秀山县城区大气环境质量特征研究

为详细了解秀山县城区大气质量状况,选择2016年9月—2017年1月大气观测数据进行分析研究,结果表明:研究时段内PM_(10)、PM_(2.5)、SO_2、NO_2和O_3大气污染物浓度均满足《GB3095-2012环境空气质量标准》中二级标准要求,随着月份变化,PM_(10)、PM_(2.5)和O_3呈先降低再升高的趋势,NO_2呈逐渐增加趋势,SO_2变化趋势相对平缓。大气污染物NO_2与PM_(10)和PM_(2.5)呈显著性相关,聚类分析结果表明PM_(10)、PM_(2.5)对大气环境质量影响较大。气象参数与大气污染物均呈明显相关性,表明气象条件对污染物的扩散起着重要作用。     

G20峰会期间杭州地区空气质量特征及气象条件分析

利用空气质量和气象要素的监测资料与再分析资料,分析了2016年G20峰会期间(2016年8月10日—9月20日)杭州及周边地区空气质量演变及区域特征,探讨了气象条件对G20峰会期间杭州空气质量的影响.结果表明:G20峰会管控期间,由于机动车排放大幅度降低,杭州NO_2浓度较管控前有所下降,对比周边城市降幅居于首位;而由于不利气象条件的影响,PM_(2.5)、PM_(10)、SO_2、CO和O_3浓度比管控前有不同程度的增长,但增幅相比周边城市较小,说明管控措施对杭州空气质量有一定的改善效果.9月7日管控措施结束后污染反弹现象明显.气象条件对杭州的空气质量有重要影响:在管控前,杭州晴热高温天气有利于O3的生成,偏东风相对洁净,污染传输较少;在管控期,杭州虽受到静稳天气和外来污染传输的影响,但得益于减排应急管控措施的有效实施,NO_2浓度下降幅度最大,其他污染物的增幅也较周边城市偏小;在管控后,气象条件不利于污染物的垂直扩散,受静稳天气和污染源恢复常态的影响,PM_(2.5)、PM_(10)、NO_2、SO_2和CO出现了整个研究时段的最大值,而台风"莫兰蒂"使得杭州PM_(2.5)、PM_(10)和O_3浓度出现了整个研究时段的最低值.     

西安市主要大气污染物的相关性分析及时空分布特征

为深入了解西安市大气污染程度,对2015年西安市主要大气污染物(SO_2、NO_2、CO、PM_(2.5)、PM_(10)、O_3)的空气质量指数进行了逐日变化分析、相关性分析及空间插值分析。结果表明:SO_2、NO_2、CO、PM_(2.5)、PM_(10)空气质量指数春冬季高于夏秋季,而O_3空气质量指数则是春冬季低于夏秋季。11月和12月份污染较为严重。在4个季度中,PM_(2.5)和PM_(10)与气态污染物SO_2、CO、NO_2均呈正相关,说明PM_(2.5)、PM_(10)与这3种气态污染物具有同源性。SO_2与CO、NO_2均呈显著性正相关,三者均受化石燃料燃烧及机动车尾气影响。O_3与CO、SO_2相关性不大,与NO_2在二季度呈现正相关。SO_2、NO_2、PM_(2.5)、CO、PM_(10)多聚集在高新西区、莲湖区、碑林区、经开区、雁塔区、长安区,O_3多聚集在阎良区、未央区和灞桥区。     

