National Sanitation Foundation Water Quality Research Articles

Suitability of treated wastewater for irrigation and its impact on groundwater resources in arid coastal regions: Insights for water resources sustainability

Water scarcity threatens agriculture and food security in arid regions like Saudi Arabia. The nation produces significant quantities of municipal wastewater, which, with adequate treatment, could serve as an alternative water source for irrigation, thereby reducing reliance on fossil and non-renewable groundwater. This study assessed the appropriateness of using treated wastewater (TWW) for irrigation in a dry coastal agricultural region in Eastern Saudi Arabia and its impact on groundwater resources. Field investigations were conducted in Qatif to collect water samples and field measurements. A multi-criteria approach was applied to evaluate the TWW's suitability for irrigation, including complying with Saudi Standards, the Irrigation Water Quality Index (IWQI), the National Sanitation Foundation water quality index (NSFWQI), and the individual irrigation indices. In addition, the impact of TWW on groundwater was assessed through hydrogeological and isotope approaches. The results indicate that the use of TWW in the study area complied with the Saudi reuse guidelines except for nitrate, aluminum, and molybdenum. However, irrigation water quality indices classify TWW as having limitations that necessitate the use for salt-tolerant crops on permeable and well-drained soils. Stable isotopic analysis (δ2H, δ18O) revealed that long-term irrigation with TWW affected the shallow aquifer, while deep aquifers were minimally impacted due to the presence of aquitard layer. The application of TWW irrigation has successfully maintained groundwater sustainability in the study area, as evidenced by increased groundwater levels up to 2.3 m. Although TWW contributes to crop productivity, long term agricultural sustainability could be enhanced by improving effluent quality, regulating irrigation practices, implementing buffer zones, and monitoring shallow groundwater. An integrated approach that combines advanced wastewater treatment methods, community involvement, regulatory oversight, and targeted monitoring is recommended to be implemented.

Assessment of the Euphrates River’s Water Quality at a Some Sites in the Iraqi Governorates of Babylon and Karbala

The majority of third-world nations with rivers running through them struggle with the issue of contaminated water. It is believed to be a very difficult challenge to get the water quality below the typical permitted levels for drinking, as well as for industrial and agricultural reasons, is thought to be a very difficult challenge. This study aims to assess the quality of water available to the governorates of Karbala and Babylon. measuring water quality with the water quality index It expresses the water quality as a single number by comparing results from the analysis of a number of physico-chemical and bacteriological parameters with current norms. The National Sanitation Foundation Water Quality Index (NSFWQI), the Canadian Council of Ministers of the Environment Water Quality Index (CCMEWQI), the Oregon Water Quality Index (OWQI), the Weight Arithmetic Water Quality Index (WAWQI), the IRCA water quality index, and The Iraqi Water Quality Index (Iraqi WQI), which was used for irrigation and drinking, will all be compared in this context. Twenty one parameters were analyzed, including pH, EC, TDS, Tem, DO, BOD, COD, NO3, Alkalinity, CL, TH, Ca, Mg, Na, K, B, SO4, Salinity, TOC, E.Coli., Total coliform. The results for five stations during three season ranged between medium and excellent for the NSF classification, while ranged between poor-marginal in CCME classification, the results were for OWQI classification between poor-fair-excellent, in WAWQI classification the results were within unsuitable to excellent, IRCA classification indicated that all stations fall within sanitary infeasible and in the last IRAQI classification the results were between very bad to bad for drinking water as for irrigation of agricultural lands, it is not acceptable for irrigation.

Evaluation of karst spring water quality in northeast Tennessee using water quality indices

