Search

The crux of groundwater protection lies in a profound understanding of the sources of pollutants and their impacts on human health. This study selected 47 groundwater samples from the Fengshui mining area in central Shandong Province, China, employing advanced hydrogeochemical techniques, positive matrix factorization (PMF), and Monte Carlo analysis methods, aimed at unveiling the characteristics, origins, and health risks of water pollutants. The results indicated that the majority of samples exhibited a slightly alkaline nature. Notably, the concentrations of fluoride (F−) and nitrate (NO3−) exceeded China's safety standards in 40.43% and 23.40% of the samples, respectively. Moreover, a water quality index (WQI) below 50 was observed in approximately 68.09% of the sites, suggesting that the water quality in these areas generally met acceptable levels. However, regions with higher WQI values were predominantly located in the northern and southern parts of the mining area. PMF analysis revealed that regional geological and industrial activities were the primary factors affecting water quality, followed by mining discharges, fundamental geological and agricultural processes, and leachate enrichment activities. The health risk assessment highlighted the heightened sensitivity of the youth demographic to fluoride, with a more pronounced non-carcinogenic risk compared to nitrate, affecting about 31.89% of the youth population. Hence, it is imperative for local authorities and relevant departments to take prompt actions to remediate groundwater contamination to minimize public health risks. [ABSTRACT FROM AUTHOR]

Groundwater is an essential freshwater resource utilized in industry, agriculture, and daily life. In the Huaibei Plain (HBP), where groundwater significantly influences socio-economic development, information about its quality, hydrochemistry, and related health risks remains limited. We conducted a comprehensive groundwater sampling in the HBP and examined its rock characteristics, water quality index (WQI), and potential health risks. The results revealed that the primary factors shaping groundwater hydrochemistry were rock dissolution and weathering, cation exchange, and anthropogenic activities. WQI assessment indicated that only 73% of the groundwaters is potable, as Fe2+, Mn2+, NO3−, and F− contents in the water could pose non-carcinogenic hazards to humans. Children were more susceptible to these health risks through oral ingestion than adults. Uncertainty analysis indicated that the probabilities of non-carcinogenic risk were approximately 57% and 31% for children and adults, respectively. Sensitivity analysis further identified fluoride as the primary factor influencing non-carcinogenic risks, indicating that reducing fluoride contamination should be prioritized in future groundwater management in the HBP. [ABSTRACT FROM AUTHOR]

Groundwater is vital to local human life and agricultural irrigation, and the quality of the water is critical to human health. As a result, it is critical to investigate the hydrochemical evolution and water quality of groundwater in the Sanjiang Plain. There were 259 samples obtained. Furthermore, hydrogeochemical simulation was performed to highlight groundwater's hydrochemical features, evolution process, and water quality. The analytical results show that the groundwater in the study area is somewhat alkaline with a mean TDS of 285.94 mgL−1 and the primary contributing ions being Ca2+ and HCO3−. The closer the concentration of TDS and NO3− is to the city, the higher the concentration, indicating that the chemical composition of the water body has been affected by certain human activities. The Piper diagram, Gibbs diagram, and correlation analysis results demonstrate that the chemical type of groundwater is mostly HCO3-Ca and the hydrochemistry is primarily regulated by weathering and carbonate and silicate dissolution. According to the entropy-weighted water quality index, the groundwater quality in this location is pretty acceptable. This study could help strengthen groundwater quality monitoring based on local conditions, identify the source of nitrate, provide data support for the safe use of local water resources, and serve as a reference for global water chemical evolution and water quality evaluation in cold regions. [ABSTRACT FROM AUTHOR]