温州城区大气污染特征数值模拟与来源解析

文章以位于温州城区的瓯海区为例,在建立大气污染源清单的基础上,利用WRF-CMAQ、CALPUFF模型分析了外来污染物区域输送对瓯海区的影响,模拟了瓯海区主要大气污染物浓度分布,解析了区域大气污染物排放来源。WRF-CMAQ模型模拟结果表明,区域大气污染物SO_2、NO_2、PM_(10)和PM_(2.5)的输送对瓯海区的贡献影响均呈现冬季(1月)>春季(4月)>秋季(10月)>夏季(7月)的变化规律,这可能与大气污染物来源有关。CALPUFF模型模拟结果显示,瓯海区SO_2和PM_(10)的年平均浓度达标,但NO_2和PM_(2.5)出现超标现象。除SO_2均能达标外,部分敏感目标处NO_2、PM_(10)和PM_(2.5)年平均浓度有不同程度的超标现象。来源分析结果表明,瓯海区大气污染物SO_2和NO_2主要来自本地源排放,而PM_(10)和PM_(2.5)本地源与外来源的排放贡献相当。     

安阳市环境空气质量状况、污染原因与对策分析

分析了2008—2017年安阳市城市空气质量自动监测数据,结果显示:影响安阳市空气质量的主要因素及大气污染防治的主要问题是:PM_(2.5)、PM_(10)污染影响普遍,SO_2排放量大,NO_X浓度呈逐渐增高的趋势,臭氧污染显现。10a间安阳市城市大气中SO_2、NO_2、PM_(10)浓度值四季变化规律均呈现冬季秋季春季夏季,且冬季SO_2、NO_2、PM_(10)浓度值均呈显著上升趋势。10a间安阳市NO_2浓度变化呈显著上升趋势,降水类型经历了从硫酸型到硫酸-硝酸混合型的过渡过程。安阳市城区内大气污染物存在显著的空间差异性,位于西北部工业区的铁佛寺监测点位PM_(10)、SO_2、NO_2三项污染因子平均浓度值均为各点位最高值。O_3成为首要污染物的天数在明显增加,2017年4个国控点位的O_3-90浓度值均不达标。     

基于气象条件下哈尔滨市污染特征分析

利用2013年哈尔滨市环境监测资料及气象资料,分析了4种主要污染物(PM_(10)、PM_(2.5)、SO_2、NO_2)的时空分布特征及各种气象条件对城市大气污染的影响。结果表明:风速在采暖期对污染物浓度的影响尤为显著,相关系数达-0.87;混合层高度对雾霾天气形成影响较大,PM_(2.5)浓度与混合层高度呈现负相关;气温、气压、降水与PM_(2.5)浓度均有较好相关性,哈尔滨市污染物特征受气象条件影响较大。     

燃放烟花爆竹对云南省环境空气质量的影响

利用2016—2018年春节期间(除夕—初六)云南省环境空气中PM_(2.5)、PM_(10)、SO_2、NO_2、CO和O3的质量浓度监测数据,研究了春节期间燃放烟花爆竹对环境空气质量的影响,并采用spearman分析了除夕—初一PM_(2.5)、PM_(10)、SO_2、NO_2、CO小时浓度值变化相关性。结果表明:春节期间(除夕—正月初六)超标天数集中出现在大年初一,首要污染物均为细颗粒物(PM_(2.5));烟花爆竹集中燃放阶段,SO_2、PM_(2.5)、PM_(10)日均值显著升高,O3、NO_2和CO的日均浓度值变化则基本不受其直接影响;总体上PM_(2.5)、PM_(10)、SO_2、NO_2和CO的小时浓度值变化趋势呈正相关,其中SO_2与PM_(2.5)、PM_(10)相关系数均值在0.800左右,高度正相关,这与全省除夕—初一污染物浓度的逐时变化趋势相一致。     

