基于时差相关分析和模糊神经网络的白洋淀流域水环境承载力评价预警

为实现水环境承载力评价和预警,运用耦合DPSR模型和时差分析方法构建了白洋淀流域水环境承载力监测预警指标体系,并结合神经网络与模糊数学构建了T-S模糊神经网络模型,根据控制图法确定了监测预警指标阈值,解决了水环境系统的随机性和模糊性问题,最终实现了白洋淀流域水环境承载力的有效评价和预警。结果表明:1)白洋淀流域水环境承载力在2012-2015年处于较弱承载状态,在2016,2017年处于中等承载状态,现状评价等级由Ⅳ级(橙色警灯)转变为Ⅲ级(黄色警灯);2)在现状发展趋势下,2018-2035年白洋淀流域水环境承载力整体呈先上升后下降趋势,自2026年以后流域水环境整体呈恶化状态,水环境承载力逐渐从中等承载(黄色警灯)向较弱承载(橙色警灯)和弱承载状态(红色警灯)转变;3)未来区域人口的增长和雄安新区的快速发展会给白洋淀流域水环境带来巨大压力,因此可加大区域水环境保护力度,实施基于空间单元的精细化环境管控方案,推动区域经济绿色转型,促进区域水环境质量全面改善和良性发展,以提高区域可持续发展水平。     

山东半岛蓝色经济区海域生态环境综合评价

海域生态环境评价作为承载力研究的基础,在近海生态管理中得到了广泛关注. 针对海洋生态环境研究中评价指标体系简单、标准相对单一及不利于实际应用等问题,以生态系统为研究视角构建了基于环境因子和生态响应的近海生态环境综合评价指标体系与指数计量方法,根据环境因子指数和生态响应指数在交叉判断矩阵中的位置,将近海生态环境状态分为优、良、中、差和劣5个等级,并将该方法应用于山东半岛蓝色经济区海域评价. 结果表明:研究海域整体环境因子指数为0.41~0.84(平均值为0.67),生态响应指数为0.17~0.75(平均值为0.45),综合评价等级为良,但已非常接近中等级别;其生态环境问题主要表现为溶解无机氮负荷较高、重金属和浮游动物密度负荷过低. 不同海域生态环境状态存在明显差异,25个近岸海域中等级优和良的共占60%,主要分布在山东半岛东部和西南部;海域等级为中和差的各占16%,另有8%海域等级为劣. 该评价模型与方法从生态环境整体性揭示海域存在问题,可为山东半岛蓝色经济区建设提供科学依据.      

基于模糊数学和灰色理论的城市生态环境竞争力评价

在综合分析了国内外有关城市竞争力理论研究的基础上,对城市生态环境竞争力的概念和内涵进行了界定,构建了面向生态环境竞争力的评价体系,并以山东省17城市为例,采用灰色系统理论确定各指标的权重,利用模糊综合评价法对各市进行综合评价,研究结果表明,生态环境竞争力排名前三的地市为临沂(0.1894)、日照(0.1705)和烟台(0.1676),而德州(0.1191)、济南(0.1232)、枣庄(0.1274)、滨州(0.1285)和淄博(0.1289)表现相对较差,其他地市处于中游水平.分别从资源禀赋竞争力、污染物减量排放竞争力、环境治理竞争力和能耗竞争力4个子维度对典型城市进行分析,指出了存在的问题,并给出了相应的对策建议.     

太湖流域水环境承载力评价研究

构建"驱动力D(人口、社会经济发展)-压力P(水资源问题与污染排放)-状态S(水质变化)-影响I(自然生态、水土资源)-响应R(污水处理、用水普及)-管理M(绿化、投资)"(DPSIRM)评价模型,并从社会经济、水资源、水质状态、投资管理等方面选取指标,建立具有3层结构的评价指标体系.引入变异系数法进行各指标权重赋值,计算太湖流域2005~2014年的水环境承载力评价指数,获得相应评价等级.结果表明:太湖流域水环境承载力有明显好转,评价等级从2005年的Ⅲ级转变为2014年的Ⅱ级.压力指标所起作用最为显著,状态指标紧随其后,其次是驱动力指标、影响指标和响应指标,管理指标作用相对较小.10年间,驱动力子系统指数明显呈上升趋势,影响和管理子系统的指数出现波动,压力、状态和响应子系统的指数均随年份增长而呈上升趋势,压力子系统指数上升幅度最大,表明2005~2014年太湖流域水环境对工农经济发展的承载能力在增强.对水环境承载力影响程度最大的指标中,万元GDP水耗和单位工业产值废水排放量都属于压力子系统指标,表明压力子系统指标所起作用最为显著.研究表明,构建的太湖流域水环境承载力评价的DPSIRM模型具有实用性和可行性,可以为区域水环境规划与综合管理的科学决策提供依据.     

