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Showing papers on "Water quality published in 2018"


Journal ArticleDOI
TL;DR: Most frequent substances as well as those found at highest concentrations in different seasons and regions, together with available risk assessment data, may be useful to identify possible future PS candidates.

545 citations


Journal ArticleDOI
TL;DR: The model exhibited excellent performance in representing the water quality in LakeTaihu Basin, especially when weights were fully considered, and could be used for rapid and low-cost water quality evaluation in Lake Taihu Basin.

363 citations


Journal ArticleDOI
TL;DR: Wang et al. as mentioned in this paper assessed the human health risk due to groundwater nitrogen pollution in Jinghui canal irrigation area in Shaanxi Province of China where agricultural activities are intense and analyzed for physicochemical indices in the study area.
Abstract: Nitrogen pollution of groundwater is becoming more and more serious due to intense and extensive industrial and agricultural activities. This may exert great influence on human health. In this paper, human health risk due to groundwater nitrogen pollution in Jinghui canal irrigation area in Shaanxi Province of China where agricultural activities are intense was assessed. Forty-seven groundwater samples were collected from shallow wells and analyzed for physicochemical indices in the study area. Water samples were analyzed for pH, total dissolved solids (TDS), total hardness (TH), major ions (Na+, K+, Ca2+, Mg2+, HCO3−, CO32−, Cl− and SO42−), nitrate (NO3–N), nitrite (NO2–N) and ammonia nitrogen (NH4–N). General groundwater chemistry was described by statistical analysis and the Piper diagram. Water quality was quantified via comprehensive water quality index (CWQI), and human health risk was assessed considering the age and exposure pathways of the consumers. The results show that the shallow groundwater is slightly alkaline and groundwater types are HCO3·SO4·Cl–Mg and HCO3·SO4·Cl–Na. Rock weathering and evaporation are main natural processes regulating the groundwater chemistry. The CWQI indicates that groundwater in the study area is seriously polluted by TH, TDS, SO42−, Cl− and NO3−. Human health risk is high because of high concentrations of nitrate in drinking water. The results also show that children are at higher risk than adults. The health risk through dermal contact is much lower than that through drinking water intake and can be ignored.

278 citations


Journal ArticleDOI
TL;DR: It is suggested the necessity for long-term monitoring of water storage variation in the global endorheic system and the inclusion of its net contribution to future sea level budgeting.
Abstract: Endorheic (hydrologically landlocked) basins spatially concur with arid/semi-arid climates. Given limited precipitation but high potential evaporation, their water storage is vulnerable to subtle flux perturbations, which are exacerbated by global warming and human activities. Increasing regional evidence suggests a probably recent net decline in endorheic water storage, but this remains unquantified at a global scale. By integrating satellite observations and hydrological modelling, we reveal that during 2002–2016 the global endorheic system experienced a widespread water loss of about 106.3 Gt yr−1, attributed to comparable losses in surface water, soil moisture and groundwater. This decadal decline, disparate from water storage fluctuations in exorheic basins, appears less sensitive to El Nino–Southern Oscillation-driven climate variability, which implies a possible response to longer-term climate conditions and human water management. In the mass-conserved hydrosphere, such an endorheic water loss not only exacerbates local water stress, but also imposes excess water on exorheic basins, leading to a potential sea level rise that matches the contribution of nearly half of the land glacier retreat (excluding Greenland and Antarctica). Given these dual ramifications, we suggest the necessity for long-term monitoring of water storage variation in the global endorheic system and the inclusion of its net contribution to future sea level budgeting.

