沱江的水生昆虫与水质污染

一、前言水生昆虫是各类淡水水体中底栖大型无脊椎动物(简称底栖动物)的主要组成部分,一般情况下,水生昆虫无论在种类或数量方面均在各类底栖动物中居首位。水生昆虫不仅是多种经济鱼类特别是底层鱼类如鲤、鲫、青鱼等的天然优良饵料,而且在水体环境保护方面也起着重要的作用。部分水生昆虫能摄食水体底部沉积的有机物质,在加速水体内的物质循环、促进水体的自净方面起着积极的作用;在环境水质系统监测及评价中,还可根据水生昆虫的种群结构、数量分布及其变动情况等资料来确定水质污染状况。     

水体底泥对污染物的吸附-解吸机理的研究

水体底泥污染已经成为世界范围内的一个重要的环境问题,其污染物主要通过大气沉降、废水排放、雨水淋溶冲刷等进入水体,最后沉积到底泥中并逐渐富集,使底泥受到严重污染。吸附-解吸是底泥污染的重要过程,为了控制水体底泥污染,对底泥对各种污染物的吸附-解吸机理及其影响因素的研究显得极其重要。本文总结了底泥中氮、磷和重金属等的吸附-解吸的影响因素及机理,对今后水体底泥污染方面的研究具有重要意义。     

黑龙滩水库水体生态系统酶活力及其生态学意义研究

本文黑龙滩水库水体生态系统中脲酶与磷酸酶活力及其与多种水质参数之间的关系进行了研究，结果表明：（１）酶活力与水质，水温变化呈出现一致的动态变化规律。（２）黑龙滩水库水体中脲酶来源与水生生物关系不大，而磷酸酶主要来自浮游植物和水生细菌。（３）水体中脲酶活力受水中总氮浓度瓣影响，而磷酸酶活力不受水中磷酸盐的抑制。     

重金属在水体中的化学状态、危害及其 防治对策

本文对目前研究最多的汞、铬、镉、铅和砷等重金属,详细分析了它们在水体中的迁移转化、价态变化、吸附与解吸附作用、吸附和共沉淀作用等动态过程;简要地阐述五种重金属对水体的污染给人体带来的危害;重点讨论了对水体重金属污染采取控制与消除土壤污染源、含重金属工业废水的排放和生物修复技术等防治对策。     

天然水体的底泥耗氧

天然水体中溶解氧的浓度是判断水质好坏的重要指标,是维持水体生态平衡的核心。它的产生和消耗问题历来为环境保护工作者及生态学家所关注。当溶解氧被过量消耗时可使水体出现氧亏。水生生物的呼吸、BOD耗氧和底泥耗氧等均是产生氧亏的重要原因。在某些水体中,底泥耗氧在总耗氧中所占的比重是相当大的(据Hans & Irvine(1968)报道,这个比例可高达50％以上)底泥还可起到     

陆地生态系统中汞的迁移与富集研究的重要意义

本文论述了汞的环境污染性质，本底地区的污染状况，水生生态系统和陆地生态系统中汞瓣迁移特征，并从汞的污染源分布，农业活动，全球变化等方面指出了开展陆地生态系统中汞的过移与富集研究的必要性。     

四川省环境中的汞

本文较系统地报道了四川省地面水环境（河，湖原水，过滤水，沉积物），土壤，大气降水及生物－鱼体中的含量及分布特点，得出四川省环境中的汞与国内外相比属于罗低水平，地面水环境中汞的含量及溶解态汞由川东南向川西北递减，土壤中汞的含量与土壤类型，成土母质，降水条件等相关，鱼类对河水中汞有较强的富集能力，大气降水是四川省环境中汞的来源之一。文章还研究了汞的水环境容量，指出汞是四川省水环境较为脆弱的重要因素之一     

水库汞污染研究进展

汞污染是水库环境存在的一个重要问题，本文概述了目前水库汞污染现状、汞的存在形态、汞的迁移转化过程及其动力学模型的研究进展，指出了不足之处，以促进下一步研究。     

我国节能灯行业推行清洁生产的问题及措施研究

清洁生产是解决节能灯推广过程中汞污染问题的最佳途径,然而节能灯行业在清洁生产开展过程中存在一系列的问题.通过文献研究和实地调研,对目前节能灯行业推行清洁生产存在的问题进行了分析和总结,并针对这些问题,从国家、社会和企业不同层面提出了相应的建议与措施.     

