Risk characterization and surface water quality assessment of Manas River,Assam (India) with an emphasis on the TOPSIS method of multi-objective decision making

The present study centers on the investigation of surface water quality with the aid of quality indices and explores the application of a multi-objective decision-making method (TOPSIS) in arranging decisions for policy makers on the basis of overall ranking of the sampling locations. A case study has been performed on the Manas River, Assam (India). Water Quality Index (WQI) involving physico-chemical parameters, and heavy metal pollution index (HPI) and contamination index (CI) involving heavy metal influences were employed for water quality assessment. WQI graded two sampling locations “very poor” and all other locations “poor”. HPIs of all the locations were below the critical value of 100, but the CI depicted that two locations were “moderately contaminated”. Risk assessment to human health was done using hazard quotient and hazard index. Cluster analysis (CA) demonstrated site similarity by grouping the relatively more polluted and less polluted (LP) sites into two major clusters. However, there surfaced difficulty in discerning the overall water quality, as all the three quality indices included different parameters and contradicted each other. A multi-objective decision-making tool, TOPSIS was therefore employed for ranking the locations on the basis of their relative pollution levels. The novelty of the study reflects in the identification of the relatively more or relatively less polluted sites within the same cluster in CA by the application of TOPSIS. The study justifies the effectiveness of TOPSIS method in prioritizing decisions in complex scenarios for policy makers.     

Groundwater characterization and quality assessment,and sources of pollution in Madinah,Saudi Arabia

Groundwater quality in the Madinah city is increasingly endangered by expanding urbanization, industrial activities, and intensified agricultural land use. In order to investigate the pollution of Madinah groundwater resources, 32 samples have been gathered and examined for major, trace, and nutrient components. Results of groundwater characterization and groundwater quality assessment show that Na⁺ and Cl^? are the main anion and cation in the groundwater, respectively. Depletion of HCO₃ that interacts with water increases salinity. Cluster analysis and principal component analysis were applied in the current study to obtain relationship between parameters and sampling site in order to identify the factors and sources influencing groundwater quality. The CA allowed the formation of three clusters between the sampling wells reflecting differences on water quality at different locations. Four major PCs were extracted, which accounted 86.05 % variance of the original data structure. Forty-four percent of the groundwater samples have high values of NO₃, due to human and agricultural activities. Four samples in the southwestern part of the study area show high content of Pb, Cd, Cr, Ni, As, and Al. This may be due to the influence of anthropogenic activities that resulted from the southwestern industrial area of Madinah. The present study illustrates explicitly the stress on groundwater quality and its vulnerability in the aquifer system.     

Spatial characteristics of surface water quality in the Haicheng River (Liao River basin) in Northeast China

Spatial variations of the water quality in the Haicheng River during April and October 2009 were evaluated for the national monitoring program on water pollution control and treatment in China. The spatial autocorrelation analysis with lower Moran’s I values displayed the spatial heterogeneity of the 12 physicochemical parameters among all the sampling sites of the river. The one-way ANOVA showed that all variables at different sampling sites had significant spatial differences (p < 0.01). Based on the similarity of water quality characteristics, cluster analysis grouped the 20 sampling sites into three clusters, related with less polluted, moderately polluted and highly polluted sites. The factor analysis extracted three major factors explaining 76.4 % of the total variance in the water quality data set, i.e., integrated pollution factor, nitrogen pollution factor and physical factor. The results revealed that the river has been severely polluted by organic matter and nitrogen. The major sources leading to water quality deterioration are complex and ascribed to anthropogenic activities, e.g., domestic and industrial wastewater discharges, agricultural runoff, and animal rearing practices.     

