鄱阳湖平原直播稻CH4通量及其与CO2通量的综合温室效应

稻田是一个既排放CH₄又吸收CO₂的复杂生态系统,在全球水碳循环和碳收支中发挥着重要作用.利用涡度相关法得到2020年鄱阳湖平原双季直播稻田的CH₄和CO₂通量,定量揭示了稻田碳通量变化特征、累积量和2种温室气体的综合温室效应.结果表明,双季直播稻田为CH₄排放源,全生育期排放量为52.6 g·m^-2,日均排放0.208 g·(m²·d)^-1. CH₄通量具有明显的季节变化特征,强排放期(排放峰)集中在早稻生长中期和晚稻生长前期,早稻85.5%和晚稻92.1%的CH₄在强排放期被释放,日尺度峰值分别为0.638 g·(m²·d)^-1和1.282 g·(m²·d)^-1.CH₄通量日变化呈显著单峰型、不显著单峰型和无规律型,强排放期主要为单峰型,该型式下早稻季峰值0...     

全球和东亚地区CH4浓度时空分布特征分析

利用最新的AIRS卫星观测资料分析了2002年12月~2016年11月全球和东亚地区（70°~140°E,10°~55°N）CH₄浓度的时空变化分布特征.研究发现,2003~2016年,全球CH₄年平均浓度从1774.2×10^-9增加到1789.1×10^-9,年增长率约为1.1×10^-9/a;东亚地区CH₄年平均浓度从1811.5×10^-9增加到1841.0×10^-9,年增长率约为2.0×10^-9/a.在美国西南部、南美洲南部、澳大利亚东南部、中国青藏高原和东北地区等地上空,CH₄浓度增幅比较明显,而在北美洲的东北部上空,CH₄浓度出现负增长.北美洲东北部和俄罗斯东部等地上空CH₄浓度的变化与温度变化呈正相关;如在冬季,该地区温度与周围地区相比更低,同时CH₄浓度更低.本文利用近10a的卫星数据获得了CH₄浓度的垂直廓线,显示不同纬度带CH₄浓度均随着高度的升高逐渐减小,且高纬度地区CH₄浓度减小的最快.近年来,在低纬度地区对流层中低层CH₄浓度变化较为明显.在对流层低层（850hPa）,北半球CH₄浓度随着纬度增加逐渐变大;在南半球则随着纬度增加先减小后变大.而在平流层内,CH₄浓度在赤道处最大,且随着纬度的升高逐渐减小.此外,CH₄的浓度分布存在明显的季节变化：在北半球,大部分地区夏季CH₄浓度高于冬季（约20×10^-9~40×10^-9）,但在撒哈拉沙漠和中国新疆塔里木盆地等地区上空,冬季CH₄浓度高于夏季（约40×10^-9~60×10^?9）.在冬季,中国四川西部上空的CH₄浓度要比青藏高原上空高（约100×10^-9~120×10^-9）.     

2015~2019年南京北郊碳质气溶胶组成变化

碳质气溶胶是大气细颗粒物的重要组成,对空气质量、人体健康和气候变化有着重要影响.为了探究碳质气溶胶在减排背景下的长期变化,本研究测定了南京北郊5 a（2014年12月17日至2020年1月5日） PM_2.5样品的有机碳（OC）和元素碳（EC）浓度.结果表明,ρ（OC）和ρ（EC）5a平均值分别为（10.2±5.3）μg·m^-3和（1.6±1.1）μg·m^-3,其中OC占PM_2.5的31.1%,EC占PM_2.5的5.2%.OC和EC均呈现出冬高夏低的季节特征.通过非参数的Mann-Kendall检验和Sen’s斜率发现,OC和PM_2.5的浓度整体呈显著下降趋势[OC:P<0.000 1,-0.79μg·（m³·a）^-1,-0.29%·a^-1; PM_2.5:P<0.000 1,-4.59μg·（m³·a）^-1,-1.5...     