The Yangtze River Basin, one of China's five major watersheds and a primary source of drinking water for the country, is experiencing serious environmental pollution as heavy metals are discharged into its rivers. To evaluate the water quality of the river, determined water quality parameters were compared with the maximum permissible limit values recommended by the World Health Organization and Chinese drinking water standards. Physical and chemical analyses were conducted on water samples taken from 19 locations along the river's path. The study quantified the contents of sodium (Na), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), lithium (Li), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), scandium (Sc) and mercury (Hg). The results show that the average values of Mg, Sr, Co, Cu, Fe, Mn and Sc are higher than the historical background values. Moreover, through a correlation analysis it was concluded that these nutrients and trace metals have high values due to anthropogenic pollution in the study area. The computed WQI values range between 9.59 and 20.26, indicating excellent water quality in the river basin. Finally, hazard quotient (HQ) values show that exposure to the detected pollutants will have no adverse effects on human health and does not pose a potential non-carcinogenic risk. [ABSTRACT FROM AUTHOR]

Urbanization has caused severe negative impacts on intra-urban river water bodies. In this paper, 22 physicochemical parameters were measured at 20 locations in the level period and 29 locations in the wet and dry period using nearby urban area surface water samples from a medium-sized polluted river (a lake–river continuum, i.e., Xunsi River, Qingling River and Tangxun Lake) in the Yangtze River watershed in Wuhan, China. In this study, the environmental quality standards for surface water of China (GB3838-2002) and the WHO drinking water standard (2011) were used as reference standards. After the basic physicochemical parameters were evaluated, the possible sources of pollution in the study area under urban pressure were examined by applying multivariate statistical techniques. The factor analysis method and entropy weighting method identified three critical factors describing the type of surface water pollution in the watershed: (1) pollution from nutrients, mainly nitrogen pollution, (2) trace metals pollution, mainly from Fe and Pb, and (3) organic pollution. Based on multivariate analysis, the weighted arithmetic water quality index (WQI) was used to assess the water quality of each period. The WQI results show that the water near the urban area of the watershed temporally shows light to moderate pollution overall in the level and wet periods, and sever pollution in the dry period. The worst water quality indicating water that is not suitable for any practical use occurs in the dry period. Spatially distributed in clusters and strips visualized in kriging method, the water quality of the lake source and upstream is better than that of the downstream. In addition, Escherichia coli was detected at consistently high levels, and although the river is not a source of drinking water, it could pose a threat to downstream waterworks. [ABSTRACT FROM AUTHOR]

Coal-bearing fractured aquifer is regarded as one of the most dynamic mine water inrush sources, and after pumping and treating, it can be used as a water supply for coal mine production, coal preparation plant, rural irrigation, and even reserved drinking water source. Hence, this study focuses on the hydrochemical characteristics, ion source, and water quality evaluation with respect to drinking and irrigation of the coal-bearing fractured aquifer in Dingji coal mine, Huainan coalfield, China. Descriptive statistics and hydrochemical classification diagrams including the Piper diagram and Chadha rectangular diagram were carried out to depict the hydrochemical characteristics and facies. The water quality of the aquifer was assessed for irrigation and drinking purposes using the WHO threshold value, water quality index (WQI), SAR, % Na and RSC. Hydrochemical formation mechanism and solute origin of major ions were explained by Gibbs diagram, bivariate diagrams, and multivariate statistical analysis. The results show that the dominant hydrochemical facies are the Cl-Na type and the HCO3-Na type. The sequence of ions is Na+ > Ca2+ > Mg2+ for cations, and HCO3- > Cl- > SO42- > CO32- for anions. The main solute sources are controlled by various factors including the dissolution of halite, sulfate, and carbonate rocks, the weathering of silicate, and cation exchange. Water quality assessment based on WQI suggests that none of the samples fall under the excellent category, even 32.5% is not suitable for direct drinking. Meanwhile, the samples of the aquifer are generally unsuitable for irrigation. Before utilization for irrigation and even drinking, appropriate water treatment should be applied to guarantee its security during usage. [ABSTRACT FROM AUTHOR]