AbstractEnsuring access to safe drinking water to protect public health in communities underserved or unserved by centralized water systems requires regular water quality testing and reporting. However, households depending on unregulated water systems like wells and springs, which are less routinely tested, may be unaware of their water quality. Access to easy‐to‐comprehend water quality information may be challenging. Therefore, this study utilized multiple water quality parameters to determine karst spring water quality using two water quality index (WQI) methods. This approach aggregates and summarizes water quality data into a single value or index characterizing the general health status of water at a given location in an easy‐to‐understand way. In situ measurements of physicochemical parameters (pH, dissolved oxygen, temperature, turbidity, conductivity, specific conductance, total dissolved solids, and oxidation–reduction potential) were taken at 50 karst springs in east Tennessee during summer 2021. Water samples were analyzed for microbial (fecal coliform and Escherichia coli), nutrients (nitrate and nitrite), and radiological (radon) constituents using standard analytical methods. WQI method 1 (Brown et al. Water Quality Index) rated 12% of springs as “very poor” water quality and 88% as “unfit for drinking.” WQI method 2 (National Sanitation Foundation Water Quality Index) rated 4% of the sampled springs as “good,” 92% as “moderate,” and 4% as “bad.” Given the prevalence of fecal contamination in the sampled springs, even springs rated good should be properly treated before consumption. Overall, these findings demonstrate the importance of selecting appropriate WQI for the end water use, and for water quality information that is easily understandable by water users.

Evaluation of the water quality of a high Andean lake using different quantitative approaches

This study assessed a high Andean lake's trophic state and water quality using methodologies with eutrophication and water quality indexes. Water samples were collected at six points in the lake, with a monthly frequency, for three winter and three summer months. Dissolved oxygen, pH, phosphates, nitrates, transparency, chlorophyll-a, fecal coliforms, biological oxygen demand (BOD), temperature, and turbidity were determined at each point. The trophic state of the lake was categorized by applying the Organization for Economic Cooperation and Development (OECD) eutrophication index, Carlson's trophic state index (CTSI) and trophic index (TRIX). In addition, National Sanitation Foundation water quality index (NSF-WQI), Canadian Water Quality Index (CCME-WQI) and Oregon Water Quality Index (OWQI) were used to evaluate water quality. Results indicated that the lake had a high level of eutrophication, suggesting an excessive accumulation of nutrients in the water. CTSI and TRIX index showed that the lake was in a hyper-eutrophic state, while according to the OECD methodology, the trophic state related to phosphorus and transparency was hypereutrophic, and according to chlorophyll, it varied from mesotrophic to eutrophic. The NSF index classified the lake with average quality, the CCME index indicated fair water quality, and the OWQI classified it as very poor. Therefore, the water quality of the high andean lake assessed by eutrophication and water quality indexes presented significant differences based on physicochemical characteristics. The human influence was identified as the main cause of eutrophication, including tourism and agriculture. These results suggest that measures should be taken to reduce human activity in the area and control pollution in the lake.

Sediment analysis and assessment of water quality in spacial variation using water quality index (NSFWQI) in Moragoda canal in Galle, Sri Lanka

The Moragoda Canal in Galle, Sri Lanka is one of the most widely used canals for water supply for various purposes. Water quality is deteriorating due to industrialization, agricultural practices and sewage disposal. Therefore, this study aims to examine the effects of industrialization and human activities on water quality and sediment composition in the Moragoda Canal in terms of water quality indices based on the National Sanitation Foundation Water Quality Index (NSF-WQI). Sampling was done in three different stretches of the streams such as upstream, middle stream, and downstream for evaluation of water quality and sediment composition analysis. Nine water quality parameters such as dissolved oxygen, chemical oxygen demand, biological oxygen demand, temperature, pH, turbidity, phosphate, nitrate, and total coliform were considered for index estimation. The correlation between water quality parameters generated by principal component analysis shows that the main parameters affecting the water quality are vary in three different stretches of the canal. Based on the water quality indicators, anthropogenic activities are accountable to deteriorate the quality of the canal. Therefore, the pollution status of the canal need to be aware publicly.

Evaluation of water quality of Chahnimeh as natural reservoirs from Sistan region in southwestern Iran: a Monte Carlo simulation and Sobol sensitivity assessment