Impact assessment of textile effluent on groundwater quality in the vicinity of Tirupur industrial area, southern India

Adverse effect of rapid industrialization on groundwater quality and quantity is widely known problem especially in developing countries. Tirupur, which is situated on the bank of Noyyal River in India, is known for intensive textile processing activities. As groundwater is the main water source for drinking water, there is an urgency to assess the groundwater quality. Twenty groundwater samples were collected for each post and pre-monsoon sampling during August 2009 and March 2010, respectively. Chemical and statistical analysis along with numerical modelling has been performed to assess the current status. The hydro-geochemical study revealed that the dominance of Mg–Cl and Na–HCO₃ groundwater type in the upstream region Tirupur industrial hub of Noyyal River basin. Na–Cl groundwater type was found increasing in industrial hub (Kasipalayam) and downstream of the industrial hub (Anaipalayam) sites. The dominance of Na–Cl type of water is mainly due to the impact of salts like NaCl, Na₂SO₄, etc. used in textile processing, which after discharge, percolate and accumulate in the aquifers. Seasonal groundwater quality of Tirupur region as a whole showed the dominance of Ca–HCO₃ ^?, Na–HCO₃ ^? and Na–Cl water types. PHREEQC model output indicates that nearly all the groundwater samples were oversaturated with respect to calcite and dolomite and undersaturated with respect to gypsum and halite. The results obtained in this study were then compared with groundwater quality of the Noyyal River basin for the year 2008–2009. Among the two sites, Kasipalayam was found to be most contaminated due to incessant industrial discharge. But with the advent of new treatment technologies like CETPs having zero liquid discharge system and MBR, there has been slight decline in the concentration of different physicochemical parameters from 2002–2003 to 2008–2009. This study not only makes situation alarming but also calls for immediate attention for sustainable management of water resources.     

Identification of river water pollution characteristics based on projection pursuit and factor analysis

Human activities contribute different pollutants to receiving waters, often with significant variations in time and space. Therefore, integrating multiple parameters of water quality and their spatiotemporal variations is necessary to identify the pollution characteristics. Based on the water quality monitoring data with 12 parameters for 2 years at 22 sampling sites in the Cao-E River system, eastern China, the projection pursuit method was used to project all parameters and their temporal variations into a one-dimensional vector through two projections. Accordingly, we could easily assess the comprehensive water quality in different sampling sites and then classify their water pollution features. Factor analysis was then used to identify the pollution characteristics and potential sources. Results showed that all sampling sites for the river system could be classified into four groups: headwater sites (HS), agricultural nonpoint sources pollution sites (ANPS), point sources pollution sites (PSPS), and mixed sources pollution sites. Water quality in HS was good, containing only a few nutrients from the woodland runoff and soil erosion. For ANPS, the main pollutants were dissolved phosphorus, total P, and nitrate nitrogen (NO₃ ^?-N), mainly from farming land. For PSPS, ammonium nitrogen (NH₄ ⁺-N) and organic pollutants originated from industrial and municipal sewage. In HS and ANPS, NO₃ ^?-N was the main form of nitrogen, and a high ratio of NO₃ ^?-N/NH₄ ⁺-N was a remarkable characteristic, whereas NH₄ ⁺-N was the main form of nitrogen in PSPS. Except in HS, water quality in the other groups could not meet the local water quality control standard. Finally, suggestions were proposed for water pollution control for the different groups.     

The influence of topography and land use on water quality of Xiangxi River in Three Gorges Reservoir region

A self-organizing map (SOM) was used to cluster the water quality data of Xiangxi River in the Three Gorges Reservoir region. The results showed that 81 sampling sites could be divided into several groups representing different land use types. The forest dominated region had low concentrations of most nutrient variables except COD, whereas the agricultural region had high concentrations of NO₃N, TN, Alkalinity, and Hardness. The sites downstream of an urban area were high in NH₃N, NO₂N, PO₄P and TP. Redundancy analysis was used to identify the individual effects of topography and land use on river water quality. The results revealed that the watershed factors accounted for 61.7% variations of water quality in the Xiangxi River. Specifically, topographical characteristics explained 26.0% variations of water quality, land use explained 10.2%, and topography and land use together explained 25.5%. More than 50% of the variation in most water quality variables was explained by watershed characteristics. However, water quality variables which are strongly influenced by urban and industrial point source pollution (NH₃N, NO₂N, PO₄P and TP) were not as well correlated with watershed characteristics.     

