Zinc and lead sequestration in an impacted wetland system

The fate and bioavailability of pollutant metals is important to the long-term health of freshwater wetland systems, particularly in areas with elevated background levels of trace metals. Precipitation of some authigenic mineral phases in wetland sediments can potentially limit metal bioavailability through sequestration in low-solubility compounds, such as metal sulfides. Zinc and Pb concentrations were analyzed in water, plant and sediment samples taken from a metal-contaminated wetland in Chicago, IL, USA in order to assess metal fate and bioavailability, while X-ray absorption spectroscopy (XAS) studies were conducted to determine zinc speciation in the wetland sediments. The results showed sequestration of metal into the pond sediments, most likely in iron precipitate phases. In surface sediments, re-release of Zn and Pb into pore waters was correlated with microbial iron reduction, while the presence of sulfide in anoxic pore waters corresponded to decreased dissolved concentrations of both elements. Analysis of extended X-ray absorption fine structure (EXAFS) data confirmed that sulfide compounds dominated zinc speciation throughout the sediment. Uptake of trace metals in Phragmites plants was limited primarily to plant roots, while concentrations of both Pb and Zn in aquatic vegetation were significantly elevated, representing a potential bioaccumulation hazard.     

BLM预测水中重金属生物有效性研究进展

生物配体模型( BLM)是利用环境参数来预测重金属生物有效性的模型.它生物受体位点作为生物配体,考虑了影响生物毒性的水化学性质,并把生物有效性的概念引入到水质标准中,在较宽的模拟水质范围内取得较好的预测效果.生物配体模型是多学科共同发展的成果,综合了金属在水环境中的化学、生物学、生理学等以及计算机科学方面的成果,这学科...     

Is the EU WFD suitable to support IWRM planning in non-European countries? Lessons learnt from the introduction of IWRM and River Basin Management in Mongolia

The Water Framework Directive (EU WFD, 2000/60EC, European Commission, 2000) is a comprehensive tool for water management taking Europe’s diverse national and local policy contexts into account. This has positioned the EU WFD as a potential tool to enhance the implementation of the globally-promoted integrated water resources management concept (IWRM) in developing and transition countries that to date lack comparable regulations. Using the case of Mongolia, a country that has shown interest in using aspects of the EU WFD for implementing its IWRM concept, we will discuss the extent to which the EU WFD also provides a framework for IWRM outside Europe. We find that the EU WFD may provide guidance for the implementation of ecosystem-based River Basin Management (RBM) within an existing national IWRM concept, in terms of public participation and in terms of economic analysis. However, the application of concepts EU WFD is easier if strong political will, good monitoring capacities and a legislative backbone covering key IWRM principles and the capacity for enforcement are in place. Also, the EU-WFD does not provide guidance in terms of water-related issues that are e.g. addressing gender, poverty and capacity development. Thus, the EU WFD cannot serve as a blueprint, as it requires adaptation to the different socio-economic, cultural and political contexts of the implementing country and it does not inform all aspects of IWRM.     

九龙江流域地表水锰的污染来源和迁移转化机制

锰是人体必需微量元素,但近年来河流湖库等地表水锰超标现象时有发生,威胁供水安全.本文于2016—2017年在福建省九龙江流域开展水系沿程梯度调查及机理实验,结合历史监测资料综合研究,探明九龙江锰含量的时空分布与迁移转化规律,揭示九龙江锰的污染来源、超标成因与调控机制.结果表明,溶解锰高值及超标站位集中在北溪上游矿区支流和干流部分水库,且主要发生在枯水期;上游矿区支流颗粒锰含量最高,随后从上游到下游沿程递减,且与总悬浮颗粒物(TSM)和pH显著正相关(p0.05).基于锰形态与pH值之间的密切关系和沿程变化,及培养实验中沉积物锰释放主要受控于pH的变化而非溶解氧的变化,推测九龙江地表水锰污染主要来自红壤颗粒的流失(特别是矿区和坡地),流域风化形成高pH(pH7.8)环境促进亚热带红壤颗粒富集锰,大量富锰颗粒进入pH逐渐下降的河流下游和电站库区后向溶解锰转化,从而导致锰超标.河流下游及库区pH值下降的主要原因包括酸沉降、酸性废水排放、富营养化条件下有机物分解等.研究结果为我国地表水锰污染防控、饮用水安全保障与流域水环境综合管理提供科学依据.     