Maintaining the water quality is essential because of the limitation of drinking water bodies and their significant effects on life. Recently, much scientific interest has been attracted to the ecological condition assessment of water resources. Because of numerous health issues connected to water quality, the present work aimed to define the water quality status of Chahnimeh reservoirs, Sistan and Baluchistan province, Iran via the Iran Water Quality Index (IRWQISC), the National Sanitation Foundation Water Quality Index (NSFWQI), and human risk assessment. This cross-sectional descriptive work was accomplished in 4 seasons in 2020. The samples were gathered from 5 various points of Chahnimeh reservoirs. This study led to the results that the NSFWQI index was between 29.4 to 49.32, which showed “bad” quality, and the IRWQI index was between 19.27 and 39.23, which indicated “bad” and “relatively bad” quality. The best water quality based on both indexes was observed in the spring, and the worst was in the fall and summer. The highest value of HQ related to nitrate in drinking water was 1.60 in the group of children. However, according to the Monte Carlo simulation, HQ95% was estimated as 1.29. The Sobol sensitivity analysis of the first-order effect showed that daily water’s daily ingestion rate (IR) was the most sensitive input. In addition, the value of the second-order effect indicated that the interaction effect of concentration—ingestion rate was the most sensitive input parameter for HQ. Therefore, regular monitoring is necessary to ensure water safety for human consumption.

Evaluating Water Quality and Distribution of Phosphates and Nitrates in Soils, Water and Sediments from Agrochemicals Usage in Santa, Cameroon

Worldwide pollution of soils, rivers, streams and lakes from anthropogenic activities has been one of the most crucial environmental problems since the beginning of the 20th century. In Santa, the increasing use of agrochemicals is disturbing, as most farmers have little or no idea about application techniques or the effects of these chemicals on the environment. The objective of this work was to determine the knowledge on pesticides and fertilizer use by tracing their availability in surface and subsurface soils, in water and sediments using nitrates and phosphates, and by evaluating the quality of some water sources in Santa. Questionnaires were used to survey the knowledge of fertilizers and pesticide utilization by farmers, while water, soil and sediment samples were collected from selected field sites to determine the distribution of phosphates and nitrates. The pollution of water from some water sources in Santa was evaluated using the National Sanitation Foundation Water Quality Index (NSFWQI). The results show that most farmers cultivate vegetables (86%), with high applications of pesticides for pest control, and 100% cultivate without fallowing using much fertilizer. 90% of the farmers used nitrogen, phosphorus and potassium (NPK) fertilizers along with urea fertilizers. Phosphates were present in soils and sediments but absent in water, while, nitrates were present in soils, water and sediments. While phosphates were significantly higher than nitrates in soils and sediments, the reverse was observed in water, where nitrate concentrations were significantly higher than those of phosphates. Phosphates showed more mobility in the soil than nitrates, as phosphate concentration values were higher in subsurface soils than surface soils. NSFWQI values for three water bodies studied indicated moderate pollution, making them not suitable for drinking. The absence of fallowing and lack of proper knowledge on soil nutrient content have led to excessive use of agrochemicals by farmers in Santa, which has resulted in soil, water, and sediment contamination.

Evaluation of oral and dermal health risk exposures of contaminants in groundwater resources for nine age groups in two densely populated districts, Nigeria

Human health and the sustainability of the socioeconomic system are directly related to water quality. As anthropogenic activity becomes more intense, pollutants, particularly potentially harmful elements (PHEs), penetrate water systems and degrade water quality. The purpose of this study was to evaluate the safety of using groundwater for domestic and drinking purposes through oral and dermal exposure routes, as well as the potential health risks posed to humans in the Nnewi and Awka regions of Nigeria. The research involved the application of a combination of the National Sanitation Foundation Water Quality Index (NSFWQI), HERisk code, and hierarchical dendrograms. Additionally, we utilized the regulatory guidelines established by the World Health Organization and the Standard Organization of Nigeria to compare the elemental compositions of the samples. The physicochemical parameters and NSFWQI evaluation revealed that the majority of the samples were PHE-polluted. Based on the HERisk code, it was discovered that in both the Nnewi and Awka regions, risk levels are higher for people aged 1 to <11 and >65 than for people aged 16 to <65. Overall, it was shown that all age categories appeared to be more vulnerable to risks due to the consumption than absorption of PHEs, with Cd > Pb > Cu > Fe for Nnewi and Pb > Cd > Cu > Fe for water samples from Awka. Summarily, groups of middle age are less susceptible to possible health issues than children and elderly individuals. Hierarchical dendrograms and correlation analysis showed the spatio-temporal implications of the drinking groundwater quality and human health risks in the area. This research could help local government agencies make informed decisions on how to effectively safeguard the groundwater environment while also utilizing the groundwater resources sustainably.