基于Balanced Score Card的滨海城市化生态风险评价

在快速城市化过程中,沿海城市经济发展迅速,导致生态环境问题日益突出。以青岛市为例,引入BalancedScoreCard(BSC)概念,从人居环境、经济发展、资源与环境、人文响应4个维度构建城市生态风险评价指标BSC模型,基于BSC模型,建立青岛生态风险评价指标体系;根据加权综合评价法,构建生态风险评价模型,评价2005~2015年青岛生态风险;通过灰色斜率关联度模型,探究影响青岛生态风险的因素。结果表明,青岛市生态风险整体呈下降趋势,从高风险下降到中等风险。生态风险的主要影响因子为:第二产业占GDP比重>建成区绿化覆盖率>第三产业占GDP比重>单位GDP能耗>每万人拥有医疗床位数>GDP增长率>工业SO_2排放量。最后,为青岛提出合理的生态风险管理建议。     

基于熵模型的城市水资源承载力研究——以开封市为例

城市水资源承载力是水资源对城市社会经济发展规模支撑能力的表征,是城市水安全的基本度量,它是涉及社会经济系统、水资源系统和生态环境系统的一个衡量指标。论文利用灰色系统理论、模糊集理论和最大熵原理相结合的熵模型对开封市未来预测年份水资源承载力进行评价,特别考虑了半湿润地区开封城市主要利用黄河客水资源的特点,选取了客水利用率这一评价指标。研究结果表明,2010年和2020年开封市城市发展无论在哪种预测情景方案下的水资源承载力综合评价都处于2级与3级之间,并且距离2级很近,说明水资源的开发强度很高,继续开发利用的潜力很小。研究成果可为中型城市水资源承载力评价及城市发展规划提供依据。     

基于DCSM模型的成都市河流水环境承载力综合评价

根据水污染流动"源头-转化-汇入"过程,综合衡量工业、农业、生活源污染排放对成都市主要河流的环境影响,提出"驱动力D （人口、社会经济发展）-承载源C （工业、农业、生活源污染排放）-承载状态S （污染程度）-管理M （治理污染投资）"4个子系统的DCSM模型,构建包含3层结构26个指标的成都市河流水环境承载力综合评价指标体系.采用投影寻踪模型得到各指标的影响程度,进一步建立区域水环境承载力各评价指标权重,根据最佳投影方向确定成都市主要河流2014—2018年的水环境承载力综合评价特征值,并得到相应评价等级.研究结果表明：影响程度最大的3项指标依次为：工业源COD排放强度、国考断面地表水TP平均浓度、环保投资占GDP的比重;通过对各个指标的权重分析,表明承载状态子系统和承载源子系统对综合评价结果所起作用最为显著,其次是管理子系统,驱动力子系统作用最小;通过评价等级分析,结果表明：2014—2018年成都市河流水环境承载力综合评价指数逐渐增加,评价等级从Ⅲ级（一般,2014—2016年）转变为Ⅱ级（较强,2017—2018年）,说明5年来成都市河流水环境承载力逐步增加.研究表明了基于DCSM模型的成都市河流水环境承载力综合评价结果具有实用性和可行性,可以为城市河流水环境承载力综合评价提供新的研究思路,为水环境规划与管理的科学决策提供依据.     

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.     

基于DPSIR-TOPSIS模型的福建省生态环境承载力评价及障碍因素研究

生态环境承载力是生态文明建设的基础,研究生态环境承载力对于深入实施生态文明建设具有重要意义.福建省在生态文明建设方面走在全国前列,通过研究福建省的生态环境承载力情况,有助于更好地推进福建省生态文明建设.基于DPSIR概念模型构建了福建省生态环境承载力评价指标体系,采用TOPSIS分析法和障碍度模型对福建省2000—2015年生态环境承载力状况和障碍因子进行了评价分析.结果表明:总体而言,福建省生态环境承载力综合贴近度不断上升,从2000年的0.09981上升到2015年的0.89625,表明福建省生态环境承载力水平稳步提升;从分类指标来看,驱动力、状态、影响和响应子系统评价指数均呈不同幅度的上升趋势,而压力子系统评价指数呈下降趋势,表明福建省在生态环境治理方面所做的努力是卓有成效的,生态文明建设压力相对减小;从障碍度分析来看,就分类指标而言,响应子系统承载力是影响福建省生态环境承载力的主要因素系统.就主要障碍因素而言,在研究期内,影响福建省生态环境承载力的主要障碍因素包括能源消耗弹性系数、城市环境基础设施投资、环境保护投资占GDP的比例等.基于上述结论,本研究最后提出了相应的对策措施.     

