首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
郑州市农村饮用水安全评价   总被引:2,自引:0,他引:2  
通过对郑州市农村饮用水安全进行了较为详细的评价.此次评价工作首先对全市每个行政村、自然村、自然片的饮水水源、饮水困难情况等进行了调查和水质抽检,共布设水质取样点255个.评价结果为:郑州市总人口为4 174 866人,饮水不安全人数为1 540 359人,占农村总人口的38.03%.饮水不安全主要是由饮用水水质引起的,包括氟水、苦咸水和污染水.水量、用水方便程度、供水保证率对其有一定的影响,但作用比较小.表2,参5.  相似文献   

2.
再生水回灌地下水环境安全风险评价技术方法研究   总被引:2,自引:0,他引:2  
再生水回灌是水资源管理的一条有效途径,也是污水再生利用的重要发展方向。然而,当再生水以农灌、土壤含水层处理(SAT)、河湖入渗和井灌等方式进行地下水回灌时,不可避免的会在回补地下水的过程中造成对地下水环境的污染风险。针对不同回灌方式建立适用于我国的再生水回灌地下水环境安全风险评价技术体系至关重要。借鉴国内外地下水污染风险评价方法,综合分析再生水回灌对地下水产生风险的关键环节,采用层析分析法,从回灌水特征污染物特性、回灌区地下水固有脆弱性以及回灌工程布设方式3个方面,针对地表灌溉、河湖入渗和井灌3种回灌方式,建立了包含污染物浓度水平、分配系数、溶解度、半衰期、半致死剂量、地下水埋深、降雨入渗补给量、地形坡度、土壤介质、包气带介质、含水层介质、含水层厚度、回灌强度、回灌周期、回灌水停留时间以及取水点与回灌点水平距离16个指标在内的风险评价指标体系。在此基础上,结合地下水使用功能,以20个典型再生水回灌场地调研结果和160种再生水回灌地下水污染风险因子物化特性为数据基础,对各指标进行了风险水平的划分,基于聚类分析法,采用各指标风险指数相乘的风险表征方法计算总风险指数,构建了再生水回灌地下水环境安全风险评价技术方法。该方法有效的避免了指标权重计算的主观性,并且能够直观的找出导致风险的主要因素。结果表明:利用建立的风险评价技术方法可将我国再生水回灌地下水环境安全风险划分为3级,风险值〈5为一级,风险值在5-15之间为二级,风险值〉15为三级。在某再生水回灌场地的应用表明,该回灌区地下水环境安全风险为二级,同时得出回灌水特征污染物特性指标是造成该回灌区地下水环境风险的主要因素。  相似文献   

3.
地下水污染形势严峻,脆弱性评价是区域地下水资源保护和污染防治的重要前提。平原河网地区地表水系复杂,城市化程度高,常规DRASTIC模型难以准确评价其地下水脆弱性。文章根据平原河网地区特点,建立了一套包括地下水埋深、净补给量、含水层介质、土壤带介质等7个本质脆弱性指标和地表水系、地下工程2个特殊脆弱性指标在内的方法体系,并以上海市金山区为例进行了地下水脆弱性评价。结果表明,地下水埋深、地下水净补给量和含水层厚度是影响评价区域本质脆弱性的主要指标,3者评价得分均在3~9之间,其中地下水埋深和净补给量得分为6的区域面积最大,分别为219.35 km~2和187.74 km~2,含水层厚度以得分为8的区域面积最大,达到286.01 km~2。金山区地表水系分布广泛,加上水质较差,其河流水质、河网密度、河流等级的脆弱性评价得分大多为6~10,相比地下工程,这3个指标对该区域的特殊脆弱性影响更大。金山区地下水综合脆弱性评价中,三级和四级面积较大,分别为274.49 km~2和157.82 km~2,两者面积之和占整个评价区的67.93%;三级区域广泛分布于整个评价区范围之内,五级脆弱性零星分布于南部和中部区域。评价结果与实际调研情况相符,能够真实地反映评价区浅层地下水脆弱性程度。该方法体系可为区域地下水环境管理及污染防治工作提供技术支撑和科学依据。  相似文献   