富营养化水体中底泥释磷的影响因素及其释放机理

磷是湖泊富营养化的主要限制因子,本文综述了沉积物中磷的赋存形态,释放机理及其影响因素.内源磷的赋存形态主要分为铝磷、铁磷、钙磷及有机磷.磷释放受pH值、溶解氧、生物、温度、扰动5种因素影响.对富营养水体内源磷释放的影响因素及其机理进行研究可为富营养化水体的治理提供理论依据.     

Regional differences in mercury levels in aquatic ecosystems: A discussion of possible causal factors with implications for the Tennessee river system and the Northern Hemisphere

Concern about mercury pollution from atmospheric deposition has risen markedly in the last decade because of high levels of mercury in freshwater fish from relatively pristine waters. Whereas high concentrations have been found principally in Canada, the northern United States, and Scandinavia, they have also recently been observed throughout much of Florida. Recent surveys of the Tennessee River system, however, have found no locations where fish levels exceed EPA guidelines for fish consumption. This paper evaluates a number of factors that may cause certain regions in the northern hemisphere to experience unacceptable fish mercury levels while other regions do not. Relevant regional differences include: (1) Waters of the Tennessee River system are generally nonacidic (pH>6) and well buffered, whereas 16%, 22%, and 40% of the lakes in upper Midwest, Northeast, and Florida, respectively, have acid-neutralizing capacities below 50 μeq/liter. Acidity correlates highly with fish mercury levels in a number of lake surveys, and experimental manipulations of acidity have significantly raised fish mercury levels. (2) The ratio of land area to water surface area in the Tennessee Valley averages about 30, whereas it is 15 in the upper Midwest and 6 in Florida. Low ratios allow mercury in precipitation to be directly deposited to aquatic bodies, without an opportunity for the mercury to be sequestered by terrestrial ecosystems. (3) Stream organic matter concentrations in Florida, the upper Midwest, and Sweden are 2–10 times those in the Tennessee Valley. Mercury binds strongly to organic matter, and organic matter transport in runoff is a major pathway by which mercury enters aquatic ecosystems.     

大气汞的时空分布研究进展

大气汞是汞全球循环的组成部分，探索汞在大气中的时空分布对于研究其地球化学循环具有重要意义。本文综述了大气汞时空分布的研究现状，主要包括大气汞的来源，形态分布，空间分布度时间分布。研究表明，大气汞具有扩散范围广，空间变异大，时间变化规律性强的特点，同时还指出扩大时空分布研究范围和建立污染和预测模型是未来的研究重点。     

Biological effects of wood ash application to forest and aquatic ecosystems

The present review aims to summarize current knowledge in the topic of wood ash application to boreal forest and aquatic ecosystems, and the different effects derived from these actions. Much research has been conducted regarding the effects of wood ash application on forest growth. Present studies show that, generally speaking, forest growth can be increased on wood ash-ameliorated peatland rich in nitrogen. On mineral soils, however, no change or even decreased growth have been reported. The effects on ground vegetation are not very clear, as well as the effects on fungi, soil microbes, and soil-decomposing animals. The discrepancies between different studies are for the most part explained by abiotic factors such as variation in fertility among sites, different degrees of stabilization, and wood ash dosage used, and different time scales among different studies. The lack of knowledge in the field of aquatic ecosystems and their response to ash application is an important issue for future research. The few studies conducted have mainly considered changes in water chemistry. The biotoxic effects of ash application can roughly be divided into two categories: primary and secondary. Among the primary effects is toxicity deriving from compounds in the wood ash and cadmium is probably the worst among these. The secondary effects of wood ash are generally due to its alkaline capacity and a release of ions into the soil and soil water, and finally, watercourses and lakes. Given current knowledge, we would recommend site- and wood ash-specific application practices, rather than broad and general guidelines for wood ash application to forests.     

