Hydrochemical Indicators Research Articles

Using Clustering, Geochemical Modeling, and a Decision Tree for the Hydrogeochemical Characterization of Groundwater in an In Situ Leaching Uranium Deposit in Bayan-Uul, Northern China

Uranium extraction through the in situ leaching method stands as a pivotal approach in uranium mining. In an effort to comprehensively assess the repercussions of in situ uranium leaching on groundwater quality, this study collected 12 representative groundwater samples within the Bayan-Uul mining area. The basic statistical characteristics of the water samples showed that the concentrations of SO42− and total dissolved solids (TDS) were relatively high. Through the use of cluster analysis, the water samples were categorized into two distinct clusters. Seven samples from wells W-d, W-u, N01, W10-2, W08-1, W10-1, and W13-1, situated at a considerable distance from the mining area, were grouped together. Conversely, five samples from wells W08-2, W13-2, W01-1, W02-2, and the pumping well located in closer proximity to the mining area, formed a separate cluster. A decision tree-based machine learning approach was employed to discern the influence of various hydrochemical indicators in forming these clusters, with results indicating that SO42− exerts the most substantial influence, followed by Ca2+. The mineral saturation indices from geochemical modeling indicated that, as the distance from the mining area increased, the trend of calcium minerals changed from dissolution to precipitation; iron minerals were in a precipitation state, and the precipitation trend was gradually weakening. In light of these findings, it is clear that in situ uranium leaching significantly impacted the groundwater in the vicinity of the mining area. The prolonged consumption of groundwater sourced near the study area, or its use for animal husbandry, poses potential health risks that demand heightened attention.

Interaction between Groundwater and Surface Water in the Qujiang River Basin in China: Evidence from Chemical Isotope Measurements

The Qujiang River Basin is a significant water system located in Zhejiang Province, China, that serves as a primary water source for Quzhou City. For this research, we collected and examined water samples from the Qujiang River Basin. In this study, we collected and analyzed water samples from the Qujiang River Basin and employed a combination of methods, including water balance analysis; Piper trilinear diagram; Gibbs diagram; and environmental tracer techniques, such as hydrochemical and isotopic analysis. These techniques helped us to analyze the spatial distribution patterns and evolutionary trends of surface water and groundwater hydrochemistry, along with the stable isotopes of hydrogen and oxygen, as well as to determine the sources of surface water and groundwater by calculating the conversion ratio between surface water and groundwater. (1) The findings of our study indicate that the primary hydrochemical types in the study area are Ca-HCO3 and Ca-HCO3·Cl, with the ion composition of water primarily influenced by rock weathering and precipitation. (2) Similar spatial variations in hydrochemical indicators were observed between surface water and groundwater in the study area, with frequent transitions between the two. (3) The hydrogen and oxygen isotope content increases downstream, signifying that both groundwater and surface water in the study area are replenished by atmospheric precipitation, as supported by the relationship between hydrogen and oxygen isotopes and the meteoric water line. (4) We determined that groundwater predominantly replenishes surface water in the upstream area. The average contribution rate of groundwater to surface water is 19.67%, with an annual average recharge volume of 1.23 × 106 m3. Midstream and downstream, surface water mainly recharges groundwater, with an average contribution rate of 22.77% and an annual average recharge volume of 1.59 × 106 m3.

Monitoring of hydrochemical indicators of water during algolization of reservoirs

Monitoring of hydrochemical indicators of water during algolization of reservoirs

Quantitative assessment of water quality in the Vidsichne reservoir (Zhytomyr, Ukraine)

The modern approach to the implementation of water management activities is based on a quantitative assessment of the quality of water resources, which includes a certain set of indicators to reflect the needs of users in the composition and properties of water, to assess their condition, etc. Ecological assessment is a preliminary stage and a condition for ecological standardization of surface water quality. To analyze the compliance of water quality with ecological standards, the obtained results are compared with the values of ecological standards for the corresponding water body. The study carried out a quantitative assessment of water quality in the Vidsichne reservoir, near Zhytomyr (Ukraine). This assessment is based on the introduction of risk weighting factors from certain types of pollutants to the calculation formula of the integral indicator. Monitoring studies on hydrochemical indicators in the reservoir showed an increase in manganese content to 0.40 mg/dm3. To calculate the integral indicator of water quality, manganese and the related level of oxygen dissolved in water, biological oxygen consumption (BOC) were selected. It was established that the water in the reservoir belongs to the fourth quality class, that is, it is polluted. A model map of manganese concentration was built and the ecological coefficient of water quality was calculated, which indicates a 5-fold excess of ecological standards. The use of a graphic method of comprehensive assessment of the state of water in any reservoir is substantiated. The increase in manganese content is due to the seasonal increase in air temperature. The constructed mathematical model of the dependence of manganese content on temperature makes it possible to predict the state of the water body depending on climatic conditions and indicates an increase in the value of this indicator from 12°C and above. Quantitative assessment of water quality in the reservoir based on the sum of ecological indicators reflects the needs of users in the composition and properties of water and makes it possible to assess their condition.