保定市冬季PM2.5的氧化潜势特征及其影响来源分析

为了探究保定市郊区2018年冬季PM_2.5氧化潜势的特征及其影响来源,利用二硫苏糖醇（DTT）测定法对PM_2.5中活性氧进行测定,采用皮尔逊相关分析PM_2.5中各化学成分与氧化潜势的关系,并且利用PMF对DTT_v进行污染源解析.结果表明,冬季保定市ρ(PM_2.5)平均值为（140.96±70.67）μg·m^-3,高于同时期北京PM_2.5浓度.氧化潜势的DTT_v和DTT_m值均表现出白天高于夜间的情况[DTT_v白天为（2.37±0.76） nmol·（min·m³）^-1,夜间为（2.14±1.17） nmol·（min·m³）^-1; DTT_m白天为（0.96±0.60） pmol·（min·μg）^-1,夜间为（0.76±0.41） pmol·（...     

漳江口不同潮滩秋茄树干CH4传输速率与呼吸速率

树干对红树林湿地CH₄和CO₂的排放有重要影响.为研究红树林湿地温室气体排放机制及其影响因子,于2017年9月利用树干静态箱-气相色谱仪法,以漳江口秋茄（Kandelia obovata）红树林为研究对象,探讨不同潮滩（中、高潮滩）下秋茄树干CH₄传输速率和呼吸速率的特征.结果表明:①中潮滩秋茄树干CH₄传输速率[（91.19±16.63）μg/（m2·h）]显著大于高潮滩[（0.71±0.24）μg/（m2·h）]（P < 0.001）,而中、高潮滩秋茄树干呼吸速率无显著性差异（P>0.05）.②秋茄树干CH₄传输速率受土壤孔隙水的影响较大,与土壤孔隙水中c（CH₄）呈极显著正相关（P < 0.01）,与孔隙水中ρ（DON）呈极显著负相关（P < 0.01）.③秋茄树干呼吸速率与胸径大小呈极显著正相关（P < 0.01）,并呈极显著性幂函数回归关系（P < 0.001）,而树干CH₄传输速率不受胸径大小的影响.研究显示,与红树林湿地的空间异质性相比,植物特征对树干呼吸速率的影响更为显著;相反,对于树干CH₄传输速率,空间异质性的影响比植物特征的影响更为显著.      

养殖塘CH4冒泡通量观测研究

为研究安徽省养殖塘CH₄冒泡通量的排放特征，作者采用倒置漏斗法对2个养殖塘CH₄冒泡通量进行了为期2年的观测研究。结果表明，CH₄冒泡通量有显著的季节变化特征，表现为夏季(233.90 mg/(m²·d))>春季(87.22 mg/(m²·d))>秋季(56.65 mg/(m²·d))>冬季(0.09 mg/(m²·d))。且CH₄冒泡通量存在空间差异，中间区域的CH₄冒泡通量显著高于岸边区域。在日尺度和季节尺度上，CH₄冒泡通量与20 cm水温显著正相关，与气压显著负相关，但季节尺度上的相关性较日尺度更好。虽然养殖塘面积较湖泊小很多，但其CH₄冒泡通量较湖泊高一个数量级以上。     

2000~2018年京津冀城市群PM2.5时空演变及其与城市扩张的关联

京津冀城市群是中国三大城市群之一,其城市化进程对大气污染造成了严重的影响.基于土地利用、站点实测和遥感反演的PM_2.5浓度数据集,辅以趋势分析和分段线性回归等方法,分析了2000～2018年京津冀城市群PM_2.5浓度的时空演变格局及其与城市扩张的关联.结果表明：（1） 2000～2018年京津冀城市群PM_2.5浓度变化呈明显的阶段特征,2000～2013年PM_2.5浓度呈显著增加的趋势[slope=1.598 0μg·（m³·a）^-1,P<0.001],其中69.97%的区域呈显著增加趋势（P<0.05）; 2013～2018年PM_2.5浓度呈显著减小的趋势[slope=-4.990 8μg·（m³·a）^-1,P<0.001],其中85.81%的区域呈显著减小的趋势（P<0.05）;（2） PM_2.5浓度整体呈从东南向西北递减的趋势,高污染区[ρ...     

