城市生态系统承载能力初步研究——以江苏省吴江市为例

城市作为一个复合生态系统,其承载能力的涵义与资源、环境承载力相比有很大差别。论文在探讨城市生态系统承载力内涵及各子系统相互关系的基础上,从承载力与压力指数的角度构建城市生态系统承载能力评价模型。以江苏省吴江市为例,建立承载力与压力指数评价的层次结构指标体系,应用评价模型对吴江市1990-2004年的城市生态系统承载水平进行评价。结果表明:吴江市在研究时段内生态系统承载能力与社会经济发展经历了由不协调到相对协调的过程。在选取的各分量指标中,环境容纳指数的平均贡献率高达38.68%,是提高城市生态系统承载力及抑制生态系统压力增长的重要因素;资源消耗的平均贡献率为54.45%,说明社会经济发展导致的资源消耗仍然是生态系统压力的主要来源。     

资源与环境综合承载力分析——以银川滨河新区总体规划为例

从自然、经济、社会环境承载力3个方面构建资源与环境承载力评价指标体系,利用层次分析法和相对比较法,确定指标体系的权重;利用模糊综合评价法和关联分析法,计算评价体系中各指标的承载力指数,最后,得出环境承载力指数,此外,对自然、经济和社会环境承载力之间的协调度进行分析。结果表明:伴随着区域发展模式的优化调整,银川滨河新区资源与环境承载力指数呈上升趋势,区域环境承载能力逐步增强,各承载力系统之间属于良好协调状态,自然、经济、社会环境系统呈良性循环的可持续发展态势。     

城市开发强度与资源环境承载力协调分析——以珠三角为例

党的十八大以来,习近平总书记提出要加快构建生态文明体系,协调生态环境保护与城市开发,积极开展国土空间规划与生态修复工作。广东省新一轮生态文明建设规划提出,要根据地区资源环境承载能力,把环境损害、生态效益等指标纳入发展综合评价体系,打造珠三角绿色生态城市群。通过构建城市开发强度及资源环境承载力指标体系,选取珠三角九市作为研究对象,运用耦合协调模型量化可持续发展水平并揭示各子系统的相互作用,制定能增强承载能力的有效路径。结果表明：（1）研究区城市开发强度对比明显,都市圈特征日益显著。其中,深圳（0.9224）开发程度最强,肇庆（0.0548）程度最弱。（2）资源环境承载力按驱动因子分为自然拉动型及经济拉动型,分别通过自然优势和社会经济投入巩固综合承载力。（3）区域内过半城市生态经济系统濒临失调。受经济因素驱动,广州、深圳协调程度相对较高。（4）应对区域内三种不同的协调发展状态,为各类城市制定因地制宜的生态修复方案。     

黄河中上游能源化工区重点产业发展战略土地资源承载力评价

结合黄河中上游能源化工区重点产业发展战略土地资源影响特点,探索了战略环评土地资源承载力评价方法和思路. 以土地资源优势、劣势、机会和威胁(SWOT)分析和主成分分析(PCA)为研究手段,构建了涵括土地资源生态属性、经济属性及社会属性的土地资源综合承载力评价指标体系,研究了重点产业战略实施前后土地资源综合承载力空间变化,深入剖析了重点产业发展战略的环境合理性. 结果表明:黄河中上游能源化工区重点产业战略实施后,能源重化工产业重点布局、大规模发展区域综合土地资源承载力指数较现状降低10%以上,而非重点发展区域土地资源综合承载力有所提升,因此,重点产业发展中必须结合土地资源承载力现状,合理调整产业发展布局.      

基于资源环境承载力的海岛生态系统适应性管理——以温州市洞头区为例

海岛资源环境承载力评估能够识别生态系统的胁迫因子,明确海岛资源保护与开发的阈值界限,对于管控海岛及其邻近海域生态系统的生态环境具有重要意义。本文选择用海矛盾日益突出的海岛县洞头作为研究区,基于承载力的PSR概念模型,运用GIS空间分析、多指标评价等技术方法,从人-海复合生态系统的角度构建了海岛资源环境承载力的综合评价体系,对区域海岛生态系统的恢复力、资源环境容纳能力和抗干扰能力进行了量化,获得了洞头区压力、承压和响应调节系统的空间分异格局,据此探讨了洞头区在海陆边界、自然条件、社会经济发展等方面的不确定性,进而提出了海岛生态适应性管理的策略和措施。结果表明,洞头区资源环境承载力综合评价指数介于0.5~1.7之间,总体承载状况较好,现阶段仅有12%的海域处于超载状态,未来需从缓解人类社会经济活动压力、保持资源环境承压能力和提高系统反馈调节能力三个方面出发,开展适应性管控。     

一种城市综合承载力双向复合动态评价方法及实证研究

随着城市的发展,其对资源、生态环境、基础设施、社会经济等各种承载的需求同步增长,单一承载力逐渐无法满足对城市发展可持续状态的综合全面评估.城市综合承载力是社会、经济、环境、资源协调作用和协调程度的具体表征.综合承载力与人口规模、社会经济活动发展带来的压力之间存在动态互动关系,只有承载力和压力维持动态平衡,才能实现城市系统的可持续发展.本文通过构建城市双向复合动态可持续评估方法,量化负向城市压力(UP)和正向城市综合承载力(UCCC)及其二者之间的复合动态关系,结合层次分析法和蒙特卡洛模拟,从经济、资源、社会三方面构建评价指标,综合考虑各影响因素的不确定性和相互作用,实现逐个单点时间城市综合承载力的概率分布模拟,进而通过复合动态关系判断模型实现单个区域单点时间的可持续发展状态的判断.最后,以广州市为例,对所提出方法进行应用.结果表明,2004—2016年,广州市的综合承载力和城市压力相互协调、相互适应,城市发展整体呈可持续状态.但2012年以来资源环境承载力有一定的下降,尤其是水资源承载力和大气环境承载力下降,需要引起重视.     

