Variation of nutrient and metal concentrations in aquatic macrophytes along the Rio Cachoeira in Bahia (Brazil)

The use of cuprous fungicides in cocoa production in the southern part of the state of Bahia (Brazil) for decades has caused an accumulation of copper in various components of the cocoa plantations, and a contamination of regional freshwater ecosystems is suspected. Urban and industrial sources are supposed to contribute to water pollution and eutrophication of the Rio Cachoeira, the main river in this region. In order to study the metal contamination and nutritional status of this freshwater ecosystem, samples of the aquatic macrophytes Eichhornia crassipes and Pistia stratiotes were collected at seven sites along the river course. The samples were analysed for their copper, aluminium, chromium, nitrogen and phosphorus concentrations. The levels of heavy metals increased in the downstream direction, particularly in the roots of water hyacinth. A dramatic increase of nitrogen and phosphorus concentrations in water as well as in plant tissues was found in samples collected downstream from the city of Itabuna. Metal input and eutrophication were attributed to agricultural, industrial and urban sources in the region. Biomonitoring of the water quality using aquatic macrophytes as accumulative indicator plants is recommended in addition to chemical water analyses.     

Role of allochthonous carbon in the energy of terrestrial invertebrate communities at different distances from the Black Sea and a freshwater lake (Isotopic Evidence)

Isotopic analysis has become an important tool in the study of lateral links between ecosystems. The isotopic composition of carbon in terrestrial and aquatic primary producers can differ significantly, which provides an opportunity to identify the “marine” or “freshwater” carbon in the tissues of terrestrial animals. We measured the isotopic composition of C and N in tissues of soil invertebrates and estimated the proportion of “aquatic” carbon in the energy budget of terrestrial food webs at different distances from the Black Sea and a freshwater lake. Terrestrial predators are actively subsidized with carbon from the Black Sea to distance of up to about 50 m. The carbon subsidy from the freshwater lake is significant in the zone extending no farther than the forest border (ca. 15 m). Thus, the effect of allochthonous organic matter on terrestrial communities in both cases manifests itself only in a relatively narrow coastal strip.     

氮素在河流生态系统中的滞留研究进展

河流是陆地生态系统和水生生态系统物质循环的主要连接通道,氮素在河流生态系统中发生复杂的物理、化学、生态过程,氮素的滞留影响输出形态、负荷,人为活动改变滞留过程,加剧水体富营养化。总结了国内外河流生态系统中的氮素滞留方面研究。滞留主要受控于生物因素和非生物因素,需要恢复河流生态系统的结构和功能,加强氮素滞留,改善区域水环境。     

Toxic risk of surface water pollution--six years of experience

Assessment of an ecological quality of surface water is necessary for effective protection, abatement and successive revitalisation of river ecosystems. This quality is primarily given by biological impact of surface water pollution. Substances contained in pollution are frequently toxic to aquatic organisms. Risk of chronic impact of surface water pollution is very often underestimated due to hidden long time action of pollutants. Proper estimation of the risk is not possible from results of chemical analyses and data of substances' toxicity. Chemical analyses are not able to detect all substances presented in water including the products of reactions between them. In addition, a simultaneous presence of substances can modify their final effect on aquatic organisms. Therefore, a complex method of assessment of toxic risk of surface water pollution based on ecotoxicological approach was developed. The toxic risk of surface water pollution is determined from results of evaluation of toxic risk of organic part and inorganic part of surface water pollution. Resultant degree of toxic risk of total pollution is given by the highest degree detected in any part of the water pollution. Presented method, which is routinely used for monitoring in the Czech part of the Odra river basin, was fully standardised and published in the form of the Czech branch technical norm of water management (TNV) in the year 2000.     

