雨水收集系统结合自循环系统下的景观湖体氮磷特征

为评估采用雨水作为城市景观湖体补充水源的富营养化发生风险,以天津文化中心景观湖为研究案例,分析了其典型的2套运营系统：雨水收集系统（雨水经沉淀井、蓄水模块和垂直潜流湿地进入景观湖）和中心湖水体的循环及净化系统（湖水抽排至垂直潜流湿地再进入景观湖）中景观湖的氮磷浓度变化规律。采用2015年3-10月的长期监测,研究湖中氮磷营养盐的时间变化趋势以及形态变化规律,提取影响湖中氮磷浓度的因素。结果表明：2015年3-10月景观湖中总氮和总磷平均浓度分别为（1.551±0.491）mg·L-1和（0.058±0.029）mg·L-1,溶解态氮和磷分别占71.7%和50%,系统运行稳定时总氮和总磷浓度主要分布在1.0~1.3 mg·L-1和0.029~0.05 mg·L-1之间;总体上,溶解态氮为湖水中氮存在的主要形式,而磷则主要以颗粒态形式存在,在降雨条件下,部分污染物随着降雨冲刷进入湖体,因此景观湖中溶解态磷的浓度增高;湿地是否稳定运行是影响景观湖中总氮、溶解态氮以及总磷浓度的因素,而降雨条件是影响景观湖体的总磷浓度以及溶解态磷浓度的因素;景观湖的富营养化风险较低,降雨期间进入湖体的溶解态磷是最大的风险因子。     

pH对沟渠沉积物截留农田排水沟渠中氮、磷的影响研究

通过摇瓶动态实验和箱体静止实验,研究了不同pH条件下沟渠沉积物对农田流失氮、磷的截留效应,分析了pH对氮、磷截留效应及其界面交换作用的影响.结果表明:在实验pH变化范围内,沟渠沉积物对NH 4-N的吸附量和NO-2-N的硝化量以及对TN的截留率都是随着pH的增加而增加;沟渠沉积物对总溶解性磷(TDP)的吸附量随着pH的增加而增加,TP的截留率在5 d前随pH的增加而增加,但在此后基本不发生变化;在不同的pH下,通过影响微生物的活动直接或间接影响氮的界面交换行为,同时pH通过影响沉积物的吸附作用和离子交换作用来影响磷在沉积物-水界面的交换行为.阐明pH对沟渠沉积物氮、磷截留效应的影响有助于掌握氮、磷在农田排水沟渠中的迁移转化机理,从而对控制农业面源污染具有重要的意义.     

基于旱作农田面源污染控制的生态沟渠构建及其拦截效果研究

针对南方平原河网地区旱作农田径流排水特征,构建了一种混凝土多孔板结构的生态沟渠,有效过水断面为0.8m~2,稳定期沟壁和沟底净化植物生物量分别为0.54、0.36kg/m,并通过引入三维植被网护坡技术,在发挥生态拦截功能的同时,大大提高了沟渠抗坡面侵蚀强度。试验表明,径流排水的水力停留时间(HRT)达48h时,生态沟渠对悬浮物(SS)、总氮(TN)和总磷(TP)拦截率分别为50.5%、53.6%、56.1%。生态沟渠对硝态氮的拦截规律与TN一致,但对可溶性磷(DP)的拦截效果与传统水旱通用混凝土排水渠无明显差别,说明生态沟渠对TP的拦截主要表现在对颗粒吸附态磷的拦截。     

外加植物碳源强化人工湿地处理农田退水效能分析

人工湿地作为一种高效处理农田退水的工程设施,其污染物去除效果会因系统内碳源缺失而降低。为了探究外加碳源强化人工湿地处理农田退水的效果,本研究选用芦苇、水葱作为外加碳源,分析了简单处理、碱泡处理、碱热处理3种预处理方式下植物碳源的静态释碳规律,并筛选优质碳源,探究了外加碳源对垂直流人工湿地净化农田退水的促进作用。结果表明,碱热处理后的芦苇具有持续析出碳源的能力,可显著提高人工湿地的脱氮除磷效能,其总氮和总磷平均去除率可达75.67%和91.37%;碱热处理后的芦苇自身析出的氮、磷含量较低,对湿地系统产生污染较小。此外,植物碳源添加的最适碳氮比为5,可实现同步强化脱氮除磷;在碳源充足的情况下,总氮、总磷在人工湿地底层的去除效果好于人工湿地中上层,底层微生物反硝化作用强,可促进系统脱氮,氧气可能是脱氮效果的限制因素之一。     