Spatial–temporal characteristics of surface water quality in the Taihu Basin,China

Taihu Basin is one of the most developed and industrialized regions in China. In the last two decades, rapid development of economy as well as an increase in population has resulted in an increase of pollutants produced and discharged into rivers and lakes. Much more attention has been paid on the serious water pollution problems due to high frequency of algal blooming. The dataset, obtained during the period 2001–2002 from the Water Resources Protection Bureau of the Taihu Basin, consisted of eight physicochemical variables surveyed monthly at 22 sampling sites in the Taihu Basin, China. Principal component analysis (PCA) and cluster analysis (CA) were used to identify the characteristics of the surface water quality in the studied area. The temporal and spatial variations of water quality were also evaluated by using the fuzzy synthetic evaluation (FSE) method. PCA extracted the first two principal components (PCs), explaining 86.18% of the total variance of the raw data. Especially, PC1 (73.72%) had strong positive correlation with DO, and was negatively associated with COD_Mn, COD, BOD, NH₄ ⁺–N, TP and TN. PC2 (12.46%) was characterized by pH. CA showed that most sites were highly polluted by industrial and domestic wastewater which contributed significantly to PC1. The sites located in the west of Lake Taihu were influenced by farmland runoff which may contribute to nitrogen pollution of Lake Taihu, whereas the monitoring sites in the eastern of Lake Taihu demonstrated that urban residential subsistence and domestic wastewater are the major contaminants. FSE indicates that there is no obvious variance between 2001 and 2002 among most sites. Only several sites free from point-source pollution appear to exhibit good water quality through the studied period.     

The study of the hydrogeological setting of the Chamshir Dam site with special emphasis on the cause of water salinity in the Zohreh River downstream from the Chamshir Dam (southwest of Iran)

Dissolution of evaporite formations, emergence of salty water springs, and intrusion of deep saline waters are important causes in changing the quality of surface water. The study area is part of the reservoir and downstream of Chamshir Dam, which is located in watershed of the Zohreh River 20?km southeast of Gachsaran City (southwest Iran). To construct powerhouse and related structures for supplying water to agricultural lands located in downstream of dam, water quality of Zohreh River was studied by eight sampling stations in the study area. Early studies showed that water quality of the Zohreh River decreases severely downstream of the Chamshir Dam. Spatial variations diagram of major ions, Piper and composition diagrams of water samples in selected stations mark the presence of two slight and major contaminating zones at sampling station R₄ and R₅. In these zones, concentration of Ca, SO₄ and Na, Cl ions increase suddenly. Results of hydrogeological, hydrochemical, lithological and tectonics studies showed that even though there are several low discharges springs in the contaminated zone they cannot be related to surface dissolution of evaporate layers by Zohreh River. There is an important fault zone including Chamshir faults I and II in the contamination zones through which intrusion of sulfate brackish and chloride brine waters occur along the fault zone and then enter Zohreh River below its base level. In the absence of any surface evidence, the fault zone is the main cause of salinity. Evaluation of water balance salinity in contaminated zones shows that the discharge rate of saline waters to the river is not low and cannot be separated. These findings show that there are serious restrictions upon the purposes of the project.     