4.
为阐明人类活动影响下廊坊市区地下水环境状况,2015年在研究区进行现场调查采集并分析了深浅层(包含3组地表水)水样50组,测试指标包括有机指标(30项)和无机指标(31项).利用基于分类指标的单指标综合评价法进行本区地下水质量评价.结果表明,研究区地下水质量综合评价结果较差,深层地下水相比浅层地下水水质较好;从分类指标来看,对区域地下水质量影响最大的为无机毒理指标,其次为一般化学指标,毒性(类)金属指标及有机指标对地下水质量影响很小,各项指标主要影响浅层地下水;单项组分分析表明,深、浅层地下水水质贡献指标相差较大,其中影响浅层地下水水质的主要指标有总硬度、"三氮"、砷、氟化物、铁锰等,深层地下水影响指标主要为氟化物(50.0%),其次为砷(13.6%);有机组分少量指标检出但无超标.分析认为原生水文地质环境和人类活动是影响该区地下水质量的主要因素,是导致地下水中污染组分异常的根源.  相似文献   

5.
经对呼和浩特盆地西部深层水1000km ̄2、浅层水600km ̄2范围内进行水质检测分析,发现其深、浅两层地下水均富砷,浅水有18.8%、深水有40.9%的水样砷含量超过国家饮用水卫生标准。测得水体总砷中以三价砷为主。溶解氧含量低,铁、锰离子为痕量,硫酸盐、亚硝酸盐氮含量也均低,同时有低硒、高氟现象,提示该地区为富含有机质的强还原环境,有利于砷的迁移富集,对饮水型砷中毒起着促进作用。  相似文献   

6.
中国饮水型砷中毒区的水化学环境与砷中毒关系   总被引:3,自引:0,他引:3  
中国各饮水型砷中毒区的水化学特点受沉积环境和气候因素所控制,砷中毒的流行和发病程度与其地下水的水化学环境、水中砷的形态和价态有密切联系。在实地考察监测和对台湾、新疆、内蒙古、山西、吉林饮水型砷中毒病区环境和地下水水化学特征总结的基础上,系统分析了饮水水源中总As、As(III)、甲基胂、腐植酸与砷中毒的关系,揭示了不同病区病情差异的原因。研究表明,除台湾外,各砷中毒区均分布在干旱半干旱区;各病区多分布在沉积盆地中心或平原内相对低洼的地带,饮用的地下水均取自中新生代地层;砷中毒病情不仅与总砷含量有明显的剂量-效应关系,还与As(III)和甲基胂的浓度直接相关。台湾、内蒙古和山西病区地下水为富含有机质的复杂还原环境,水中不仅As(III)含量高,且检出有机物、腐植酸和甲基胂,新疆和吉林病区地下水为以无机砷中As(V)为主的氧化环境,吉林病区未检测出甲基胂,这是新疆与吉林病区患病率较低的主要原因。研究成果可为区域防病改水、砷中毒的预报提供重要技术支撑。  相似文献   

7.
柳凤霞  史紫薇  钱会  冯文文 《环境化学》2019,38(9):2055-2066
研究地下水的水化学特征演化规律及水质评价,对地下水水资源保护和可持续开发利用具有重要意义.本文根据银川地区1991—2016年地下水水质监测资料,运用经典统计学、Piper三线图解法、Gibbs图解法、离子比值法对研究区地下水水化学特征及演化规律进行分析,并利用模糊综合评价法对研究区62个水样点进行水质评价.结果表明,26年来研究区地下水化学组分未发生明显变化,为偏碱性硬水.多年地下水中各离子含量排序一致,阳离子含量排序为:Na~+Mg~(2+)Ca~(2+)K~+,阴离子含量排序为HCO~-_3 Cl~-SO■.当前银川地区地下水水质基本满足生活饮用水的标准,山前冲洪积平原地区水质良好,丰登镇及北部地区水质最差,部分井孔的TDS大于2000 mg·L~(-1).地下水水质在1996年最差,自2006年以来得到明显改善.研究区地下水化学组分及水质受到水文地质条件、蒸发浓缩作用、岩石风化作用、补给水成分及人类活动的综合影响.  相似文献   