河北省中南部对流层CH4时空分布特征的飞机探测研究

为研究河北省中南部对流层内CH₄时空分布特征,2018年6~7月利用空中国王350飞机搭载高精度CH₄分析仪和相关辅助设备,对河北中南部城市上空（600~5500m）CH₄浓度进行飞机探测.探测期间共飞行4架次,取得7组CH₄浓度垂直廓线数据.结果表明：探测期间CH₄浓度最小值为1884×10^-9,最大值为2038×10^-9,多架次垂直方向上平均浓度为（1915±90）×10^-9.不同探测架次CH₄浓度随高度变化趋势有较好的一致性,随高度增加,均出现先增大后减小,后稳定不变的趋势,且在混合层顶以下（约1000m）存在明显分界线.1000m以下,同高度层CH₄浓度变化较大,不同架次间浓度相差最大值达124×10^-9,同一架次CH₄浓度的垂直梯度变化受大气层结影响明显,位温垂直梯度接近零时,CH₄浓度的垂直梯度变化不明显.1000m以上,CH₄浓度垂直随高度增加呈指数减小,同高度层CH₄浓度变化较小,变化偏差在平均值的5%以内,4000m以上,同高度层CH₄浓度振幅最小,差值<15×10^-9,此时浓度可代表该区域背景大气的平均浓度.石家庄上空同高度层CH₄浓度白天整体大于夜间,随高度降低差值变大,说明石家庄白天CH₄排放源强度大于夜间.     

填埋场覆盖土微生物好氧/厌氧共代谢降解氯乙烯的特性、贡献度及微生态研究

填埋场已成为氯乙烯污染的重要来源,明晰覆盖层土壤中氯乙烯的降解特性及功能微生物群落组成对氯乙烯污染控制具有重要意义.基于填埋场覆盖土系统开展了典型氯乙烯的好氧/厌氧共代谢降解研究.结果显示,好氧和厌氧条件下CH₄均可发生降解,二氯乙烯（DCE）只能在好氧条件下被降解,净降解速率为50μg·h^-1·L^-1;三氯乙烯（TCE）可同时发生好氧共代谢和厌氧共代谢转化,净降解速率分别为38和5μg·h^-1·L^-1;四氯乙烯（PCE）只能发生厌氧共代谢,降解速率为0.77μg·h^-1·L^-1,发现好氧共代谢速率远高于厌氧共代谢速率.构建了覆盖层中氯乙烯的分布模型并评估了CH₄及氯乙烯好氧/厌氧共代谢贡献度,CH₄好氧和厌氧降解贡献度分别为59%～70%和30%～41%,TCE好氧和厌氧共代谢降解贡献度分别为73%和27%.对氯乙烯厌氧/好氧共代谢降解过程的微生物群落组成及潜在功能菌属进行了分析,发现好氧...     

东海海水和大气中挥发性卤代烃的分布

运用吹扫-捕集气相色谱法于2016年6月对东海海水和大气中5种短寿命挥发性卤代烃的浓度含量、分布来源特征及海-气通量进行了研究.结果表明,表层海水中CH₃I、CH₂Br₂、CHBrCl₂、CHBr₂Cl和CHBr₃浓度平均值及范围分别为8.93（0.39~23.49） pmol/L、15.02（4.77~32.75） pmol/L、0.97（0.30~2.16） pmol/L、9.35（6.8~18.46） pmol/L和12.24（2.60~50.04） pmol/L.受陆源输入、水团和生物活动释放的影响,表层海水中CH₃I、CH₂Br₂和CHBrCl₂的浓度分布呈现近岸高远海低的趋势,CHBr₂Cl和CHBr₃浓度呈现点状分布.相关性分析发现CHBr₃和Chl-a存在显著相关性,推断浮游植物生物量可能影响CHBr₃的浓度分布.大气中CH₃I、CH₂Br₂、CHBrCl₂、CHBr₂Cl和CHBr₃浓度平均值及范围分别为3.52×10^-12（1.72×10^-12~10.00×10^-12）、3.82×10^-12（0.20×10^-12~34.95×10^-12）、1.40×10^-12（0.46×10^-12~6.18×10^-12）、1.55×10^-12（0.16×10^-12~4.66×10^-12）和6.63×10^-12（2.20×10^-12~11.61×10^-12）.受陆源气团输送、生物生产和气象条件的共同影响,春季大气中5种短寿命挥发性卤代烃浓度分布较为复杂.海-气通量的估算结果表明春季东海是大气中CH₃I、CH₂Br₂、CHBrCl₂、CHBr₂Cl和CHBr₃的源.     

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.     

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.     

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.