Hydrochemical studies of Cross River Basin (southeastern Nigeria) river systems using cross plots, statistics and water quality index

Water quality assessment study of the three major rivers within the Cross River Basin have been carried out using cross plots, ionic ratio, correlation analysis, factor analysis and water quality index (WQI) based on the World Health Organization and world average data guidelines. The primary aim was to determine their suitability for domestic and irrigation uses, while the secondary aim was to determine the sources of the ions in the river water. The results showed that the water samples from the Cross River estuary generally had elevated values of dissolved ions as compared to the Calabar and Great Kwa Rivers. Cross plots, ionic ratios, correlation and factor analyses showed tidal influence, silicate weathering, nitrate pollution and dissolution of carbonate minerals from soil CO₂ as the origin of the variables. Chemical indices including sodium adsorption ratio and residual sodium carbonate indicate that the river water of the study area are suitable for domestic and irrigation, while sodium percentage (Na %) indicate unsuitability for irrigation applications. The WQI values on the average indicate water of very poor to excellent quality. Generally in terms of quality for the different rivers, the Great Kwa River is best as compared to the Calabar River and Cross River estuary for domestic and irrigation purposes.     

基于双权重的评价模型在矿井水质评价中的应用

在论述双权重的基础上,建立了水质评价的模糊综合模型。通过监测总硬度、SO42-、Cl-、Cr6+、Pb、Fe等水质影响指标,计算了各指标的程度权重和因素权重,采用灰色模糊综合评价的方法评价了临涣矿区10个采样点的水质。研究结果表明:8个点属于IV类水,1个点属于V类水,1个点属于Ⅲ类水。评价结果为矿区废水处理方法的选择和资源化提供了依据,并为矿区水污染环境的治理提供了基础数据。     

基于组合权重法的河流水质综合评价

以盐城市河流为研究对象构建组合准则权重(Weight of Combination Criteria)与次序权重(Ordered Weighted Averaging)相结合的水质风险评价模型,通过控制决策风险水平得到不同条件下的次序权重,最终获取多种情况下的水质评价结果,为水质治理与保护提供参考。评价结果表明:当控制决策风险水平a=1时,该方法划分对监测点的水质类别划分结果与国标法基本一致,表明该方法在水质评价方面满足可行性和实用性两个基本要求;其次对研究区域主要水质指标的提取显示,研究区域水质受总有机碳(TOC)、总磷(TP)、氨氮和石油类影响较大;水环境受地理位置的影响入海口水质较差(IV类和V类),总体来说研究区域污染来源主要是农业污水、工业废水及城市污水。     

利用WASP模型和GIS可视化集成的水质监测与模拟——以渭河为例

近年来,随着经济发展大量工业和生活污水的大量排放,严重的影响了河流水质状况,作为黄河主要支流的渭河流域更是如此.根据渭河下游水环境特性,选取化学需氧量(COD)作为水质模拟因子,采用WASP水质模型对渭河下游水质进行监测和模拟,将GIS集成到WASP水质模拟中同时利用外联式集成利用GIS对渭河下游水质的时空变化特征进行...     

基于级别特征值的岩溶含水层水质模糊综合评价修正

为改进传统水质模糊综合评价中存在评价指标不能全面反映水质状况、评价结果不清晰,评价等级区分度不明显等缺陷,文章以位于六枝特区威宁-郎岱褶皱群的第一层岩溶含水层水质为例,根据岩溶区水质评价特点和研究区含水层超标因子特征,建立涵盖物理、化学和微生物等因子的评价指标体系,利用级别特征值对传统模糊综合评价结果进行了适当修正,并与综合污染指数法、传统模糊评价综合法的评价精度进行定量化比较。研究结果表明:六枝特区的研究区探采点水质综合评价等级都达到Ⅲ类生活饮用水卫生标准,但仍有71%的探采点存在氨氮（NH4+）、氟化物(F-)、高锰酸盐指数(CODMn)、溶解性总固体（TDS）和大肠杆菌等指标超标,且超标因子浓度呈点状扩散分布于三叠系中下统地层;另外,传统模糊综合评价中有57.1%的水质达到Ⅰ类标准,与多个探采点存在因子超标的情况不符,而通过级别特征值修正的模糊综合评价结果中分别有57.1%和28.6%的探采点水质为Ⅱ类或Ⅲ类标准,与着重突出最大超标因子权重的综合指数法类别标准差低0.011。因此,基于级别特征值的模糊综合评价能有效的反映水质整体水平,探采点水样超标因子浓度和同类水质的区分度,评价结果合理、可信。      

