An assessment of global groundwater quality is needed in response to the threats posed by anthropogenic and geogenic contaminants. This essay summarises the challenges involved, including a large ...number of potentially relevant water quality parameters, the poor availability of data in many regions and the complex nature of groundwater systems. Direct monitoring data can sometimes be augmented by indirect methods such as earth observations, and by involving citizen science. A new web portal is being developed to complement existing databases.
Water quality improvement is one of the top priorities in the global agenda endorsed by United Nation. In this review manuscript, a holistic view of water quality degradation such as concerned ...pollutants, source of pollution, and its consequences in major river basins around the globe (at least 1 from each continent and a total of 16 basins) is presented. Additionally, nine contemporary techniques such as field scale evaluation, watershed scale evaluation, strategies to identify critical source areas, optimization strategies for placement of best management practices (BMPs), social component in watershed modeling, machine learning algorithms to address water quality problems in complex natural systems concomitant with spatial heterogeneity, establishing a total maximum daily loads (TMDLs), remote sensing in monitoring water quality, and developing water quality index are discussed. Next, the existing barriers to improve water quality are classified into primary and secondary impediments. A detail discussion of three primary impediments (climate change, urbanization and industrial activities, and agriculture) and ten secondary impediments (availability of water quality data, complexity of system, lack of skilled person, environmental legislation, fragmented mandate, limitation in resources, environmental awareness, resistance to change, alteration of nutrient ratio by river damming, and emerging pollutants) are illustrated. Finally, considering all the existing knowledge gaps pertaining to contemporary strategies, a future direction of water quality research is outlined to significantly improve the water quality around the globe.
Display omitted
•Water quality status of 15 major River Basins around the world is discussed.•A detail discussion of nine contemporary strategies to improve water quality in major River Basins are provided.•Three primary and ten secondary impediments to degrade water quality is described thoroughly.•Based on the existing knowledge gaps, a future direction of water quality research is outlined.
Multivariate statistical techniques, including cluster analysis (CA), discriminant analysis (DA), principal component analysis (PCA) and factor analysis (FA), were used to evaluate temporal and ...spatial variations in and to interpret large and complex water quality datasets collected from the Shuangji River Basin. The datasets, which contained 19 parameters, were generated during the 2 year (2018-2020) monitoring programme at 14 different sites (3192 observations) along the river. Hierarchical CA was used to divide the twelve months into three periods and the fourteen sampling sites into three groups. Discriminant analysis identified four parameters (CODMn, Cu, As, Se) loading more than 68% correct assignations in temporal analysis, while seven parameters (COD, TP, CODMn, F, LAS, Cu and Cd) to load 93% correct assignations in spatial analysis. The FA/PCA identified six factors that were responsible for explaining the data structure of 68% of the total variance of the dataset, allowing grouping of selected parameters based on common characteristics and assessing the incidence of overall change in each group. This study proposes the necessity and practicality of multivariate statistical techniques for evaluating and interpreting large and complex data sets, with a view to obtaining better information about water quality and the design of monitoring networks to effectively manage water resources.
The impact of land use on water quality is becoming a global concern due to the increasing demand for freshwater. This study aimed to assess the effects of land use and land cover (LULC) on the ...surface water quality of the Buriganga, Dhaleshwari, Meghna, and Padma river system in Bangladesh. To determine the state of water, water samples were collected from twelve locations in the Buriganga, Dhaleshwari, Meghna, and Padma rivers during the winter season of 2015 and collected samples were analysed for seven water quality indicators: pH, temperature (Temp.), conductivity (Cond.), dissolved oxygen (DO), biological oxygen demand (BOD), nitrate nitrogen (NO
3
-N), and soluble reactive phosphorus (SRP) for assessing water quality (WQ). Additionally, same-period satellite imagery (Landsat-8) was utilised to classify the LULC using the object-based image analysis (OBIA) technique. The overall accuracy assessment and kappa co-efficient value of post-classified images were 92% and 0.89, respectively. In this research, the root mean squared water quality index (RMS-WQI) model was used to determine the WQ status, and satellite imagery was utilised to classify LULC types. Most of the WQs were found within the ECR guideline level for surface water. The RMS-WQI result showed that the “fair” status of water quality found in all sampling sites ranges from 66.50 to 79.08, and the water quality is satisfactory. Four types of LULC were categorised in the study area mainly comprised of agricultural land (37.33%), followed by built-up area (24.76%), vegetation (9.5%), and water bodies (28.41%). Finally, the Principal component analysis (PCA) techniques were used to find out significant WQ indicators and the correlation matrix revealed that WQ had a substantial positive correlation with agricultural land (
r
= 0.68,
P
< 0.01) and a significant negative association with the built-up area (
r
= − 0.94,
P
< 0.01). To the best of the authors’ knowledge, this is the first attempt in Bangladesh to assess the impact of LULC on the water quality along the longitudinal gradient of a vast river system. Hence, we believe that the findings of this study can support planners and environmentalists to plan and design landscapes and protect the river environment.