Quantification and control of microbial pollution from agriculture: a new policy challenge?

Faecal indicator organisms (FIOs) are commonly used to quantify pollution of public health significance. Health protection, as indexed by FIO control, is a central aim of new ‘catchment-scale’ water quality management required in the USA by the Clean Water Act and in the European Union (EU) by the Water Framework Directive (WFD). Experience of the former, after a decade of implementation, suggests that the most significant reason for water quality ‘impairment’ is elevated FIO concentrations, mainly in recreational and shellfish harvesting waters. This provides an early warning of possible problems which the EU regulatory authorities are likely to face. To date, however, a surprising lack of EU attention has been given to prediction and control of catchment fluxes of this key parameter. This is likely to prove embarrassing if the experience of the US regulatory community is not acted upon with some urgency. There is a growing, though still partial, body of empirical science to form the ‘evidence-base’ for good regulatory practice. However, adoption of ‘best management practices’ (BMPs) to effect remediation of impacted waters will require close integration of water policy with policies on financial support for the farming community. This is likely to require enhanced communication and integration within the discrete policy communities addressing the agricultural sector through the Common Agricultural Policy and water regulation through the Water Framework Directive.     

Phosphorus accumulation and eutrophication in feed-supply freshwater fishponds

The rapid growth and intensification of freshwater fishery can cause imbalances between phosphorus （P） input in feed and its output in produce. This aquaculture can result in enriching exogenous P in fishponds and, consequently, accelerates the process of eutrophication. To assess relations among input, accumulation, release of P and as a consequence degrading water quality in terms of chlorophyll-a （Chl-a） in freshwater fishponds, fourteen fishponds with feed supply, nine fishponds without feed supply, and five nonfish ponds in Shaoxing Plain, southeast China were selected for comparing P accumulation in their waters and surface sediments. Surface sediment samples were collected from each pond to evaluate their total P, water soluble P, Olsen P, algal available P, and P fractions. Water samples were also collected from the ponds to measure concentrations of dissolved P and Chl-a. Total P in the sediments ranged from 0.88 to 1.73 g/kg in the fishponds with feed supply, that in the non-fish ponds ranged from 0.47 to 0.86 g/kg. Organic P, accounted for 23% to 60% of total P in the sediments, was an important P fraction and increased linearly with increasing organic matter. Long-term application of feeds resulted in increased P availability in the bottom sediments and degradation of water quality in the freshwater fishponds. Compared with non-fish ponds, sediments from the feed-supplied fishponds contained considerably higher Olsen P, algal available P, and water soluble P. Higher proportions of the labile P （NH4Cl-P） and potentially labile P （NaOH-IP） were also found in the sediments from the fishponds. High solubility of P in the sediments resulted in elevation of P and chlorophyll-a concentration in the pond water. The dissolved P concentration in the pond water increased in the order of non-fish ponds （12μg/L） 〈 fishponds without feed supply （24 μg/L） 〈 fishponds with feed supply （66 μg/L）. Linear correlations between concentrations of total P, Olsen-P, algal available P, water-soluble P and P concentration in saturation extracts in the sediments and dissolved P in the pond water indicated that there was a buffering action of the sediment constituents on the dissolved P.     

Did you say reference conditions? Ecological and socio-economic perspectives on the European Water Framework Directive

Reference conditions are a key concept in the European Water Framework Directive (WFD). The WFD stipulates that the ecological status of a given water body shall be assessed by quantifying the deviation from a set of reference conditions that represent the stable state of an ecosystem in the absence of significant human disturbance. This concept is subject to criticism from several authors, particularly because underlying ecological concepts are weak and the distinction between natural variability and the effects of anthropogenic activities on ecosystem function will become increasingly artificial. In this paper, a sociologist and an aquatic ecologist examine the origin, successes and limits of the reference conditions concept and raise important questions about applying this concept in practice. We argue that this concept fitted specific needs from different institutions and stakeholders which promoted the WFD. Monitoring practices using this concept require some adaptations. Setting goals for restoration based on reference conditions is more problematic. A more adaptive management approach would be wiser.     

