Showing papers on "Water quality published in 2020"

Water Quality Assessment in Terms of Water Quality Index

Abstract: Water quality index (WQI) is valuable and unique rating to depict the overall water quality status in a single term that is helpful for the selection of appropriate treatment technique to meet the concerned issues. However, WQI depicts the composite influence of different water quality parameters and communicates water quality information to the public and legislative decision makers. In spite of absence of a globally accepted composite index of water quality, some countries have used and are using aggregated water quality data in the development of water quality indices. Attempts have been made to review the WQI criteria for the appropriateness of drinking water sources. Besides, the present article also highlights and draws attention towards the development of a new and globally accepted “Water Quality Index” in a simplified format, which may be used at large and could represent the reliable picture of water quality.

Pollution exacerbates China's water scarcity and its regional inequality.

Abstract: Inadequate water quality can mean that water is unsuitable for a variety of human uses, thus exacerbating freshwater scarcity. Previous large-scale water scarcity assessments mostly focused on the availability of sufficient freshwater quantity for providing supplies, but neglected the quality constraints on water usability. Here we report a comprehensive nationwide water scarcity assessment in China, which explicitly includes quality requirements for human water uses. We highlight the necessity of incorporating water scarcity assessment at multiple temporal and geographic scales. Our results show that inadequate water quality exacerbates China's water scarcity, which is unevenly distributed across the country. North China often suffers water scarcity throughout the year, whereas South China, despite sufficient quantities, experiences seasonal water scarcity due to inadequate quality. Over half of the population are affected by water scarcity, pointing to an urgent need for improving freshwater quantity and quality management to cope with water scarcity.

Statistical and multivariate statistical techniques to trace the sources and affecting factors of groundwater pollution in a rapidly growing city on the Chinese Loess Plateau

Abstract: Groundwater quality is defined by various water quality parameters. The aims of the research are to understand the relationships among different groundwater quality parameters and to trace the sour...

Concerns and Threats of Contamination on Aquatic Ecosystems

Abstract: Aquatic ecosystems are the ultimate sinks for the contaminants. Water contamination is the outcome of human activities such as urbanization, industrialization, and agricultural activities. The overuse of pesticides and fertilizers and sewage from residential and industrial areas ultimately find its way to aquatic environment. Thus results in the degradation of the water quality and leads to the spread of infectious diseases such as dysentery, diarrhea, and jaundice. Contamination in aquatic environs is one of the leading types of pollution which has significant negative health issues and mortality. Water has a natural capacity to neutralize the contamination, but when contamination becomes uncontrolled, water will lose its self-generating capacity. Therefore, there is a need for regular monitoring and controlling of pollutant discharge into the nearby aquatic environs.

Groundwater chemistry and groundwater quality index incorporating health risk weighting in Dingbian County, Ordos basin of northwest China

Abstract: Groundwater is essential to secure the safety of water supply in the Ordos basin, China. In this study, 35 groundwater samples were collected from part of the Dingbian County, a significant part of the Ordos energy base in China, and were analyzed for 17 physicochemical parameters. The health risk was quantified through the model recommended by the United States Environmental Protection Agency (USEPA). In addition, water quality index (WQI), which is incorporated with human health risk weighting, was adopted to evaluate the overall groundwater quality. The results show that groundwater in the study area is slightly alkaline water, and the hydrochemical types of groundwater is mainly HCO3-Na, HCO3-Na·Mg·Ca and mixed SO4·Cl-Na types. The non-carcinogenic health risks follow the order: NO3−>F−>Cr6+>As>NO2−>Mn, and the carcinogenic risks is mainly contributed by Cr6+. Children face higher risks than adults, and most groundwater samples are associated with unacceptable health risks for both adults and children. WQI results show that poor quality water and very poor quality water account for 11.43 % and 17.14 % of all sampled groundwater, respectively, which are not suitable for drinking. In terms of sodium hazard, nearly half of the groundwater samples are not suitable for irrigation. The results of this study will be helpful in groundwater management and protection in this area, and the health risk weighting method can be referenced by international scholars.

Occurrence of contaminants in drinking water sources and the potential of biochar for water quality improvement:A review

Abstract: In this work, the occurrence of contaminants in drinking water sources was described in relation to their treatment options based on both conventional (e.g., coagulation-flocculation, sedimentation...

