不同波长的激光雷达来探测雾、霾过程,并结合地面气象要素,分析雾、霾过程中气溶胶的光学特性和吸湿性质。结果表明,雾后向散射强度较大,后向散射系数在垂直方向上变化率大,出现高度较低;霾后向散射强度较小,空间分布均匀,后向散射系数垂直变化率小,出现高度较高。对雾、霾天气中气溶胶吸湿性质进行分析,得出随着气溶胶粒子的吸湿增长,较长的波长对大粒子更为敏感,且相对湿度越大,气溶胶粒子的吸湿增长速度越快。吸湿增长因子和Angstrom指数呈负相关,气溶胶粒子增长的越快,Angstrom指数减小的速度也越快。在近地面处,雾、霾天气的Angstrom(910 nm/532 nm)指数小于Angstrom(532 nm/355 nm)指数,而晴天与之相反,表明雾、霾天气时,大气中有较多的粗粒子存在,而晴天则以细粒子为主。     

基于地基便携式FTIR的CO2与CH4柱浓度观测研究

地基傅里叶变换红外光谱技术(Fourier transform infrared spectroscopy, FTIR)由于其具有高的时空分辨率、对地表大气浓度变化敏感等优点，已成为遥测温室气体柱浓度的重要技术。基于便携式的傅里叶变换红外光谱仪(EM27/SUN)采集的太阳光谱来反演北京市区CO₂与CH₄柱浓度。通过与高分辨率FTIR观测结果比对，验证了EM27/SUN观测的准确性和可靠性。同时利用正午观测的CO₂和CH₄柱浓度结果计算了CO₂与CH₄观测精度。其中CO₂的观测精度为0.16×10^-6,CH₄的观测精度为1.4×10^-9。最后，给出了CO₂与CH₄时间序列变化，CO₂与CH₄在观测期间的变化较为一致。该研究表明了便携式FTIR观测CO₂与CH     

选择双波长分光光度法测定废水中铁

依据Fe~(2+)——邻菲咯啉显色光谱在520—560nm波长范围与悬浊液吸收光谱相似性,建立双波长光度法测定铁(Fe~(2+))的数学模型,曲线稳定性好,任意选择两波长均能计算铁的准确浓度。通过对废水实验,相对标准偏差6%,加标回收率92%～103%。该方法简单易操作。     

杭州市春季大气超细颗粒物粒径谱分布特征

2012年3~5月,采用快速迁移率粒径谱仪(fast mobility particle sizer,FMPS)对杭州市大气超细颗粒物数浓度进行了连续监测和分析研究.结果表明,核模态(5.6~20 nm)、爱根核模态(20~100 nm)、积聚模态(100~560 nm)以及总颗粒物(5.6~560 nm)日均数浓度值分别为0.84×104、1.08×104、0.47×104和2.38×104cm-3.晴天天气下,爱根核模态颗粒物浓度较高,且可观测到核模态和爱根核模态颗粒在早上10:00~11:00开始增加,3~4 h后结束,这说明太阳照射强度促进了新粒子形成.在工作日与周末,人为活动因素使各模态颗粒物浓度分布有明显差异.结合天气因素分析可知,风速和风向也直接影响颗粒物浓度;颗粒物浓度与能见度分析结果表明:杭州地区大气能见度的高低受核模态和爱根核模态的颗粒影响较小,与积聚模态颗粒物浓度呈负相关关系.     

南京青奥会期间不同天气条件下大气气溶胶中水溶性离子的分布特征

为研究青奥会期间不同天气条件下水溶性离子粒径分布特征,使用β射线测尘仪、安德森9级采样器和IC型离子色谱分析仪对南京2014-08-06~2014-09-04的PM_(2.5)、水溶性离子进行观测分析.将观测期间划分为晴天、雨天和阴天这3种天气类型.PM_(2.5)在不同天气条件下的平均浓度为晴天阴天雨天.PM_(1.1)、PM_(1.1~2.1)和PM_(2.1~10)中水溶性离子的浓度均是晴天阴天雨天,且降雨过程对细粒子的去除作用更为明显.Ca~(2+)和Mg~(2+)谱分布类似,呈双峰分布,降雨对SO_4~(2-)和NH_4~+在0.65~1.1μm清除作用较强.不同天气条件下NO_3~-/SO_4~(2-)比值均小于1,雨天和阴天时的NO-3/SO_4~(2-)值高于晴天.3种天气条件下SOR和NOR的值均大于0.1,SO_2和NO_2发生不同程度的二次转化,大气中存在更多的二次颗粒物.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

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.