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1.
对湖北省咸宁市某水库淤积物的富营养化和重金属元素进行了取样调查与分析,采用地质累积指数和潜在生态危害指数对淤积物中的重金属污染状况和生态风险进行评价。富营养元素的检测结果显示,总氮和总磷含量的分布大体呈现上游高下游低的趋势,淤泥试样的总氮和总磷含量明显高于砂样。重金属元素的检测结果显示,除含铅量外,上游区域的重金属元素含量明显高于下游区域。地质累积指数评价结果显示,咸宁市某水库中的Cd、Cu、Hg、Cr、As的污染程度主要集中处于无污染区域,而Pb的污染程度集中处于无污染-中度污染区域。潜在生态危害指数法的评价结果显示,咸宁市某水库中的重金属元素生态风险水平均较低,S7试样的潜在生态危害风险相对更大。围绕咸宁市某水库淤积泥、砂的资源化利用问题,提出了可用于农用土壤、工程建设用地、环境修复材料、路基填料以及建筑原材料等资源化利用途径。  相似文献   

2.
基于模糊数学模型的土壤肥力质量评价   总被引:1,自引:0,他引:1  
采取科学评价方法,客观准确评价土壤肥力质量,是解决土地整理区农业生产的关键手段。以利川市东城区为研究对象,对采集的土壤样品进行科学实验分析,测定有机质、碱解氮、速效磷、速效钾、pH值和黏粒含量等7项属性指标,采取博弈论组合赋权法确定指标的最优权重值,选用恰当的隶属函数模型求解各项指标的隶属度值,并结合土壤肥力综合指数法对研究区土壤肥力进行综合评价。结果表明,研究区土壤碱解氮和速效磷含量偏少,土壤肥力综合指数在0. 42左右,且变异较大,整体隶属中等水平,且有机质严重不足,故研究区应相应增施氮磷肥料和有机肥以提高土壤肥力质量。  相似文献   

3.
利用珠江三角洲地区1∶25万区域地下水污染调查评价项目所取得的水质数据,采用数理统计方法,在判断元素质量浓度分布类型的基础上,计算该地区卤族元素质量浓度的背景集中特征值和背景值范围,并对背景值统计特征及分布规律进行分析。结果表明,浅层地下水受人类活动影响较大,多呈偏态分布;地下水中卤族元素的分布主要受岩土性质、地下水径流条件、氧化还原环境的影响,另外,Cl、Br的背景质量浓度受海水入侵作用的影响明显,F的高背景质量浓度与温泉出露密切相关。对地下水中卤族元素质量浓度背景值的研究将为地方病防治工作提供重要科学依据。  相似文献   

4.
土壤肥力评价方法探讨   总被引:10,自引:0,他引:10  
总结了土壤肥力的评价方法,探讨了土壤肥力评价的流程。土壤肥力的评价流程如下:首先选择最小指标数据库,其次对指标进行标准化,最后将所有指标综合成一个土壤肥力指数。指标标准化时,根据土壤指标与作物生长之间的关系,可分为“S型曲线”、“反S型曲线和“抛物线型曲线”。评价方法包括多变量指标克立格法、土壤质量动力学方法、土壤质量综合评分法等。在某地区评价土壤质量时,要仔细查对各种土壤质量评价方法的优缺点,选出适合本地区土壤质量的评价方法。  相似文献   

5.
通过1∶250 000多目标区域地球化学调查、采样和化验,获得了阜阳市东南部地区表层、深层土壤中22项指标的土壤地球化学背景值、基准值等数据,研究其分布特征,并依据相应规范进行土壤质量评价。结果显示,与邻区(淮北-亳州)土壤基准值相比,N、Mn、I、Cr等8种元素(指标)土壤基准值略高,而P、MgO、S、Cd等8种元素(指标)则低于邻区;N、Corg和Mn土壤背景值高于邻区的土壤背景值;而P、CaO、MgO、S等8种元素(指标)土壤背景值低于邻区。土壤养分主要处于中等水平、土壤环境质量以清洁为主,仅存在少量轻微污染土壤,影响土壤环境的地球化学指标主要为Cd。区内土壤质量综合评价以优质等级为主,约占研究区总面积的76.33%;其次为良好等级,占研究区总面积的23.67%,就此提出了土地资源分质利用的建议。  相似文献   

6.
坡耕地水土流失严重,选取大理市洱源县永乐小流域研究了坡改梯工程前后土壤养分及土壤肥力变化状况,并对不同土层土壤肥力的变化进行比较分析。结果表明,在0~90 cm的土层内,土壤有机质和土壤全氮、全磷养分及土壤肥力的垂直变化特征明显,均表现为上层中层下层。随着坡改梯工程的实施,坡改梯初期、后期土壤养分及土壤肥力质量整体均呈上升趋势,其中全氮含量在坡改梯前后增加的变化规律相当明显。通过对比坡改梯前后土壤综合肥力指数增加变化幅度分析,表明坡改梯初期、后期两次改造土壤肥力增加变化幅度分别达12.8%、18.7%。坡改梯的实施对土壤养分的改善有明显作用,土壤肥力质量有一定提高。  相似文献   

7.
硒元素作为人体必需的微量营养元素之一,与人体健康密切相关。选取黄河下游滩区原阳段为研究区,通过采样分析获得该区表层及深层硒元素及镉、汞、铅、砷、铜、铬元素的含量,并对硒元素进行质量评价,结果表明:研究区表层土壤硒含量为0.022~1.232 mg/kg,平均值为0.448 mg/kg,深层土壤硒含量为0.081~2.570 mg/kg,平均值为0.945 mg/kg,总体上属于中等及高硒土壤;缺硒区域主要分布在研究区西部,硒含量较高区域则主要集中在研究区中部,且表层和深层硒元素分布范围一致;研究区硒含量主要受成土母质、土壤pH值和有机质含量的影响;研究区镉、汞、铅、砷、铜、铬元素含量较低,土壤环境质量整体良好。  相似文献   