生态承载力评价方法研究进展

生态承载力是当前生态学、地理学、经济学等领域的研究热点,生态承载力评价方法的研究对于区域社会经济协调可持续发展具有重要的意义。在详细阐述生态承载力概念、内涵、国内主要研究领域、研究机构的基础上,重点分析比较了目前生态承载力所涉及的研究方法,并比较了不同模型之间的优缺点,最后分析总结了目前生态承载力研究存在的不足和未来需要加强的领域和方向。从方法上来看,目前所用方法主要有:(1)指标体系综合评价法;(2)产品周期综合评价法;(3)结合不同学科和不同方法的综合评价法。目前生态承载力的研究缺乏科学完整的研究体系,尚未构建具有普适性的评价指标体系,演化趋势与模拟预测研究不足,格局分异研究较少,未来应该在以下几个方面深入研究:(1)加强生态承载力模型集成研究。由于生态承载力问题十分复杂,涉及资源、环境、生态、社会、经济等诸多要素,因此需要综合各个要素之间的相互关系及影响机制,进行不同模型集成和综合研究;(2)应从影响生态承载力的主动与被动因子,动态与静态因子出发,构建综合性和普适性较强的评价体系;(3)加强生态承载力的动态模拟研究,实现对生态承载力潜力的估算和动态变化过程的监测;(4)研究不同尺度下生态承载力时空变化特征及空间分异,并对比分析各模型对不同尺度的精度要求和结果的可靠性。     

黄河三角洲中心城市资源环境承载力时空变化规律与趋势研究——以东营市为例

东营市地处黄河入海口,是黄河三角洲地区最为重要的中心城市。该区生态环境脆弱,要实现黄河三角洲地区经济的可持续发展,必须改善环境质量、提高资源环境承载力。利用主成分分析法对东营市2011—2015年资源环境承载力进行了时空两维度的综合评价研究。结果表明:在时间尺度上,综合得分最高的是广饶县,东营区在4个年度排名第二,河口区及垦利区在2012—2015年综合得分始终较低,这表明东营市河口区及垦利区的资源环境承载力需要多加关注,应把河口区、垦利区纳入重点监测范围;在空间尺度上,东营市5个区县历年的资源环境承载力评价综合得分在逐渐提高,承载力逐年增长、资源环境和社会经济发展越来越好,应继续加大城市生态环境保护力度、大力发展循环经济等以促进东营市资源环境承载力良性发展。     

山地城镇化与资源环境承载力耦合协调发展的时空演变

中国是山地大国,在生态文明建设理念下,如何实现山地城镇化与资源环境承载力的协调发展,已经成为我国亟待解决的重大难题. 基于我国西南地区三省一市(重庆市、四川省、云南省、贵州省)的31个地级市2004—2018年面板数据,运用综合评价法和耦合协调度模型,揭示了山地城镇化与资源环境承载力耦合协调的时空演变特征. 结果表明:①西南地区综合城镇化指数和资源环境承载力均呈稳步增长趋势,二者差距逐渐缩小,但由于发展水平较低,仍处于低度耦合协调阶段. ②在空间格局上,都市圈内城市属于高承载、高发展、中度耦合协调度地区,但重庆市、昆明市以及一些工业型城市由于人口和财富在城市高度集聚,其资源环境承载力显著低于西南地区平均值;以高山大川为界的省际交界地区,由于自然地理上的“分割”,城镇化发育不足,属于高承载、低发展、低度耦合协调度地区. 研究显示,山地城镇化与资源环境承载力之间的耦合关系日趋紧密,应推进以人为本的绿色城镇化道路,使两大系统处于良好的耦合协调状态.      

基于VIKOR法的潍坊市水资源承载力综合评价

水资源承载力综合评价通常涉及到社会、经济、资源和环境等多种因素的影响.多准则妥协解排序法（VIKOR）可协调处理多种因素间的相互关系,是评价城市水资源承载力的有效手段之一.本文利用VIKOR法对潍坊市水资源承载力进行综合评价,通过构建水资源承载力综合评价指标体系,利用CRITIC法计算权重,标准化数据并进行分析计算和排序,以利益比率Q_i作为综合评价值,Q_i值越小,表明水资源承载力越高.结果发现,在2008-2017年,潍坊市水资源承载力综合评价值呈下降趋势,从2008年的0.7378下降至2017年的0.0000,表明潍坊市水资源承载力稳步提高.通过分析潍坊市水资源承载力各子系统的变化趋势发现,潍坊市水资源承载能力依然有较大的提升空间.通过对2017年潍坊市各市、区、县水资源承载力进行对比可知,诸城市、青州市、安丘市和临朐县综合评价值较低,分别为0、0.1645、0.2267和0.2503,说明水资源承载力较高;潍城区、坊子区、寒亭区和奎文区综合评价值较高,分别为0.3475、0.4739、0.5938和0.9131,说明水资源承载力较低.表明潍坊市部分地区产业结构和布局与水资源条件不相匹配,水资源开发利用水平超出当地水资源承载力.     

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.