大型水生植物对骆马湖氮、磷元素的影响

对骆马湖有草区和无草区水体和沉积物中氮、磷元素含量分析,结果表明:无草区水体中总氮、总磷含量高于有草区;有草区表层沉积物总氮含量随时间变化明显,而无草区表层沉积物总氮含量随时间的变化很小;有草区与无草区表层沉积物中总磷含量的时间变化并无明显差异;有草区表层沉积物总氮含量基本上均高于无草区,而有草区表层沉积物总磷含量均要低于无草区。骆马湖有草区与无草区采样点沉积物碱性磷酸酶活性大小在58.41～315.07 mg/(kg.h)范围内变化,有草区的碱性磷酸酶的活性普遍低于无草区的碱性磷酸酶活性。在湖泊中种植大型水生植物确实可以减少水体污染,达到净化水质的目的。     

农村沟渠水体的磷污染水平对底泥磷释放规律的影响研究

为揭示农村生活污水排放导致沟渠底泥磷形态转化对农村生态环境的影响,用K2HPO4配置不同水平磷污染水体(TP质量浓度分别为0、5、10、20 mg/L),考察在静态及扰动试验中底泥磷的转化规律.结果表明:(1)当水体TP为0 mg/L,底泥为磷源,逐步向水体释放磷;随水体TP增大,底泥为磷汇,吸附水体中的磷,水体扰动会...     

太湖地区典型降雨水稻田径流污染物输出特点及相关性分析

为研究降雨过程中水稻田径流污染物的输出特点及其主要污染物之间的内在关系,在太湖地区何家浜流域划定若干块水稻田作为研究区域,并分别选取单块封闭水稻田沿河岸的直入河点和多块水稻田沿沟渠汇流后的沟渠入河点为采样点,对比封闭小区域和非封闭大区域污染物随降雨径流的输出特点及其相关性。结果表明,降雨引起水田水的扰动,对水田土壤及其污染物只产生间接的扰动或冲刷,而非直接冲刷,因此,不同降雨强度对SS(悬浮态固体)的冲刷并未表现出明显的差异。无论短历时强降雨还是长历时弱降雨,其径流中SS、氮、磷均随降雨历时的延长而降低,其中溶解态氮、磷随降雨历时的变化较小。相比大面积的汇水区域,较小的汇水区域SS峰值点出现的时间更接近降雨峰值点,对降雨的响应时间更短,降雨前期,大汇水区域径流中SS比小汇水区域小很多,而降雨后期要大很多,其主要污染物随降雨历时的延长而降低的规律性更显著,小汇水区域的径流SS和TN(总氮)、TP(总磷)具有很好的线性相关性。     

中国重点污染源总磷、总氮排放状况研究

中国氮、磷污染较为突出,然而氮、磷排放负荷底数不清,尤其是对具有监管优势的工业源和城镇生活源研究不足。利用《中国环境统计公报》数据和污染源监督性监测数据,对中国重点污染源的总磷、总氮排放状况分析得出:农业源是总磷、总氮的主要排放源;污水处理厂、工业企业的总磷、总氮排放浓度基本持平,规模化畜禽养殖企业总磷排放浓度较高;工业源中化工、农副食品加工等大类行业总磷、总氮排放量较大,淀粉制造等小类行业总磷、总氮排放量也较大;中国总磷、总氮排放主要集中在中东部地区。     