Surface Water Pollution in the Middle Chinese Loess Plateau with Special Focus on Hexavalent Chromium (Cr6+): Occurrence, Sources and Health Risks

Abstract: Due to the combined influence of unique natural environment and increasing human activities, water quality in the Chinese Loess Plateau is deteriorating. Hexavalent chromium (Cr6+) contamination is a critical water environmental issue in the loess areas. In this study, surface water, spring water, Quaternary phreatic water, and soil and rock samples were collected in the middle Chinese Loess Plateau to quantify the surface water pollution and its main affecting factors. Particularly, the occurrence and potential sources of Cr6+ as well as associated health risks in surface water were thoroughly investigated. The results show that Cr6+ is widely found in Luo River, Xingzi River, Wuding River and Bali River. The upper reaches of the Luo River are the main high-Cr6+ water distribution area. For Bali River, Wuding River, Xingzi River and the downstream of the Luo River, the values of Cr6+ in surface water were below the WHO drinking water limit (0.05 mg/L). The high Cr values in the soil and rock samples indicate that the loess and mudstone are important sources of high-Cr6+ water in the area. Groundwater which is characterized by high Cr6+ concentration is also an important factor affecting Cr6+ concentration in surface water which receives recharge from groundwater. In addition to Cr6+, TDS and nitrate are also important pollutants in surface water. The hydrochemical evolution of the surface water is controlled by rock weathering and evaporation crystallization. The health risk assessment results suggest that the inhabitants in the study area face high carcinogenic risks induced by Cr6+.

Seasonal Variation of Drinking Water Quality and Human Health Risk Assessment in Hancheng City of Guanzhong Plain, China

Abstract: This research was conducted to understand the seasonal characteristics of water quality for domestic purpose in Hancheng City of the Guanzhong plain, China. The health risks were also assessed using the water quality monitoring data collected from the Hancheng Center for Disease Control and Prevention. For this study, 48 samples were collected from the drinking water distribution system (chlorinated water and terminal tap water) in the dry and wet seasons, and were analyzed for pH, total hardness (TH), total dissolved solids (TDS), Cl−, SO42−, F−, NH4-N, NO3-N, Cr6+, As, Hg and Mn. The water quality was assessed using the entropy water quality index (EWQI) and the results show that above 80% of the water samples are of good quality which is suitable for drinking and other domestic purposes. The potential non-carcinogenic risks of Cr6+, As, F−, and NO3-N and carcinogenic risks of Cr6+ and As to consumers were assessed by the model recommended by the US Environmental Protection Agency (USEPA). The non-carcinogenic health risks in the dry season are higher than the risks in the wet season for both adults and children. Water quality indicators considered in the risk assessment contribute with different degrees to the total non-carcinogenic risk during the dry and wet seasons. The order of the average non-carcinogenic risk values of the chlorinated water and terminal tap water in the dry season was F− > As > NO3-N > Cr6+, while that in the wet season was F− > NO3-N > Cr6+ > As. People face higher carcinogenic risk in the wet season in terms of terminal tap water consumption, while they face higher carcinogenic risk in the dry season in terms of the chlorinated water. Children face almost twice higher the carcinogenic risks than the adults.

Finding High-Quality Groundwater Resources to Reduce the Hydatidosis Incidence in the Shiqu County of Sichuan Province, China: Analysis, Assessment, and Management

Abstract: The prevalence of hydatidosis due to animal husbandry development poses significant health risks to people in the Shiqu County of Sichuan Province, China, where people depend mainly on surface water for domestic uses, which, however, is contaminated due to the development of the animal husbandry. Therefore, groundwater which is protected by the vadose zone and has better quality is now proposed to replace the contaminated surface water as a new source of water supply in this area. To find a high-quality groundwater resource, a detailed investigation and assessment was carried out in this study. The occurrence and distribution of the hydatidosis caused by the consumption of the contaminated surface water were analyzed. The World Health Organization (WHO) and national standards were applied to assess the suitability of groundwater for drinking purpose, and SAR, RSC, %Na, PI were used to evaluate the groundwater quality for irrigation usage. In addition, the overall groundwater quality was assessed using an entropy water quality index (EWQI), and its relationships with the physicochemical indices were discussed using the multiple linear regression models to explore the most important physicochemical indices affecting the groundwater quality. Finally, some measures for the prevention and treatment of the hydatidosis disease were proposed. The results show that the groundwater found beneath the study area is generally in good to excellent quality with low salinity and major ions. Groundwater in all constructed wells except only one is suitable for domestic and irrigation purposes with majority of the samples falling into HCO3-Ca·Mg type. The overall groundwater quality is mainly affected by COD, SO42−, and TH. Measures to reduce the incidence of hydatidosis such as cutting off the hydatidosis exposure pathway and improving the sanitation system are proposed.

