水体悬移质对重金属吸附规律研究——以长江宜昌段为例

随着长江三峡工程的建设 ,上游来水的流速在此减缓 ,随江水而下的大量泥沙在此沉淀 ,将使坝下 (长江中下游 )水中的悬移质浓度降低、粒径改变 ,从而改变水环境容量。利用长江宜昌江段的周年悬移质样及水样 ,研究了悬移质对重金属 (铜、锌、铅、镉及铬 )的吸附特征。结果表明 ,悬移质对上述金属的吸附可用Freundlich型及Langmuir型等温式较好进行拟合 ;当较高浓度的金属污染物排入江水后 ,在吸附及沉淀的共同作用下 ,浓度明显降低 ;单位悬移质的吸附量随悬移质浓度降低而上升 ,但总吸附量降低 ,从而导致水中的金属污染物的平衡浓度升高。所得结果为预测水环境容量提供了依据     

Investigation of metallothionein level,reduced GSH level,MDA level,and metal content in two different tissues of freshwater mussels from Atatürk Dam Lake coast,Turkey

Atatürk Dam Lake is one of the important freshwater ecosystems in the world in terms of the size of the surface area and the biodiversity. The objective of this study was to determine the effects of metal pollution in the Atatürk Dam Lake on some biochemical markers in the gills and digestive glands of mussels (Unio mancus). Mussel samples were collected in July-2018 from four stations. The metal residues (Cd, Cu, Pb, Zn, and Ni) in the tissues were determined by ICP-MS. The MT, reduced GSH, and MDA levels were analysed using the proposed spectrophotometric methods. According to the results, toxic metals such as Cd and Pb in both tissues were determined mostly in mussels collected from St1. The highest MT and MDA levels in the gills were determined in St3 and St2 respectively, while the highest MT and MDA levels in the digestive glands were determined in St1. Although there was no significant difference in the reduced GSH level in the gills among the stations, the highest reduced GSH level in the digestive glands was determined in St4. These results indicated that mussels are appropriate sentinel organisms for metal contamination with effects on oxidative stress and metal exposure biomarkers.     

ENVIRONMENTAL IMPACT MITIGATION UNDER THE CLEAN WATER ACT AND THE NATIONAL ENVIRONMENTAL POLICY ACT: THE CASE OF TWO FORKS DAM1

ABSTRACT: The role of environmental mitigation in permitting decisions under Section 404 of the Clean Water Act and the National Environmental Policy Act is examined, addressing the extent to which compensatory mitigation is acceptable. The role of mitigation is examined both generically and specifically: first in the requirements of the Clean Water Act and NEPA, and then in the case study of the proposed Two Forks Dam. In both cases, the paper describes dual purposes of environmental protection legislation and mitigation: to protect the biophysical environment and maintain associated human values. Mitigation is found to be sometimes necessary and acceptable as compensation for unavoidable impacts of project development. However, the Two Forks case exemplifies that compensatory mitigation has also been employed as a mechanism to facilitate project development when practicable alternatives entailing less environmental impact are available. Acceptance of compensatory mitigation in such cases violates both the Guidelines of the Clean Water Act and the intent of that Act and NEPA to protect the biophysical environment and human welfare. A recent memorandum of agreement between the Corps and the EPA clarifies this policy, and suggests that permit applications which rely on compensatory mitigation when impacts are available may be denied.     

A river might run through it again: criteria for consideration of dam removal and interim lessons from California

Resource managers are increasingly being challenged by stakeholder groups to consider dam removal as a policy option and as a tool for watershed management. As more dam owners face high maintenance costs, and rivers as spawning grounds for anadromous fish become increasingly valuable, dam removal may provide the greatest net benefit to society. This article reviews the impact of Endangered Species Act listings for anadromous fish and recent shifts in the Federal Energy Regulatory Commission's hydropower benefit-costs analysis and discusses their implications for dam removal in California. We propose evaluative criteria for consideration of dam removal and apply them to two case studies: the Daguerre and Englebright Dams on the Yuba River and the Scott and Van Horne Dams on the South Eel River, California.     