8.
大安市苏打碱土区地下水质与灌溉盐渍化风险评价   总被引:1,自引:0,他引:1  
测试了吉林省大安市苏打碱土区6—7、20—30和60—70m^3种深度地下水的基本化学特征,对利用地下水灌溉可能引起的土壤盐化、碱化和盐碱化问题及其灌溉适宜性进行了评价。结果表明,各深度地下水均具有不同程度的苏打化特征,地下水中普遍含有较多NaHCO3;30m深度以内地下水中含有较多HCO3^-和Cl^-,用其作为灌溉水源存在潜在的盐化和碱化双重威胁;从各盐化和碱化指标看,该区60m深度以下的地下水质较好,作为灌溉用水不会产生盐渍化风险。30m深度以内的地下水均不适合灌溉。  相似文献   

9.
平寨水库是黔中水利枢纽唯一源头水库,其水环境质量直接影响包括安顺和贵阳在内的整个黔中地区的农业灌溉和城市居民饮水安全.为了深入分析平寨水库的水环境质量状况,于2018年1月、5月、8月和11月对平寨水库7个监测断面水样进行采集,测定TP、TN、NH_3-N、COD和DO等5个监测指标,基于分形维数权重建立水质评价模型,对平寨水库水环境质量状况进行综合评价,并与模糊综合评价法和综合污染指数法进行对比分析.结果表明,平寨水库TP、NH_3-N和DO浓度均达到Ⅱ类水质标准,TN和COD浓度均超过Ⅱ类水质标准,主要为Ⅳ类和Ⅴ类,是主要污染因子;TP、NH_3-N和COD浓度在春季最高,TN浓度在秋季最高,DO浓度在冬季最低.平寨水库全年水质类别主要为Ⅲ类和Ⅳ类,在28个监测序列中,水质达到水功能区划标准的仅21.43%;平寨和跨桥断面水质最差,扈家河断面水质相对最好;春、秋季水质最差,冬、夏季次之.分形插值模型不仅能评价水质状况,而且能对同等级水质状况的优劣进行排序,具有较高的分类精度;其评价结果更客观、有效,在水质综合评价中具有良好的适用性.  相似文献   

10.
滤速对慢滤池深度处理生活污水的影响   总被引:1,自引:0,他引:1  
曹相生  刘杰  孟雪征  王玥 《生态环境》2010,19(8):1947-1950
为进一步提高再生水水质,将慢滤池用于污水二级处理出水的进一步处理。选取浊度、COD、色度和细菌总数4个指标,利用实验室小试装置,研究了0.1、0.3、0.5m/h这3种滤速下慢滤池的性能。结果表明,滤速由0.1m/h升高至0.3m/h时,慢滤池出水水质略有下降。而滤速由0.3m/h升高至0.5m/h时,慢滤池出水水质下降显著。滤速小于等于0.3m/h时,慢滤出水浊度、COD、色度和细菌总数平均为0.4NTU、25.9mg/L、14.9°、5×10^3CFU/mL。慢滤对这4个指标的平均去除率分别为78.6%、36.0%、34.0%、62.3%。为获得优良的水质,建议慢滤池用于污水深度处理时,滤速宜小于0.3m/h。但实际工程中,用户对再生水水质要求不高时,则可适当增大慢滤池滤速。  相似文献   