Groundwater Quality Assessment Using Improved Water Quality Index (WQI) and Human Health Risk (HHR) Evaluation in a Semi-arid Region of Northwest China

Abstract: To ensure the safety of drinking water, 51 groundwater samples were collected from a semi-arid area of China and various physicochemical parameters were analyzed. Groundwater quality for drinking purposes along with the associated health risks was assessed using a water quality index (WQI) which was improved using the Criteria Importance Through Inter-criteria Correlation weighting method. The results show that the groundwater was slightly alkaline and the total dissolved solids ranged from 497.26 to 2198.82 mg/L. The ionic dominance pattern was in the order of K+ + Na+ > Ca2+ > Mg2+ > NH4+ for cations, and HCO3− > SO42+ > Cl− > NO2− > NO3− > CO32− > F− for anions, respectively. In the study region, HCO3–Na and HCO3–Ca·Mg were the dominant water types, followed by the SO4·Cl–Na type, which are mainly controlled by rock weathering, leaching, and evaporation. 94.12% of the total samples are suitable for drinking; the poor and extremely poor water for human consumption are mainly located in the center and northeast of the study area. The non-carcinogenic health risk for males ranged from 0.0002 to 38.7575, for females 0.0002 to 49.2935, and for children 0.0003 to 84.3167, respectively. The health risk for children was approximately 2.18 times and 1.71 times higher than that for males and females, indicating that children are more susceptible to water contamination. The major pollutants in the study region are nitrite, nitrate, and fluoride. Therefore, the necessary steps to be taken to clean up this highly nitrite-, nitrate-, and fluorine-contaminated groundwater and health risks in this study region.

Using Principal Components Analysis and IDW Interpolation to Determine Spatial and Temporal Changes of Surface Water Quality of Xin'anjiang River in Huangshan, China.

Abstract: This study was aimed at assessing the spatial and temporal distribution of surface water quality variables of the Xin’anjiang River (Huangshan). For this purpose, 960 water samples were collected monthly along the Xin’anjiang River from 2008 to 2017. Twenty-four water quality indicators, according to the environmental quality standards for surface water (GB 3838-2002), were detected to evaluate the water quality of the Xin’anjiang River over the past 10 years. Principal component analysis (PCA) was used to comprehensively evaluate the water quality across eight monitoring stations and analyze the sources of water pollution. The results showed that all samples could be analyzed by three main components, which accounted for 87.24% of the total variance. PCA technology identified important water quality parameters and revealed that nutrient pollution and organic pollution are major latent factors which influence the water quality of Xin’anjiang River. It also showed that agricultural activities, erosion, domestic, and industrial discharges are fundamental causes of water pollution in the study area. It is of great significance for water quality safety management and pollution control of the Xin’anjiang River. Meanwhile, the inverse distance weighted (IDW) method was used to interpolate the PCA comprehensive score. Based on this, the temporal and spatial structure and changing characteristics of water quality in the Xin’anjiang River were analyzed. We found that the overall water quality of Xin’anjiang River (Huangshan) was stable from 2008 to 2017, but the pollution of the Pukou sampling point was of great concern. The results of IDW helped us to identify key areas requiring control in the Xin’anjiang River, which pointed the way for further delicacy management of the river. This study proved that the combination of PCA and IDW interpolation is an effective tool for determining surface water quality. It was of great significance for the control of water pollution in Xin’anjiang River and the reduction of eutrophication pressure in Thousand Island Lake.

Development and Evaluation of a Water Quality Index for the Iraqi Rivers

Abstract: 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.

Controlling factors and mechanism of groundwater quality variation in semiarid region of South India: an approach of water quality index (WQI) and health risk assessment (HRA)

Abstract: The study region comprises fractured granitic, basaltic and lateritic aquifer system constituted by Precambrian rocks. Groundwater is the primary source for drinking and household needs. Its quality is a big issue in the three aquifers, which are mostly of human health concern. Many developing regions suffer from lack of safe drinking water, thereby health problems arise in many parts of the regions, and Telangana state is one of them. For this reason, 194 groundwater samples were collected and analyzed for fluoride, nitrate, chloride and other physicochemical parameters. The concentrations of fluoride (F−), nitrate (NO3−), magnesium (Mg2+), total dissolved solids and total hardness are above the acceptable limits for drinking purposes, prescribed by the World Health Organization. The higher concentrations of fluoride and nitrate in drinking water cause health hazards, and above 50% of the groundwater samples are not suitable for drinking purposes with respect to fluoride and nitrate. Weathering of rocks and dissolution of fluoride-bearing minerals can be a cause for higher fluoride concentrations, while anthropogenic sources are one of the major reasons for higher nitrate concentrations in the study area. Groundwater suitability for irrigation suggests that more than 90% of the groundwater sampling locations are suitable for irrigation. In addition, health risk assessments were evaluated by using the United States Environmental Protection Agency model, to determine the non-carcinogenic risk of fluoride and nitrate in drinking water for adults (females and males) and children. The ranges of hazard index in all sampling locations are varied from 0.133 to 8.870 for males, 0.146 to 10.293 for females and 0.419 to 29.487 for children, respectively. The health risk assessment results indicated that children were more exposed to health risk, due to the intake of high contaminated drinking water with respective of nitrate and fluoride in the study region.