太湖地区何家浜流域初期雨水对水稻田污染物的冲刷效应

为研究农田非点源污染物在降雨过程中初期冲刷效应的变化规律,在太湖地区何家浜流域划定若干块水稻田作为研究区域,并分别选取单块封闭水稻田沿河岸的直入河点和多块水稻田沿沟渠汇流后的沟渠入河点为采样点,对比封闭小区域和非封闭大区域污染物输移的特征,通过监测在降雨-径流过程中的水量、水质,并结合相关分析方法,分析降雨初期污染物的冲刷规律。结果表明,初期雨水对水稻田污染物的冲刷强度从颗粒态悬浮物(SS)、颗粒态氮(PN)、颗粒态磷(PP)到溶解态氮、磷逐渐减弱,其中最明显的是SS,定义新的雨水初期冲刷效应强度量化考核指标后,计算得各主要指标的冲刷效应强度I值从大到小依次为:SS(0.059 3) >PP(0.021 2) >TP(总磷,0.013 0) >TN(总氮,0.006 8) >PN(0.004 6) >PO43--P(磷酸盐,0.003 7) >NN(硝态氮,-0.002 8);封闭小区域的初期冲刷效应非常明显,非封闭大区域的初期效应相对较弱,比较小区域和大区域,颗粒态污染物如SS、PP和PN等初期冲刷效应被弱化的程度较小,溶解态污染物如NN、PO43-初期冲刷效应被弱化的程度较大。     

城市生活污泥和矿化垃圾中氮磷淋失的模拟研究

通过模拟土柱实验,分析了城市生活污泥和矿化垃圾中氮磷的迁移对地下水的影响以及矿化垃圾对氮磷的去除特性.测定项目包括总磷、总氮、硝态氮、pH和电导率(EC).结果表明:施用污泥和矿化垃圾后淋滤液的pH呈下降趋势;EC和总氮都有显著增加;硝态氮增加特别明显,容易造成地下水污染;总磷变化不大,污染地下水的可能性较小.矿化垃圾对氮的去除作用不明显,反而增加了淋滤液中的氮素含量,但对磷的去除效果明显.因此,在利用矿化垃圾取代土壤时,应注意矿化垃圾中氮特别是硝态氮的污染.     

Sorption and desorption of Cu and Cd by macroalgae and microalgae

The sorption and desorption of Cu and Cd by two species of brown macroalgae and five species of microalgae were studied. The two brown macroalgae, Laminaria japonica and Sargassum kjellmanianum, were found to have high capacities at pHs between 4.0 and 5.0 while for microalgae, optimum pH lay at 6.7. The presence of other cations in solution was found to reduce the sorption of the target cation, suggesting a competition for sorption sites on organisms. Sorption isotherms obeyed the Freundlich equation, suggesting involvement of a multiplicity of mechanisms and sorption sites. For the microalgae tested, Spirulina platensis had the highest capacity for Cd, followed by Nannochloropsis oculata, Phaeodactylum tricornutum, Platymonas cordifolia and Chaetoceros minutissimus. The reversibility of metal sorption by macroalgae was examined and the results show that both HCl and EDTA solutions were very effective in desorbing sorbed metal ions from macroalgae, with up to 99.5% of metals being recovered. The regenerated biomass showed undiminished sorption performance for the two metals studied, suggesting the potential of such material for use in water and wastewater treatment.     

Kinetic and structural relationships of transition monomeric and oligomeric carboxyl- and choline-esterases

The kinetic and structural relationships of eight electrophoretically pure mammalian serum and liver serine carboxylesterases (CE) and cholinesterases (ChE) have been studied. Eight CE's and ChE's, which were fully resolved but only partially purified, provided additional information. Five of the electrophoretically pure esterases were monomeric, and of these, four belonged to a new and widely distributed class. These four monomeric esterases hydrolyzed choline esters, but at widely differing rates. Thus two were termed monomeric butyrylcholinesterases, mBuChE I and II, and two were monomeric CE's (mCE). The rabbit liver mCE was not a subunit of the oligomeric CE (oCE), although the oCE also hydrolyzed choline esters at a very low rate. The complex kinetics of the mCE's, mBuChE's, oCE's, and of the oligomeric BuChE's of horse and human serum could be interpreted according to a single reaction scheme involving an allosteric site and the equation derived from it. Thus activation and inhibition at high substrate concentrations, together with sigmoidal activity versus substrate concentration plots, all of which characterize the reactions of these esterases, could be interpreted by a single scheme and equation. Structural and kinetic comparisons showed a progressive transition of properties from the oCE's through the mCE's to the oBuChE's. One of the purified mCE's was from horse serum, and it exhibited physical and kinetic properties unlike those of the liver mCE's or oCE's.     