Water quality evaluation in Lake Taihu, China, is vital for the regional water security. Recent studies have focused on understanding the spatio‐temporal dynamics of water conditions using long‐term data series. In this study, water conditions of Lake Taihu during non‐cyanobacterial/cyanobacterial growth periods were assessed based on water quality index (WQI), trophic level index (TLI), chlorophyll a concentration, and algal density; the spatio‐temporal changes in water quality were quantified, and their corresponding driving forces were discussed. The study employed water quality data from 2013 to 2018 and algal density data from 2013 to 2017. The results revealed that the water conditions varied over the years; it was the poorest in 2013, improved slightly in 2014, deteriorated during 2015–2017, and improved again in 2018. Slow algal growth was observed from May to July, which accelerated from August–September. The TLI in Lake Taihu may increase due to significant inflow during wet years, which may increase the eutrophication area and algae density in the following year, necessitating extreme caution. The northwestern part of Lake Taihu exhibited a lower WQI and higher TLI than its southeastern part. In the bays with high TLI, the WQI during the cyanobacterial growth period was lower than the non‐cyanobacterial growth period; the converse was observed in bays with low TLI. The results of this study imply that water conditions of Lake Taihu could be enhanced by reducing the nutrient load in wet seasons and wet years and improving the hydrodynamic conditions through water diversion, especially in Zhushan and Meiliang bays. [ABSTRACT FROM AUTHOR]

Dongping Lake is one of the most important regulation and storage lakes along the eastern route of the South-to-North Water Diversion Project in China, the water quality condition of which directly influences the safety of water diverting, because it serves as a Yangtze River water redistribution control point. However, the changes in algae, and in environmental factors affecting their community structures, before and after the water diversion project are rarely reported. In this study, the temporal variations of phytoplankton abundance were examined based on monthly samples collected at three stations from May 2010 to April 2022. The total abundance of algae greatly decreased after the water diversion project was implemented, with a relatively stable biodiversity and evenness before and after the water translocation. Multiple statistical methods were used together with the water quality indices (WQIs) and the nutrient status index (TSI M) to evaluate overall water condition and analyse relationships among environmental factors. The WQIs demonstrated a general "Good" water quality with a seasonal differentiation, and that water conditions during water transfer periods were better than during non-water transfer periods, which may be ascribed to the improved hydraulic conditions and purified water environment during water transfer periods. Redundancy analysis showed that water temperature, ammonia nitrogen, water transparency, and total phosphorus were the most important environmental factors, with relatively decreased contribution rates towards phytoplankton communities after the water translocation. Importantly, some dominant phytoplankton genera of Chlorophyta, Bacillariophyceae, and Cyanophyceae were similarly affected by water transparency, and nitrogen and phosphorus nutrients in summer after the water translocation. These research findings helped us gain a comprehensive understanding of the changing patterns of water quality and microalgae and their relationships before and after the water diversion project, providing a guidance for future lake management in regulating hydraulic conditions and improving water quality of Dongping Lake. [Display omitted] • Phytoplankton abundance in Dongping Lake significantly decreased after SNWDP. • Phytoplankton diversity and evenness remained stable before and after SNWDP. • WQI indicated better water quality during the water transfer period. • Environmental factors contributed less towards phytoplankton communities after SNWDP. • More attention to lake water management is recommended after SNWDP. [ABSTRACT FROM AUTHOR]

Due to the impact of human agricultural production and climate and environmental changes, the applicability of groundwater for drinking purposes has attracted widespread attention. In order to quantify the hydrochemical characteristics of groundwater in Changchun New District and evaluate its quality for drinking purposes, 53 shallow groundwater samples were collected and analyzed. The results show that groundwater in aquifers in the study area is weakly alkaline. The abundance is in the order Ca2+ > Na+ > Mg2+ for cations, and HCO3− > Cl− > SO42− for anions. Ca-HCO3•Cl water type dominated the area, constituting about 26.41% of the total samples; Ca-HCO3 water type constituted about 22.64%; Ca•Na-HCO3 and Ca•Na-HCO3•Cl water types constituted 15.09% each, whereas Ca•Na-HCO3•Cl•SO4, Ca-HCO3•Cl•SO4, and Ca-SO4•Cl types made up 22.64% each. Correlation analysis (CA) and principal component analyses (PCA) show that rock weathering and dissolution, and human activities are the main reasons affecting the chemical composition of water in Changchun. The high concentrations of Pb, NO2−, Fe, and Mn must be widely concerned and may become the main environmental geological problems in the area. The analysis of water samples based on the water quality index model revealed that about 5.66%, 56.60%, 15.09%, 18.86%, and 3.77% of the shallow groundwater samples were excellent, good, poor, very poor, and unsuitable for drinking purposes, respectively. The analysis of groundwater samples based on the synthetic pollution index model showed that more than 37.74% of the groundwater samples were moderately polluted. The spatial distribution maps of the water quality index and the synthetic pollution index show that most of the shallow groundwater resources in the study area are clean and suitable for drinking, despite the risks of the shallow groundwater in the southeast of the study area. [ABSTRACT FROM AUTHOR]