Influence of runoff regulation on hydrochemical indicators of water in small rivers on the example of the Teplaya river in the Saratov region

Small rivers are extremely sensitive to any anthropogenic activity, including runoff regulation, and serve as a kind of indicator of the ecological state of natural complexes. In general, large rivers are well studied, and small water bodies are practically not studied, although they are of great economic importance. For Teplaya river of the Saratov region was given an ecological and geographical characteristic, sources of anthropogenic load on the reservoir were identified, an analysis was made of the degree of knowledge and background indicators of the rivers of this basin. On the example of Teplaya river effect of runoff regulation of a small river by a dam on a number of physical and chemical parameters of pond water quality is considered. It has been established that the water temperature in the Teplaya river in the autumn period before the runoff regulation was a constant value, and after the dam it increased to the last sampling point downstream. The hydrogen index varied within 7.5-8.4, the total mineralization of water consistently increased in the studied section of the river (0.66-1.08 g/dm3). It is shown that the content of ammonium ions and nitrites was much higher than the sanitary and hygienic standards, which indicates the uniform nature of fresh organic water pollution in this section of the river. An increase in the concentration of chlorides in the last of the cascade of ponds was established - almost 1.5 times compared to the higher sampling points, which, however, did not exceed the standard values.

Tracking groundwater pollution plumes at landfill sites using borehole hydrochemical and hydrodynamic profile (BHHP) method

Groundwater pollution at landfill sites poses a significant risk to human health and ecological security. However, efficiently tracking pollution plumes in a polluted aquifer with variable pollutants remains challenging. In order to track groundwater pollution plumes at landfill sites, an in-situ borehole hydrochemical and hydrodynamic profile (BHHP) method was developed. Total dissolved solids (TDS), oxidation-reduction potential (ORP), and ammonia nitrogen were selected as the hydrochemical indicators. Meanwhile, the hydrodynamic indicators included flow direction and flow velocity of groundwater. Among the three hydrochemical indicators, TDS and ORP were analyzed to be the prior alternative ones for the BHHP application. The BHHP method was successfully applied to track groundwater pollution plumes at a typical valley-type landfill site and its neighboring downstream zone. Consequently, four groundwater pollution plumes of different types and different scales were identified in both horizontal and vertical directions within the depth of 0–50 m, and the various pollution sources for the detected pollution plumes were revealed. Furthermore, the BHHP method was validated using sampling test results of groundwater chloride and chemical oxygen demand at the surveyed landfill site.

Study the Nexus between Indicators of Surface Water Quality on the Small River for Better Basin Management

Purpose is determination of interdependencies between hydrochemical indicators of surface water quality in the example of a small river as a limiting factor of formation of aquatic ecosystem of territories. Correlation analyses of the studied indicators of water quality was conducted on an average value of each indicator (pH, phosphates, nitrates, BOD, COD, soluble oxygen). Found a significant increase in phosphates with time, with a coefficient of correlation R=0.71, indicating contamination of the water facility. This can be explained by the arrival of various surface-active substances and, to a lesser extent, the lack of quality sewage treatment facilities. Positive changes are founded in water object that is related to a decrease in the value of BOD. This is due to a decrease in the use of oxygen on oxidation of inorganic and organic substances. In general, the use of river runoff of the river above normal, and the overall environmental state of river basin is defined as "extremely poor".