Assessment of Water Quality and Heavy Metal Environmental Risk on the Peri-Urban Karst Tropical Lake La Sabana, Yucatán Peninsula

In the Yucatán Peninsula, anthropogenic activities such as urbanization and the final disposal of solids and wastewater critically impact aquatic systems. Here, we evaluated the anthropogenic-related environmental alteration of Lake La Sabana, located in the northern limits of one of the main cities of the Mexican Caribbean. We evaluated lake water quality, using physical, chemical, and microbiological indicators, and heavy metals in surficial sediment and fish tissue to evaluate the potential environmental risk. Multivariate analyses revealed that environmental conditions in La Sabana are spatially and temporally heterogeneous. Medium to bad water quality was determined within different basins by the National Sanitation Foundation water quality index, related to the degree of anthropogenic influence at each zone. The central-south zones displayed critical microbiological values largely exceeding national standards. Heavy metals in sediment and fish tissue such as Zn and Hg were relatively low, but Hg concentrations threaten the ecological environment. Incipient wastewater treatment and its final disposal in La Sabana are mainly responsible for the changes in the trophic status and availability of nutrients, which in turn may have promoted changes in the biological structure and aquatic plant invasions. Lake La Sabana can be considered a model of the potential and sequential effects of anthropogenic alterations in the oligotrophic karst tropical aquatic systems in the Yucatan Peninsula.

Impact of COVID-19 lockdown on the water quality of the Damodar River, a tributary of the Ganga River in West Bengal.

The online version contains supplementary material available at 10.1007/s40899-022-00790-2.

Assessment of urban river water quality using modified NSF water quality index model at Siliguri city, West Bengal, India

Rivers are the source of freshwater for any urban community and hence, monitoring of river water is an obligatory yet challenging task. This study was conducted in a subtropical urban river in India with the view of developing a quantitative approach to assess its water quality (WQ) status. For the purposes of this study, water samples were collected from five locations across the Mahananda River main streams encompassing both urbanised and non-urbanised parts of the Siliguri city during April to June of 2021 and collected samples were analysed for fourteen common WQ indicators: pH, Temperature, Conductivity, TDS, Turbidity, Total Hardness (TH), DO, BOD, COD, NO 3 − , PO 4 3− , Cl − , Fecal Coliform (FC) and E. coli for assessing water quality. In order to obtain WQ status, the present study utilised the modified national sanitation foundation (NSF) water quality index (WQI) model, whereas the crucial WQ indicators were identified using the principal components analysis (PCA) technique. All WQ indicators were considered to compute the NSF-WQI except water pH and TH. Most WQ indicators were breached the guideline values of the Bureau of Indian Standards (BIS) and Indian Standards (IS) for surface water. The modified NSF-WQI results revealed that the Mahananda River water quality was “good” to “medium” quality and the water is only suitable for limited purposes under certain conditions. The findings of this study provided evidence that the river WQ is heavily influenced by urban pressures because relatively “good” WQ was found at the sampling location of the outer part of the urban area. The results of this research could be effective in improving the Mahananda River's water quality and maintaining its complex ecosystem in order to ensure sustainable urban growth.

The use of PCA and ANN to improve evaluation of the WQIclassic, development of a new index, and prediction of WQI, Coastel Constantinois, northern coast of eastern Algeria

Abstract The objective of this research was to arrive at a better assessment of the quality of surface water in the Constantine region. The focus was on the comparison of three classical indices WQINSF (National Sanitation Foundation Water Quality Index), WQICCME (Canadian Council of Ministers of the Environment Water Quality Index) and WQIAP (weighted arithmetical Water Quality Index), the development of a new index and the prediction by ANN (artificial neural network) of WQI indices. The principal components analysis (PCA) allows the selection of 10 parameters to be used in the calculation of the classical WQI, and eight principal components to be used as input for the new proposed index (regularized WQI). However the ANN is applied for the search for prediction models of classical WQI and developed WQI. The results show that the WQIAP index assesses water quality better, and that the regularized WQI further promotes the assessment of water quality. WQIR shows that, after the pollution peak, the water quality does not return to its initial state. The modeling approach by ANN offers an effective alternative to predict the WQI, it subsequently appears that the ANN predicts the new index WQIRregularized (R2 = 0.999) better than the classic model WQIAP (R2 = 0.99).

