The current study was carried out to delineate the seasonal hydrochemical characteristics and to quantify the suitability of groundwater for drinking and irrigation purposes in an alluvial plain ...adjacent to a paper wastewater irrigation zone, northwest China. Groundwater samples were collected from 14 groundwater monitoring wells in pre-monsoon, monsoon and post-monsoon seasons, respectively. Statistical analysis and Chadha diagram were used to delineate the groundwater hydrochemical characteristics. The matter element extension analysis (MEEA) model was proposed to quantify the overall groundwater quality. Irrigation water quality indicators were applied to assess the suitability of groundwater for irrigation purpose. The research results show that the hydrochemical facies for the majority of the groundwater samples is SO
4
·Cl–Na type with some minor hydrochemical facies of HCO
3
–Ca·Mg, HCO
3
–Na, and Cl·SO
4
–Ca·Mg types. The sequences of ions are Na
+
> Ca
2+
> Mg
2+
> K
+
for cations, and HCO
3
−
> Cl
−
> SO
4
2−
> CO
3
2−
for anions. The major ions and contaminants in the groundwater are controlled by multiple factors including hydrogeological conditions, rock weathering, water–rock interactions and human activities. The values of pH, TDS and TH show reduction in the monsoon season, indicating slight improvement of water quality during the monsoon season. Water quality assessment results based on MEEA show that the overall groundwater quality in the wastewater irrigation zone is generally fair to poor quality. Some groundwater samples are even classified as very poor quality, which is unsuitable for human consumption. They are also unsuitable for irrigation because of potential sodium hazard and salinity hazard. Groundwater from the Yellow River irrigation zone and the alluvial plain is generally suitable for domestic and irrigation uses. Some local water sampling locations may experience water quality improvement during the monsoon season, which, however, will generally not affect the final water quality classification for domestic and irrigation purposes. Interestingly, the study also finds that the variation trend of the correlation degree computed from MEEA can be useful in determining water quality improvement. This study may provide insights for people to make educated decisions in efficient groundwater quality protection and sustainable groundwater quality management.
Development of river water quality indices—a review Sutadian, Arief Dhany; Muttil, Nitin; Yilmaz, Abdullah Gokhan ...
Environmental monitoring and assessment,
2016, 1-2016, 2016-Jan, 2016-1-00, 20160101, Volume:
188, Issue:
1
Journal Article
Peer reviewed
Open access
The use of water quality indices (WQIs) as a tool to evaluate the status of water quality in rivers has been introduced since the 1960s. The WQI transforms selected water quality parameters into a ...dimensionless number so that changes in river water quality at any particular location and time could be presented in a simple and easily understandable manner. Although many WQIs have been developed, there is no worldwide accepted method for implementing the steps used for developing a WQI. Thus, there is a continuing interest to develop accurate WQIs that suit a local or regional area. This paper aimed to provide significant contribution to the development of future river WQIs through a review of 30 existing WQIs based on the four steps needed to develop a WQI. These steps are the selection of parameters, the generation of sub-indices, the generation of parameter weights and the aggregation process to compute the final index value. From the 30 reviewed WQIs, 7 were identified as most important based on their wider use and they were discussed in detail. It was observed that a major factor that influences wider use of a WQI is the support provided by the government and authorities to implement a WQI as the main tool to evaluate the status of rivers. Since there is a lot of subjectivity and uncertainty involved in the steps for developing and applying a WQI, it is recommended that the opinion of local water quality experts is taken, especially in the first three steps (through techniques like Delphi method). It was also observed that uncertainty and sensitivity analysis was rarely undertaken to reduce uncertainty, and hence such an analysis is recommended for future studies.
In the recent times, water quality of most of the rivers in India has been steadily degrading due to increasing numbers of point and non-point sources of pollution. The tremendous increase in ...population, rapid urbanization, change in irrigation patterns, and unplanned growth of industries without proper enforcement of environmental standards are some of the major causes for poor quality of river water. In addition, unpredictable and scanty rainfall is resulting in uncertain natural stream flow which further leads to uncertainty in assessing and predicting the quality of river water. This paper deals with the assessment of the overall status of water quality of a river by developing a fuzzy-based water quality evaluation system. The quality of water needed for different beneficial uses is based on the value of various parameters. Since the quality attributes of the parameters are fuzzy in nature, they have been described by the linguistic variables. The water quality index of each specific site is then calculated by aggregating the attributes with respect to their degree of importance, which is also expressed in the form of linguistic terms. Finally, a case study of the river Yamuna has been carried out to evaluate the fuzzy comprehensive water quality index (FCWQI). In this study, the FCWQI has been determined only for the use of water for drinking purposes though this model can be applied for other uses as well. The FCWQI developed herein is based on an integrated approach, which clearly describes the overall state of the water quality by a single rational number. Spatial and parametric sensitivity of the FCWQI model of the river basin is also determined using GIS-based geographically weighted regression technique. The methodology suggests a novel way of introducing parametric sensitivity in defining water quality indices used for surface water quality assessment.