基于AHP-熵权法的水环境承载力模糊综合评价

针对水环境承载力评价存在的不确定性和模糊性问题,该研究采用层次分析法和熵权法进行组合赋权,利用模糊综合评价法对粤港澳大湾区9个城市的水环境承载力进行评价,并引入障碍度模型确定影响水环境承载力的主要障碍度因素.结果 表明:2013-2018年9个城市的水环境承载力总体呈上升趋势,但城市间的变化差异明显;9个城市水环境承载力的障碍指标差异明显,其中人均水资源量以20.7％的障碍度均值成为首要障碍度指标;通过障碍度频率分析可得9个城市的主要障碍度指标包括人均水资源量、生态用水率、万元GDP污(废)水排放量和第三产业比重,这4项指标的频率均为89％.将该方法应用于区域水环境承载力的评价,其结果可为区域水环境的管理和相关政策的制定提供依据.     

Evaluation of phytoextracting cadmium and lead by sunflower, ricinus, alfalfa and mustard in hydroponic culture

Soil contaminated with heavy metals cadmium(Cd)and lead(Pb)is hard to be remediated.Phytoremediation may be a feasible method to remove toxic metals from soil,but there are few suitable plants which can hyperaccumulate metals.In this study,Cd and Pb accumulation by four plants including sunflower(Helianthus annuus L.),mustard(Brassica juncea L.),alfalfa(Medicago sativa L.), ricinus(Ricinus communis L.)in hydroponic cultures was compared.Results showed that these plants could phytocxtract heavy metals, the ability of accumulation differed with species,concentrations and categories of heavy metals.Values of BCF(bioconcentration factor)and TF(translocation factor)indicated that four species had dissimilar abilities of phytoextraction and transportation of heavy metals.Changes on the biomass of plants,pH and Eh at different treatments revealed that these four plants had distinct responses to Cd and Pb in cultures.Measurements should be taken to improve the phytoremediation of sites contaminated with heavy metals,such as pH and Eh regulations,and so forth.     

Oxidation of As(Ⅲ) by potassium permanganate

The oxidation of As(Ⅲ) with potassium permanganate was studied under conditions including pH, initial As(Ⅲ) concentration and dosage of Mn(Ⅶ). The results have shown that potassium permanganate was an effective agent for oxidizing of As(Ⅲ) in a wide pH range. The pH value of tested water was not a significant factor affecting the oxidation of As(Ⅲ) by Mn(Ⅶ). Although theoretical redox analyses suggest that Mn(Ⅶ) should have better performance in oxidization of As(Ⅲ) within lower pH ranges, the experimental results show that the oxidation efficiencies of As(Ⅲ) under basic and acidic conditions were similar, which may be due to the adsorption of As(Ⅲ) on the Mn(OH)2 and MnO2 resulting from the oxidation of As(Ⅲ).     

Chlorobenzenes in waterweeds from the Xijiang River （Guangdong section） of the Pearl River

The Xijiang River is the major source of water for about 4.5 millions of urban population and 28.7 millions of rural population. The water quality is very important for the health of the rural population. The concentration and distribution of chlorobenzenes (CBs) in both water and waterweeds collected from 4 stations in the Xijiang River (Gangdong section) of the Pearl River in April and November were determined. The result showed that nearly every congener of CBs was detected. The total contents of CBs (∑CBs) in the river water ranged from 111.1 to 360.0 ng/L in April and from 151.9 to 481.7 ng/L in November, respectively. The pollution level of CBs in the water in April was higher than that in November. The contents of ∑ CBs in waterweeds ranged from 13.53×102 μg/g to 38.27×102μg/g dry weight (dw). There was no significant difference between April and November in waterweeds. The distribution of CBs in roots, caulis, and leaves of Vallisneria spiralis L. showed different patterns. The leaves mainly contained low-molecular-weight CBs(DCBs), whereas the roots accumulated more PCBs and HCBs. The average lgBCFlip (bioconcentration factor) of CBs ranged from 0.64 to 3.57 in the waterweeds. The spatial distribution character of CBs in the Xijiang River was: Fengkai County ＜ Yunan County ＜Yun'an County ＜ Gaoyao County according to the ∑CBs, and the pollution deteriorated from the upstream to the downstream of the Xijiang River. Further analysis demonstrated that the discharge of waste containing CBs may be the main source of CBs pollution in the Xijiang River.     

