自贡市大气颗粒物污染特征及来源解析

利用自贡市大气监测数据、同期气象数据以及颗粒物源解析在线监测资料,对颗粒物污染的特征及成因进行研究.结果表明:颗粒物年均浓度受浮尘天气影响明显,季均浓度呈冬高夏低变化,月均浓度呈"U"字形变化,日均浓度呈双峰型变化;颗粒物与降水、温度、气压、风速存在相关性,与相对湿度无相关性,PM10、CO、NO2、SO2、O3浓度对PM2.5浓度变化影响显著;PM2.5主要成分为元素碳、有机碳、富钾颗粒等,主要来源为机动车尾气、燃煤、工业工艺源等.     

厦门秋季近郊近地面CO2浓度变化特征研究

利用CO2监测仪在厦门近郊中国科学院城市环境研究所超级监测站进行了秋季CO2数据采集,并结合监测站气象要素和气体污染物监测,分析了近地面CO2浓度变化特征、风速风向对其变化特征的影响以及CO2与部分气体污染物的相互关系.结果表明,厦门近郊秋季近地面CO2浓度主要集中分布在375～415μmol.mol-1范围内,约占70.87%;近地面大气CO2日变化曲线呈单峰型结构,CO2浓度日变化范围375.74～418.18μmol.mol-1,日平均最高值出现在黎明前后(408.54μmol.mol-1),最小值出现在午后附近(379.14μmol.mol-1),夜晚(18:00～05:00,北京时间)平均浓度(400.87±4.05)μmol.mol-1高于白天(06:00～17:00)平均浓度(388.86±9.40)μmol.mol-1;风速日变化曲线与CO2呈现完全相反的变化趋势,夜晚时段(22:00～04:00)风速波动范围在1.0～1.5 m.s-1时,对应的CO2浓度变化平稳,基本稳定在(400.72±2.12)μmol.mol-1.白天时段(09:00～18:00)风速变化范围在2.0～2.5 m.s-1时,对应的CO2浓度变化范围较大为379.14～394.83μmol.mol-1;用指数函数模型估测到该站点区域CO2背景浓度为386.84μmol.mol-1;观测期间该站点主要风向为东北偏东,统计该方向上CO2浓度与风速的相关关系,得出CO2浓度与风速呈极显著负相关(r=-0.67),相关系数高于所有方向统计的CO2浓度与风速的相关系数(r=-0.41,P<0.01),不同风向上CO2浓度贡献来源不同;此外,CO2浓度与温度、辐射量呈负相关(r=-0.541/-0.515,P<0.01),与湿度呈正相关(r=0.66,P<0.01);与其它大气气体污染物相比CO2与CO、NO的相关程度较高(r=0.469/0.436,P<0.01),与SO2相关程度较弱(r=0.126,P<0.01),经分析推测监测站点区域CO2排放源部分来自机动车排放,而燃煤排放贡献较小.     

中国长江三角洲地区黑碳特征和来源分析

利用2016年中国气象局设于长江三角洲地区的上海崇明东滩（DT）.上海浦东（PD）,安徽寿县（SX）,浙江临安（LA）和浙江洪家（HJ）5个站点的BC观测资料,结合气象资料和污染物数据等,对该地区BC特征和来源展开研究.上海东滩,上海浦东,安徽寿县,浙江临安和浙江洪家5个站点BC年平均浓度分别为（1834±1713）,（2410±1537）,（2823±1759）,（2651±1518）和（2544±1399）ng/m³.上海东滩浓度较低,其他站点较为接近.各站点BC都有明显的季节变化.上海崇明东滩冬季BC浓度高于其他季节.其他4个站点都是冬季 > 春季 > 秋季 > 夏季.上海东滩四季BC日变化不明显,而其他站点四季BC浓度日变化的高值都出现在交通高峰期（06：00~09：00,18：00~21：00）.上海浦东,安徽寿县,浙江临安和浙江洪家BC主要来源于机动车尾气排放和燃煤.所有站点风速较低（风速<3m/s）,BC受风速影响显著,风速越大,BC浓度越低.相对湿度在50~60之间,BC平均浓度最高.潜在源区贡献（PSCF）的分析结果显示,冬夏两季长江三角洲5个站点BC潜在源区主要集中在江苏,安徽和浙江等地.     