Assessment of the Hydrophysical and Hydrochemical Characteristics of Lake Burabay (Akmola Region, North Kazakhstan)

This paper shows the results of a study on the morphometric, hydrophysical, and hydrochemical indicators of Lake Burabay, North Kazakhstan. The Burabay Protected Area, also known as Burabay National Park or Kokshetau National Park, is a protected natural area located in the north of Kazakhstan. It encompasses a diverse landscape characterized by lakes, forests, and unique rock formations. This analysis includes an eco-toxicological assessment of the hydrochemical composition of waters and benthal deposits by studying the content of metals. The degree of mineralization, ionic composition of water, hydrogen index, pollution index, and water quality class were also determined. Reductions in the area and depth of the lake were identified. The pollution index is 1.5–1.7, which belongs to class 3—moderately polluted. Relatively high concentrations of cadmium, nickel, copper, and arsenic were found in the lake sediments. Therefore, Lake Burabay and its surrounding ecosystem face certain environmental risks and potential water pollution. Although the increase in the number of tourists did not have a significant impact on the water pollution index in Lake Burabay, some of the common threats that impact the area are induced by touristic development, agricultural practices and industrial pollution. Significant efforts should be made to reduce these risks using the environmental indicators as a reference for control environmental quality.

Hydrochemical composition of the water of the Okkerville river

Okkervil is one of the small rivers of St. Petersburg, the source of which is located on the territory of the Leningrad Region, and the mouth is within the city of St. Petersburg. The length of the river is 18 kilometers, and in its course it passes through several rapidly developing settlements, including the village of Novosergievka and Kudrovo. The Okkervil River and its coastal zone, both within the city and beyond its borders, are actively used for various purposes, including recreation and amateur fishing. However, like many other rivers flowing through the territories of large cities, the river. Okkervil is subject to diverse anthropogenic pressure, leading to water pollution. Thus, the water quality of this river may not be of adequate quality for use in fisheries and recreational purposes. The main objective of this work is to determine the chemical composition of the waters of the river and to establish its suitability for fisheries and recreational water use. Sampling was carried out during the open water period at three points with different types of anthropogenic load: outside the city, near the village of Novosergievka; at the entrance to the city; and in the residential area, near the Prospekt Bolshevikov metro station. At each point, the main hydrochemical indicators were determined: the concentrations of iron, copper, ammonium ions, phosphates, nitrates and nitrites, heavy metals, as well as the concentration of dissolved oxygen and BOD5. At all sampling points during the research period in the river, the standard values for the content of nitrites, phosphates, iron and copper were exceeded.The results obtained indicate a high level of pollution associated, among other things, with the ingress of untreated storm drains into the river, and untreated and undertreated household waste. The highest level of water pollution was noted at a point located in a residential area. The water here corresponded to the V class of quality (dirty). Both in the spring-summer and autumn periods of the study, the water of the Okkervil River in the other two sections corresponded to III-IV quality class (moderately polluted - polluted). The water quality of the Okkervil River deteriorates from the source to the mouth. In all the studied areas, the river is unsuitable for fisheries and recreational water use.

СТРУКТУРА ВОД МОРЕЙ ДЕЙВИСА И МОУСОНА ПО ДАННЫМ ОКЕАНОГРАФИЧЕСКИХ ИССЛЕДОВАНИЙ, ВЫПОЛНЕННЫХ В ХОДЕ 67-й РАЭ

We present the results of oceanographic studies from 64 stations occupied on the slope and shelf in the Davis Sea and the Mawson Sea during the 67th Russian Antarctic Expedition (RAE) from the R/V “Akademik Fedorov” in January–February 2022. The analysis of unique highprecision CTD data and hydrochemical indicators, together with a comparison with the results of previous studies, allowed us to obtain valuable information about the interannual variability of thermohaline characteristics of Antarctic shelf water on the shelf in the central part of the Davis Sea, to determine the structure of water masses on the slope and shelf in the western part of the Davis Sea and the eastern part of the Mawson Sea. Cascading and dense Antarctic shelf water not been recorded during the research. The thermohaline characteristics of Antarctic shelf water recorded in the central part of the Davis Sea in 2001, 2017, 2021 and dense Antarctic shelf water presence in the basins in February 2022 suggest the participation of Davis Sea shelf water in the ventilation of deep waters and suggest an irregular nature of the source of Antarctic bottom waters in the Davis Sea.

The Use of Neural Network Modeling Methods to Determine Regional Threshold Values of Hydrochemical Indicators in the Environmental Monitoring System of Waterbodies.