Evaluation of the benthic macroinvertebrate distribution in a stream environment during summer using biotic index

The purpose of this study is to evaluate the benthic macroinvertebrate distribution in the Ke?ap Stream (in the Eastern Black Sea Region of Turkey) for the summer period using biotic index. The water quality was assessed through the application of the Belgian biotic index. For this purpose, benthic macroinvertebrate sampling was performed in six sites along the Ke?ap Stream in the summer period, in July 2007. The distribution of dominant genera of the sites was evaluated according to water quality. According to the Belgian biotic index, II, III and IV water quality classes (slightly, moderately and heavily polluted, respectively) were determined in the stream. In addition, diversities of benthic macroinvertebrates in six sites were calculated. The biotic index values are found also consistent with the diversity values. Especially, in areas of the stream after industrial facilities water quality decreased. However, very heavy pollution was not observed accord to the biotic index values. It was found that Ephemeroptera was the dominant major taxon in all sampling sites. As a result of this biological evaluation, Ephemeroptera were concluded to be the most common taxa in the stream and the ephemeropterans, Potamanthus, Baetis and Ephemerella were dominant genera in the conditions of slightly, moderately and heavily polluted.     

华北典型河道地下水回补效果评价

针对华北地区严重的地下水超采问题,选取河北境内的滹沱河、滏阳河、南拒马河3条补水河道的试点河段开展地下水回补效果评价。采用层次分析法,建立了包括入渗回补率、地下水水位回升率、水质改善度、水面面积变化率、水生态改善度和公众满意度等6项指标的地下水回补效果评价指标体系;选择简便实用的指标计算方法对河段补水前后指标的变化进行计算分析,并对生态补水的效果进行评价分级。结果表明：补水结束时,滹沱河、滏阳河、南拒马河3条试点河段的平均入渗回补率为65%,地下水水位相对回升率为分别为36%,17%,6%,水质改善度依次为51%,34%,90%,水面面积总计增加了8.56 km²,水生态改善度依次为46%,87%,94%,公众满意度分别为90%,90%,80%。利用建立的地下水回补效果评价方法计算滹沱河、滏阳河、南拒马河综合得分分别为84,47,64分,评价等级分别为"非常好" "一般" "较好"。3条试点河段评价结果与实际补水效果基本一致。     

汉江上游重点保护水源污染控制方案研究

汉江上游是我国“十五”水环境规划的重点区域之一, 丹江口水库是具有战略意义的重点保护水源.汉江干流和丹江库区现状水质已达Ⅱ类标准, 但因为支流污染严重而形成巨大威胁, 主要污染物COD在“十五”有超标趋势.COD来源以生活源为主, 占77.2%;工业源中制浆造纸业为主要污染行业, COD排量占38.29%.列出了以城镇污水处理厂建设为主体的含A, B, C三种工程项目类型的污染控制方案.实施A类项目需投资27 500万元, 可使汉江上游COD在2005年降至32 682.25 t, 低于基准年1998年的排放水平, 落在省下达的目标总量控制范围内, 保证干流和丹江库区保持Ⅱ类水质; 接踵实施B, C类项目, 可保证其水质稳定达标, 并使支流水质得到明显改善.      

Effects of discharge of municipal waste on water quality of the lower Mississippi River