Due to the impact of human agricultural production and climate and environmental changes, the applicability of groundwater for drinking purposes has attracted widespread attention. In order to quantify the hydrochemical characteristics of groundwater in Lianhuashan and evaluate its suitability for assessing water for drinking purposes, 71 groundwater samples were collected and analyzed. The results show that groundwater in aquifers in the study area is weakly alkaline. The abundance is in the order HCO3 ->Cl->SO4 2- for anions, and Ca2+>Na+>Mg2+ for cations. Groundwater chemical types were dominated by HCO3-Ca, HCO3-Ca• Mg, and HCO3-Ca • Na. The Factor analysis, and PCA analysis show that ion exchange, and rock weathering are the main reasons affecting the water chemical composition in Lianhuashan. The analysis of water samples based on the WQI model revealed that about 69.09%, 25.45%, 1.81%, and 3.63% of the water samples were excellent, good, very poor, and unsuitable for drinking purposes, respectively. The analysis of water samples based on the SPI model showed that 18.30%, 66.19%, 7.04%, and 8.45% of the water samples were suitable, slightly polluted, moderately polluted, and highly polluted, respectively. The spatial distribution maps of the water quality index and the synthetic pollution index show that most of the groundwater resources in the study area are clean and suitable for drinking, despite the risks in the north and southwest of the study area. [ABSTRACT FROM AUTHOR]

Lake Taihu Basin, one of the most developed regions in China, has received considerable attention due to its severe pollution. Our study provides a clear understanding of the water quality in the rivers of Lake Taihu Basin based on basin-scale monitoring and a water quality index (WQI) method. From September 2014 to January 2016, four samplings across four seasons were conducted at 96 sites along main rivers. Fifteen parameters, including water temperature, pH, dissolved oxygen (DO), conductivity, turbidity (tur), permanganate index (COD Mn ), total nitrogen, total phosphorus, ammonium (NH 4 -N), nitrite, nitrate (NO 3 -N), calcium, magnesium, chloride, and sulfate, were measured to calculate the WQI. The average WQI value during our study period was 59.33; consequently, the water quality was considered as generally “moderate”. Significant differences in WQI values were detected among the 6 river systems, with better water quality in the Tiaoxi and Nanhe systems. The water quality presented distinct seasonal variation, with the highest WQI values in autumn, followed by spring and summer, and the lowest values in winter. The minimum WQI (WQI min ), which was developed based on a stepwise linear regression analysis, consisted of five parameters: NH 4 -N, COD Mn , NO 3 -N, DO, and tur. The model exhibited excellent performance in representing the water quality in Lake Taihu Basin, especially when weights were fully considered. Our results are beneficial for water quality management and could be used for rapid and low-cost water quality evaluation in Lake Taihu Basin. Additionally, we suggest that weights of environmental parameters should be fully considered in water quality assessments when using the WQI min method. [ABSTRACT FROM AUTHOR]