11.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

12.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

13.
Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.  相似文献   

14.
Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.  相似文献   

15.
Abstract: The last century has seen the ascendance of a core economic model, which we will refer to as Walrasian economics. This model is driven by the psychological assumptions that humans act only in a self‐referential and narrowly rational way and that production can be described as a self‐contained circular flow between firms and households. These assumptions have critical implications for the way economics is used to inform conservation biology. Yet the Walrasian model is inconsistent with a large body of empirical evidence about actual human behavior, and it violates a number of basic physical laws. Research in behavioral science and neuroscience shows that humans are uniquely social animals and not self‐centered rational economic beings. Economic production is subject to physical laws including the laws of thermodynamics and mass balance. In addition, some contemporary economic theory, spurred by exciting new research in human behavior and a wealth of data about the negative global impact of the human economy on natural systems, is moving toward a world view that places consumption and production squarely in its behavioral and biophysical context. We argue that abandoning the straightjacket of the Walrasian core is essential to further progress in understanding the complex, coupled interactions between the human economy and the natural world. We call for a new framework for economic theory and policy that is consistent with observed human behavior, recognizes the complex and frequently irreversible interaction between human and natural systems, and directly confronts the cumulative negative effects of the human economy on the Earth's life support systems. Biophysical economics and ecological economics are two emerging economic frameworks in this movement.  相似文献   

16.
Effects of Coffee Management on Deforestation Rates and Forest Integrity   总被引:1,自引:0,他引:1  
Knowledge about how forest margins are utilized can be crucial for a general understanding of changes in forest cover, forest structure, and biodiversity across landscapes. We studied forest‐agriculture transitions in southwestern Ethiopia and hypothesized that the presence of coffee (Coffea arabica)decreases deforestation rates because of coffee's importance to local economies and its widespread occurrence in forests and forest margins. Using satellite images and elevation data, we compared changes in forest cover over 37 years (1973–2010) across elevations in 2 forest‐agriculture mosaic landscapes (1100 km2 around Bonga and 3000 km2 in Goma‐Gera). In the field in the Bonga area, we determined coffee cover and forest structure in 40 forest margins that differed in time since deforestation. Both the absolute and relative deforestation rates were lower at coffee‐growing elevations compared with at higher elevations (?10/20% vs. ?40/50% comparing relative rates at 1800 m asl and 2300–2500 m asl, respectively). Within the coffee‐growing elevation, the proportion of sites with high coffee cover (>20%) was significantly higher in stable margins (42% of sites that had been in the same location for the entire period) than in recently changed margins (0% of sites where expansion of annual crops had changed the margin). Disturbance level and forest structure did not differ between sites with 30% or 3% coffee. However, a growing body of literature on gradients of coffee management in Ethiopia reports coffee's negative effects on abundances of forest‐specialist species. Even if the presence of coffee slows down the conversion of forest to annual‐crop agriculture, there is a risk that an intensification of coffee management will still threaten forest biodiversity, including the genetic diversity of wild coffee. Conservation policy for Ethiopian forests thus needs to develop strategies that acknowledge that forests without coffee production may have higher deforestation risks than forests with coffee production and that forests with coffee production often have lower biodiversity value. Efectos de la Administración Cafetalera sobre las Tasas de Deforestación y la Integridad de los Bosques  相似文献   

