农业排水渠结构对别拉洪河流域湿地景观结构的影响

从流域尺度,利用GIS技术和景观生态学方法,对三江平原别拉洪河流域1967-2005年3个时段农业排水渠和湿地景观结构时空变化进行分析,定量化讨论了排水渠系对湿地景观结构的影响,结果显示：①1967年后农业排水渠的修建改变了流域水文格局,使完整流域分化为特征明显的3个亚区;②在过去的30多年中,流域内排水渠规模和密度不断增加,结构复杂化,尤其在1983年后增加趋势尤为明显;排水渠密度在空间上发生明显分异,上游>中游>下游;③流域湿地的景观结构随着时间的变化,呈现湿地面积减少、景观多样性降低、结构严重破碎化趋势;④农业排水渠的建设是导致流域湿地景观结构变化的主要驱动力。     

典型流域土地利用/覆被变化及其景观生态效应——以浙江省西苕溪流域为例

土地利用/覆被变化的环境效应是相关领域今后研究的重点。论文利用1985、1995和2000年的TM数据及调查资料,研究西苕溪流域的土地利用/覆被变化及其景观生态效应。结果表明:流域内农田不断减少,居民及工矿用地持续扩大,林地前期减少、后期缓慢增加;林地和农田是流域内的主要景观类型,空间集中性及斑块碎化、形状规则化、景观同化是景观结构和景观异质性变化的主要表现;土地利用/覆被变化产生了生境质量下降、边缘效应增强、土地退化和生态系统成分单调等景观生态效应;恢复与建设西苕溪流域的景观生态系统需对景观尺度上的土地利用方式进行必要的调整。     

快速城市化进程中海岛景观格局变化研究

以厦门岛为例,通过一般景观格局分析指标和特殊景观格局分析指标,研究城市化进程中海岛生态景观格局的变化以及人工景观对自然景观的胁迫作用.结果显示:从1987年至2004年,人工景观对自然景观的胁迫作用迅速增加;厦门岛建成区占海岛面积的比例迅速增长,而斑块数量明显减少;厦门岛景观多样性迅速下降,同时破碎度指数和优势度迅速提高;受到海岸带开发活动影响,海岛岸线趋向平滑,海岛形状逐步趋向圆形;厦门岛人工景观对自然景观的胁迫程度逐步升高,城市化侵蚀指数也快速提高.     

基于一级水生态分区辽河流域景观格局时空动态分析

以辽河流域四个一级水生态分区为研究区,基于1990、2000、2005年TM影像,应用GIS技术,采用转移矩阵和景观指数方法,对辽河流域1990～2000年和2000～2005年期间土地利用和景观格局的变化进行了综合分析。结果表明:1990～2000年间水生态Ⅰ区耕地减少显著,减少的耕地主要转变为林地,而2000～2005年间草地面积大幅度减少,减少的草地主要转变为耕地;1990～2000年间水生态Ⅱ区耕地面积大幅度减少,耕地主要转变为草地和林地,2000～2005期间耕地大幅度增加,主要来源于草地;1990到2000年间水生态Ⅲ区耕地面积大幅减少,耕地主要转变为林地,2000～2005年大量林地转变为耕地和建设用地;水生态Ⅳ区包括浑河和太子河流域,其中浑河流域在1990～2000年时期景观格局的变化类型主要是由耕地转变为林地和建设用地,太子河流域耕地主要转变为林地。2000～2005年时期浑太河流域景观格局变化类型主要由减少的林地流向耕地。景观指数分析得到辽河流域景观变化的总体趋势是:形状更加复杂,异质性增加,破碎化程度加剧,尤其以建设用地的破碎度最高,并且有逐年增加的趋势。Ⅰ区和Ⅱ区景观连通性和聚合度在1990～2005年时期呈上升趋势,而在Ⅲ区和Ⅳ区在2000年景观结合度和连通度最低。研究时间内Ⅰ、Ⅱ、Ⅳ区景观多样性和均匀性指数在前期变化不显著,后期显著上升,Ⅲ区多样性和均匀度最高时期是2000年,1990年和2005年差别不显著。     

新开河流域湿地景观格局动态变化过程研究

论文利用遥感和GIS技术手段,运用土地利用转移矩阵和景观格局指数的模型,对新开河流域湿地近33年(1969-2001年)景观格局的动态变化过程进行了定量分析。结果显示:①随着流域人口的增加、土地利用活动的加强和水文条件的变化,新开河流域湿地不同程度地转化为草地、耕地、沙地和盐碱地,植物群落发生逆向演变。期间湿地总面积经历了大幅度减少到显著增加的落起过程;②新开河流域湿地景观破碎化严重,2001年沼泽地平均斑块面积、最大斑块面积、最大斑块周长较1969年分别减少了71.02%、71.08%、64.76%,景观破碎化指数由0.78上升到0.93。有关研究成果可为该流域湿地保护及其合理利用提供科学依据。     