Water quality assessment in the ecologically stressed lower and estuarine stretches of river Ganga using multivariate statistical tool.

Water quality of the Ganga River system is changing day by day due to multifold increase in population, especially near the banks of river Ganga, and associated exponential amplification of anthropogenic activities also played a remarkable role in it. The ecologically important lower and estuarine stretch of river Ganga comprising 7 different sampling stations, i.e., Jangipur, Berhampore, Balagarh, Tribeni, Godakhali, Diamond Harbour and Fraserganj, were selected for the study as the stretch is enriched with the vast number of floral and faunal diversity. The study was conducted for a period of 5years, i.e., from 2016 to 2020. In the study, various analytical tools and techniques were used for the assessment of riverine water quality, i.e., for calculation of water quality index(WQI); The National Sanitation Foundation Water Quality Index (NSF-WQI) and the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI) were used for the assessment.Along with WQI various statistical univariate as well as multivariate analytical tools like principal component analysis, correlation, ANOVA, and cluster analysis were also used to achieve the desired outputs. In the study, it has been observed that NSF-WQI varied from 61 to 2552, in which the higher value of NSF-WQI denoted the unsuitability of the water quality concerning the drinking water standards and vice versa. The CCME-WQI represented a similar trend as that of NSF-WQI, as it varied from 18 to 92 in which the lower value denoted degradation in the drinking water quality and vice versa. The study revealed that the Diamond Harbour-Fraserganj stretch is having an undesired level of water quality which were analyzed based on the drinking water guideline values of the Bureau of Indian Standards and that of NSF-WQI and CCME-WQI.

Optimal Location of Water Quality Monitoring Stations Using an Artificial Neural Network Modeling in the Qarah-Chay River Basin, Iran

The economic development, livelihood and drinking water of millions of people in the central plateau of Iran depend on the Qarah-Chay River, but due to a lack of inappropriate monitoring, it has been exposed to destruction and pollution. Consequently, an assessment of the river’s water quality is of utmost importance for both the management of human health and the maintenance of a safe environment, which can be achieved by determining the best locations for pollution monitoring stations along rivers. In this study, artificial neural networks (ANNs) has been used to optimize the locations for Qarah-Chay River monitoring stations in Markazi province, Iran. The data are collected based on the Iranian Water Quality Index (IRWQI), the US National Sanitation Foundation Water Quality Index (NSFWQI) and the Oregon Water Quality Index (OWQI). The database is given to a multilayer perceptron (MLP) neural network along with a geographic information system (GIS). The output of this study identified six pollution monitoring stations on the river, which are mainly downstream due to the accumulation of land uses and the concentration of pollution. The gradient of the MLP network training courses model from the proposed monitoring stations is 0.062299. In addition, the performance evaluation criteria of the proposed MLP model for F1-score, recall, precision and accuracy were 0.85, 0.84, 0.88 and 0.88, respectively. The results obtained help managers to properly monitor the river’s water resources with accuracy, efficiency and lower cost; furthermore, the findings were able to provide scientific references for river water quality monitoring and river ecosystem protection.

Ecological Health Assessment of Renuka Lake, Himachal Pradesh, India

Researchers, policymakers, and governments are increasingly interested in assessing the ecological health (EH) of lakes and streams. The EH of a lake can be expressed in terms of water quality, trophic state and biodiversity of riparian vegetation, macroinvertebrates and fishes. The ecological health index (EHI) of Renuka lake, Himachal Pradesh of India, was analyzed based on National Sanitation Foundation Water Quality Index (NSFWQI), Carlson’s Trophic State Index (TSI), Simpson Diversity Index (SDI), and Shannon-Weiner index (SWI). The results of NSFWQI and CTSI are found in the range of 40-59 and 49.9-58.9 respectively indicating that the water quality was poor to medium and not suitable for drinking purposes but can be used for secondary purposes such as agriculture, industry, and recreation etc. The trophic state of the lake is similarly in the eutrophic range, with an overall EHI of 1.81-2.47, indicating poor to medium trophic status. Apart from analyzed results, the EH category from mesotrophic to a eutrophic state of the lake is caused due to the cultural siltation/nutrient loading, religious practices, land tenurial issues, and uncontrolled tourist pressure followed by recreational activities on water bodies and lake vicinity. Accordingly, suitable restoration methods such as source control, desilting/dredging, and lake aquatic plantation are suggested to recover the ecological health of the lake back to a mesotrophic or oligotrophic state.