NO2浓度变化及气象因子清除能力分析

为了解NO2浓度变化特征及其影响因子,利用2013—2018年沧州市NO2监测数据和气象数据,探讨了NO2浓度的时间变化特征及其与各影响因子的关系,重点讨论了气象因子对NO2的清除能力。结果表明:沧州市NO2平均浓度为41μg·m-3,其中冬季浓度最高为69. 7μg·m-3,日分布呈“双峰双谷”型,存在周末浓度高于工作日的“反周末效应”;通过相关性和灰色关联度分析发现,太阳辐射、风速与NO2浓度变化的相关性最好,降水、太阳辐射、风速与NO2浓度变化的关联度最高;通过分类统计发现,不同强度降水、1. 5m·s-1以上风速、40%以下相对湿度、中等到强的太阳辐射非常有利于NO2的清除。     

重庆市大气污染特征及影响因素分析

利用重庆市17个国控点实时发布的监测数据,对SO2与NO2污染特征、时间变化规律以及与气象影响因素的相关性进行了研究分析。结果表明:2013年SO2和NO2质量浓度的年均值分别为32μg·m-3和38μg·m-3,满足国家年均值Ⅱ级标准。SO2的质量浓度呈两头高中间低的"μ"型分布,月均值变化趋势明显;而NO2的质量浓度呈现波浪形变化。SO2与NO2峰值分别出现在2013年12月(49μg·m-3)和9月(47μg·m-3)。重庆市2013年SO2的质量浓度与降雨量极显著相关,与平均大气压、平均气温显著相关。SO2浓度更易受到近地面气象因子降雨量、平均温度、平均气压的影响而积累或扩散;而NO2浓度更易受到近地面气象因子平均相对湿度的影响而积累或扩散。2013年全年偏西风时对SO2的污染起着主要的清除作用,东风时对NO2的污染起着主要的清除作用。     

绵阳市大气污染物浓度变化特征及相关性分析

随着我国工业化、城市化和机动化的高速发展,大气环境质量越来越受民众关注,我国已建成国控—省控—市控—县控四级环境空气自动监测网络,监测项目包括SO2、NO2、CO、O3、PM2.5和PM10.基于2018年绵阳市环境空气监测数据、颗粒物化学组分及气象资料分析上述6个监测项目年均、季度、月均、日均及每日最大小时浓度变化特征,并进一步探讨污染物浓度与气象条件的相关性,结合颗粒物化学组分对产生原因进行剖析.结果表明:绵阳市冬季环境空气质量较差,夏季相对较好.Pearson相关性分析表明:SO2、NO2、CO和颗粒物(PM2.5和PM10)之间存在显著相关性,冬季PM2.5与SO2、NO2的相关系数分别为0.610和0.635,PM10与SO2、NO2的相关系数分别为0.655和0.655,颗粒物主要化学组分为硫酸盐、硝酸盐、铵盐和二次有机气溶胶,颗粒物二次转化尤为明显,冬季需重点管控颗粒物;春季和夏季O3与PM2.5、PM10呈显著正相关,需做好颗粒物和O3的协同管控.O3每日最大小时浓度多集中在13:00?—?18:00,其他污染物每日最大小时浓度多集中于08:00?—?12:00和20:00?—?24:00,同时NO2在20:00?—?24:00出现每日最大小时浓度的频次占67.1％,控制机动车等污染源排放尤为重要.     

2008北京残奥会期间大气黑碳气溶胶污染特征

利用单颗粒黑碳光度计(SP2)对2008年残奥会期间北京市黑碳(BC)气溶胶的质量浓度、粒径分布及单颗粒混合态进行连续在线观测.结果表明:观测期间BC浓度均值为1.65μg/m3,低于往年同期水平;质量粒径分布呈单峰型,峰值位于207nm;内混态BC比例平均为56.1%,高于其他国内外城市,说明本地源排放贡献相对较小.随大气边界层高度及本地源排放变化,BC浓度在上午8:00和午夜0:00出现2个峰值,内混态BC比例日变化趋势与之相反.风向风速分析表明,残奥会期间来自五环外未限行区域的机动车排放对市区BC浓度有明显影响.     