The nitrogen cycle has been radically changed by human activities
. China consumes nearly one third of the world's nitrogen fertilizers. The excessive application of fertilizers
and increased ...nitrogen discharge from livestock, domestic and industrial sources have resulted in pervasive water pollution. Quantifying a nitrogen 'boundary'
in heterogeneous environments is important for the effective management of local water quality. Here we use a combination of water-quality observations and simulated nitrogen discharge from agricultural and other sources to estimate spatial patterns of nitrogen discharge into water bodies across China from 1955 to 2014. We find that the critical surface-water quality standard (1.0 milligrams of nitrogen per litre) was being exceeded in most provinces by the mid-1980s, and that current rates of anthropogenic nitrogen discharge (14.5 ± 3.1 megatonnes of nitrogen per year) to fresh water are about 2.7 times the estimated 'safe' nitrogen discharge threshold (5.2 ± 0.7 megatonnes of nitrogen per year). Current efforts to reduce pollution through wastewater treatment and by improving cropland nitrogen management can partially remedy this situation. Domestic wastewater treatment has helped to reduce net discharge by 0.7 ± 0.1 megatonnes in 2014, but at high monetary and energy costs. Improved cropland nitrogen management could remove another 2.3 ± 0.3 megatonnes of nitrogen per year-about 25 per cent of the excess discharge to fresh water. Successfully restoring a clean water environment in China will further require transformational changes to boost the national nutrient recycling rate from its current average of 36 per cent to about 87 per cent, which is a level typical of traditional Chinese agriculture. Although ambitious, such a high level of nitrogen recycling is technologically achievable at an estimated capital cost of approximately 100 billion US dollars and operating costs of 18-29 billion US dollars per year, and could provide co-benefits such as recycled wastewater for crop irrigation and improved environmental quality and ecosystem services.
•Twenty-one different WQI models were identified and reviewed.•Rivers are by far the most common application of WQI models.•Most models comprised of four key components, the specifics of which varied ...significantly.•Uncertainty and eclipsing problems are key issues affecting model accuracy.
The water quality index (WQI) model is a popular tool for evaluating surface water quality. It uses aggregation techniques that allow conversion of extensive water quality data into a single value or index. Globally, the WQI model has been applied to evaluate water quality (surface water and groundwater) based on local water quality criteria. Since its development in the 1960s, it has become a popular tool due to its generalised structure and ease-of-use. Commonly, WQI models involve four consecutive stages; these are (1) selection of the water quality parameters, (2) generation of sub-indices for each parameter (3) calculation of the parameter weighting values, and (4) aggregation of sub-indices to compute the overall water quality index. Several researchers have utilized a range of applications of WQI models to evaluate the water quality of rivers, lakes, reservoirs, and estuaries. Some problems of the WQI model are that they are usually developed based on site-specific guidelines for a particular region, and are therefore not generic. Moreover, they produce uncertainty in the conversion of large amounts of water quality data into a single index.
This paper presents a comparative discussion of the most commonly used WQI models, including the different model structures, components, and applications. Particular focus is placed on parameterization of the models, the techniques used to determine the sub-indices, parameter weighting values, index aggregation functions and the sources of uncertainty. Issues affecting model accuracy are also discussed.
Water quality evaluation is fundamental for water resources management. Water quality index (WQI) is an accurate and easily understandable method for assessing water quality for different purposes. ...In this study, the Iraqi water quality index (Iraq WQI) was constructed to be used to evaluate the Iraqi rivers for drinking. For this purpose, some statistical techniques, experts’ advice, literature reviews, and authors’ experience were used. First, the principal component analysis (PCA) method and the modified Delphi method were used to select the most influential water quality parameters and their relative weights. Second, the quality curves of selected parameters were drawn to calculate the WQI scores basing on the water quality standards. Of twenty-seven parameters, six parameters were chosen to be within the index depending on their effect on water quality in order to reflect the specific characteristics of the Iraqi waters. The Iraq WQI was applied to the Tigris River within Baghdad as a case study and for some sites on other Iraqi rivers, and gave acceptable results. Results revealed that the statistical techniques used in this paper can be applied in all Iraqi rivers considering their specific characteristics. Based on the reliability of the Iraq WQI, there is no longer a need to use Indices designed for water for other countries.
