天津滨海新区秋冬季大气污染特征分析

为了解天津滨海新区大气污染物浓度水平和污染来源,2009年9月1日~2010年2月28日对NOx、CO、SO2、O3、PM2.5、PM10进行了连续在线观测,并同步观测了气象要素.结果表明,秋冬季上述污染物最高日均值(秋冬平均值±标准差,O3为日小时均值最大值)分别达到300.7(65.4±52.9)×10-9、7.278(1.324±1.169)×10-6、53(13±12)×10-9、95(28±21)×10-9(体积分数)和287.4(62.3±53.6)μg/m3、1421.4(161.9±136) μg/m3. NOx和SO2秋季低于冬季,O3和PM10反之. CO和PM10相对国家二级标准超标率为2%和38%,PM2.5相对WHO标准(75μg/m3)超标率为31%.季节统计日变化显示CO和NOx为早晚双峰型,SO2为中午的单峰型,O3为午后单峰型,且秋季日变化振幅远大于冬季, PM10为早晚双峰型,但冬季比秋季晚出峰2~3h.除冬季PM10,大气污染物浓度49%~74%的逐日变化由气象要素影响.滨海新区大气污染受局地排放和外源输送共同影响,西南方向气流易造成污染物积累,其次是东北方向,而东和东南气流最有利于污染物扩散;各污染物具体表现为NOx主要受局地源控制;SO2主要受外来输送影响;CO和PM2.5同时受本地源和外来源的共同影响;PM10秋季表现为本地源污染,而冬季为本地源和外来源的共同影响.     

大气污染物及AQI时空特征分析——以山西省2015年上半年为例

根据2015年上半年山西省11个地级市PM 2.5、PM 10、NO 2、SO2、CO、O 3的日污染浓度监测数据及AQI值,分析其污染特征。结果表明:全省11市PM 2.5、PM 10超标率较高;NO 2、SO 2、CO、O 3超标率则较低;全省PM2.5/PM1 0的比值范围在0.367 7~0.718 9,且PM 2.5和PM 10之间存在较显著的线性关系;PM 2.5、PM 10、NO 2、SO 2、CO以及AQI监测值在1~6月份逐渐递减,O3则呈总体上升趋势;AQI达标天数比例范围在61.88%~85.08%,平均比例为71.42%,平均超标天数比例为38.58%,其中重度及以上污染天数比例为1.50%。     

2010年广州亚运期间空气质量与污染气象条件分析

利用2010年11月4日～12月10日广州地区NO2、O3、SO2、PM、能见度实测资料,区域空气污染指数RAQI及大气输送扩散特征参数,分析广州亚运期间空气质量与气象条件变化特征.结果表明,亚运期间空气质量比亚运前后好,能见度比亚运前后大,PM1和PM2.5浓度比亚运前后小,能见度与PM1和PM2.5有较好的反相关;亚运期间NO2和SO2日均值和小时均值均达到国家一级标准,PM10日均值和O3小时均值均满足国家二级标准,污染物得到较好的控制;广州地区SO2受本地源和外地源远距离输送叠加影响,NO2受本地源影响较大;广州周边城市NO2、SO2和PM10有向广州输送的潜势,而广州O3有向其周边城市扩散的潜势;亚运期间污染气象条件比亚运前后有利,亚运期间污染物浓度降低得益于政府实施的减排措施及良好的气象条件.     

2016-2020年成都市大气质量变化特征及健康风险评价

本文基于成都市2016—2020年PM2.5、PM10、SO2、NO2、CO和O3浓度监测数据,运用主成分分析(PCA)和复合污染特征分析污染物特征及来源,并采用美国环境保护署(USEPA)推荐的健康风险评价模型评估了PM2.5、PM10、SO2、NO2的健康风险,结果表明:2016-2020年成都市除O3外其余5种大气污染物浓度逐年降低,O3浓度总体呈上升趋势.相比2016年,2020年PM2.5、PM10、SO2、NO2、CO平均质量浓度降低幅度为26.79％,30.44％,50.00％,24.49％,41.18％;O3平均质量浓度上升9.03％.主成分分析和复合污染特征分析表明大气污染物来源具有同一性.2016—2020年成都市PM2.5非致癌风险指数均大于PM10非致癌风险指数.与其它年份相比,成都市2016年PM2.5和PM10的健康风险值均最高,分别为2020年的1.55倍和1.54倍.SO2和NO2的健康风险存在年龄差异,大气污染物的健康风险随年龄的增加而降低,对老人造成的健康风险最小,儿童最大.2016年男童和女童(<6岁)SO2/NO2健康风险值最高,是2020年的2.50/1.46倍.6～17岁和60岁以上人群,男性健康风险小于女性,其余年龄段男性健康风险均大于女性.成都市各人群PM2.5、PM10、SO2和NO2的健康风险均未超过USEPA推荐的1×10-6～1×10-4可接受风险范围.     