17.
As drivers of terrestrial ecosystems, humans have replaced large carnivores in most areas, and human influence not only exerts striking ecological pressures on biodiversity at local scales but also has indirect effects in distant corners of the world. We suggest that the multibillion dollar cashmere industry creates economic motivations that link western fashion preferences for cashmere to land use in Central Asia. This penchant for stylish clothing, in turn, encourages herders to increase livestock production which affects persistence of over 6 endangered large mammals in these remote, arid ecosystems. We hypothesized that global trade in cashmere has strong negative effects on native large mammals of deserts and grassland where cashmere‐producing goats are raised. We used time series data, ecological snapshots of the biomass of native and domestic ungulates, and ecologically and behaviorally based fieldwork to test our hypothesis. In Mongolia increases in domestic goat production were associated with a 3‐fold increase in local profits for herders coexisting with endangered saiga (Saiga tatarica).That increasing domestic grazing pressure carries fitness consequences was inferred on the basis of an approximately 4‐fold difference in juvenile recruitment among blue sheep (Pseudois nayaur)in trans‐Himalayan India. Across 7 study areas in Mongolia, India, and China's Tibetan Plateau, native ungulate biomass is now <5% that of domestic species. Such trends suggest ecosystem degradation and decreased capacity for the persistence of native species, including at least 8 Asian endemic species: saiga, chiru (Pantholops hodgsoni), Bactrian camel (Camelus bactrianus), snow leopard(Panthera uncia), khulan(Equus hemionus), kiang (E. kiang), takhi (E. przewalski), and wild yak (Bos mutus). Our results suggest striking yet indirect and unintended actions that link trophic‐level effects to markets induced by the trade for cashmere. Globalización del Mercado de Cachemira y la Declinación de Mamíferos Mayores en Asia Central  相似文献   

18.
The high conservational value of the lichen-rich vegetation and landscape of the marine foreland Ørkenen on the isle of Anholt is treated from a Danish as well as a European perspective. The sensitivity of the lichen-rich vegetation to physical disturbance is emphasized. The impact of invasive species such asPinus mugo as well as the effect of atmospheric deposition of nutrients on the heaths at Anholt is described. Considerations related to the development of a management plan for Ørkenen are presented.  相似文献   

19.
Summary The attraction of Old World leaf beetles in the genusAulacophora to kairomones and parakairomones which are effective lures for New WorldDiabrotica andAcalymma were investigated. Beetles captured on sticky traps baited with single and multicomponent lures were no different from the control traps for two species ofAulacophora. Yellow colored traps and squash blossoms are attractive toAulacophora beetles which detect sub-microgram quantities of cucurbitacins on silica gel. Leaf feeding behavior and flight activity data are correlated with varietal preference of threeAulacophora species. The common response byDiabrotica andAulacophora to cucurbitacins reinforces the two groups' coevolutionary association with the Cucurbitaceae. The apparent lack of a common response toCucurbita blossom volatiles suggests recent evolutionary pathways are substantially different for these two groups of beetles.  相似文献   

20.
Invasive non-native species are important drivers of ecosystem change, yet the driving forces of biological invasions themselves are poorly understood. Such information is essential to ensure policies focus on the most relevant drivers, and that future scenarios capture the full range of potential outcomes for invasive non-native species. I carried out a bibliometric analysis of articles published from 2000 to 2020 that address either invasive non-native species or biodiversity and ecosystem services and that also mention 1 or more drivers of ecosystem change. I examined 5 indirect drivers (demographic, economic, governance, sociocultural, and technological) and 6 direct drivers (climate change, invasive non-native species, land-use or sea-use change, natural hazards, pollution, and resource extraction). Using the Web of Science core collection of citation indexes, I undertook searches of article titles and keywords and retrieved 27,462 articles addressing invasive non-native species and 110,087 articles dealing with biodiversity or ecosystem services. Most research to date on biological invasions as well as on biodiversity and ecosystem services has focused on anthropogenic direct drivers of ecosystem change rather than indirect drivers. Yet currently, less than 18% of articles addressing biological invasions examined drivers of ecosystem change, a similar level to that found over 20 years ago for biodiversity or ecosystem services. Knowledge of the drivers of biological invasions is limited, emphasizes tractable drivers over those that require an interdisciplinary approach, and is biased toward developed economies. Drivers generally deemed important for biological invasions, such as governance and resource extraction, accounted for less than 2% of research effort. The absence of a systematic understanding of the forces that drive invasive non-native species and how they interact means that attempts to mitigate or forecast biological invasions are likely to fail. To address biological invasions requires a much better orientation of national and international research on drivers in relation to both their actual importance as well as their policy relevance.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号