High-frequency water quality measurements in streams and rivers have expanded in scope and sophistication during the last two decades. Existing technology allows in situ automated measurements of ...water quality constituents, including both solutes and particulates, at unprecedented frequencies from seconds to subdaily sampling intervals. This detailed chemical information can be combined with measurements of hydrological and biogeochemical processes, bringing new insights into the sources, transport pathways, and transformation processes of solutes and particulates in complex catchments and along the aquatic continuum. Here, we summarize established and emerging high-frequency water quality technologies, outline key high-frequency hydrochemical data sets, and review scientific advances in key focus areas enabled by the rapid development of high-frequency water quality measurements in streams and rivers. Finally, we discuss future directions and challenges for using high-frequency water quality measurements to bridge scientific and management gaps by promoting a holistic understanding of freshwater systems and catchment status, health, and function.
Optical sensing of chlorophyll-a (chl-a), turbidity, and fluorescent dissolved organic matter (fDOM) is often used to characterize the quality of water. There are many site-specific factors and ...environmental conditions that can affect optically sensed readings; notwithstanding the comparative implication of different procedures used to measure these properties in the laboratory. In this study, we measured these water quality properties using standard laboratory methods, and in the field using optical sensors (sonde-based) at water quality monitoring sites located in four watersheds in Canada. The overall objective of this work was to explore the relationships among sonde-based and standard laboratory measurements of the aforementioned water properties, and evaluate associations among these eco-hydrological properties and land use, environmental, and ancillary water quality variables such as dissolved organic carbon (DOC) and total suspended solids (TSS). Differences among sonde versus laboratory relationships for chl-a suggest such relationships are impacted by laboratory methods and/or site specific conditions. Data mining analysis indicated that interactive site-specific factors predominately impacting chl-a values across sites were specific conductivity and turbidity (variables with positive global associations with chl-a). The overall linear regression predicting DOC from fDOM was relatively strong (
R
2
= 0.77). However, slope differences in the watershed-specific models suggest laboratory DOC versus fDOM relationships could be impacted by unknown localized water quality properties affecting fDOM readings, and/or the different standard laboratory methods used to estimate DOC. Artificial neural network analyses (ANN) indicated that higher relative chl-a concentrations were associated with low to no tree cover around sample sites and higher daily rainfall in the watersheds examined. Response surfaces derived from ANN indicated that chl-a concentrations were higher where combined agricultural and urban land uses were relatively higher.
Groundwater quality in the Lower Bhavani River basin has been evaluated for drinking, irrigation and industrial purposes. To study drinking water quality, the Water Quality Index (WQI) method was ...applied along with classic hydrochemical methods, and the results then compared with World Health Organisation (WHO) standards. TDS and other ionic constituents showed that 66% of the samples were good qualityfor drinking water. These results are compatible with the WQI results, which showed 64% of the samples were excellent or good quality. High values of WQI are associated with elevated fluoride and nitrate concentration. A spatial variation map shows that the southern region of the basin havelower quality water compared to the central region. Both natural and anthropogenic activities, such as industrial effluents, agricultural fertilisers etc., influence the groundwater quality. Analysis of groundwater quality for irrigation purposes shows that the water is prone to have a medium to high salinity hazard. While the sodium absorption ratio (SAR) of the groundwater shows that 98% of the samples are excellent for irrigation and the permeability index (PI) shows that 63% of the samples are excellent for irrigation, on the other hand, the water is unfit in around 55% of samples in terms of magnesium hazard (MH) and Kellys index (KI) because a higher than normal concentration of Mg, Ca and K is observed. In the water quality parameters for industrial purposes, Langelier Index (LI) and Aggressive Index (AI)showed significant scaling tendency. In contrast to this, Puckorius Index (PI), Ryznar Stability Index (RI) and Larson-Skold Index (LS) indicate that the water samples have significant corrosion tendencies.Routine monitoring of water quality is suggested in the regions where groundwater quality issues are reported in this study.