京津冀污染物跨界输送通量模拟

发展了关键影响因子加权人为源分配方法(WKIF),增添了依赖于气象条件和下垫面类型的生物源,动态更新了气象场和浓度场的边界条件.然后利用WRF-CAMx模式定量给出了四季北京、天津和河北大气边界层中PM2.5、O3、CO、SO2、NO2和NO跨界输送通量和北京净输入或输出通量.结果表明WKIF方法合理反映了中小城市人为源的空间分布特征,模式重要输入参量、初值与边界条件的改进显著改善了WRF-CAMx模式对京津冀地区6个观测站点近地面NOx、O3和PM2.5浓度的模拟.北京向天津冬、春季主要通过西北方向,夏、秋季主要经过偏西方向输入NO、NO2、SO2、CO、O3、PM2.5,输送通量夏季均最小,冬季均最大,且四季北京向天津输入的CO、O3、PM2.5通量显著高于NO、NO2、SO2通量.河北的污染物冬、春季主要通过西北方向,夏季主要经由偏南方向,秋季主要途径偏西方向进入北京;四季北京向河北输入NO和NO2,但跨界输送通量小于20t·d-1;四季河北向北京输入的CO、O3、PM2.5通量远高于北京向河北输送的NO、NO2通量,明显大于北京向河北输送的SO2通量,且河北向北京输入CO、O3、PM2.5通量夏季均最小,冬季均最大;四季北京大气边界层中NO、NO2、SO2最大净输出通量小于50t.d-1,CO、O3、PM2.5净输入或输出通量分别为111～2309、567～6244、715～1778t·d-1.这些定量结果为京津冀区域污染源调控对策的制定提供了科学依据.     

佛山惠景城大气污染物浓度时序特征

基于佛山市惠景城区2013年1月1日-12月31日SO2、NO2、O3、PM2.54种大气污染物的时序监测数据,分析其时序特征,4种污染物质量浓度的平均水平和离散程度表现为NO2PM2.5O3SO2。不同时间际的浓度变化以及污染物之间的互相关、自相关分析结果表明:(1)细颗粒污染、臭氧污染分别集中于冬春季和秋季。周一、周二的SO2、NO2、PM2.5浓度高于一周内的其他时日,O3则相反。尤其是周二NO2浓度显著高于其他日该值,可能与周一车流高峰期机动车直接排放NO转化耗时导致NO2峰值延迟有关。在12:00-15:00时段,SO2、NO2、PM2.5浓度最低,O3浓度最高,可能原因为中午高气温可促使地表污染物向高空扩散,而O3作为NO2的光解反应产物,其浓度水平更大程度上受制于太阳辐射强度。(2)4种污染物的自相关系数各不相同,整体上间隔期为1、3(天或时)的历史污染物浓度能够有效影响当前时刻的污染物浓度。SO2、NO2、PM2.5三者之间存在明显的正相关关系,而O3与NO2呈现弱负相关关系,可能与站点地理位置有关,即该站点PM2.5受机动车直接排放影响为主。O3除受NO2的制约外,更大程度上受太阳辐射的影响。     

重庆市黔江区春季大气污染物浓度变化与气象因素关系研究

分析了2015年重庆市黔江城区2个自动监测站点PM10,SO2,NO2,O3日均值和小时均值,结合同期气象因素,对污染物浓度与气象因素进行分析.表明,PM10、SO2、NO2和O3春季平均值呈显著差异,PM10超标6天,SO2,NO2,O3污染水平较低,未超标;PM10、SO2和NO2呈现早晚双峰型,O3呈典型单峰型;风速与SO2和NO2浓度呈负相关,与O3浓度则呈正相关关系,风速较小时,利于PM10浓度降低,当风速达到一定程度,会导致PM10浓度升高;污染物浓度和相对湿度呈明显负相关;降水对大气污染物有削减作用.     

河南省2015-2019年大气污染时空变化特征研究

河南省位于京津冀周边区域,其大气复合污染形势较为严峻.本研究利用河南省2015-2019年83个国控站点数据,综合探究了 PM10、PM2.5、SO2、NO2、CO和O3MAD8(臭氧日最大8h平均值)的时空变化特征.与2015年相比,2019年河南省PM10、PM2.5、SO2、NO2和CO年均浓度分别下降了 26....     

大气例行点位常规监测污染物的相关性分析及防控措施研究

根据济南市历下区5个大气例行监测点位2015年上半年PM2.5、PM10、SO2、CO、NO2、O3逐小时浓度的监测数据,通过SPSS软件对各项污染物的相关性进行分析得出:CO与PM2.5、PM10、SO2、NO2强相关性出现次数最多,表明CO排放源是引起颗粒物污染的主要原因之一.对监测点位周边2 km范围内机动车尾气和餐饮燃煤两项污染源进行排放量估算得出:机动车尾气CO、NOx、PM2.5和PM10年排放量分别为388.18吨、111.18吨、4.35吨和4.72吨;餐饮燃煤CO、SO2、NOx年排放量分别为36.0吨、24.0吨和9.6吨.因此,控制CO排放源对改善济南市大气环境质量至关重要.     

2018～2020年春节期间宜春市中心城区空气质量分析

基于2018-2020年除夕至初六的环境空气质量监测数据,分析了烟花爆竹禁放对宜春市中心城区空气质量状况的影响。结果表明:该地区空气质量逐年改善,优良天数明显提高; PM2.5、PM10、SO2、NO2、CO浓度总体呈下降趋势,这五项参数2020年的日均浓度都在低位持平或略有波动; O3浓度则受气象条件影响,与相对湿度呈负相关关系;中心城区4个国控站点2020年PM2.5、PM10、NO2、CO、O3日均浓度变化趋势基本一致,空气质量受城区生活源的影响较大。     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

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.     

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.     

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.     

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.     

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.     

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.