淡水沉积物中重金属生物有效性的研究进展

淡水重金属污染已成为全球关注的热点环境问题之一。沉积物作为重金属的重要储库与污染内源,可对水环境质量及水生态系统产生严重危害。生物有效性是评价重金属生物可利用性及其毒性效应的关键指标,研究淡水沉积物中重金属的生物有效性与调控机制,有助于阐明重金属的污染机理及其生态环境效应,可为重金属的污染防治提供科技支撑。本文回溯了沉积物重金属生物有效性的定义内涵、发展历史,重点介绍了重金属生物有效性评价的主要方法、适用性及其优缺点,归纳了影响重金属生物有效性的主要因素与内在机制,概述了目前国内外典型河流、湖泊和水库等淡水水体沉积物中相关研究的最新进展。本文进一步指出,在今后研究中亟需整合现有分析方法,形成统一的沉积物重金属生物有效性评价指标与方法体系,并开展权威实验室比对研究。同时,应考虑不同淡水生态系统的区域差异性,采用生物监测方法与原位被动采样技术相结合,将生物配位体模型纳入重金属的生态毒理效应研究中。最终,依据不同淡水环境的特性,尽快建立相应的沉积物重金属质量基准,加强重金属环境污染的科学管理。     

2006年春季长江口砷形态分析及其生物有效性

于2006年春季在长江河口开展野外调查.采集水和表层沉积物样品,并进行总砷、砷形态分析和生物有效性评估.将过滤水样用于测定溶解态砷含量,而未过滤水样经酸消解后用于测定总砷含量,两者之差则为颗粒态砷含量.结果表明.长江口青草沙水源地各层水体中总砷含量为0.88-1.35ug·L-1(涨憩),2.37-3.35ug·L-1(落憩).溶解态和颗粒态砷含量均随潮汐变化明显,各形态砷含量在落憩时均高于涨憩时,颗粒态砷所占总砷的比例也是落憩时明显高于涨憩时.以0.3 mol·L-1磷酸溶液为萃取剂.在微波辅助下可以有效地将沉积物中砷酸盐[As(V)]、亚砷酸盐[As(Ⅲ)]、一甲基胂酸盐(MMA)和二甲基胂酸盐(DMA)提取出来,然后利用高效液相色谱一氢化物发生.原子吸收光谱(HPLC-HG-AAS)联用技术进行检测.结果表明,长江口表层沉积物中总砷含量为6.3-30.7 mg·kg-1,主要为无机砷形态,在江心沙洲及离岸沉积物中且以砷酸盐为主.而在近岸沉积物中以亚砷酸盐为主;利用醋酸纤维素/氧化铁复合膜方法(FeO/CAM)所得沉积物中有嫂砷含量占总砷含量0.6%-3.9%,平均约为2.1%.有效砷含量与总砷含量没有显著相关性,与亚砷酸盐含量呈显著正相关性,与砷酸盐含量呈显著负相关性.结果还表明,长江口南支沉积物中的砷形态分布特征及其生物有效性受城市支流输入和排污活动影响显著.     