The chemical characteristics of groundwater can indicate water quality condition and provide useful information for pollution source identification. This study aimed to understand the effects of dissolved organic matter (DOM) on ionic composition of groundwater and identify the main ions and sources of pollution. The Lake Taihu is a typical eutrophic lake in China. In this study, the hydrochemical composition of groundwater in the surrounding aquifer of Lake Taihu Basin was analyzed. The results showed that the values of water quality index (WQI) range from 13.29 to 56.26 (good water quality). The dominant hydrochemical type of groundwater was Ca–Mg–HCO3 type, and the rock dominance was the major mechanism controlling the groundwater chemistry. With an increasing concentration in dissolved organic carbon (DOC), the Na+, Mg2+, and HCO3– concentrations all showed a sharp increase followed by a slow increase, while the NO3– concentration showed an opposite trend, indicating the DOM can affect the ions composition. In addition, K+ was positively correlated with NO3–, As, and Cd. Hence, DOM input may directly or indirectly change the hydrochemistry of groundwater. Besides, the NO3– concentration in groundwater was much higher than that in Lake Taihu, indicating that the NO3– in groundwater mainly came from surface soil leaching. The anthropogenic sources are probably the main sources of different ions, including K+, NO3–, As, and Cd. This study can help to better understand the effects of lake eutrophication on groundwater and its pathways. [Display omitted] • Groundwater hydrochemical characteristics in Lake Taihu was explored. • DOC can affect the concentrations of Na+, Mg2+, HCO 3 − and NO 3 − in groundwater. • K+, As, and Cd were mainly derived from the application of chemical fertilizers. • Pb was mainly originated from the water–rock interactions in the aquifer. [ABSTRACT FROM AUTHOR]

Studies regarding the temporal-spatial variability of water source quality are crucial for protecting urban drinking water and for urban planning. With 41 typical drinking water sources in Guangdong Province as the research object, this study investigated temporal-spatial trend of different kinds of water sources in different seasons, a subject that has received little attention. The water quality index (WQI) method was used to study the quality of water sources, and the seasonal Kendall testing method was used to analyze the trends in changing water quality. The following results were obtained: (1) Overall, 22 water sources showed tendencies towards improvement and 13 showed a steady trend towards improvement. In addition, 6 sources faced water quality deterioration problems. The quality of the water source and its variations in eastern, northern and western Guangdong are satisfactory. However, the water sources with the poorest quality or that exhibited deteriorative trends were concentrated in the Pearl River Delta. (2) More water sources exhibited improving quality during the non-flood season than during the flood season. In addition, this effect was more pronounced in river-type source water than in reservoir-type source waters. During the flood season, 5 water sources exhibited deteriorative trends. Of these water sources, 3 were river-type. In addition, 18 water sources had improving water quality. Of these, 12 were river-type. During the non-flood season, only 2 river-type water sources exhibited a deteriorative trend. In addition, 19 water sources showed water quality improvements. Of these, 14 were river-type sources. (3) According to the calculated WQI and its temporal variations, this paper suggests that water sources in Guangdong can be classified into four groups, high WQI, saltatory WQI, fluctuant WQI, and low WQI. In addition, the WQI method and seasonal Kendall testing methods are appropriate for investigating the temporal-spatial variability of water source quality and can provide guidance for regional water source planning. [ABSTRACT FROM AUTHOR]

Groundwater and artificial reservoirs are in a continuous dynamic interaction that can affect not only water quantity but the quality. In this paper, taking the DR (Doumen Reservoir) as an example, the level dynamic changes between the DRTS (Doumen Reservoir Test Section) and groundwater were discussed, and the water quality used by SFE (single-factor evaluation) and WQI (water quality index) method were analyzed. A coupling model is presented to quantify the leakage impact range and groundwater budget and regionalize the impact of surface water on regional groundwater quality. The results show that the level dynamics of the reservoir and groundwater are highly consistent, with a cross-correlation coefficient of 0.85 and a lag time of about 7 days. The reservoir recharges the groundwater with an increase-decrease-stationary wave dynamic potential. After 3 years of operation of the DR, the groundwater still is recharged, the groundwater level will rise obviously, with a maximum of 8.5 m. The amount of surface water recharged is always 0. NH3-N, and COD will have varying degrees of impact, both of which are mainly the pollution halo around North Lake. The results can provide support for water resources management and environmental protection of urban plain reservoirs. [ABSTRACT FROM AUTHOR]