255 citations


Journal ArticleDOI
14 Sep 2018
TL;DR: In this article, the authors take a probabilistic approach to assess global water scarcity projections following feasible combinations of shared socioeconomic pathways and representative concentration pathways for the first half of the twenty-first century and identify changes in the uncertainty range of anticipated water scarcity conditions.
Abstract: Water scarcity, a critical environmental issue worldwide, has primarily been driven by a significant increase in water extractions during the last century In the coming decades, climate and societal changes are projected to further exacerbate water scarcity in many regions worldwide Today, a major issue for the ongoing policy debate is to identify interventions able to address water scarcity challenges in the presence of large uncertainties Here, we take a probabilistic approach to assess global water scarcity projections following feasible combinations of shared socioeconomic pathways and representative concentration pathways for the first half of the twenty-first century We identify—alongside trends in median water scarcity—changes in the uncertainty range of anticipated water scarcity conditions Our results show that median water scarcity and the associated range of uncertainty are generally increasing worldwide, including many major river basins On the basis of these results, we develop a general decision-making framework to enhance policymaking by identifying four representative clusters of specific water policy challenges and needs Designing interventions to address water scarcity under climate change is challenging given the large uncertainties in projected water availability In this study, changes in the uncertainty range of anticipated water scarcity conditions are identified, and a general decision-making framework to support policy decisions is developed

218 citations


Journal ArticleDOI
TL;DR: In this article, the quality studies have been undertaken on 105 groundwater samples collected from the rock dominant semi-arid region of central Telangana and analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), calcium (Ca2+), magnesium (Mg2+, sodium (Na+), potassium (K+), chloride (Cl−), sulphate (SO42−), nitrate (NO3−), and fluoride (F−).
Abstract: Groundwater is the major source for drinking and irrigation purposes in the Central parts of Telangana. The demand for groundwater has recently increased due to intensive irrigation practices and population growth which in turn caused depletion of resource and deterioration of quality. In view of this, quality studies have been undertaken on 105 groundwater samples collected from the rock dominant semi-arid region of central Telangana and analysed for pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH), calcium (Ca2+), magnesium (Mg2+), sodium (Na+), potassium (K+), chloride (Cl−), sulphate (SO42−), nitrate (NO3−), and fluoride (F−). Results revealed that 51% and 71% of groundwater has more than the maximum acceptable limits of fluoride (1.5 mg/L) and nitrate concentrations (45 mg/L), respectively, thus making the groundwater unsuitable for drinking purpose. Data plotted in Gibbs diagram reveal that the groundwater chemistry is primarily controlled by rock-water interaction. According to water quality index (WQI), 60% and 36% of groundwater samples fall in excellent and good categories for drinking purpose. A majority of groundwater samples fall in deep meteoric percolation and Na+-SO42− types, but most belong to Ca2+–Mg2+–HCO3−, Na+–HCO3− facies, and few are of Ca2+–Mg2+–Cl− and Na+–Cl− facies. 90% of groundwater in the study region is well suitable for irrigation. It is advised that groundwater with high fluoride and nitrate concentration should be avoided for drinking purposes.

216 citations


Journal ArticleDOI
TL;DR: A review of existing reuse schemes and regulations across the world, found variation, demonstrating the need for assessing benefits and risks on a case-by-case basis as discussed by the authors, and therefore, care must be taken with regulating and monitoring levels of contaminants in the recycled water according to its use.

216 citations


Journal ArticleDOI
TL;DR: It is shown that health-based drinking water quality violations are widespread, with 9–45 million people possibly affected during each of the past 34 years, and hot spots and vulnerability factors associated with violations are identified, which can allow public policies to target underperforming water systems.
Abstract: Ensuring safe water supply for communities across the United States is a growing challenge in the face of aging infrastructure, impaired source water, and strained community finances. In the aftermath of the Flint lead crisis, there is an urgent need to assess the current state of US drinking water. However, no nationwide assessment has yet been conducted on trends in drinking water quality violations across several decades. Efforts to reduce violations are of national concern given that, in 2015, nearly 21 million people relied on community water systems that violated health-based quality standards. In this paper, we evaluate spatial and temporal patterns in health-related violations of the Safe Drinking Water Act using a panel dataset of 17,900 community water systems over the period 1982-2015. We also identify vulnerability factors of communities and water systems through probit regression. Increasing time trends and violation hot spots are detected in several states, particularly in the Southwest region. Repeat violations are prevalent in locations of violation hot spots, indicating that water systems in these regions struggle with recurring issues. In terms of vulnerability factors, we find that violation incidence in rural areas is substantially higher than in urbanized areas. Meanwhile, private ownership and purchased water source are associated with compliance. These findings indicate the types of underperforming systems that might benefit from assistance in achieving consistent compliance. We discuss why certain violations might be clustered in some regions and strategies for improving national drinking water quality.