长江中下游稻-麦轮作系统生命周期环境影响评价——以江苏南京为例

长江中下游地区是我国稻麦主产区,辨析该区农业生产过程的环境效应,可为实现农业绿色发展提供理论指导。以稻麦轮作典型生产区江苏南京为例,应用生命周期评价方法对该系统生命周期的资源消耗和污染物排放清单进行分析和评价。结果表明:在该稻-麦轮作体系中,水稻生命周期的环境影响主要是富营养化、水体毒性、环境酸化和土壤毒性,环境影响指数分别为2.32、0.76、0.33和0.27;而小麦生命周期的环境影响主要为富营养化、水体毒性、土壤毒性和环境酸化,环境影响指数分别为2.50、2.09、0.32和0.23。肥料、农药、柴油的生产和使用是引起能源消耗和气候变暖的主要因素;农户超量施用氮肥是造成潜在环境酸化和富营养化的关键;农药的使用是造成水体毒素和土壤毒素的最主要原因;而氮肥和农药投入对人类毒性均有较大影响。因此,在工业领域加快新型能源开发,实施清洁生产;在农业领域优化田间管理措施(如减少氮肥施用、研发多功能一体化农机及推广低毒高效农药)能有效控制长江中下游地区稻麦生产负面环境影响,提高该区农业可持续发展能力。     

Ethological Structure of Freshwater Benthic and Nektobenthic Communities and Its Changes under the Influence of Abiotic and Anthropogenic Factors

Classification of the mode of life and behavior of zoobenthic, nektobenthic, and neustonic organisms was used as a basis for elucidating the formation of ethological structure of their communities in small lakes and streams of northeastern Fennoscandia. It is shown that the general response of these communities to anthropogenic impact is manifested in the reduction of the number of ethological groups. The specific response to eutrophication and heat pollution involves a decrease in the relative biomass of clingers and burrowers and an increase in the biomass of sprawling–walking and wormy animals; the response to toxic pollution and acidification is manifested in the prevalence of sprawlers–walkers.     

Stability of aquatic ecosystems and their variation under conditions of toxic pollution

The development of concepts concerning the stability of aquatic ecosystem and their variation under conditions of toxic pollution and after its reduction is considered. General trends in ecosystem transformation are explained in terms of theoretical ecology and thermodynamic mechanisms of energy ordering in living systems. Basic symptoms of disorganization in ecosystems under extreme loads and of their regenerative self-organization are discussed. It is shown that the development of a new modification of an aquatic ecosystem after a decrease in toxic pollution complies with the pattern of ecosystem succession: from a natural ecosystem, via the critical stage, to its more stable but structurally different modification.     

蓝藻水华的成因及其生态控制进展

从水体生态系统的平衡、供水水质、人类及其它动物的健康风险、水域生态景观等方面分析了蓝藻水华的危害。对蓝藻水华形成的内在因素（高温适应的一系列特殊的生化调控机制或特性、三套色素系统——低光补偿机制、奢侈消费机制、固氮——营养补偿机制、休眠——回避不良条件机制、产生天然毒素来抑制竞争者和捕食者的机制）和环境因素（物理，如温度、光照、扰动及混合和水的滞留时间等；化学，如主要营养盐、微量营养元素、溶解无机碳、溶解有机碳和盐度等；生物因子，如牧食、微生物作用和与较高等动植物的共生等）进行了分析。并对蓝藻水华的生态控制（微生物控藻、大型水生植物抑藻、水生动物控藻如经典生物操纵、非经典生物操纵和罗非鱼控藻）的研究进展进行了综述。〖     