Simultaneous radioassays of bacterial production and mercury methylation in the periphyton of a tropical and a temperate wetland

Laboratory radioassays were made to study mercury (Hg) methylation together with bacterial production in the periphyton of two aquatic macrophytes, the submerged Myriophyllum spicatum, from a constructed wetland in Sweden and the floating Eichhornia crassipes, from a eutrophied tropical lake in Brazil. Time course incubations were made by addition of (203)HgCl(2) and the methylmercury formed was extracted at pre-defined time intervals. Bacterial production ((14)C-leucine incorporation) was measured at the same time intervals, with plants removed from parallel incubations made with and without addition of cold HgCl(2). For E. crassipes, higher methylmercury production was observed at elevated bacterial production, whereas for M. spicatum, the bacterial production was significantly lower, and Hg methylation was below the detection limit. The combined results confirm the importance of microbial processes for Hg methylation, although other factors are known to influence this process in complex ways. The addition of Hg did not significantly influence bacterial production, while the incubation temperatures used (25 and 35 degrees C) resulted in different methylation rates. Radiotracer techniques for measurements of bacterial production such as (14)C-leucine uptake can provide useful insights into the Hg cycle in aquatic environments, and our data suggest that they may be used as a proxy of mercury methylation potentials.     

土-气界面汞交换特征研究进展

本文综述了20多年来汞在土壤-大气界面间交换的研究现状，包括汞在大气和土壤中的存在形态、大气汞的干湿沉降、土壤汞释放及影响因素的研究，分析其存在的问题，并提出了未来的研究重点。     

Public Lakes, Private Lakeshore: Modeling Protection of Native Aquatic Plants

Protection of native aquatic plants is an important proenvironmental behavior, because plant loss coupled with nutrient loading can produce changes in lake ecosystems. Removal of aquatic plants by lakeshore property owners is a diffuse behavior that may lead to cumulative impacts on lake ecosystems. This class of behavior is challenging to manage because collective impacts are not obvious to the actors. This paper distinguishes positive and negative beliefs about aquatic plants, in models derived from norm activation theory (Schwartz, Adv Exp Soc Psychol 10:221–279, 1977) and the theory of reasoned action (Fishbein and Ajzen, Belief, attitude, intention, and behavior: an introduction to theory and research, Addison-Wesley, Boston 1975), to examine protection of native aquatic plants by Minnesota lakeshore property owners. We clarify how positive and negative evaluations of native aquatic plants affect protection or removal of these plants. Results are based on a mail survey (n = 3,115). Results suggest that positive evaluations of aquatic plants (i.e., as valuable to lake ecology) may not connect with the global attitudes and behavioral intentions that direct plant protection or removal. Lakeshore property owners’ behavior related to aquatic plants may be driven more by tangible personal benefits derived from accessible, carefully managed lakeshore than intentional action taken to sustain lake ecosystems. The limited connection of positive evaluations of aquatic plants to global attitudes and behavioral intentions may reflect either lack of knowledge of what actions are needed to protect lake health and/or unwillingness to lose perceived benefits derived from lakeshore property.     

Hydrological,Physical, and Chemical Functions and Connectivity of Non‐Floodplain Wetlands to Downstream Waters: A Review

We reviewed the scientific literature on non‐floodplain wetlands (NFWs), freshwater wetlands typically located distal to riparian and floodplain systems, to determine hydrological, physical, and chemical functioning and stream and river network connectivity. We assayed the literature for source, sink, lag, and transformation functions, as well as factors affecting connectivity. We determined NFWs are important landscape components, hydrologically, physically, and chemically affecting downstream aquatic systems. NFWs are hydrologic and chemical sources for other waters, hydrologically connecting across long distances and contributing compounds such as methylated mercury and dissolved organic matter. NFWs reduced flood peaks and maintained baseflows in stream and river networks through hydrologic lag and sink functions, and sequestered or assimilated substantial nutrient inputs through chemical sink and transformative functions. Landscape‐scale connectivity of NFWs affects water and material fluxes to downstream river networks, substantially modifying the characteristics and function of downstream waters. Many factors determine the effects of NFW hydrological, physical, and chemical functions on downstream systems, and additional research quantifying these factors and impacts is warranted. We conclude NFWs are hydrologically, chemically, and physically interconnected with stream and river networks though this connectivity varies in frequency, duration, magnitude, and timing.     