214 citations



Journal ArticleDOI
TL;DR: In this article, 31 groundwater samples were collected and analyzed to determine suitability of groundwater for drinking and irrigation uses, and the results showed that 97% of groundwater samples are in suitable class and the remaining 3% constituting doubtful class for irrigation use.

194 citations


Journal ArticleDOI
TL;DR: The results add to the existing evidence suggesting increased CRC risk at drinking water nitrate concentrations below the current drinking water standard, and a discussion on the adequacy of the drinking waterStandard in regards to chronic effects is warranted.
Abstract: Nitrate in drinking water may increase risk of colorectal cancer due to endogenous transformation into carcinogenic N-nitroso compounds. Epidemiological studies are few and often challenged by their limited ability of estimating long-term exposure on a detailed individual level. We exploited population-based health register data, linked in time and space with longitudinal drinking water quality data, on an individual level to study the association between long-term drinking water nitrate exposure and colorectal cancer (CRC) risk. Individual nitrate exposure was calculated for 2.7 million adults based on drinking water quality analyses at public waterworks and private wells between 1978 and 2011. For the main analyses, 1.7 million individuals with highest exposure assessment quality were included. Follow-up started at age 35. We identified 5,944 incident CRC cases during 23 million person-years at risk. We used Cox proportional hazards models to estimate hazard ratios (HRs) of nitrate exposure on the risk of CRC, colon and rectal cancer. Persons exposed to the highest level of drinking water nitrate had an HR of 1.16 (95% CI: 1.08-1.25) for CRC compared with persons exposed to the lowest level. We found statistically significant increased risks at drinking water levels above 3.87 mg/L, well below the current drinking water standard of 50 mg/L. Our results add to the existing evidence suggesting increased CRC risk at drinking water nitrate concentrations below the current drinking water standard. A discussion on the adequacy of the drinking water standard in regards to chronic effects is warranted.

Journal ArticleDOI
01 Aug 2018-Catena
TL;DR: In this article, the authors evaluated the influence of land use/land cover on water quality of tropical low-order streams, comparing watershed and riparian zone models, and found that forest cover plays a significant role in keeping water clean, while agriculture and urban areas lead to water quality degradation.
Abstract: Land-use/land-cover (LULC) pattern influences water quality, however, this relation may be different for various spatial scales. We evaluated the LULC effects on water quality of tropical low-order streams, comparing watershed and riparian zone models. Water quality parameters were analyzed separately and together using linear mixed and multivariate models. The results indicate that the forest cover plays a significant role in keeping water clean, while agriculture and urban areas lead to water quality degradation. Pasture land had mixed effects, but in general was not correlated with poor water quality. Dissolved oxygen, phosphorus, sediment, and fecal coliforms were influenced by LULC pattern at the watershed scale, while nitrogen and organic matter were more affected by the riparian zone composition. The water quality also varies with seasonal changes in streamflow and temperature. The overall water quality variation is explained better by the LULC composition within the watershed than in the riparian zone.

Journal ArticleDOI
TL;DR: In this article, the relationship between landscape characteristics and stream water quality is investigated and the strength of this relationship can be influenced by the distance and spatial arrangement of constituent sources within the catchment, cross correlations between landscapes characteristics, and seasonality.
Abstract: Globally, many rivers are experiencing declining water quality, for example, with altered levels of sediments, salts, and nutrients. Effective water quality management requires a sound understanding of how and why water quality differs across space, both within and between river catchments. Land cover, land use, land management, atmospheric deposition, geology and soil type, climate, topography, and catchment hydrology are the key features of a catchment that affect: (1) the amount of suspended sediment, nutrient, and salt concentrations in catchments (i.e., the source), (2) the mobilization ,and (3) the delivery of these constituents to receiving waters. There are, however, complexities in the relationship between landscape characteristics and stream water quality. The strength of this relationship can be influenced by the distance and spatial arrangement of constituent sources within the catchment, cross correlations between landscape characteristics, and seasonality. A knowledge gap that should be addressed in future studies is that of interactions and cross correlations between landscape characteristics. There is currently limited understanding of how the relationships between landscape characteristics and water quality responses can shift based on the other characteristics of the catchment. Understanding the many forces driving stream water quality and the complexities and interactions in these forces is necessary for the development of successful water quality management strategies. This knowledge could be used to develop predictive models, which would aid in forecasting of riverine water quality. For further resources related to this article, please visit the WIREs website.