博斯腾湖流域景观生态风险评价与时空变化

以博斯腾湖流域为研究区,利用eCognition软件对博斯腾湖流域1990年、2000年、2010年和2015年4期Landsat遥感影像分类。基于土地利用类型的生态脆弱度和景观干扰度指数构建景观生态风险评价模型,并利用空间自相关分析方法,开展博斯腾湖流域景观生态风险评价的时空变化研究。结果表明:(1)1990-2015年,博斯腾湖流域景观格局变化明显,主要特征为水域景观面积减少了64.33%,景观优势度降低;林地、耕地和城镇用地增幅显著,三者分别增加了47.96%、44.77%和85.15%;草地仍是流域主导景观类型。流域整体斑块数量减少,景观破碎化程度减弱。(2)低风险区和较低风险区主要分布在流域北部,土地利用以草地为主;高风险区主要分布在流域东南部,土地利用以未利用地为主;较高风险区主要围绕高风险区分布;中等风险区分布比较零散。(3)1990-2015年间,高风险区面积增加了386 263 hm2,低风险区面积减少了217 216 hm2,研究区总体生态风险等级增加,博斯腾湖流域生态质量存在进一步退化的趋势。     

长江三角洲国际重要湿地人为胁迫遥感解析

以长江三角洲上海崇明东滩鸟类国家级自然保护区、江苏大丰麋鹿国家级自然保护区、西溪国家湿地公园和江苏盐城国家级珍禽自然保护区4处国际重要湿地为研究对象,以Landsat MSS/TM/OLI遥感影像为基础信息源,采用面向对象的遥感分类方法获取了1980~2015年4个国际重要湿地（Ramsar）的5期土地覆被数据.通过分析湿地面积、景观格局动态及景观指数变化等,定量解析人类活动对湿地景观变化的影响,研究发现：（1）35a间,研究区内湿地面积持续减少,其中上海崇明东滩鸟类国家级自然保护区的湿地损失比例最高,为27.2%;（2）4个国际重要湿地的斑块数量和斑块密度都在增加,湿地趋于破碎化,景观间连通度降低.（3）耕地和人工表面增加是造成湿地损失的主要因素,耕地、人工表面、外来物种入侵和养殖池扩张等人为胁迫呈现上升趋势.（4）总体而言,入选国际重要湿地对人为活动有一定抑制作用,尤其是江苏大丰麋鹿国家级自然保护区湿地保护成效最为显著;但湿地保护有效性仍有待提升.     

西双版纳景观格局时空变化及其生态效应研究

西双版纳景观格局演变对合理利用区域土地和维护生态平衡具有重要意义.以四期Landsat影像为数据源,研究了西双版纳1990年-2010年的景观格局变化特征,分析其生态效应.结果表明:林地景观面积减少293 km2,斑块数量一直增加;灌木林景观面积增加,斑块数量持续减少;耕地面积增加,斑块数量增加,表明在经济发展时,生物环境逐渐恶化;各类地表景观形状复杂程度增加,破碎化程度加重,分布趋于均匀化,表明在人类活动干扰下,生态环境质量呈现下降趋势,不利于生物的保护.     

长江流域景观格局变化对生态系统水质净化服务的影响

流域景观格局通过改变营养物质累积浓度空间分布而影响水质净化服务,探讨流域景观格局变化对水质净化服务的影响对于流域景观规划、生态系统保护和生态系统服务提升具有重要意义。以长江流域为研究区域,分析了两者变化特征及相关关系,结果表明:2000~2010年,长江上游农田减少0.92%、森林增加0.34%;中下游城镇增加6.87%、农田减少6.83%。景观配置变化中,流域各景观斑块复杂程度增加、景观聚集连通性降低、景观异质性增加;1 000 m河岸带中,各斑块大片聚集趋势更明显;流域水质净化服务量增强区域主要集中在上游的乌江水系、嘉陵江水系及宜宾至宜昌干流水系,最大增加10.5%,中下游大部分子流域水质净化服务下降,下降率最高达22.8%;景观配置中,景观聚集连通性降低、景观复杂程度增加和景观异质性的增加,都会削弱水质净化服务;子流域与河岸带景观格局变化解释水质净化服务空间变异的贡献率分别为29.4%和79.0%,表明河岸带景观格局的改变更能影响污染物的截留效率。     

三峡建坝前后洞庭湖区湿地景观格局变化

根据洞庭湖区1987—2008 年的6 期遥感影像数据资料,利用景观格局指数及转移矩阵模型等方法重点分析了三峡工程建坝前后洞庭湖区湿地景观格局的变化特征,以及对洞庭湖区湿地演变的主要影响。结果表明：①整体景观破碎化程度增大,景观异质性减小,景观形状趋于复杂化;②水体的破碎化程度增加,斑块间的结合度降低;泥沙滩地的破碎化程度先加大后降低,最大斑块面积有所增大;苔草滩地和芦苇滩地的破碎化程度先后经历了增大→减小→增大的过程;防护林滩地的破碎化程度由减小到增大到再增大;耕地（水田、旱地）破碎化程度在逐渐增大;建设用地斑块数增加最多;林地的结构相对稳定;③三峡工程运行使洞庭湖区湿地的水沙和泥沙淤积发生变化,导致湿地呈正向演替,自然湿地面积减少。     

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.     

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.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.     

Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.