Photocatalytic Production of Methane and Hydrogen Through Reduction of Carbon Dioxide with Water Using Titania Pellets

This paper presents an experimental study on employing a pellet form of catalyst in photo-reduction of carbon dioxide with water. Water was first absorbed into titania pellets. Highly purified carbon dioxide gas was then discharged into a reactor containing the wet pellets, which were then illuminated continuously for 65 hours using UVC lamps. Analysing the products accumulated in the reactor confirmed that methane and hydrogen were produced through photo-reduction of carbon dioxide with water. No other hydrocarbons were detected. Increasing the temperature in the reactor has showed little change on the amount of methane produced.     

Establishing aquatic restoration priorities using a watershed approach

Since the passage of the Clean Water Act in 1972, the United States has made great strides to reduce the threats to its rivers, lakes, and wetlands from pollution. However, despite our obvious successes, nearly half of the nation's surface water resources remain incapable of supporting basic aquatic values or maintaining water quality adequate for recreational swimming. The Clean Water Act established a significant federal presence in water quality regulation by controlling point and non-point sources of pollution. Point-sources of pollution were the major emphasis of the Act, but Section 208 specifically addressed non-point sources of pollution and designated silviculture and livestock grazing as sources of non-point pollution. Non-point source pollutants include runoff from agriculture, municipalities, timber harvesting, mining, and livestock grazing. Non-point source pollution now accounts for more than half of the United States water quality impairments. To successfully improve water quality, restoration practitioners must start with an understanding of what ecosystem processes are operating in the watershed and how they have been affected by outside variables. A watershed-based analysis template developed in the Pacific Northwest can be a valuable aid in developing that level of understanding. The watershed analysis technique identifies four ecosystem scales useful to identify stream restoration priorities: region, basin, watershed, and site. The watershed analysis technique is based on a set of technically rigorous and defensible procedures designed to provide information on what processes are active at the watershed scale, how those processes are distributed in time and space. They help describe what the current upland and riparian conditions of the watershed are and how these conditions in turn influence aquatic habitat and other beneficial uses. The analysis is organized as a set of six steps that direct an interdisciplinary team of specialists to examine the biotic and abiotic processes influencing aquatic habitat and species abundance. This process helps develop an understanding of the watershed within the context of the larger ecosystem. The understanding gained can then be used to identify and prioritize aquatic restoration activities at the appropriate temporal and spatial scale. The watershed approach prevents relying solely on site-level information, a common problem with historic restoration efforts. When the watershed analysis process was used in the Whitefish Mountains of northwest Montana, natural resource professionals were able to determine the dominant habitat forming processes important for native fishes and use that information to prioritize, plan, and implement the appropriate restoration activities at the watershed scale. Despite considerable investments of time and resources needed to complete an analysis at the watershed scale, the results can prevent the misdiagnosis of aquatic problems and help ensure that the objectives of aquatic restoration will be met.     

滨江湖泊湿地生态旅游开发潜力与发展规划——以西凉湖为例

湿地生态旅游对保护湿地资源和促进区域可持续发展具有极其重要的意义。通过构建湿地生态旅游评价指标体系,采用层次分析法确定指标权重,以西凉湖为例对滨江湖泊湿地生态旅游资源进行了评价。结果表明,西凉湖旅游开发目前尚处在起始阶段,综合得分较低,但由于生态环境状况良好,加之便利的交通条件,因此具有较大的开发潜力。根据所在区域近五年的旅游客源变化,对旅游客源市场进行了预测。结果表明,未来五年旅游客源市场将进入快速增长期,成为推动湿地生态旅游快速发展的潜在动力。在此基础上,进一步为西凉湖湿地生态旅游总体发展拟定了规划方案和对策建议。