Journal ArticleDOI
TL;DR: This study examined the relationship between LSWTs and water quality thresholds for Dianchi Lake through an analysis of 54 water quality indicators from 10 water quality monitoring sites from 2005 to 2016 and constructed a hybrid forecasting model that showed limited errors and highly generalized levels of predictive performance.

Book
28 Nov 2018
TL;DR: In this paper, a new relationship between ECe (mS/cm) and total soluble salts (meq/l) established on UAE soils has been reported which is different to that established by US Salinity Laboratory Staff in the year 1954, suggesting the latter is specific to US soils, therefore, other countries should establish similar relationships based on their local conditions.
Abstract: It is widely recognized that soil salinity has increased over time. It is also triggered with the impact of climate change. For sustainable management of soil salinity, it is essential to diagnose it properly prior to take proper intervention measures. In this chapter soil salinity (dryland and secondary) and sodicity concepts have been introduced to make it easier for readers. A hypothetical soil salinity development cycle has been presented. Causes of soil salinization and its damages, socio-economic and environmental impacts, and visual indicators of soil salinization and sodicity have been reported. A new relationship between ECe (mS/cm) and total soluble salts (meq/l) established on UAE soils has been reported which is different to that established by US Salinity Laboratory Staff in the year 1954, suggesting the latter is specific to US soils, therefore, other countries should establish similar relationships based on their local conditions. Procedures for field assessment of soil salinity and sodicity are described and factors to convert EC of different soil: water (1:1, 1:2.5 & 1:5) suspensions to ECe from different regions are tabulated and hence providing useful information to those adopting such procedures. Diversified salinity assessment, mapping and monitoring methods, such as conventional (field and laboratory) and modern (electromagnetic-EM38, optical-thin section and electron microscopy, geostatistics-kriging, remote sensing and GIS, automatic dynamics salinity logging system) have been used and results are reported providing comprehensive information for selection of suitable methods by potential users. Globally accepted soil salinity classification systems such as US Salinity Lab Staff and FAO-UNESCO have been included.

Journal ArticleDOI
TL;DR: This paper intends to review the developments in water quality monitoring technologies for the detection of biological and chemical contaminants in accordance with instrumental limitations and focuses on the most recently developed techniques for water contaminant detection applications.
Abstract: Water monitoring technologies are widely used for contaminants detection in wide variety of water ecology applications such as water treatment plant and water distribution system. A tremendous amount of research has been conducted over the past decades to develop robust and efficient techniques of contaminants detection with minimum operating cost and energy. Recent developments in spectroscopic techniques and biosensor approach have improved the detection sensitivities, quantitatively and qualitatively. The availability of in-situ measurements and multiple detection analyses has expanded the water monitoring applications in various advanced techniques including successful establishment in hand-held sensing devices which improves portability in real-time basis for the detection of contaminant, such as microorganisms, pesticides, heavy metal ions, inorganic and organic components. This paper intends to review the developments in water quality monitoring technologies for the detection of biological and chemical contaminants in accordance with instrumental limitations. Particularly, this review focuses on the most recently developed techniques for water contaminant detection applications. Several recommendations and prospective views on the developments in water quality assessments will also be included.