The effects of discharge of municipal wastes on water quality within the lower Mississippi River below Old River have been reevaluated using published water quality data in the Louisiana reach of the river for the water years 1974–1984. A novel graphical technique has facilitated the evaluation of upriver controls on water quality and the identification of sources and sinks along the lower Mississippi. Comparison of calculated annual fluxes at different downstream monitoring stations has simplified some of the problems inherent in evaluating analyses of samples collected from different water masses during a typical sampling run. The absolute concentrations of chloride, nitrite plus nitrate, total phosphorous, dissolved oxygen, BOD, and COD are all strongly dependent on processes occurring upriver. Nonpoint influx of materials from agricultural wastes and natural plant debris may be the dominant upstream sources of N, P, BOD, and COD. Increases in chloride and phosphorous downstream within the Lower Mississippi appear to be caused by discharge of industrial wastes. Nitrogen fluxes decrease downriver, except where there is local discharge of high-N, high-P industrial waste water, possibly from fertilizer plants. Removal of N and increases in BOD may be due in part to biological uptake. High river discharge rates and efficient, natural processes of reaeration maintain high oxygen saturation levels. With the exception of an increase in bacterial count, the discharge of municipal waste into the Mississippi River in Louisiana appears to have had no significant effect on water quality, a finding consistent with the earlier U.S. Geological Survey study of Wells (1980). It would be highly desirable for future mass balance studies if existing water quality programs on the Mississippi River were to adopt a Lagrangian sampling approach.     

Influence of water quality change in Fu River on Wetland Baiyangdian

Fu River is the only river that has perennial flow into Wetland Baiyangdian and is mainly composed of living sewage and industrial wastewater from Baoding city. Pollutant concentrations were monitored at three sections in the upstream, midstream, and downstream of Fu River and water quality in Wetland Baiyangdian was monitored at seven monitoring sites from 2001 to 2005. Results show that pollutant concentrations in Fu River and pollution load entering Wetland Baiyangdian generally increased during 2001–2005. On average, the concentrations of COD_Mn and BOD₅ increased by 46.5% and 50% from 2001 to 2005 in Fu River and COD_Mn increased by 17% in Wetland Baiyangdian. The total amount of COD_Mn and BOD₅ entering Wetland Baiyangdian increased from 1630 and 997 t/a to 2243 and 1583 t/a from 2001 to 2005, respectively. Total amount of water within the wetland and non-point source pollution input from surrounding areas also influenced the water quality in the wetland.     

Classification of rivers based on water quality assessment using factor analysis in Taizi River basin, northeast China

A method for river classification based on water quality assessment (WQA) was introduced using factor analysis (FA) in this paper. Sixty-nine sampling sites and 20 water quality parameters in Taizi River basin were selected for monitoring and analysis. Five factors were determined in FA, denoted as general, hardness, trophic, nitrogen pollution, and physical factors. The total factor scores (TFSs) of the WQA results from all sampling sites were calculated by the eigenvalue and factor score of each factor. The TFSs of 69 sites were interpolated with the measure of inverse distance weighted in the river buffer zone generated by ArcGIS 9.2 software to form a continuous spatial distribution along river channels. All streams were divided into five classes marked “excellent”, “good”, “fair”, “poor”, and “seriously polluted”. The classification result showed that the water quality of Taizi River basin deteriorated gradually from the mountain area to the plain area. Sewage and intensive human activities contributed to the deterioration of water quality since towns and farmland were dotted densely along the river basin.     

基于模糊综合优化模型的地下水质量评价

在应用模糊综合评判法进行地下水水质评估中,存在地下水质量标准与方法要求的分级标准不匹配以及隶属度绝对化的问题。文中在模糊综合评判法的基础上,引入相对隶属度概念表征评价指标与水质标准间的模糊关系,从而建立起模糊综合优化模型。应用该模型对青岛市大沽河地下水源地水质状况进行评价和分析对比,研究结果表明,地下水质量标准符合优化模型对评判标准类型的要求,克服了传统模型存在的标准不兼容问题。指标实测值介于某中间等级时,该等级与左右相邻等级的相对隶属度值均大于0。与绝对的隶属度分布相比,优化模型拓展了指标在各等级隶属度的分布,真实反映了其相对的特征。水源地南部地区(监测井S1和S3)地下水的总硬度、溶解性总固体与其他特征污染物的含量均超过Ⅳ类水质标准,优化模型判定的水质等级也为Ⅳ类水,评价结果符合研究区的实际情况,表明优化模型是可靠的。