Degradation of 2,4-dichlorophenol with a novel TiO2/Ti-Fe-graphite felt photoelectrocatalytic oxidation process

Degradation of 2,4-dichlorophenol(2,4-DCP)was studied in a novel three-electrode photoelectrocatalytic(PEC)integrative oxidation process,and the factors influencing the degradation rate,such as applied current,flow speed of O_2,pH,adscititious voltage and initial 2,4-DCP concentration were investigated and optimized.H_2O_2 was produced nearby cathode and Fe~(2 )continuously generated from Fe anode in solution when current and O_2 were applied,so,main reactions,H_2O_2-assisted TiO_2 PEC oxidation and E-Fenton reaction,occurred during degradation of 2,4-DCP in this integrative system.The degradation ratio of 2,4-DCP was 93% in this integrative oxidation process,while it was only 31% in E-Fenton process and 46% in H_2O_2-assisted TiO_2 PEC process.So,it revealed that the degradation of 2,4-DCP was improved greatly by photoelectrical cooperation effect.By the investigation of pH,it showed that this integrative process could work well in a wide pH range from pH 3 to pH 9.     

Effect of copper on the degradation of pesticides cypermethrin and cyhalothrin

The influence of coexisting copper (Cu) ion on the degradation of pesticides pyrethroid cypermethrin and cyhalothrin in soil and photodegradation in water system were studied.Serial concentrations of the pesticides with the addition of copper ion were spiked in the soil and incubated for a regular period of time,the analysis of the extracts from the soil was carried out using gas chromatography (GC).The photodegradation of pyrethroids in water system was conducted under UV irradiation.The effect of Cu~(2 ) on the pesticides degradation was measured with half life (t_(0.5)) of degradation.It was found that a negative correlation between the degradation of the pyrethroid pesticides in soil and Cu addition was observed.But Cu~(2 ) could accelerate photodegradation of the pyrethroids in water.The t_(0.5) for cyhalothrin extended from 6.7 to 6.8 d while for cypermethrin extended from 8.1 to 10.9 d with the presence of copper ion in soil.As for photodegradation,t_(0.5) for cyhalothrin reduced from 173.3 to 115.5 rain and for cypermethrin from 115.5 to 99.0 min.The results suggested that copper influenced the degradation of the pesticides in soil by affecting the activity of microorganisms.However, it had catalyst tendency for photodegradation in water system.The difference for the degradation efficiency of pyrethroid isomers in soil was also observed.Copper could obviously accelerate the degradation of some special isomers.     

Effects of arsenic on seed germination and physiological activities in wheat seedlings

The effects of arsenic(As)were investigated on seed germination,root and shoot length and their biomass and some other factors to elucidate the toxicity of As.The results showed low concentrations of As(O-1 mg/kg)stimulated seed germination and the growth of root and shoot,however,these factors all decreased gradually at high concentrations of As(5-20 mg/kg).The contents Of O2-,MDA,soluble protein and peroxidase(POD)activity all increased with increasing As concentrations.Soluble sugar content,ascorbate peroxidase(APX),and superoxide dismutase(SOD)activities decreased at low concentrations of As,and increased at high concentrations of As.While acetylsalicylic acid(ASA)and chlorophyll contents,catalase(CAT)activity displayed increasing trend when the concentrations of As was lower than 1 mg/kg,and then decreasing trend.By polyacrylamide gel electrophoresis(PAGE).As induced the expression of POD isozymes of wheat seedlings.As induced the expression of CAT isozymes but inhibited the expression of SOD isozymes of wheat seedlings at concentrations lower than 1 mg/kg.However,As inhibited the expression of CAT isozymes but induced the expression of SOD isozymes at concentrations higher than 5 mg/kg.The results indicated As could exert harmfulness in the early development stage of wheat at inappropriate concentrations.     

Bioconcentration kinetics of PCBs in various parts of the lifecycle of the tadpoles Xenopus laevis

Polychlorinated biphenyls （PCBs） in Xenopus laevis have been reported only for a few congeners. Additionally, there is very little information on the ability of Xenopus laevis to bioconcentrate PCBs. To address these issues, the tadpole Xenopus laevis was exposed to Aroclor 1254 mixtures in water at room temperature for 110 d followed by an additional 110 d of nonspiked PCBs in the water for the control group. During the whole process, bioconcentration factors （BCFs） of PCBs ranged from 1180 to 15670. For most PCB congeners, the highest and lowest bioconcentrations of the kinetic curves were found to be remarkably simultaneous, respectively. All 141 PCB congeners under the same experimental conditions had no linear correlation on the lgBCF versus lgKow relationship. The relationship between lgBCFs and lgKow followed a parabolic pattern indicative of selective bioconcentration, suggesting that the kinetic curves of the PCB congeners observed in the lifecycle of the tadpoles may be concentrated due to the amphibian special species and internal metabolism. In contrast, lgBCFs for PCBs were inversely related to lgKow, suggesting that a metabolism of the higher Kow PCB congeners occurred. These results support the author＇s conclusion that the tadpole Xenopus laevis plays major roles in the bioconcentration of PCB congeners, and demonstrated that the exposure kinetic curves of PCB congeners are complex. Besides the amphibian metamorphous development, the lifecycle of the tadpole Xenopus laevis also may be of importance in determining the bioconcentration of PCB congeners.     