Journal ArticleDOI
TL;DR: In this article, the authors explored the river-flow-induced impacts on the performance of machine learning models applied for forecasting of water quality parameters in the coastal waters in Hilo Bay, Pacific Ocean.
Abstract: This study explores the river-flow-induced impacts on the performance of machine learning models applied for forecasting of water quality parameters in the coastal waters in Hilo Bay, Pacific Ocean...

Journal ArticleDOI
TL;DR: In this paper, the authors show that under moderate-high streamflow, wetlands are five times more efficient per unit area at reducing riverine nitrate concentration than the most effective land-based nitrogen mitigation strategies, which include cover crops and land retirement.
Abstract: Intensively managed row crop agriculture has fundamentally changed Earth surface processes within the Mississippi River basin through large-scale alterations of land cover, hydrology and reactive nitrogen availability. These changes have created leaky landscapes where excess agriculturally derived nitrate degrades riverine water quality at local, regional and continental scales. Individually, wetlands are known to remove nitrate but the conditions under which multiple wetlands meaningfully reduce riverine nitrate concentration have not been established. Only one region of the Mississippi River basin—the 44,000 km2 Minnesota River basin—still contains enough wetland cover within its intensively agriculturally managed watersheds to empirically address this question. Here we combine high-resolution land cover data for the Minnesota River basin with spatially extensive repeat water sampling data. By clearly isolating the effect of wetlands from crop cover, we show that, under moderate–high streamflow, wetlands are five times more efficient per unit area at reducing riverine nitrate concentration than the most effective land-based nitrogen mitigation strategies, which include cover crops and land retirement. Our results suggest that wetland restorations that account for the effects of spatial position in stream networks could provide a much greater benefit to water quality then previously assumed.

Journal ArticleDOI
TL;DR: Analyses of the suitability of the water supply for drinking and irrigation in the Gandaki River Basin of the Central Himalaya reveal that the river has mostly retained its natural water quality but poses safety concern at a few locations.

Journal ArticleDOI
TL;DR: In this article, the suitability of groundwater for domestic and agricultural purposes in Yan'an City on the Chinese Loess Plateau and to assess its implications to sustainable groundwater management on the plateau were investigated.
Abstract: Groundwater is critical for the sustainable development of the Loess Plateau, while groundwater quality is generally poor in this area due to natural factors and anthropogenic pollution. This study was carried out to investigate the suitability of groundwater for domestic and agricultural purposes in Yan’an City on the Chinese Loess Plateau and to assess its implications to sustainable groundwater management on the plateau. The index levels were compared with the threshold values established by the national and the WHO drinking water guidelines, and the suitability of groundwater for irrigation purposes was assessed using multiple agricultural water quality indicators. An entropy-weighted Technique for Order Preference by Similarity to an Ideal Solution (entropy-weighted TOPSIS) was adopted for overall groundwater quality assessment. The results indicate that the study area is characterized by saline, hard, and slightly alkaline groundwater, mainly of the HCO3–Ca·Mg type, accompanied by some minor SO4·Cl–Ca·Mg type. The dissolution of carbonates and gypsum and the leaching of soluble salts are important natural processes influencing the groundwater ion chemistry. The parameters TH, TDS, and SO42− are major indices, while Fe, Mn, F−, and NH4+ are minor contaminants affecting groundwater quality. The overall groundwater quality is generally acceptable for irrigation, and most of the water is suitable for drinking. Rainwater harvesting, water quality improvement programs, regular water quality monitoring, and multidisciplinary water research programs are suggested as measures for sustainable groundwater management on the Loess Plateau.