Modeling the impact of potentially harmful elements on the groundwater quality of a mining area (Nigeria) by integrating NSFWQI, HERisk code, and HCs.

With excess potentially harmful elements (PHEs), drinking water is marked unsuitable and could pose some health risks when ingested or absorbed by humans. Different age groups are exposed to varied risk levels of PHEs. Analyzing the health risks of PHEs for several age groups could provide detailed insights for effective water resources management. No known study in Ameka Pb-Zn mine province (Nigeria) investigated the health risks of PHEs in water resources for several age groups. Therefore, in this paper, the carcinogenic and non-carcinogenic health risks (due to ingestion and dermal contact) of PHEs in groundwater resources of this area were investigated for nine age groups. To achieve its aim, this study integrated novel HERisk code, NSFWQI (national sanitation foundation water quality index), and hierarchical clusters (HCs) in modeling the groundwater quality. Standard elemental composition analysis revealed that the groundwater is polluted with PHEs. The NSFWQI indicated that 15% of the analyzed water samples have moderate water quality whereas 85% are unsuitable for drinking. The HERisk code, which considered nine age groups (1 to < 2years, 2 to < 3years, 3 to < 6years, 6 to < 11years, 11 to < 16years, 16 to < 18years, 18 to < 21years, 21 to < 65years, and > 65years), revealed that all the samples pose high chronic and cancer risks to all the age groups due to oral ingestion. However, it was realized that age groups 1 to < 16 and > 65 are posed with higher risks than age groups 18 to < 65. Overall, it was realized that all the age groups are far more exposed to ingest or absorb Se, Co, Cd, Se, As, Ni, and Pb than Cu, Fe, and Zn. Nevertheless, the health risks due to dermal absorption are far lower than the risks due to oral ingestion. Conclusively, children and aging people are more predisposed to the health threats than middle-aged populations. HCs and geospatial maps aided the spatiotemporal analysis of the groundwater quality.

Assessing Water Quality Status Using a Mathematical Simulation Model of El Abid River (Morocco)

In semi-arid or arid regions, where available freshwater is limited, surface water requires repeated quality testing to avoid pollution. Sampling trips of different frequencies are onerous and require expensive laboratory analysis. Simulation appears to be a reliable alternative method to overcome such challenges. The simulation presented here was conducted by solving the mass balance equation while considering the inputs controlling each simulated parameter. The mass balance equation (a differential equation) was solved by finite difference numerical approximation to provide parameters for pollutant concentrations at each station or moment (based on selected steps). This solution was integrated to simulate pollution indicators (biochemical oxygen demand and dissolved oxygen), nitrogen forms, and orthophosphates. The National Sanitation Foundation water quality index (NSF-WQI) was calculated using these parameters. Using 12 months of measurement data, results were compared for NSF-WQI calculated through measured and simulated data, showing a significant correlation with R2 = 0.8, meaning the model demonstrated good calibration and validation. The elaborated model is a useful tool for decision makers to test and propose quality improvement solutions for watercourses suffering from quality deterioration.

Ground and surface water quality assessment of Palladam Taluk using Geographical Information System and Modified National Sanitation Foundation -Water Quality Index