Sustainability： A view from the wind-eroded field

This article explores the assessment of sustainability in fields subject to wind erosion. In the first part, simple sustainability audits are examined, as of soil depth and nutrients. Direct measurement of these characteristics has many problems, largely because of huge variability in space and time at all scales. Modelling still has its problems, but it may be possible to overcome many of them soon. It is true that wind erosion preferentially removes soil nutrients, but there are imponderables even here. The nutrient balance in many of these soils includes considerable input from dust. In West Africa, it has been shown that the amounts of calcium and potassium that are added in dust are sufficient to fertilize dispersed crops. In mildly acidic sandy soils, such as those found on the widespread palaeo- aeolian deposits, much of the phosphorus is fixed and unavailable to plants by the time it is removed by wind erosion, so that erosion has no added downside. Most of the nutrients carried by dust have been shown to travel close to the ground （even when they are attached to dust-sized particles）, and so are trapped in nearby fallow strips, and are thus not lost to the farming system. Second, the sustalnabillty of a whole semi-arid farming system is explored. Wind erosion in semi-arid areas （like China, the Sahel and Norflawestern Europe） generally takes place on aeolian deposits of the recent geological past. Most of these soils are deep enough to withstand centuries of wind erosion before they are totally lost to production, and some of these soils have greater fertility at greater depth （so that wind erosion may even improve the soil）. Finally some remarks are made about environmental change in relation to sustainability.     

Amplification of plasmid DNA bound on soil colloidal particles and clay minerals by the polymerase chain reaction

Polymerase chain reaction(PCR)was used to amplify a 600-base pair(bp)sequence of plasmid pGEX-2T DNA bound on soil colloidal particles from Brown soil(Alfisol)and Red soil(Ultisol),and three different minerals(goethite,kaolinite,montmorillonite). DNA bound on soil colloids,kaolinite,and montmorillonite was not amplified when the complexes were used directly but amplification occurred when the soil colloid or kaolinite-DNA complex was diluted,10- and 20-fold.The montmorillonite-DNA complex required at least 100-fold dilution before amplification could be detected.DNA bound on goethile was amplified irrespective of whether the complex was used directly,or diluted 10- and 20-fold.The amplification of mineral-bound plasmid DNA by PCR is,therefore,markedly influenced by the type and concentration of minerals used.This information is of fundamental importance to soil molecular microbial ecology with particular reference to monitoring the fate of genetically engineered microorganisms and their recombinant DNA in soil environments.     

Arsenic uptake and transport of Pteris vittata L. as influenced by phosphate and inorganic arsenic species under sand cu｜ture

In order to understand the similarity or difference of inorganic As species uptake and transport related to phosphorus in As-hyperaccumulator, uptake and transport of arsenate (As(Ⅴ)) and arsenite (As(Ⅲ)) were studied using Pteris vittata L. under sand culture. Higher concentrations of phosphate were found to inhibit accumulation of arsenate and arsenite in the fronds of P. vittata. The reduction in As accumulation was greater in old fronds than in young fronds, and relatively weak in root and rhizome. Moderate increases, from 0.05 to 0.3 mmol/L, in phosphate reduced uptake of As(Ⅲ) more than As(Ⅴ), while the reverse was observed at high concentrations of phosphate (≥ 1.0 mmol/L). Phosphate apparently reduced As transport and the proportion of As accumulated in fronds of P. vittata when As was supplied as As(Ⅴ). It may in part be due to competition between phosphorus and As(Ⅴ) during transport. In contrast, phosphate had a much smaller effect on As transport when the As was supplied as As(Ⅲ). Therefore, the results from present experiments indicates that a higher concentration of phosphate suppressed As accumulation and transport in P. vittata, especially in the fronds, when exposure to As(Ⅴ); but the suppression of phosphate to As transport in the root or rhizome may be insignificant when P. vittata when exposure to As(Ⅲ) under sand culture conditions. The finding will help to understand the interaction of P and As during their uptake process in P. vittata.