Journal ArticleDOI
TL;DR: The Sentinel-2 MultiSpectral Instrument is suitable for estimating chlorophyll a in water bodies and tracking the spatial and temporal dynamics in the lakes, however, atmospheric corrections are sensitive to surrounding land and often fail in narrow and small lakes.
Abstract: The European Parliament and The Council of the European Union have established the Water Framework Directive (2000/60/EC) for all European Union member states to achieve, at least, “good” ecological status of all water bodies larger than 50 hectares in Europe. The MultiSpectral Instrument onboard European Space Agency satellite Sentinel-2 has suitable 10, 20, 60 m spatial resolution to monitor most of the Estonian lakes as required by the Water Framework Directive. The study aims to analyze the suitability of Sentinel-2 MultiSpectral Instrument data to monitor water quality in inland waters. This consists of testing various atmospheric correction processors to remove the influence of atmosphere and comparing and developing chlorophyll a algorithms to estimate the ecological status of water in Estonian lakes. This study shows that the Sentinel-2 MultiSpectral Instrument is suitable for estimating chlorophyll a in water bodies and tracking the spatial and temporal dynamics in the lakes. However, atmospheric corrections are sensitive to surrounding land and often fail in narrow and small lakes. Due to that, deriving satellite-based chlorophyll a is not possible in every case, but initial results show the Sentinel-2 MultiSpectral Instrument could still provide complementary information to in situ data to support Water Framework Directive monitoring requirements.

Journal ArticleDOI
TL;DR: The results showed that the surface water from Mari catchment and Lom River was unsuitable for human consumption, and the high concentrations of TSS and trace elements found in this basin were mainly due to gold mining activities (exploration and exploitation) as well as digging of rivers beds, excavation and gold amalgamation.

Journal ArticleDOI
TL;DR: Ganga water quality is deteriorating day by day and at several places even in upper stretch of Ganga the water is not suitable for domestic uses and the increasing trend of trace and toxic elements is alarming and the prolong exposure to polluted Ganga water and/or consumption of Ganges water fishes may cause serious illness including cancer.

Journal ArticleDOI
TL;DR: This study tracks tap water microbiome assembly in situ, showing that bacterial community composition changes rapidly from the city supply following ~6-day stagnation, along with an increase in cell count along with a developed size-effect model to simulate this process.
Abstract: What happens to tap water when you are away from home? Day-to-day water stagnation in building plumbing can potentially result in water quality deterioration (e.g., lead release or pathogen proliferation), which is a major public health concern. However, little is known about the microbial ecosystem processes in plumbing systems, hindering the development of biological monitoring strategies. Here, we track tap water microbiome assembly in situ, showing that bacterial community composition changes rapidly from the city supply following ~6-day stagnation, along with an increase in cell count from 103 cells/mL to upwards of 7.8 × 105 cells/mL. Remarkably, bacterial community assembly was highly reproducible in this built environment system (median Spearman correlation between temporal replicates = 0.78). Using an island biogeography model, we show that neutral processes arising from the microbial communities in the city water supply (i.e., migration and demographic stochasticity) explained the island community composition in proximal pipes (Goodness-of-fit = 0.48), yet declined as water approached the faucet (Goodness-of-fit = 0.21). We developed a size-effect model to simulate this process, which indicated that pipe diameter drove these changes by mediating the kinetics of hypochlorite decay and cell detachment, affecting selection, migration, and demographic stochasticity. Our study challenges current water quality monitoring practice worldwide which ignore biological growth in plumbing, and suggests the island biogeography model as a useful framework to evaluate building water system quality.

Journal ArticleDOI
TL;DR: The results obtained from the case study show that impervious urban surfaces and rainfall intensity are significant predictors of combined sewer overflows and consequently of the water quality of the receiving water body and reduction in imperviousness was found to be a suitable strategy to adapt to these scenarios.

Journal ArticleDOI
TL;DR: Evaluation of effluent water quality from published wetland case studies and the expected performance from disinfection processes shows that under appropriate conditions these two unit processes together can likely produce effluent of sufficient quality to meet all nonpotable reuse standards.