哈尔滨市2016年春节期间空气质量时空变化特征

利用2016年2月7-13日春节期间哈尔滨市11个监测站点空气质量监测数据,分析春节期间6种主要污染物时空特征,并与非燃放期间进行对比,进一步分析污染物的时空变化,同时结合气象降雪数据,探讨降雪天气对空气污染物造成的影响。结果表明:哈尔滨市春节期间空气污染物7 d平均浓度,PM_(2.5)、PM_(10)污染最严重的区域为香坊区,NO_2污染最严重的区域为阿城区,SO_2污染最严重的区域为道外区,CO和O_3污染严重的区域为平房区;在除夕夜期间,烟花爆竹燃放对PM_(2.5)、PM_(10)和SO_2浓度的短期影响极大,空气质量在短时间内迅速恶化,甚至成倍增长,在初一凌晨时浓度达到最大值,但对NO_2、CO和O_3的影响较小;烟花爆竹的燃放对空气中不同污染物的影响程度有所区别,对气态污染物SO_2的贡献程度最大,其次,对大气粗颗粒物的贡献程度大于细颗粒物;降雪天气对空气污染物具有去除效应,其中,对大气粗颗粒物去除效应高于大气细颗粒物,而对气态污染物有较小影响。从空间上看,降雪天气对于城市边缘、城郊等区域的大气颗粒物的去除效应高于城市中心区域。     

哈尔滨市2016年春节期间空气质量时空变化特征

利用2016年2月7-13日春节期间哈尔滨市11个监测站点空气质量监测数据,分析春节期间6种主要污染物时空特征,并与非燃放期间进行对比,进一步分析污染物的时空变化,同时结合气象降雪数据,探讨降雪天气对空气污染物造成的影响。结果表明:哈尔滨市春节期间空气污染物7 d平均浓度,PM_(2.5)、PM_(10)污染最严重的区域为香坊区,NO_2污染最严重的区域为阿城区,SO_2污染最严重的区域为道外区,CO和O_3污染严重的区域为平房区;在除夕夜期间,烟花爆竹燃放对PM_(2.5)、PM_(10)和SO_2浓度的短期影响极大,空气质量在短时间内迅速恶化,甚至成倍增长,在初一凌晨时浓度达到最大值,但对NO_2、CO和O_3的影响较小;烟花爆竹的燃放对空气中不同污染物的影响程度有所区别,对气态污染物SO_2的贡献程度最大,其次,对大气粗颗粒物的贡献程度大于细颗粒物;降雪天气对空气污染物具有去除效应,其中,对大气粗颗粒物去除效应高于大气细颗粒物,而对气态污染物有较小影响。从空间上看,降雪天气对于城市边缘、城郊等区域的大气颗粒物的去除效应高于城市中心区域。     

北京地区颗粒物健康效应研究——沙尘天气、非沙尘天气下颗粒物(PM_(2.5)、PM_(10))对心血管疾病入院人次的影响

为了研究沙尘天气、非沙尘天气及霾污染类型下,颗粒物(PM_(10)、PM_(2.5))与心脑血管疾病日入院人次的联系,本文采用半参数广义相加泊松回归模型(GAM),在剔除了混杂因素:如季节趋势、日历效应、气象要素等作用下,将颗粒物浓度进行等级划分的基础上,分析了北京地区2006~2010年PM_(10)和PM_(2.5)在沙尘天气和非沙尘天气下与心脑血管疾病日入院人次相对危险度(RR)的关系,进而对比研究了沙尘污染与霾污染对心脑血管疾病的不同影响.结果表明:沙尘天气PM_(10)、PM_(2.5)能引起心脑血管疾病入院人次的增加,且存在0~2d滞后效应,PM_(2.5)与PM_(10)的RR值较为接近;非沙尘天气下,PM_(2.5)、PM_(10)与心脑血管疾病入院人次的RR存在一定的剂量效应关系,对于PM_(2.5),随着浓度的上升RR值逐渐增大,对于PM_(10),随着浓度的上升RR先增大而后逐渐降低;在相同的PM_(10)暴露浓度下,沙尘天气的RR低于非沙尘天气,在相同的PM_(2.5)暴露浓度下,沙尘天气与非沙尘天气的RR基本接近.而相对于沙尘天气污染,霾天气对心脑血管疾病的影响也具有滞后效应,随着霾天气加重,对人群心脑血管疾病危害也越大.     

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.     

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.     

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.     

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.     

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.     

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.