基于高时空辨识度实时数据的重庆二环内外区域车流特征差异分析

高时空辨识度的车流时空分布特征是研究区域机动车排放的重要基础,通过射频识别技术和车辆注册登记数据获得重庆市二环区域每10 min的车流量以及车辆技术特征信息,对比分析内环以内及以外区域的分车型、分道路类型、分排放标准和燃料类型的车流量时空变化特征.结果表明:①重庆市内环以内区域日均流量为1.8×104辆,约为内环以外区域的1.8倍.②内环以内区域小型客车、公交车、出租车的日均流量分别为内环以外区域的1.7、2.1和2.5倍,而重型货车的日均流量为内环以外区域的54.8%.③ 2个区域车辆的主要燃料类型为汽油、天然气、柴油、新能源,占比分别为71.7%~73.7%、15.1%~21.4%、5.5%~9.6%、1.3%~1.5%.④ 2个区域车辆的排放标准分布基本一致,主要排放标准为国Ⅳ（约占76.5%）,国Ⅴ约占11.4%,国Ⅲ约占9.0%,国Ⅱ、国Ⅰ和国Ⅰ前的占比之和约为3.1%.⑤ 2个区域的小时总流量变化特征呈“M”型分布,早高峰时段为08:00—10:00,晚高峰时段为16:00—18:00.⑥ 2个区域小型客车、公交车的小时流量变化特征均与总流量变化特征基本一致,但出租车、轻型货车和重型货车在08:00仍保持明显的上升趋势,直到14:00才缓慢下降.⑦内环以内区域高速路、快速路、县道的高峰时段流量明显较高,分别为内环以外区域的5.5、2.5、6.2倍;而内环以外区域国道的高峰时段流量相对较高,约为内环以内区域的1.8倍.研究显示,重庆市二环内外区域的车流量和车辆技术特征信息的时空分布存在较大差异,建议完善城市实际道路车流的时空监测网络,为机动车排放清单的编制提供更好的数据支撑.      

济南市秋末冬初大气颗粒物和气体污染物污染水平及来源

2009年11月23日─12月7日在济南市区对PM2.5、BC(黑碳)和污染物(SO2、NOx、NO、NO2和CO)进行实时监测与分析.观测期间ρ(PM2.5)、φ(SO2)和φ(NOx)分别为171μg/m3、54.3×10-9和107×10-9.其中,φ(SO2)与GB 3095─1996《环境空气质量标准》日标准值相当,φ(NOx)是标准的2.2倍,ρ(PM2.5)是美国环境空气质量标准(35μg/m3)的4.89倍.污染事件期间ρ(PM2.5)、φ(SO2)和φ(NOx)分别达到222μg/m3、74.4×10-9和158×10-9,是非污染期间的1.78、1.67和1.77倍.观测期间SO2主要来源于燃煤排放.在11月25─26日的污染事件中,NOx、BC和PM2.5主要来源于机动车尾气排放,除局地源外,东北风经过济南东北部工业区时也将污染物传输到采样点;而在12月1─2日的污染事件中,以静风为主,污染物积聚,NOx和BC主要来源于机动车尾气排放,PM2.5除了一次污染物,很可能包含一定比例的二次污染物.在非污染事件中,NOx和BC主要来源于机动车尾气排放,部分NOx很可能来源于燃煤排放,而PM2.5主要来源于一次源排放.     

乌鲁木齐市“煤改气”对冬季气态污染物浓度空间分布变化的影响

乌鲁木齐市冬季大气污染严重,SO2浓度不断增加,且超标频率增多,已成为不容忽视的环境问题。2012年乌鲁木齐市实施"煤改气"工程,旨在改善乌鲁木齐市的大气环境质量。工程的实施是否对SO2浓度的控制起到决定性的作用?选用冬季污染最为严重的时段(1—2月),对"煤改气"前后城市不同区域的SO2日均浓度变化进行了分析。结果显示:"煤改气"对SO2浓度的降低效果显著,但降低幅度在区域间存在差异,"煤改气"后冬季SO2日均浓度在空间上呈现出由南向北逐渐增加的态势,南面SO2日均浓度基本达标,而北面SO2浓度虽有降低,但超标频率依然较高。而NO2日均浓度并未降低,反而呈增加的趋势,主要与快速增加的机动车保有量排放大量尾气有关。"煤改气"后,冬季NO2日均浓度在空间上呈现出由南向北逐渐降低的态势,南面NO2日均浓度超标最严重,而北面NO2日均浓度超标频率变动不大,但超标频率依然较高,值得当地政府在环境治理过程中关注。     

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.     

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.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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