城市湖泊有机质氮同位素差异及其对水污染的指示作用分析

如何对湖泊生态环境修复效果进行评价是当前湖泊生态修复工作的难点所在，以武汉市内不同修复状态湖泊为研究对象，通过分析湖泊水体营养盐浓度、水质类别、综合营养状态指数TLI（Σ）与湖泊不同有机质δ15N的关系，探讨以水体中某一有机质δ15N指示城市湖泊水污染状态，进而作为湖泊修复效果评价指标的可行性。结果表明：武汉南湖、东湖、内沙湖水质分别为劣Ⅴ类、Ⅳ类、Ⅲ类；水体富营养化程度分别为重度富营养、轻度富营养、中营养；南湖有机质δ15N均值最高为13.193‰（8.394‰~19.380‰）；东湖δ15N次之为8.191‰（5.162‰~13.488‰）；内沙湖δ15N最低为2.940‰（0.001‰~6.433‰）。不同湖泊有机质δ15N与表层水 c(TN)、c(DIN)、c(NH+4-N)、c(TP)、水质类别和TLI（Σ）呈正相关趋势，其中悬浮有机质、沉水植物δ15N与水污染参数的相关性最为显著，均能有效表征城市湖泊水污染状态；为了采样的简便性及样品的通用性，建议以悬浮有机质δ15N作为城市湖泊水污染状态及水环境治理效果的快速评价指标。     

氮素形态及浓度对互花米草生长的影响

近年来，由于人类生产生活的影响，以化肥农药使用为主的面源污染和以工业排放为主的点源污染日益加剧，全球尤其是海岸带氮含量逐渐升高，对滨海植被的生长产生了巨大的影响。在这个背景下，通过温室模拟实验研究不同供氮水平对互花米草的影响，对研究氮对入侵植物的影响作用机制有重大意义。互花米草在两种氮肥不同氮水平处理下，株高、叶面积、生物量等生长指标以及根冠比、根长/株高等指标的变化情况不同。结果表明：随着氮量增加，米草株高、叶面积、总生物量和地上部分生物量呈先上升后下降的趋势，地下部分生物量、根冠比和根长/株高比则呈下降趋势；各项指标在无机氮肥不同氮水平处理之间存在显著差异，但在有机氮肥的各处理间差异无显著性。这说明适当的供氮水平有利于互花米草的生长，而高氮则抑制其生长     

Analysis of microcystins in cyanobacteria blooms and surface water samples from Meiliang Bay,Taihu Lake,China

Taihu Lake is the third largest freshwater lake in China. In recent years, the water pollution of cyanobacteria blooms has become a severe problem in this area. Microcystins (MCs) are an important group of toxic compounds mainly produced by some cyanobacteria species and have both acute and chronic hepatotoxic effects on animals and humans. This paper presents the first data on the identification and detection of MCs in both natural occurring cyanobacteria blooms and surface water samples (0-0.5 m), collected from Meiliang Bay, Taihu Lake, China. A conventional method for extraction and isolation of MCs from cyanobacteria blooms was applied. High-performance liquid chromatography (HPLC) analysis showed that the main toxic component in the cyanobacteria materials was MC-LR. The monoclonal antibody (mAb) against MC-LR produced by hybridoma technique was employed for direct competitive ELISA to detect the concentrations of MCs in bloom and water samples collected in 2001. The results not only revealed the presence of MCs but also temporal variations of MCs levels of three sampling stations in Meiliang Bay in 1 year. It is obvious that the MC contents were relatively higher during warm months and related with the status of eutrophication. Our study indicates the threat associated with MCs in water body of Taihu Lake. To prevent the MCs potential hazard on public health in this area, some necessary measures of monitoring and control of growth of cyanobacteria are urgently needed.     

太湖流域农田生态系统管理与非点源污染控制

太湖是我国的五大淡水湖之一,正面临着严重的水体富营养化问题。随着点源污染得到逐步治理,农田非点源污染已成为太湖水体富营养化的主要污染源。概述了太湖流域农田生态系统管理与非点源污染控制,指出随着流域内化肥用量以及农田氮磷盈余量的不断增加,流域内农田非点源污染负荷将进一步加大。农田中的氮磷通常通过农田排水和地表径流等途径进入地表水体。为有效控制农田非点源污染,应实施科学合理的农田生态系统管理：避免氮磷肥的过量使用,适当增施有机肥和钾肥,推广应用测土配方施肥,加强微生物肥和控效肥等新型肥料的研制和推广,实行保护性耕作,合理安排农事活动时间,以此减少非点源污染物形成;调整土地利用方式,优化土地资源配置,对潜在的非点源污染物进行有效的截留。     