天山山地河流水体中微量重金属的分布特征及形态分析

为了解绿洲经济迅速发展背景下天山山地河流水体中重金属分布特征及形态特征,对乌鲁木齐-阿克苏、巴里坤-伊吾、昭苏-特克斯等3个区段河流干支流重金属Zn、Cu、Pb、Cr、As、Hg、Cd的分布、来源、污染状况及存在形态进行了分析.结果表明:1天山山地各取样河流的p H值大部分在8.0左右,为偏碱性的环境;各取样点水体的氧化还原反应电位值在150~200 m V之间,为弱氧化的环境.水质评价表明,3个采样区段河流中7种重金属的含量均低于国家Ⅰ类水质标准及WHO饮用水健康的建议标准.2多元统计分析表明,7种重金属可以归为3个主成分,其中PC1(Hg、Zn和Pb)主要受人为污染因素的影响;PC 2(Cr和As)主要受自然地质背景的影响;PC 3(Cd和Cu)同时受人为和自然因素的共同影响.3污染评价表明,天山山地河流中7种重金属的单因子污染指数值和综合污染指数值均小于1,属于安全等级,清洁水平.4形态分析表明,重金属Pb、Cd和Hg在天山中部的乌鲁木齐-阿克苏区段干支流,重金属As和Cu在天山东部的巴里坤-伊吾区段和天山西部的昭苏-特克斯区段干支流中溶解态的含量均大于50%,生物毒性较大.总体上,3个采样区段河流干支流重金属的总量及溶解态含量均较低,未造成污染.但在天山山地中部的乌鲁木齐-阿克苏区段,河流干支流中重金属Pb、Cd和Hg的总量及溶解态含量较高.应加强对该区域人类活动的合理规划以及河流水质监测,防止因人为污染而导致河流水体中重金属的含量过高,危害生态环境.     

我国流域铜的长期水质基准预测模型研究——MLR vs. BLM

铜在实际水环境中的毒性效应受多种环境理化要素影响,识别典型环境因子进而建立生物有效性模型是获得“原位”水质基准的基础. 国际上广泛应用的生物配位体模型(biotic ligand model, BLM)在实际使用过程中有局限性. 本研究旨在BLM模型的基础上,探究更适用于铜的“原位”毒性校正方法,以更少的环境因子降低环境监管过程的经济和技术成本,为“因地制宜”确定金属水质基准提供理论依据和技术支撑. 同时基于4门22种水生生物的慢性毒性数据,以影响铜生物有效性的关键水化学参数为自变量,即硬度(hardness,H)、pH和溶解有机碳(dissolved organic carbon,DOC),采用带有交互项的3种逐步多元线性回归(Multiple Linear Regression,MLR)方法建模,从9个模型中筛选出最佳预测模型〔R2=0.553 1,F=61.23,P<0.000 1,AIC(赤池信息准则,Akaike information criterion)=0.9457,BIC(贝叶斯信息准则,Bayesian information criterion)=23.43〕. 并参考我国典型流域水环境特征,正交设计216组水环境条件,对所有物种的慢性毒性值(chronic toxicity value,CTV)进行模型校正. 结果表明:①以预测准确率(RF_x,2.0)为评价指标,MLR模型较BLM模型提升了20%,MLR模型残差分析的等级评分也优于BLM模型. ②确定最佳模型为Sigmoidal-Weibull函数(R2=0.986 1,F=1 609,P<0.001),构建的三环境因子耦合的基准预测模型准确度高(R2=0.990 2,RMSE=0.041 06,F=7 238,P<0.001). ③主要环境因子(H、pH和DOC)只使得SSD曲线水平移动〔与中心(X_c)有关〕,曲线形状无影响〔振幅(A)、指数(d)和协同系数(k)恒定〕. ④在模型的适用范围内,我国流域水体中铜的长期水质基准为4.619~53.75 μg/L. 研究显示,基于BLM模型框架的新MLR模型,具有高稳健性和准确性,有助于体现流域水生态管理的区域性差异.      

欧洲水管理实践对中国流域水环境管理的启示

针对流域水环境管理的顶层设计,Water Framework Directive（WFD）是一部具有法律约束力的水框架法令,已成为欧洲水环境管理的有效的工具,实现了流域水环境的经济和生态的协调、综合管理。综述了欧洲水框架指令WFD研究进展,介绍了WFD提出的背景、要点、编制路线图和相应WFD水环境管理经验,对了解和掌握国际先进的流域水环境管理经验和最新形势具有一定借鉴意义。     

Monitoring of diffuse pollution from agriculture to support implementation of the WFD and the Nitrate Directive in Estonia