This work provides those involved in water purification research and administration with a comprehensive resource of methods for analyzing water to assure its safety from contaminants, both natural ...and human caused. The book first provides an overview of major water-related issues in developing and developed countries, followed by a review of issues of sampling for water analysis, regulatory considerations and forensics in water quality and purity investigations. The subsequent chapters cover microbial as well chemical contaminations from inorganic compounds, radionuclides, volatile and semi- volatile compounds, disinfectants, herbicides, and pharmaceuticals, including endocrine disruptors, as well as potential terrorist-related contamination. The last chapter describes the Grainger prize-winning filter that can remove arsenic from water sources and sufficiently protect the health of a large number of people. * Covers the scope of water contamination problems on a worldwide scale * Provides a rich source of methods for analyzing water to assure its safety from natural and deliberate contaminants * Describes the filter that won the $1 million Grainger prize and thereby highlighting an important approach to remediation
Water plays a critical role in securing the mine production and domestic consumption in mining areas. This research was carried out to assess the water quality status and to identify the ...hydrochemical processes contributing to the dissolved constituents of the water in the Guohua phosphorite mine, Guizhou Province, China. Multivariate statistical techniques and correlation analysis were employed to gain a better understanding of the hydrogeochemical processes, and water quality for domestic and irrigation purposes was also assessed. The results indicate that groundwater and surface water quality in the phosphorite mine area is currently excellent with low concentrations of major ions, salinity, and trace metals. Whereas,
E. coli
is excessive in groundwater and surface water, and treatment is required before the water is used for drinking purpose. Groundwater and surface water are, however, suitable for agricultural purposes. The major ions are Ca
2+
, Mg
2+
, and HCO
3
−
, and all water samples are predominantly of the HCO
3
–Ca·Mg type. Hierarchical cluster analysis (HCA) indicates that the water chemistry in the mining area is regulated by natural processes that are controlled by the different geological formations and different hydrogeological settings. Carbonate dissolution/precipitation is the key factor controlling the concentrations of Ca
2+
, Mg
2+
, and HCO
3
–
. Pyrite oxidation is an important factor influencing the concentration of SO
4
2–
, whereas evaporation is a minor factor regulating the water chemistry in the mining area. The study results are beneficial for sustainable water quality management in the mining area, and they will also interest mine hydrogeologists and practitioners of the world as a reference for relevant studies in other regions.
Assessment of groundwater and surface water quality along a river is important as it directly affects the agricultural, industrial activities and population. The objective of the study is to assess ...the quality of the Cauvery river water and adjacent groundwater for drinking and irrigational purposes and to identify the infuence of geogenic and anthropogenic sources. Groundwater and surface water samples were collected along the course of the river at approximate intervals of 25 km. The samples were analysed for electrical conductivity, pH, sodium, calcium, magnesium, potassium, bicarbonate, chloride and sulphate. Sodium was identified as the dominant cation and bicarbonate was the dominant anion for both river water and groundwater. These values were compared with limits recommended by the Bureau of Indian Standards for drinking purposes. The total dissolved solids were found to exceed the permissible limits for drinking water in most of the groundwater samples, and it was below the permissible limits in river water samples. Most of the river water samples were found to be suitable as per the drinking water quality standards, but most of the groundwater samples were unsuitable based on the concentration of major ions. Irrigation water quality was also assessed based on magnesium hazard, residual sodium carbonate, sodium percentage, sodium adsorption ratio, permeability index and salinity hazard. Most of the river water samples collected were suitable for irrigation, whereas most of the groundwater samples collected were doubtful for irrigation based on residual sodium carbonate and sodium percentage. Drinking water and irrigation water quality indices were also computed to assess the characteristics of water. Groundwater quality in locations nearer to the confluence of tributaries and industrial areas was of poor quality, while both river water and groundwater near the coast were poor, both for drinking and irrigation purposes. Comparison of the dissolved load with other rivers of the world was also made, which reveals that the Cauvery River yields comparatively higher dissolved load per area than most of the rivers. The chemical load in the river is due to natural and anthropogenic sources. Therefore, it is necessary to enforce the existing norms for the discharge of treated effluents by industries and townships along the river so as to reduce the chemicals contributed by anthropogenic sources.
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