8.
区域农田土壤水和氮素行为的模拟   总被引:10,自引:0,他引:10  
黄元仿  李韵珠  李保国  陈德立 《水利学报》2001,32(11):0087-0093
本文以华北平原为研究区域,根据第二次全国土壤普查资料,应用地理信息系统的方法(ARC/INFO),研究了土壤类型的区域分布,并得出了以72个典型土壤剖面为代表的华北平原土壤类型分布的概化图。通过对作物生长发育参数、土壤和气候资料的简化处理,将土壤水、热、氮联合模拟模型应用于区域农田土壤水、氮素行为的模拟计算。结果表明,通过模型计算与地理信息系统相结合,便于评价不同水氮管理、不同降雨年型条件下区域农田土壤水、氮素行为。通过以中等水氮处理为例的计算,评价了不同降雨年型所得到的水分利用效率(WUE)和氮素利用效率(NUE).区域内WUE明显在干旱年型下最高,湿润年型下最低,而NUE的规律相似但不太明显。各指标在区域上分布有一定的规律,与气候分异和土壤类型分异密切相关。  相似文献   

9.
<正>《河北省生态环境保护"十三五"规划》已经印发,规划明确指出,要建设京津冀生态环境支撑区,实施大气、水、土污染防治三大行动计划,全力改善环境质量。规划提出的目标是:到2020年,生态环境质量明显改善。生产和生活方式绿色、低碳水平上升,主要污染物排放总量大幅减少,空气质量明显好转。饮用水安全保障水平持续提升,污染严重水体较大幅度减少,地下水污染趋势得到有效遏制,近岸海域环境质量稳中趋好。全省土壤环境质量稳中向好,重点区域土壤污染加重趋势得  相似文献   

10.
以长三角中心区27个城市为研究实例,构建3个层次、20个指标的生态环境质量评价模型,运用熵值法与变异系数法组合赋权的综合指数法来测度生态环境质量综合指数。同时运用空间自相关来分析长三角中心区城市生态环境质量变动态势和空间分布格局。结果表明:(1)多阶段以来,生态环境质量准则层权重表现为"三升一降"的趋势,且权重差距逐渐减小,体现了经济、社会、环境协调发展的态势。(2)"十三五"以来,从市域上看,宣城市、台州市、南通市的生态环境质量较好,芜湖市、马鞍山市的生态环境质量较差;从省市域上看,上海市的生态环境质量较好,安徽省的生态环境质量较差。(3)研究区的生态环境质量呈现为显著的高-高或低-低集聚,研究期间Moran’s I呈现下降的趋势,显示出应加强生态环境质量空间的协调性。针对分析评价结果提出了相应的对策及建议,研究成果可为长三角中心区域的生态绿色一体化发展进程提供理论支撑。  相似文献   

11.
Call for Papers     
正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.  相似文献   

12.
根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。  相似文献   

13.
Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.  相似文献   

14.
The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.  相似文献   

15.
Cyanobacteria often dominate eutrophic lakes, outcompeting green algae that are required by fish and zooplankton. This study was undertaken to ascertain the impact of the cyanobacterium, Microcystis, on algal biodiversity. Under laboratory conditions, we found that the presence of Microcystis decreased phyla richness by 58%, phyla evenness by 47%, genera richness by 66% and genera evenness by 51%. Analysis by mixed anova s demonstrated a significant interaction between treatment and time and confirmed a significant reduction in richness and evenness of phyla and genera. We also conducted a phosphate restriction assay on the algae in Mason Lake (Irvine, CA, USA) and found that the threshold needed for algal growth there was 0.02 mg L?1 PO4. A pilot study was then conducted to test the effectiveness of the Blue Pro? water treatment facility in removal of this colonial organism from Mason Lake, in addition to removal of dissolved nutrients required for its growth. We measured a 97% reduction in Microcystis cells, a 72% reduction in chlorophyll‐a, and a 96% reduction in phosphate after just one 10 min cycle through the unit. Our study demonstrated that removal of Microcystis colonies may allow green algae to increase in numbers. This may improve algal biodiversity, which will benefit zooplankton and fishes.  相似文献   

16.
为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。  相似文献   

17.
The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L?1, the median total phosphorus was 0.29 mg L?1 and the median total nitrogen was 1.56 mg L?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.  相似文献   

18.
解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明:库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。  相似文献   

19.
簸箕李引黄灌区水沙分布及优化调度的经验   总被引:1,自引:0,他引:1  
灌区利用水沙观测所取得的资料和试验数据,运用水沙运动力学理论,总结分析和揭示了灌区水沙分布的规律和特点。在此基础上,结合灌区的实际运行情况,围绕减少骨干渠道的淤积进行探讨、研究,进而,优化水沙调度方案。该方案实施后,骨干渠道减旅伴效果明显,取得了成功的经验。  相似文献   

20.
小湾水库大坝防渗面板及其裂缝的加固处理   总被引:1,自引:0,他引:1  
小湾水库大坝防渗面板整体抗渗性能差,且存在多条裂缝,通过对面板钢丝网喷涂丙乳砂浆加固处理及其裂缝修补,大坝渗漏量明显减少,且左岸上灌浆廊道内及大坝下游坝面92~93 m高程下廊道入口处原有小股射流全部消失.  相似文献   

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