This paper discusses the monitoring network for diffuse pollution from agriculture in Estonia in the context of implementation of the EU Water Framework Directive (WFD) and the Nitrate Directive (ND). Seven surface water monitoring stations in agricultural catchments represent two out of three river basin districts designated in Estonia according to the WFD criteria. The national monitoring programme of ground water quality involves 516 stations of which about half were monitored in 2005. The monitoring sites cover all main ground water bodies in Estonia but are largely concentrated in the Nitrate Vulnerable Zone (NVZ). Analyses did not reveal any significant trends in total nitrogen (TN) and total phosphorus (TP) concentrations in studied rivers during the last 15 years except in one site. The ground water quality stabilised after decrease of nitrate concentrations in the early 1990s, especially in the south part of the NVZ, but even in 2005 the nitrate concentration exceeded 50 mg l⁻¹ in 42 out of 145 ground water samples in this region. The existing surface water quality monitoring network provides only restricted information to select between different management options when implementing action programmes for the NVZ and the river basin management plans (RBMP) under the WFD.     

广东沿岸海域生物可利用性重金属的地理分布

利用牡蛎做监测生物，研究了广东沿岸海域生物可利用性重金属Ｃｄ，Ｃｕ和Ｚｎ的地理分布。牡蛎体的Ｃｄ，Ｃｕ和Ｚｎ含量存在着显著的地域差异，反映了广东沿岸海域生物可利用性的Ｃｄ，Ｃｕ和Ｚｎ在地域上存在很大的梯度。由牡蛎显示出的广东沿岸海域生物可利用性重金属的地理分布与广东沿岸海域受人为来源的重金属输入状况相一致，如实地反映了广东沿岸海域重金属污染的基本特征。     

A process integration approach to industrial water conservation: a case study for an Indian starch industry

A case study for water using network of a Starch industry in the state of Gujarat, India, is undertaken with an aim to reduce demineralised water and freshwater flow rates and consequently the wastewater flow rate. The problem was identified as a multi contaminant, reuse and recycle problem. The freshwater consumption and demineralised water consumption were 100 t/h and 51 t/h respectively before modification and the network was dealing with three major contaminants such as total organic content, total dissolved solids and total suspended solids. A program was developed in MATLAB for analysis using Water Pinch. The improved water using network designed for the present work consumed less demineralised and freshwater. The reductions are of the tune of 28% and 64.38% for demineralised and fresh water respectively. Due to alteration in piping, there will be a saving of 406 026 INR per year, which will be utilized for development of efficient environment policy for the company. The entire concept had been implemented on plant level on 1st February-2009 and the reductions are of the tune of 25% and 60% for demineralised and fresh water respectively.     

淡水沉积物的生物测试方法研究

描述了淡水沉积物毒性的生物测试方法。沉积物基质可以通过直接采样法和掺入法制备,储存会影响其生物可利用性。全底泥相,间隙水相和复溶相是目前沉积物毒理学研究常用的试验相,其中,间隙水相被认为是进行沉积物毒理学研究较为理想的试验相。同时推荐采用离心法制备间隙水。此外,为增加试验结果的可比性,文中还讨论了试验生物的选择问题。      

Disproportionate costs in the EU Water Framework Directive—How to justify less stringent environmental objectives

The ambitious objective pursued by the European Water Framework Directive (WFD) is good status for all European waters. However, “less stringent environmental objectives” are permissible if the costs of achieving good status are disproportionately high. This exemption, if abused, carries the risk of watering down the ambitions of the Directive. Currently, no transparent, well-established, universally applicable method for routinely testing disproportionality exists throughout Europe. In this paper, such a method is developed for surface water bodies. The core idea is to determine a water body-specific disproportionality threshold which is then compared to the projected costs of achieving “good status/potential”. For the sake of practicability, the benchmark for disproportionality is estimated on the basis of prior expenditure on water quality enhancement. The paper argues that the proposed method combines both possible interpretations of (dis-)proportionality—affordability and cost-benefit considerations. Due to the method’s moderate data requirements it can be used readily in most German federal states and is transferable in principle to other EU Member States. The method was tested empirically for a river in the German federal state of Rhineland–Palatinate.     