In this work, the assessment of surface and ground water quality of Palladam Taluk, Tiruppur, district, Tamil Nadu, India were carried out using Geographical Information System (GIS) and Modified National Sanitation Foundation -Water Quality Index (MNSF-WQI). Four samples from surface and twenty seven samples from ground water sources were taken from Palladam Taluk, Tiruppur District. In the current study, the surface and ground water samples were analysed for temperature, pH, dissolved oxygen (DO), electrical conductivity (EC), biological oxygen demand (BOD), turbidity, total dissolved solids (TDS), total hardness (TH), faecal coliforms (FC), total phosphate (TP), total nitrate (TN), chlorides (Cl-), sodium (Na+) and fluoride (F-) ions to investigate the suitability of surface and ground water for drinking and agricultural purposes through Geographic information system (GIS) and modified national sanitation foundation water quality index (MNSF-WQI) technique. The concentrations of TH, TDS, Cl- and Na+ were observed to be above the desirable limit of World Health Organization (WHO) guidelines and Bureau of Indian Standards (BIS). whereas F-, BOD, DO, EC, TP, TN, FC and temperature were within the acceptable limits. The GIS-based WQI map analysis indicated that 45% of the study area having good water quality index and the remaining area showed medium quality water. Dyeing and textile industries in the study area are responsible for deteriorating the quality to medium quality of water which was not appropriate for direct utilization and needed prior treatment. There is no detailed report on assessment of the surface and ground water quality of Palladam Taluk in Tamil Nadu using GIS and MNSF-WQI techniques.

Multivariate statistics and entropy theory for irrigation water quality and entropy-weighted index development in a subtropical urban river, Bangladesh.

Currently, a well-developed combination of irrigation water quality index (IWQIs) and entropy water quality index (EWQIs) for surface water appraisal in a polluted subtropical urban river is very scarce in the literature. To close this gap, we developed IWQIs by establishing statistics-based weights of variables recommended by FAO 29 standard value using the National Sanitation Foundation Water Quality Index (NSFWQI) compared with the proposed EWQIs based on information entropy in the Dhaleshwari River, Bangladesh. Fifty surface water samples were collected from five sampling locations during the dry and wet seasons and analyzed for sixteen variables. Principal component analysis (PCA), factor analysis (FA), Moran's spatial autocorrelation, and random forest (RF) model were employed in the datasets. Weights were allocated for primary variables to compute IWQI-1, 2 and EWQI-1, 2, respectively. The resultant IWQIs showed a similar trend with EWQIs and revealed poor to good quality water, with IWQI-1 for the dry season and IWQI-2 for the wet season is further suggested. The entropy theory recognized that Mg2+, Cr, TDS, and Cl- for the dry season and Cd, Cr, Cl-, and SO42- for the wet season are the major contaminants that affect irrigation water quality. The primary input variables were lessened to ultimately shortlisted ten variables, which revealed good performance in demonstrating water quality status since weights have come effectively from PCA than FA. The results of the RF model depict NO3-, Mg2+, and Cr as the most predominant variables influencing surface water quality. A significant dispersed pattern was detected for IWQImin-3 in the wet season (Moran's I>0). Overall, both IWQIs and EWQIs will generate water quality control cost-effective, completely objective to establish a scientific basis of sustainable water management in the study basin.

Spatio-seasonal variation of water quality influenced by land use and land cover in Lake Muhazi

Understanding the influence of land use/land cover (LULC) on water quality is pertinent to sustainable water management. This study aimed at assessing the spatio-seasonal variation of water quality in relation to land use types in Lake Muhazi, Rwanda. The National Sanitation Foundation Water Quality Index (NSF-WQI) was used to evaluate the anthropogenically-induced water quality changes. In addition to Principal Components Analysis (PCA), a Cluster Analysis (CA) was applied on 12-clustered sampling sites and the obtained NSF-WQI. Lastly, the Partial Least Squares Path Modelling (PLS-PM) was used to estimate the nexus between LULC, water quality parameters, and the obtained NSF-WQI. The results revealed a poor water quality status at the Mugorore and Butimba sites in the rainy season, then at Mugorore and Bwimiyange sites in the dry season. Furthermore, PCA displayed a sample dispersion based on seasonality while NSF-WQI’s CA hierarchy grouped the samples corresponding to LULC types. Finally, the PLS-PM returned a strong positive correlation (+ 0.831) between LULCs and water quality parameters in the rainy season but a negative correlation coefficient (− 0.542) in the dry season, with great influences of cropland on the water quality parameters. Overall, this study concludes that the lake is seasonally influenced by anthropogenic activities, suggesting sustainable land-use management decisions, such as the establishment and safeguarding protection belts in the lake vicinity.