The regulation of the anthropogenic load on waterbodies is carried out based on water quality standards that are determined using the threshold values of hydrochemical indicators. These applied standards should be defined both geographically and differentially, taking into account the regional specifics of the formation of surface water compositions. However, there is currently no unified approach to defining these regional standards. It is, therefore. appropriate to develop regional water quality standards utilizing modern technologies for the mathematical purpose of methods analysis using both experimental data sources and information system technologies. As suggested by the use of sets of chemical analysis and neural network cluster analysis, both methods of analysis and an expert assessment could identify surface water types as well as define the official regional threshold values of hydrochemical system indicators, to improve the adequacy of assessments and ensure the mathematical justification of developed standards. The process for testing the proposed approach was carried out, using the surface water resource objects in the territory of the Republic of Tatarstan as our example, in addition to using the results of long-term systematic measurements of informative hydrochemical indicators. In the first stage, typing was performed on surface waters using the neural network clustering method. Clustering was performed based on sets of determined hydrochemical parameters in Kohonen's self-organizing neural network. To assess the uniformity of data, groups in each of the selected clusters were represented by specialists in this subject area's region. To determine the regional threshold values of hydrochemical indicators, statistical data for the corresponding clusters were calculated, and the ranges of these values were used. The results of testing this proposed approach allowed us to recommend it for identifying surface water types, as well as to define the threshold values of hydrochemical indicators in the territory of any region with different surface water compositions.

Using dual stable isotopes method for nitrate sources identification in Cao-E River Basin, Eastern China

Excess nitrate (NO3−) of water is a worldwide environmental problem. Therefore, identifying the sources and analyzing respective contribution rates are of great importance for improving water quality. The current study was carried out to identify the potential sources of NO3− pollution in Cao-E River basin, in Eastern China. Surface water samples were collected during the dry season and wet season. Multiple hydrochemical indices, dual NO3− isotopes (δ15N–NO3− and δ18O–NO3−) and a Bayesian model (stable isotope analysis in R, MixSIAR) were applied to identify NO3− sources and estimate the proportional contributions of multiple NO3− sources. During the sampling period, nitrification was a dominant nitrogen transformation process in the study area. The results of the NO3− isotopes suggested that manure and sewage (M&S), soil nitrogen (SN) and nitrogen fertilizer (NF) were the major contributors to NO3−. Moreover, the results obtained from the MixSIAR model showed that the proportional contributions of atmospheric deposition (AD), NF, M&S and SN to NO3− were 2.82, 15.45, 44.25, 37.47% and 3.14, 23.39, 31.78, 41.69% in the dry and wet season, respectively. This study provided evidence to further understand the sources, transport, and transformation of N in Cao-E River basin, which deepens the understanding of the management of N contaminant.

Hydrochemical characteristics of the Upper reaches of the Tisza River


 
 
 The purpose of this study is to analyse the hydrochemical regime and surface water quality of the upper reaches of the Tisza River from its source to Tiachiv, which also includes the transboundary section of the river. The data of the Borys Sreznevskyi Central Geophysical Observatory of the State Emergency Service of Ukraine for the period 1984-2018, as well as the results of route surveys during 2015-2018 served as materials for the study. The hydrological parameters of the river, in particular the level and flow of water, the distribution of the flow and the change of power sources throughout the year were analysed. Based on of the collected materials, a detailed analysis of the hydrochemical indicators of the water quality of the Tisza, Black Tisza, and White Tisza rivers was carried out. During the research, the natural conditions of the territory and economic activity were studied and their influence on the values of physic-chemical indicators, main ions and mineralization of water, biogenic substances, heavy metals and specific pollutants was analysed. The ratio of seasonal, average annual, average multi-year and maximum permissible concentra-tions (MPC) of hydro-chemical indicators was considered to determine their seasonal variability and multi-year dynamics. The role of natural factors in the formation of the chemical composition of river waters is determined, and the main sources of anthropogenic influence are also indicated. Seasonal variability of the indicated groups of indicators was also analysed considering different phases of river water content. It was determined that the waters of the headwaters of the Tisza River are calcium carbonate, moderately fresh with average mineralization (192-245 mg∙dm-3) and clear seasonal variability. Cases of increased concentrations of nitrogen-containing compounds in the waters of the upper reaches of the Tisza River due to the intensive decomposition of organic substances from house- hold wastewater were revealed. High concentrations of iron in river waters were recorded, which is related to the peculiarities of the geological structure of the territory. The seasonal variability of the content of synthetic surfactants was established. A decrease in the content of specific pollutants during the study period was observed.
 