三峡库区土壤中有效态微量元素含量的区划

本文建立了三峡库区土壤中有效态微量元素含量的区划原则。根据确立的有效态微量元素含量丰缺的指标，运用等值线图法，采用微机处理，最后将库区划分为八个土壤亚区。     

Geographic information systems and environmental impact assessment

The analytical structure of environmental impact assessment is continually changing as the applicability of established techniques from other fields and the development of novel methods become known. This paper illustrates the applicability of using existing data bases, through a geographic information system, for theex ante evaluation of land use disruption. More specifically, the Canada Geographic Information System was employed to retrieve, to analyze, and to produce land capability statistics and land use maps for the proposed Glengowan dam and reservoir.     

城市防洪堤坝适时适度维护的经济决策方法

本文应用最优控制理论，提出了城市防洪堤坝适时适度维护的经济决策模型。在一定条件下，给出堤坝最优反馈维护决策方法，并给出了一个简单的算例，说明了该法的应用和经济效益。     

基于能值分析的大坝生态效应评价——以尼尔基大坝为例

能值分析可提供客观真实的统一量化平台,在自然、经济系统整合分析方面具有显著优越性.将能值分析方法引入大坝生态效应评价,提出基于能值分析的大坝生态效应评价概念框架,绘制库区生态系统能值流图,构建包括生态系统运行效率、生态系统组织结构、生态系统功能维持和生态系统环境安全4方面共9个指标的能值综合评价指标体系.对尼尔基大坝建设前后库区生态系统变化进行对比性评价,结果表明,生态系统的运行效率、功能维持能力有较大提升,组织结构出现不平衡,环境负荷较高,可持续发展能力受损,需减少因流域水土流失与塌岸导致的库区泥沙淤积,以控制不可更新资源能值输入.     

Dissolved heavy metal concentrations of the Kralkızı, Dicle and Batman dam reservoirs in the Tigris River basin,Turkey

Water samples were collected at monthly intervals during 1 year of monitoring from Kralk?z?, Dicle and Batman dam reservoirs in the Tigris River basin to assess the concentrations of dissolved heavy metals and to determine their spatial and seasonal variations. The results indicated that dissolved heavy metal concentrations in the reservoirs were very low, reflecting the natural background levels. The lowest total metal concentrations in the three dam reservoirs were detected at sampling sites close to the dam wall. However, the highest total concentrations were observed at sites, which are located at the entrance of the streams to the reservoirs. Fe, Cr and Ni were the most abundant elements in the reservoirs, whereas Cd and As were the less abundant. The mean concentrations of dissolved metals in the dam reservoirs never exceeded the maximum permitted concentrations established by EC (European Community), WHO and USEPA drinking water quality guidelines. All heavy metals showed significant seasonal variations. As, Cd, Cr, Cu, Fe, Ni and Pb displayed higher values in the dry season, while higher values for Zn in the wet season. Cluster analysis grouped all ten sampling sites into three clusters. Clusters 1 and 2, and cluster 3 corresponded to relatively low polluted and moderate polluted regions, respectively. PCA/FA demonstrated the dissolved metals in the dam reservoirs controlled by natural sources.     

三峡水库库首地区大气降水化学特征

2009年6月~2010年7月对三峡水库库首地区大气降水的水化学特征进行了连续1年的研究.结果表明:三峡库首地区大气降水酸化严重,超过1/3的降水pH值低于4.5.SO42-和NO3-为降水中的最主要阴离子,雨量加权平均值分别为161.90,65.24μeq/L,二者分别占无机阴离子总量的66%、27%.Ca2+是最主要的阳离子,离子含量在8.89~932.90μeq/L之间,雨量加权平均浓度为108.34μeq/L,占无机阳离子总量的43%.季节变化分析表明,夏秋季节降水酸化严重,而冬春季节降水酸化不明显.不同季节相对酸度(FA)和中和因子(ＮＦ)分析表明,冬春季节的降水酸度主要受Ca2+离子的中和作用控制.主要离子来源分析表明,SO42-和NO3-主要来源于化石燃料燃烧,Na+、Cl-主要为海源输入的贡献,而Ca2+、Mg2+主要来源于陆壳颗粒物质.