黄土高原高浑浊水体CDOM光学特性及影响因素

为确定黄土高原地区高浑浊水体有色溶解有机物(CDOM)组成来源及研究环境因素对其的影响,本文基于2018年5月陕蒙黄土高原地区河流与湖泊(咸水湖和淡水湖)的实测数据对CDOM光学吸收特性,各组分对水体吸收的贡献,光谱斜率S_(275～295)及水质参数与CDOM光学特征参数的相关性进行分析.结果表明,陕蒙黄土高原区河湖CDOM吸收光学特性差异显著(P0.01),湖泊CDOM吸收系数a_(CDOM)(440)(8.45 m~(-1))高于河流(2.70 m~(-1)),咸水湖CDOM浓度(13.52 m~(-1))高于淡水湖(3.38 m~(-1)),淡水湖对光的有效利用率高于咸水湖和浑浊河流.河流与湖泊、咸淡水湖之间酸碱度(pH)和溶解有机碳(DOC)差异均呈显著水平(P0.01);河湖水体电导率(EC)、浊度(Tur)和总悬浮物浓度(TSM)差异显著;排除极大值点,咸水湖与淡水湖叶绿素a(Chla)相接近.基于S_(275～295)分析发现,湖泊CDOM分子量小于河流,咸水湖分子量小于淡水湖;由SUVA_(254)得出,河流陆源腐殖质输入比湖泊多,淡水湖陆源腐殖质输入较咸水湖多.通过冗余分析(RDA)发现,河流与湖泊水质参数累积方差解释率分别为35.2%和61.4%,咸淡水湖均达到100%;溶解氧(DO)、水温和EC对河流CDOM光学特性影响较大(P0.01),而DOC、 TSM和Tur对湖泊CDOM光学特性影响较大(P0.01);咸水湖水体中DOC以及淡水湖水体的pH与CDOM吸收系数相关性较强(P0.05).     

欧盟水框架指令优先污染物筛选方法的应用

利用欧盟水框架指令(EU WFD)方法筛选优先污染物,得到适用于我国的水环境优先控制污染物清单。检索了包括中国、美国、欧盟、日本等国家和地区的水质标准和污染物清单,对这些清单污染物进行初筛选,得到449种污染物为我国登记在用的污染物,在此基础上运用改进的WFD优先污染物筛选方法对这些污染物进行计分筛选,并按照其半致命毒性LD50排序,得到包含19种污染物的水环境优先控制污染物排序清单。结果表明,WFD优先污染物筛选方法能较全面的筛选出环境危害大的污染物,根据我国实际情况,对WFD现有污染物清单做出补充与筛选后,适合作为水环境优控污染物筛选的方法。     

The biotic ligand model: a model of the acute toxicity of metals to aquatic life

The United States Environmental Protection Agency (USEPA) has established nationally applicable water quality criteria (WQC) for metals that are designed to be protective of aquatic life. However, in some instances these criteria may be over-protective as a result of natural, site-specific differences in water quality characteristics. These differences affect metal speciation and bioavailability, fundamental considerations in assessing toxicity. Laboratory studies completed during recent years have advanced the current understanding of metal chemistry in aquatic systems, including the formation of organic and inorganic metal complexes and sorption to particulate organic matter. Parallel investigations have led to an improved understanding of the physiological basis of why metals are toxic to aquatic organisms. These studies have, in combination, led to an improved understanding of how site-specific water chemistry affects bioavailability, and how metals exert toxicity at the organism site of action, at the biotic ligand in the context of the model to be described. The biotic ligand model provides a quantitative framework for assessing metal toxicity over a range of hardness, pH and dissolved organic carbon (DOC) levels. The chemical equilibrium sub-model incorporates metal-biotic ligand interactions to compute metal accumulation at the site of action (e.g., the gill of a fish) as a function of water quality. The toxicity sub-model uses this computed accumulation level as the basis for successfully predicting observed variations in toxicity associated with changes in water quality. The results highlight the potential utility of this approach to provide an alternative means of developing site-specific permit limits and WQC. The ability of the model framework to quantitatively assess the effects of hardness, pH and DOC on toxicity, in comparison to current WQC for metals that typically vary with hardness alone, is a significant advance in understanding how site-specific conditions affect the toxicity of metals.