In developing regions that engage in agricultural and industrial activities, access to high-quality water for drinking, domestic, irrigation and industrial purposes is limited. In this study, ...comprehensive water quality assessment has been carried out to unravel the suitability of water supplies in Umunya suburb for human consumption, industrial and irrigation purposes. Water samples from spring, streams, and boreholes were analysed for physicochemical properties and heavy metals pollution. Pollution index of groundwater (PIG) was used to assess the drinking suitability of the waters whereas several indexical methods were integrated to unravel their suitability for irrigation and industrial purposes. The pH (4.61-6.53) revealed that majority of the samples are acidic. All the chemical ions were within their respective standard allowable limits, except for Fe, Pb and Ni. Generally, these heavy metals significantly impacted the water quality of the area. The PIG evaluation of the waters for drinking purpose revealed that 40% of the samples are unsuitable. However, most of the indices used for the irrigation water quality evaluation showed that majority of the samples are suitable for irrigation uses. The industrial water quality assessment indicated that the natural waters have more corrosive tendency than scaling tendency. Corrosivity and scaling indices, such as Langelier index, Larson-Skold index, chloride-sulphate mass ratio, aggressive index, Ryznar stability index, and Puckorius scaling index, unveiled that the natural waters are severely corrosive, having the tendency to damage domestic, irrigational, and industrial water distribution systems. This paper provides significant information necessary for the management and sustainability of water resources in Umunya suburb.
One hundred two groundwater samples were collected from the Bokaro district of Jharkhand state, India, during the pre-and post-monsoon seasons of the year 2014–2015. In the present study, groundwater ...samples were analysed for pH, TDS, TH, Ca
2+
, Mg
2+
, Na
+
, K
+
, Cl
−
, SO
4
2−
, HCO
3
−
, F
−
and NO
3
−
to evaluate the suitability of the groundwater for drinking purposes through geographic information system (GIS)-based water quality index (WQI) model. For quality assessment, values of analysed parameters of the groundwater samples were compared with the Bureau of Indian standards (BIS) and World Health Organization (WHO) water quality standards. The analytical results indicate slightly acidic to slightly alkaline nature of the groundwater in the study area. Concentrations of Ca
2+
, Mg
2+
, HCO
3
−
, F
−
, NO
3
−
, TDS and TH exceeded the desirable as well as permissible limits of drinking water quality standards recommended by the BIS (Indian Standard Drinking Water Specification, 2012) and WHO (Guidelines for drinking water quality: training pack, WHO, Geneva, 2004) in the study area during the pre- and post-monsoon seasons, respectively. However, Na
+
, K
+
, Cl
−
and SO
4
2−
concentrations were within the permissible limits during both seasons. The hydrochemical analysis of the studied groundwater samples documented with ternary and Durov diagram revealed that most of the groundwater samples belong to HCO
3
−
type of anions facies and no dominant type of cation facies. The GIS-based WQI maps for the study area indicate that the poor quality of water was found the maximum in the pre-monsoon season as compared to the post-monsoon season in the study area, respectively. The high values of WQI in the several groundwater samples of the Bokaro district indicate that water is not suitable for direct consumptions and it required sustainable treatment before its utilization for drinking uses.
Evaluation of groundwater quality and related health hazards is a prerequisite for taking preventive measures. The rural region of Telangana, India, has been selected for the present study to assess ...the sources and origins of inferior groundwater quality and to understand the human health risk zones for adults and children due to the consumption of nitrate (
NO
3
-
)- and fluoride (F
−
)-contaminated groundwater for drinking purposes. Groundwater samples collected from the study region were determined for various chemical parameters. Groundwater quality was dominated by Na
+
and
HCO
3
-
ions. Piper’s diagram and bivariate plots indicated the carbonate water type and silicate weathering as a main factor and man-made contamination as a secondary factor controlling groundwater chemistry; hence, the groundwater quality in the study region is low. According to the Groundwater Quality Index (GQI) classification, 48.3% and 51.7% of the total study region are excellent (GQI: < 50) and good (GQI: 50 to 100) water quality types, respectively, for drinking purposes. However,
NO
3
-
ranged from 0.04 to 585 mg/L, exceeding the drinking water quality limit of 45 mg/L in 34% of the groundwater samples due to the effects of nitrogen fertilizers. This was supported by the relationship of
NO
3
-
with TDS, Na
+
, and Cl
−
. The F
−
content was from 0.22 to 5.41 mg/L, which exceeds the standard drinking water quality limit of 1.5 mg/L in 25% of the groundwater samples. The relationship of F
−
with pH, Ca
2+
, Na
+
, and
HCO
3
-
supports the weathering and dissolution of fluoride-rich minerals for high F
−
content in groundwater. They were further supported by a principal component analysis. The Health Risk Index (HRI) values ranged from 0.20 to 20.10 and 0.36 to 30.90 with a mean of 2.82 and 4.34 for adults and children, respectively. The mean intensity of HRI (> 1.0) was 1.37 times higher in children (5.70) than in adults (4.16) due to the differences in weight size and exposure time. With an acceptable limit of more than 1.0, the study divided the region into Northern Safe Health Zone (33.3% for adults and 28.1% for children) and Southern Unsafe Health Zone (66.7% for adults and 71.9% for children) based on the intensity of agricultural activity. Therefore, effective strategic measures such as safe drinking water, denitrification, defluoridation, rainwater harvesting techniques, sanitary facilities, and chemical fertilizer restrictions are recommended to improve human health and protect groundwater resources.
PDF
