农业非点源污染研究综述

针对农业非点源污染的研究现状,综述了非点源污染的定义、特征、污染现状以及危害,并介绍了国内外学者在非点源污染研究的技术方法方面的进展,指出利用与RS、GIS的紧密结合来建立基础信息数据库,对非点源污染过程进行模拟是进行非点源污染研究必然的发展趋势,并简单介绍了两个在国内外应用较广泛的非点源污染模型AnnAGNPS和SWAT模型,最后讨论了利用模型模拟非点源污染过程的优势。     

城市水环境非点源污染总量控制研究与应用

在调查和分析仪征市非点源污染过程中，对建成区进行网格处理，根据土地利用状况和特点，通过采样分析，确定了各网格的非点源污染负荷量和空间变化特征。在非点源污染发生的时段民假设在时间上分配均匀的点源污染负荷进行比较，分析二对区域水环境的叠加影响。     

珠江流域云南片区水污染负荷调查及计算方法研究

详细介绍了珠江流域云南片区点源及非点源污染负荷排放量及入河量的计算方法，并根据污染控制区的计算结果分析了珠江流域云南片区点源及非点源排放量及入河量分布特征，认为非点源污染物排放量所占的比例明显高于点源，而点源污染物入河量所占的比例明显高于非点源。     

辽河流域非点源污染空间特征遥感解析

应用遥感技术研究了辽河流域非点源污染发生特征.将环境卫星遥感数据耦合非点源(non-point Source,NPS)污染负荷估算模型,探索基于遥感像元尺度的非点源污染估算方法,目的是分析2010年辽河流域非点源污染特征,从而明确非点源污染的重点防治区和防治措施,为辽河流域水环境污染防治提供技术支持.结果表明,2010年辽河流域总氮排放量为10.3万t,总磷排放量为0.68万t,化学需氧量排放量为13.1万t,氨氮排放量为1.8万t;目前,对于辽河流域主要的非点源污染类型为农业面源;2010年辽河流域面源污染对水质污染的贡献率表现为总氮67.4%,总磷76.4%,化学需氧量39.4%和氨氮21.9%;空间分布上辽河流域的南部是污染最严重的地区,其次是东北部.本研究结合遥感技术发展了以遥感像元为基本模拟单位的非点源污染负荷估算方法,明确了2010年辽河流域的非点源污染产生量和空间分布特征,为辽河流域污染治理防治工作提供了理论依据.     

城市非点源污染特征及控制管理

随着点源污染控制的不断完善,城市非点源污染成为城市水体的重要污染源。本文从非点源污染的概念入手,从汇水面性质、水文响应、污染物种类等方面阐述了城市非点源污染的特点,总结了控制非点源污染的技术性及非技术性措施,并以上海为例,分析了该地区的非点源污染特征及采取的调控对策,以期为我国城市非点源污染的防治提供参考和借鉴。     

农业非点源氮污染研究进展分析

概述了非点源污染的概念、特征及非点源氮素对水环境的影响,阐述了两种形态的非点源氮素NH+4-N和NO-3-N的迁移机理、流失途径(地表径流和渗漏淋失)及其自然和人为影响因素;非点源污染负荷定量计算的方法,及计算非点源污染负荷模型的发展趋势。提出了控制农田非点源氮素的措施。     

基于改进输出系数模型的非点源污染评估及关键源区识别：以北运河上游流域为例

非点源污染对水生态环境威胁极大,定量解析非点源污染空间分布特征和准确识别关键源区是实现其高效精准治理的基础.输出系数模型广泛应用于非点源污染的模拟,但该模型忽略污染物迁移过程中的损失量,需要进一步改进.以北运河上游流域为例,通过对非点源污染物迁移物理过程的模拟,量化产流、产沙和下渗过程中污染物的损失率改进输出系数模型,并分析Johnes、常用和改进输出系数模型的模拟精度,探究3个输出系数模型对非点源污染空间分布特征和关键源区模拟结果的影响.结果表明：(1)改进输出系数模型模拟误差(-6.79%)明显低于Johnes模型(50.44%)和常用模型(-84.01%),显著提高了非点源污染模拟精度.(2)不同输出系数模型得到的非点源污染空间分布特征和关键源区存在较大差异,改进的输出系数模型模拟结果更符合流域非点源污染特征.流域非点源污染呈西北部低东南部高的空间特征,城镇用地和耕地是主要污染源.(3)基于改进输出系数模型确定的流域非点源污染关键源区主要分布在昌平、沙河、史各庄、温泉乡北部和马连洼街道西部等区域,占流域总面积6.71%.研究可为缺资料地区的非点源污染评估和治理提供更有效的工具支撑...     

全国非点源污染分区分级

从非点源污染产生和迁移的水文过程机理出发,结合中国<水资源分区>和<中国水文区划>,提出了全国非点源污染分区分级体系;在地理信息系统(GIS)空间数据库支持下,基于非点源污染负荷产生和迁移的规律分析,在全国范围内进行了非点源污染分区分级,进而初步绘制全国非点源分区分级图,确定了全国非点源污染负荷估算模型的空间框架.全国非点源污染分区分级体系包括5级,非点源污染一级区为中国主要十大流域;主干河流自然流域分区作为非点源污染的二级区,共80个;在二级区基础上,依据非点源污染产生的水文气候特征,划分三级区共214个;在三级分区内,以影响非点源污染产生、迁移和转化的产汇流条件、社会经济结构、地形条件等为指标,划分非点源污染的四级分区322个;五级分区以非点源污染类型为标准进行划分.     

地表水环境非点源污染研究的进展与展望

随着点源污染的有效管理和控制,非点源污染已经成为导致地表水环境污染的主要原因。本文在概述地表水环境非点源污染的概念、分类、特征、及典型发生方式基础上,从模型化、径流研究、水体富营养化、非点源毒性污染物、新技术应用、调控与管理等角度对国内外地表水环境非点源污染的研究进展进行了综述。并展望了其未来研究的五个方向:建立集成化的非点源污染模型软件;加强非点源污染物的毒理学研究;重视高速公路和城市路面的非点源污染;利用生物工程技术控制和治理流域非点源污染;以及在总量控制的背景下,制定排污交易政策。     

概念性非点源污染动态模型(CNPDM)及其应用研究

概念性非点源污染动态模型(CNPDM)根据非点源污染的产生机理和动态过程,直接模拟了具有不同非点源产生特征与产生潜力的各类下垫面,并采用空间、时间离散化的方法使整个模拟结果具有时空差异性,从而更客观和直接地表述了区域性非点源污染的分布与程度,为非点源污染的控制及对策的研究提供了依据。CNPDM已在广东省的江门市、深圳市等地的研究中得到验证。并应用到珠江三角洲的非点源污染计算中。      

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.