Effects of acidification on aquatic ecosystems

Effects of acidification on aquatic ecosystems are analyzed on the basis of an analytical synopsis of relevant data. Major active agents influencing aquatic organisms and main trends in the reorganization of microbial, phyto- and zooplanktonic, benthic, and fish communities in an acidified environment are described. A generalized concept of changes in ecosystems caused by acid precipitation and accompanying factors is formulated. These changes include the reduction of biodiversity of all structural elements due to the disappearance of species sensitive to acidification, modification of trophic structure, and decrease of fish stock.Translated from Ekologiya, No. 2, 2005, pp. 110–119.Original Russian Text Copyright © 2005 by Moiseenko.     

Occurrence,fate and effects of azoxystrobin in aquatic ecosystems: A review

The use of pesticides for crop protection may result in the presence of toxic residues in environmental matrices. In the aquatic environment, pesticides might freely dissolve in the water or bind to suspended matter and to the sediments, and might be transferred to the organisms' tissues during bioaccumulation processes, resulting in adverse consequences to non-target species. One such group of synthetic organic pesticides widely used worldwide to combat pathogenic fungi affecting plants is the strobilurin chemical group. Whereas they are designed to control fungal pathogens, their general modes of action are not specific to fungi. Consequently, they can be potentially toxic to a wide range of non-target organisms. The present work had the intent to conduct an extensive literature review to find relevant research on the occurrence, fate and effects of azoxystrobin, the first patent of the strobilurin compounds, in aquatic ecosystems in order to identify strengths and gaps in the scientific database. Analytical procedures and existing legislation and regulations were also assessed. Data gathered in the present review revealed that analytical reference standards for the most relevant environmental metabolites of azoxystrobin are needed. Validated confirmatory methods for complex matrices, like sediment and aquatic organisms' tissues, are very limited. Important knowledge of base-line values of azoxystrobin and its metabolites in natural tropical and estuarine/marine ecosystems is lacking. Moreover, some environmental concentrations of azoxystrobin found in the present review are above the Regulatory Acceptable Concentration (RAC) in what concerns risk to aquatic invertebrates and the No Observed Ecologically Adverse Effect Concentration (NOEAEC) reported for freshwater communities. The present review also showed that there are very few data on azoxystrobin toxicity to different aquatic organisms, especially in what concerns estuarine/marine organisms. Besides, toxicity studies mostly address azoxystrobin and usually neglect the more relevant environmental metabolites. Further work is also required in what concerns effects of exposure to multi-stressors, e.g. pesticide mixtures. Even though Log K_ow for azoxystrobin and R234886, the main metabolite of azoxystrobin in water, are below 3, the bio-concentration factor and the bioaccumulation potential for azoxystrobin are absent in the literature. Moreover, no single study on bioaccumulation and biomagnification processes was found in the present review.     

Simulation of pollution buffering capacity of wetlands fringing the Lake Victoria

Lake Victoria has undergone substantial and most negative changes, especially over the last 30 years. One of the driving factors is nutrient enrichment from human activities in the catchment, which is causing eutrophication. This has been associated with, among others, the rapid proliferation of water hyacinth, alga blooms, and with general disruption of the lake ecosystem. Most of pollution to the lake flow via the natural wetlands. In order to understand how wetlands function within the Lake Victoria ecosystem a wetland model has been developed. The main objective of the model is to establish and simulate the buffering processes and capacity of individual wetlands (that is, their ability to absorb sediments, nutrients and pollutants) within the Lake Victoria basin. It was found that in both seasonal and permanent swamp there is a net export of organic matter produced in the wetlands. Most of the inorganic phosphorous were retained in the wetlands (60% to 90% removal) while there was a negative retention of nitrates probably due to the export of organic matter which associate very much with nitrates.     