Quality criteria for groundwater use from a rural part of Wanaparthy District, Telangana State, India, through ionic spatial distribution (ISD), entropy water quality index (EWQI) and principal component analysis (PCA)

Abstract: The present study region comprises granite and granite gneisses aquifer system constituted by Precambrian rocks. Groundwater is the primary source for drinking and other domestic purposes. Many developing regions in the world suffer from lack of safe drinking water. A rural part of Wanaparthy District in Telangana State, India, is one of them. For this reason, the groundwater samples collected from the study region were analyzed for pH, TDS, Ca2+, Mg2+, Na+, K+, HCO3−, Cl−, SO42−, NO3− and F− and evaluated groundwater quality criteria, using ionic spatial distribution (ISD), entropy water quality index (EWQI) and principal component analysis (PCA). The ISD maps show that some locations are not suitable for drinking purpose due to exceeding concentrations of TDS, Mg2+, Na+, K+, HCO3−, Cl−, NO3−and F−, compared to those with national drinking water quality standards. According to the EWQI, about 3%, 47%, 43% and 7% of the total area come under the excellent, good, medium and extremely poor water quality types for drinking purpose, respectively. Chadha’s diagram classified the area as carbonate hardness (63%), non-carbonate alkali (17%), carbonates alkali (13%) and non-carbonate hardness (7%) zones. The binary diagrams (Na+ + K+ vs TC, Na+ vs Ca2+ and HCO3− vs TC) indicate that the quality of groundwater is controlled by influences of water–rock interactions, mineral weathering and dissolution, ion exchange and evaporation as well as the impact of anthropogenic sources. The PCA transferred the chemical variables into three principal components accounts for about 81% of the total variance. The high positive loadings of PC1 (Cl−, TDS, SO42−, Na+, NO3−, Mg2+ and HCO3−) stand for processes of silicate weathering and dissolution, ion exchange and evaporation, and the influence of domestic waste waters, irrigation return flows and chemical fertilizers on the groundwater system, the PC2 (F− and pH) signifies the alkaline nature of groundwater, which causes fluorosis, and the PC3 (K+) is a result of potassium fertilizers. The study helps to take remediate measures at a specific site and hence suggests the treatment of water before its drinking and also the recharge of the aquifer artificially to improve the groundwater quality.

Changes in global groundwater organic carbon driven by climate change and urbanization

Abstract: Climate change and urbanization can increase pressures on groundwater resources, but little is known about how groundwater quality will change. Here, we use a global synthesis (n = 9,404) to reveal the drivers of dissolved organic carbon (DOC), which is an important component of water chemistry and substrate for microorganisms that control biogeochemical reactions. Dissolved inorganic chemistry, local climate and land use explained ~ 31% of observed variability in groundwater DOC, whilst aquifer age explained an additional 16%. We identify a 19% increase in DOC associated with urban land cover. We predict major groundwater DOC increases following changes in precipitation and temperature in key areas relying on groundwater. Climate change and conversion of natural or agricultural areas to urban areas will decrease groundwater quality and increase water treatment costs, compounding existing constraints on groundwater resources. Groundwater is Earth’s largest source of freshwater, but the cost and ease with which it is turned to drinking water is dependent on the concentration of organic carbon. Here the authors show that climate change and urbanization will likely elevate future levels of groundwater dissolved organic carbon across the globe.

China’s improving inland surface water quality since 2003

Abstract: Increased human activity threatens inland water quality in China. Major efforts have been made to alleviate water pollution since 2001. Understanding how water quality responds to these forces can help to guide future efforts to maintain water security and sustainability. We here analyzed the nationwide variability of inland water quality across China from 2003 to 2017 and its responses to anthropogenic discharges. We show that water quality has been improved markedly or was maintained at favorable levels over the country because of reduced discharges in the industrial, rural, and urban residential sectors. However, growing discharges from the agricultural sector threaten these gains. Moreover, the present status of water pollution is relatively severe in north and northeast China. Our findings suggest that China's water quality would further benefit from more flexible strategies for mitigation measures, which respond to regional differences in the factors that influence water pollution levels in specific regions.