 

Assessment of the hydro-ecological situation of the Verkhno-Ivachivsk Reservoir in Ternopil using the fuzzy logic apparatus


 
 
 The work purpose is to investigate the water parameters of the Verkhno-Ivachivsk water intake, Ternopil and develop a model of water quality assessment and management. Common methods of hydroecological studies of surface water were used to determine hydrochemical indicators. A model based on fuzzy logic and neural networks implemented in Matlab software was used to assess the water quality of the water intake. As a result of a complex hydroecological study of the water intake, which provides the drinking water majority supply in Ternopil, the content of the main pollutants (compounds of nitrogen, phosphorus, petroleum products, phenols, surface active agents) was determined (May, June, November, January 2019-2020). We compared the obtained indicator values with the ecological regulations and drinking water quality standards and we also assessed the ecological danger by the content of individual substances and the ecotoxicological situation in general. It was established that the water is slightly alkaline, which contributes to the presence of carbon dioxide in the form of a hydrogen carbonate ion, ensuring an environ-mentally acceptable gas regime of water. The reason for water alkalinity is the rotting of organic substances from the agricultural sector. The water quality according to the phosphate indicator is good even in the conditions of intensive supply of phosphates with sewage, due to their transition into insoluble forms and accumulation in sediments (silt), which is also facilitated by the low alkalinity of the water. An increased content of nitrogen compounds (ammonium, nitrates) in the water was revealed. Pollution and disruption of the nitrogen-containing compound cycle can be associated with the inflow of nitrogen compounds from surface runoff water and municipal and household washes, the organic substance decomposition in the agricultural sector and a violation of the production and destruction process ratio. The aquifer significant pollution by anthropogenic origin organic substances is reflected in the value of BOD5 indicator, which is higher than the permissible level. The established values indicate high organic pollution and correlates with the formation of significant ammonia amounts which is a product of anaerobic and aerobic organic substance oxidation. After defuzzification of all neural connections in Matlab program we obtained a model for evaluating the quality of water intake at an average level with an indicator of 1.52, which corresponds to the rating scale - an average level in the range (1.36-2.18).
 
 

Contrasting water quality in response to long-term nitrogen fertilization in rainfed and irrigated apple-producing regions on China’s Loess Plateau

Overfertilization prevails in developing apple-producing countries, but its long-term effects on regional water resources are scarcely documented. In this study, a total of 114 water samples, including groundwater, river water, and tap water, were collected from rainfed and irrigated apple-planting regions on China’s Loess Plateau. The primary objectives were to (1) systematically evaluate changes in hydrochemistry using hydrochemical indices and major ion ratios, (2) quantify NO3−-N pollution and its driving factors using δ15N- and δ18O-labeled nitrate and a Bayesian isotope mixing model (MixSIAR), and (3) identify water suitable for drinking using an entropy water quality index and for irrigation by integrating electrical conductivity and Na%. All water samples contained Ca-Mg-HCO3 facies, except for low-elevation water samples in the irrigated region with Na-HCO3 facies. Hydrochemistry changed considerably from the 2000–2020 s in both rainfed and irrigated regions, primarily associated with agricultural activities (e.g., fertilization). Although absent in the rainfed region, NO3−-N pollution was severe in the irrigated region, with 40.0 % of tap water, 25.0 % of river water, and 32.7 % of groundwater samples exceeding the World Health Organization limit of 10 mg L−1. MixSIAR indicated the contribution of chemical fertilizer to NO3− was higher in irrigated than in rainfed regions, regardless of the water source. With the exception of sewage/manure-derived NO3–-N in the rainfed region’s groundwater, chemical fertilizer was the highest contributor to NO3−-N in river water and groundwater, whereas sewage/manure was the most important nitrate source in tap water, whether irrigated or rainfed region. Regression analysis revealed N-fertilizer inputs and water level and well depths were key factors affecting groundwater NO3−-N in the irrigated region compared with those in the rainfed region. Notably, all water samples in the rainfed region were suitable for drinking and irrigation, whereas in the irrigated region, 27.3 % of groundwater samples were unsuitable for drinking and 40.0 % of tap water, 75.0 % of river water, and 63.6 % of groundwater samples were doubtful-to-unsuitable for irrigation. Collectively, overfertilization in long-term apple cultivation changed regional hydrochemistry, with flood irrigation aggravating nitrate pollution and water degradation. The study provides new insights into optimum water–nitrogen management of apple production systems in China and other developing countries with similar problems.