Persistence and dissipation kinetics of trifloxystrobin and tebuconazole in onion and soil

The persistence and dissipation kinetics of trifloxystrobin and tebuconazole on onion were studied after application of their combination formulation at a standard and double dose of 75 + 150 and 150 + 300 g a.i. ha^?1. The fungicides were extracted with acetone, cleaned-up using activated charcoal (trifloxystrobin) and neutral alumina (tebuconazole). Analysis was carried out by gas chromatograph (GC) and confirmed by gas chromatograph mass spectrometry (GC-MS). The recovery was above 80% and limit of quantification (LOQ) 0.05 mg kg^?1 for both fungicides. Initial residue deposits of trifloxystrobin were 0.68 and 1.01 mg kg^?1 and tebuconazole 0.673 and 1.95 mg kg^?1 from standard and double dose treatments, respectively. Dissipation of the fungicides followed first-order kinetics and the half life of degradation was 6–6.6 days. Matured onion bulb (and field soil) harvested after 30 days was free from fungicide residues. These findings suggest recommended safe pre-harvest interval (PHI) of 14 and 25 days for spring onion consumption after treatment of Nativo 75 WG at the standard and double doses, respectively. Matured onion bulbs at harvest were free from fungicide residues.     

Sorption and Desorption Behavior of Chloroanilines and Chlorophenols on Montmorillonite and Kaolinite

The bioavailability of pollutants, pesticides and/or their degradation products in soil depends on the strength of their sorption by the different soil components, particularly by the clay minerals. This study reports the sorption-desorption behavior of the environmentally hazardous industrial pollutants and certain pesticides degradation products, 3-chloroaniline, 3,4-dichloroaniline, 2,4,6-trichloroaniline, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol on the reference clays kaolinite KGa-1 and Na-montmorillonite SWy-l. In batch studies, 2.0 g of clay were equilibrated with 100.0 mL solutions of each chemical at concentrations ranging from 10.0 to 200.0 mg/L. The uptake of the compounds was deduced from the results of HPLC-UV-Vis analysis. The lipophilic species were best retained by both clay materials. The most lipophilic chemical used in the study, 2,4,6-trichloroaniline, was also the most strongly retained, with sorption of up to 8 mg/g. In desorption experiments, which also relied on HPLC-UV-Vis technique, 2,4,6-trichloroaniline was the least desorbed from montmorillonite. However, on kaolinite all of the compounds under study were irreversibly retained. The experimental data have been modelled according to the Langmuir and Freundlich isotherms. A hypothesis is proposed concerning the sorption mechanism and potential applications of the findings in remediation strategies have been suggested.     

Sorption and desorption behavior of chloroanilines and chlorophenols on montmorillonite and kaolinite

The bioavailability of pollutants, pesticides and/or their degradation products in soil depends on the strength of their sorption by the different soil components, particularly by the clay minerals. This study reports the sorption-desorption behavior of the environmentally hazardous industrial pollutants and certain pesticides degradation products, 3-chloroaniline, 3,4-dichloroaniline, 2,4,6-trichloroaniline, 4-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol on the reference clays kaolinite KGa-1 and Na-montmorillonite SWy-l. In batch studies, 2.0 g of clay were equilibrated with 100.0 mL solutions of each chemical at concentrations ranging from 10.0 to 200.0 mg/L. The uptake of the compounds was deduced from the results of HPLC-UV-Vis analysis. The lipophilic species were best retained by both clay materials. The most lipophilic chemical used in the study, 2,4,6-trichloroaniline, was also the most strongly retained, with sorption of up to 8 mg/g. In desorption experiments, which also relied on HPLC-UV-Vis technique, 2,4,6-trichloroaniline was the least desorbed from montmorillonite. However, on kaolinite all of the compounds under study were irreversibly retained. The experimental data have been modelled according to the Langmuir and Freundlich isotherms. A hypothesis is proposed concerning the sorption mechanism and potential applications of the findings in remediation strategies have been suggested.     

Bacterial and archaeal diversity in oil fields and reservoirs and their potential role in hydrocarbon recovery and bioprospecting

Environmental Science and Pollution Research - Hydrocarbon is a primary source of energy in the current urbanized society. Considering the increasing demand, worldwide oil productions are declining...     