富营养浅水湖泊的退化与生态恢复

初步讨论了富营养浅水湖泊的退化现象的造成退化的主要原因，对湖泊生态恢复的目标和对策等问题也作了探讨，以武汉东湖为例，提出以水源保护地为主要功能的富营养浅水胡泊的恢复和整体优化对策，即恢复沉水植被、建立控制面源污染的半自然的人工湿地生态系统，优化水产养殖结构和恢复湖泊生物多样性等。对生物操纵在长江中下游富营养浅水湖泊恢复中的作用也进行了讨论。     

Removal of residual pharmaceuticals from aqueous systems by advanced oxidation processes

Over the past few years, pharmaceuticals are considered as an emerging environmental problem due to their continuous input and persistence to the aquatic ecosystem even at low concentrations. Advanced oxidation processes (AOPs) are technologies based on the intermediacy of hydroxyl and other radicals to oxidize recalcitrant, toxic and non-biodegradable compounds to various by-products and eventually to inert end-products. The environmental applications of AOPs are numerous, including water and wastewater treatment (i.e. removal of organic and inorganic pollutants and pathogens), air pollution abatement and soil remediation. AOPs are applied for the abatement of pollution caused by the presence of residual pharmaceuticals in waters for the last decade. In this light, this paper reviews and assesses the effectiveness of various AOPs for pharmaceutical removal from aqueous systems.     

Ecotoxicological aspects of the tolerance of hydrobionts to acidification of the aquatic environment in the Taiga natural climatic zone

Experimental ecotoxicological studies on the norm of reaction to anthropogenic acidification were performed with representative hydrobionts from aquatic ecosystems of the northern taiga zone. Interspecific, interpopulation, and age-related differences in tolerance to acidity and the significant dependence of this parameter on water pH in natural habitats of corresponding populations were revealed.     

湖北省主要大中型水库富营养状况及特征分析

水库在城市供水、工业用水、水产养殖、农业灌溉、水利防汛以及景观旅游等方面发挥着重要的作用，但随着社会经济的发展，部分水库的富营养化状况日益严重，成为影响社会经济发展的重大环境问题。通过在2010年的3、6、7、10月对湖北省30座主要大中型水库进行布点采样，对水体的水质状况分别进行了调查、监测，采用《地表水环境质量标准》湖库标准进行水质类别分析，采用湖库营养状态指数法对湖泊富营养化评价, 并运用因子聚类分析方法对这些水库进行了类型划分。结果表明：30座大、中型水库有14座水库水质类别为Ⅱ类~Ⅲ类, 占467%; 有8座水库水质类别为IV类，占267%；有8座水库水质类别为Ⅴ类或劣Ⅴ类，占267%；除白云湖水库为轻富营养化外，其余29座水库均属中营养状态；氨氮、磷作为营养物质是这些水库富营养化的主要影响因素，溶解氧对水体富营养化有重要影响，总氮、水温和有机物污染对水体富营养化产生较大影响；30座水库聚类分为城市工业废水污染源型、生活污水污染源型、农业非点源污染源型和养殖轻污染型4种水库类型。针对水库的污染类型，分别提出了减缓防治措施     

Effects of geothermal effluents on aquatic ecosystems

The use of geothermal energy for electrical generation and a variety of other purposes requires the handling and disposal of large volumes of geothermal fluids. These fluids contain constituents such as dissolved ammonia, hydrogen sulfide gas, and trace elements. Facilities in the United States are not expected to routinely discharge large volumes of toxic geothermal fluids. However, chronic effects on aquatic ecosystems are possible at concentrations where acute toxicity would be neither expected nor observed. Also, some trace elements may accumulate to hazardous levels in ecosystems, even when released at nontoxic concentrations.