Influence of Environmental Factors on the Dynamics of Zooplankton in Lake Kulunda (Western Siberia)

The results of studying the influence of the main natural environmental factors on the interannual (2017–2021) and seasonal (from April to October) zooplankton dynamics of the large hypersaline Lake Kulunda located in the Kulunda steppe (Altai krai, Russia) are presented. The relationship of 13 main indicators of the structure of zooplankton (number and biomass in total, the main taxonomic groups: rotifers, copepods, cladocerans, and branchiopods, as well as different stages of the life cycle of Artemia) with the main hydrophysical and hydrochemical indicators (temperature, density, salinity, and pH of water) was analyzed separately by monthly and average annual (for the growing season) values. The influence of the studied factors on the characteristics of the brine shrimp population (number, biomass, and age structure), which dominated the zooplankton of this lake, was analyzed in more detail. It was revealed that the hydrophysical and hydrochemical regimes of the lake in different years are subject to significant changes and are reflected in the indicators of zooplankton. Changes in the structure of zooplankton under the influence of natural factors are mainly due to the stimulating effect of an increase in water mineralization on the Artemia population and its depressing effect on the brackish fauna. With a decrease in water salinity less than 100 g/dm3 since 2017 (127 g/m3) to 2021 (96 g/dm3) maximum (summer) Artemia biomass decreased from 167 to 17.7 g/m3. At the same time, the maximum biomass of rotifers, cladocerans, and copepods increased from 0.003, 0, and 0.63 to 6.21, 1.35, and 2.65 g/m3 respectively.

Assessing the State of Aquatic Ecosystems Based on Integral Hydrochemical Indicators in the National Monitoring of the State and Pollution of the Environment

Assessing the State of Aquatic Ecosystems Based on Integral Hydrochemical Indicators in the National Monitoring of the State and Pollution of the Environment

ОЦЕНКА СОСТОЯНИЯ ВОДНЫХ ЭКОСИСТЕМ ПО ИНТЕГРАЛЬНЫМ ГИДРОХИМИЧЕСКИМ ПОКАЗАТЕЛЯМ В ГОСУДАРСТВЕННОМ МОНИТОРИНГЕ СОСТОЯНИЯ И ЗАГРЯЗНЕНИЯ ОКРУЖАЮЩЕЙ СРЕДЫ

The paper presents some methodological approaches to the development of the aquatic ecosystems state classifier according to integral hydrochemical indicators. The classifier has been developed based on the analysis of the Roshydromet long-term routine hydrochemical information for a large number of rivers and their reaches located in various natural and climatic zones of Russia. Criteria for assessing the state of aquatic ecosystems have been established taking into account water salinity: from natural, equilibrium, and stressful to critical or catastrophic. Testing of the methodological approaches and verification of the state assessment results was carried out by the example of individual river ecosystems in the European part of Russia. The majority of ecologically safe river ecosystems functioning in their natural state have been shown to belong to waters with low salinity and to be located in northern regions. In the center and the south of the European part of Russia, river ecosystems in equilibrium, stressful, or critical state dominate.

ANALYSIS OF KNOWN METHODS OF DETERMINING OF THE WATER QUALITY INDEX SUITABLE FOR PREDICTING THE ENVIRONMENTAL STATE OF SURFACE WATER BODIES

The article considered the ecological index of water quality, which is used for planning water protection activities, developing water protection measures, carrying out ecological and ecological and economic zoning, ecological mapping; water pollution index, which is determined by hydrochemical indicators; modified Horton water quality index models; the Water Quality Index is proposed by the Canadian Council of Ministers of the Environment; the Said index, which is used to assess the quality of water for general use; water quality index in the river subbasin in a certain year; The Nemerov Pollution Index, which is used to comprehensively assess water, precipitation, or soil quality, and the Oregon Water Quality Index. Advantages and disadvantages of water quality and pollution indices are determined.

Hydrochemical indices as a proxy for assessing land-use impacts on water resources: a sustainable management perspective and case study of Can Tho City, Vietnam

Hydrochemical indices as a proxy for assessing land-use impacts on water resources: a sustainable management perspective and case study of Can Tho City, Vietnam