畜禽养殖业污染与循环经济

解决畜禽养殖业的污染问题要以充分利用资源为根本出发点，通过对污染全过程控制及废物综合利用，达到畜禽粪便的减量化、无害化、资源化，走循环经济的发展道路。     

Isocyanatocyclohexane and isothiocyanatocyclohexane levels in urban and industrial areas and possible emission-related activities

Isocyanatocyclohexane and isothiocyanatocyclohexane are becoming relevant compounds in urban and industrial air, as they are used in important amounts in automobile industry and building insulation, as well as in the manufacture of foams, rubber, paints and varnishes. Glass multi-sorbent tubes (Carbotrap, Carbopack, Carboxen) were connected to LCMA-UPC pump samplers for the retention of iso- and isothiocyanatocyclohexanes. The analysis was performed by automatic thermal desorption (ATD) coupled with capillary gas chromatography (GC)/mass spectrometry detector (MSD). TD-GC/MS was chosen as analytical method due to its versatility and the possibility of analysis of a wide range of volatility and polarity VOC in air samples. The method was satisfactory sensitive, selective and reproducible for the studied compounds. The concentrations of iso- and isothioisocyanatocyclohexanes were evaluated in different urban, residential and industrial locations from extensive VOC air quality and odour episode studies in several cities in the Northeastern edge of Spain. Around 200–300 VOC were determined qualitatively in each sample. Higher values of iso- and isothiocyanatocyclohexane were found in industrial areas than in urban or residential locations. The concentrations ranged between n.d.−246 and n.d.−29 μg m⁻³ for isocyanatocyclohexane and isothiocyanatocyclohexane, respectively, for industrial areas. On the other hand, urban and residential locations showed concentrations ranging between n.d.−164 and n.d.−29 μg m⁻³ for isocyanatocyclohexane and isothiocyanatocyclohexane, respectively. The site location (urban or industrial), the kind and nearness of possible iso- and isothiocyanatocyclohexane emission activities (industrial or building construction) and the changes of wind regimes throughout the year have been found the most important factors influencing the concentrations of these compounds in the different places.     

Degradation in soil and water and ecotoxicity of rimsulfuron and its metabolites.

The degradation and ecotoxicity of sulfonylurea herbicide rimsulfuron and its major metabolites were examined in batch samples of an alluvial sandy loam and in freshwater. An HPLC-DAD method was adapted to simultaneously identify and quantify rimsulfuron and its metabolites, which was successfully validated by GC-MS analysis. In aqueous solutions, pure rimsulfuron was rapidly hydrolyzed into metabolite 1 (N-(4,6-dimethoxypyrimidin-2-yl)-N-(3-(ethylsulfonyl)-2-pyridinylurea)), which itself was transformed into the more stable metabolite 2 (N-((3-(ethylsulfonyl)-2-pyridinyl)-4,6-dimethoxy-2-pyrimidineamine)), with half-life (t(1/2)) values of 2 and 2.5 days, respectively. Hydrolysis was instantaneous under alkaline conditions (pH = 10). In aqueous suspensions of the alluvial soil (pH = 8), formulated rimsulfuron had a half-life of 7 days, whereas that of metabolite 1 was similar to that in water (about 3.5 days). The degradation of the two major metabolites was also studied in soil suspensions with the pure compounds at concentrations ranging from 1 to 10 mg l(-1). The half-life of metabolite 1 ranged from 3.9 to 5 days, close to the previous values. Metabolite 2 was more persistent and its degradation is strongly dependent on the initial concentration (C0): half-life values ranged from 8.1 to 55 days at 2-10 mg l(-1), respectively. These values are higher than those determined from the kinetics of metabolite 1 transformation into metabolite 2 (t(1/2) = 8-19 days). The ecotoxicity of the three chemicals was evaluated through their effect on Daphnia magna and Vibrio fischeri (Microtox bioassay). No effect was observed on D. magna with 24 and 48 h acute toxicity tests. Similarly, no toxic effect was observed with the Microtox test for the three chemicals in the range of concentrations tested that included the field application dose. Thus, being of low persistence and lacking acute toxicity, these chemicals present a low environmental risk. However, chronic effects should be studied in order to confirm the safety of rimsulfuron and its major metabolites.