Journal ArticleDOI
TL;DR: In a recent special issue as mentioned in this paper, 20 papers from academia, agency researchers and non-governmental organisations, each with fresh perspectives on the science and management of environmental water allocations have been published.
Abstract: 1. The implementation of environmental flow regimes offers a promising means to protect and restore riverine, wetland and estuarine ecosystems, their critical environmental services and cultural/societal values. 2. This Special Issue expands the scope of environmental flows and water science in theory and practice, offering 20 papers from academics, agency researchers and non‐governmental organisations, each with fresh perspectives on the science and management of environmental water allocations. 3. Contributions confront the grand challenge for environmental flows and water management in the Anthropocene—the urgent need for innovations that will help to sustain the innate resilience of social–ecological systems under dynamic and uncertain environmental and societal futures. 4. Basin‐scale and regional assessments of flow requirements mark a necessary advance in environmental water science in the face of rapid changes in water‐resource management activities worldwide (e.g. increases in dams, diversions, retention and reuse). Techniques for regional‐scale hydrological and ecohydrological modelling support ecological risk assessment and identification of priority flow management and river restoration actions. 5. Changing flood–drought cycles, long‐term climatic shifts and associated effects on hydrological, thermal and water quality regimes add enormous uncertainty to the prediction of future ecological outcomes, regardless of environmental water allocations. An improved capacity to predict the trajectories of ecological change in rivers degraded by legacies of past impact interacting with current conditions and future climate change is essential. Otherwise, we risk unrealistic expectations from restoration of river and estuarine flow regimes. 6. A more robust, dynamic and predictive approach to environmental water science is emerging. It encourages the measurement of process rates (e.g. birth rate, colonisation rate) and species traits (e.g. physiological requirements, morphological adaptations) as well as ecosystem states (e.g. species richness, assemblage structure), as the variables representing ecological responses to flow variability and environmental water allocations. Another necessary development is the incorporation of other environmental variables such as water temperature and sedimentary processes in flow–ecological response models. 7. Based on contributions to this Special Issue, several recent compilations and the wider literature, we identify six major scientific challenges for further exploration, and seven themes for advancing the management of environmental water. We see the emerging frontier of environmental flows and water science as urgent and challenging, with numerous opportunities for reinvigorated science and methodological innovation in the expanding enterprise of environmental water linked to ecological sustainability and social well‐being.

Journal ArticleDOI
TL;DR: Analysis of indicators of water quality and drivers of change in three large European river basins with different climatic, soil and water use conditions shows that air temperature, considered as a proxy of climatic change, has a significant impact, in particular in the Adige and Ebro.

Journal ArticleDOI
TL;DR: According to as discussed by the authors, the major pollution sources for surface waters are the urban and industrial discharges of untreated effluents into the water, but it is unknown whether these standards are being enforced.
Abstract: Africa is blessed with natural and mineral resources, but exploitation of these resources has led to extreme pollution of the environment. Population growth and urbanization due to developments have also contributed immensely to the current pollution in Africa. Traffic emissions, transported dust and open burning are all significant contributors to air pollution in Africa. The Sahara desert is a major source of transported dust, especially during the harmattan season in West Africa. Mercury emissions are very high in South Africa due to coal combustion and gold mining. Air pollutants may contaminate water and soil through atmospheric deposition. However, the major pollution sources for surface waters are the urban and industrial discharges of untreated effluents into the water. A few African countries have standards for effluent discharge into surface waters, but it is unknown whether these standards are being enforced. Though groundwater sources in wells and boreholes are the major sources of drinking water for the African populace, the biological water quality of these groundwater sources is mostly low in the region due to close proximity to sanitary facilities. Identified sources of soil pollution in Africa include agricultural activities, mining, roadside emissions, auto-mechanic workshops, refuse dumps and e-waste. Oil spills are a major problem in oil-rich African countries such as Nigeria and Angola. Agricultural activities are the lowest impacting the soil in Africa, while e-waste recycling was the highest with Pb, Cu and Zn at extremely high concentrations (>1%). There is a need for proper regulation of environmental pollutants in Africa.

Journal ArticleDOI
01 Dec 2018
TL;DR: Wang et al. as mentioned in this paper used statistical analysis and Chadha diagram 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.
Abstract: 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 SO4·Cl–Na type with some minor hydrochemical facies of HCO3–Ca·Mg, HCO3–Na, and Cl·SO4–Ca·Mg types. The sequences of ions are Na+ > Ca2+ > Mg2+ > K+ for cations, and HCO3 − > Cl− > SO4 2− > CO3 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.