Water Quality Index Research Articles

Evaluation of the acute toxicity of IHPLUS® on the biomodel water quality indicator: Poecilia reticulata

La agricultura convencional depende de la aplicación de fertilizantes con el fin de lograr mayores rendimientos; sin embargo, es necesario encontrar un equilibrio entre sus beneficios y las alteraciones que pudieran producir a los ecosistemas. Organizaciones internacionales regulan su uso y comercialización teniendo en cuenta la eficacia y seguridad. IHPLUS®, producido por la Estación Experimental de Pastos y Forrajes “Indio Hatuey” (Cuba), ha mostrado ser efectivo en diferentes cultivos y es objeto en este estudio evaluar los efectos sobre la calidad del agua en el bioindicador Poecilia reticulata. Los peces fueron expuestos al producto, en régimen estático durante 96 h, a la concentración efectiva en la agricultura (6 %) o diluido hasta 106 UFC/ml según recomienda la EPA OPPTS 885.4000. Asimismo, se incluyó un grupo tratado con el producto al 6 %, pero esterilizado y un grupo control que no recibió tratamiento alguno. Se observaron durante 30 días posinoculación y se evaluó el peso, la mortalidad y otros efectos subletales. Posteriormente, se determinó la concentración letal media (CL50) y la influencia del pH sobre la mortalidad de los peces. Se pudo comprobar que al 6 % provocó eventos clínicos adversos y efecto letal en el biomodelo. Las lesiones histopatológicas se corresponden tanto para el producto activado como para el inactivado. La CL50 fue de 3.19 %, asociándose la toxicidad al pH ácido y no a la carga microbiana presente en el bioproducto. Se concluye que IHPLUS® es seguro para Poecilia reticulata a concentraciones inferiores al 3 %.

Comprehensive Water Quality Indicators Modeling by Environmental Protection View using New Optimized Weighted Ensemble Machine Learnings and Multi Algorithms

Comprehensive Water Quality Indicators Modeling by Environmental Protection View using New Optimized Weighted Ensemble Machine Learnings and Multi Algorithms

Macrozoobenthos Diversity as an Indicator of the Water Quality of the Salusu River in Ogomatanang Village, Central Sulawesi and Its Use as a Learning Media

The diversity of macrozoobenthos plays an important role as an indicator of water quality. The purpose of this study was to describe the level of macrozoobenthos diversity in the waters of the Salusu River, Ogomatanang Village, Central Sulawesi as an indicator of pollution levels and to produce suitable learning media. The type of research is descriptive. The sampling technique used systematic random and used a subber net using a zig-zag transect line and analyzed the diversity index value. The results of the study found 9 species, divided into 8 families including Baetis sp., Alloperla sp., Parathelphusa convexa, Heptagenia solitaria, Orthetrum sabina, Nemoura sp., Tylomelania arabica, Tylomelania sp., Planaria sp. The diversity index (H') was consecutively at station III (upstream) which was 2.14 with a light level of pollution, the H 'index at station II (ecotone) was 1.91 and the H 'index at station I (downstream) was 1.28 with a moderate level of pollution. The research results obtained were used as validated learning media by a team of content experts by 80%, design 78.6%, media 80%, large group student group trials 85.5% and small group 89.0%. Learning media is very feasible to use with a result of 82.62%.

Deriving water quality index using site-specific water quality parameter guidelines for real-time water quality stations

ABSTRACT The Newfoundland and Labrador real-time water quality (RTWQ) monitoring program operates a network of surface water monitoring stations, measuring physical water quality parameters in near real time. The network generates vast amounts of data that are too complex for many stakeholders to interpret. While the Canadian Council of Ministers of the Environment water quality index (WQI) has been a valuable tool to simplify and summarize the ambient quality of water, its usage in RTWQ is virtually non-existent. This is largely due to the lack of alignment/congruency between the limited number of parameters from real-time networks and the availability of aquatic water quality guidelines. This paper is the first attempt to outline a method of utilizing real-time water quality data to generate site-specific water quality guidelines using the background concentration method. Using these guidelines, we compute weekly WQI scores for select monitoring stations and examine various influences on the scores, including precipitation. The influence of each parameter on the WQI score is also plotted in the computation of the RTWQ WQI. Comparison is made between the yearly scores of the Canadian Environmental Sustainability Indicators WQI and RTWQ WQI. The paper also discusses the challenges and benefits of using this methodology as well as the sensitivity of WQI scoring at stations with various anthropogenic influences.

Analysis of Groundwater Quality in Semi-arid Region of Eastern - South Rajasthan on the Basis of Water Quality Index (WQI)

Abstract: The present study was conducted to evaluate the groundwater quality for drinking purposes in selected locations of the Eastern- South Rajasthan of India. Total eight sights groundwater samples were collected during 2022 and the samples were analyzed for physicochemical parameters i.e., pH, total hardness, total dissolved solids, Nitrate, Sulphate, fluoride, Chloride, and alkalinity were calculated. The results of the study are illustrated with the help of descriptive statistics, diagrams, and the water quality index (WQI). The focus of this research was to assess the current state of groundwater quality and the spatial distribution of characteristics in order to determine the quality of drinkable water. The WQI was used to categorize the samples into categories based on its acceptability for consumption. It is observed that most of the samples fall in the water unsuitable for drinking purposes category and a few samples are in the very poor water category.

Determination of the Quality of Groundwater in Mankweng, Limpopo Province, South Africa, Using the Water Quality Index

There is a lack of groundwater quality monitoring, especially in developing countries like South Africa. This study aimed to evaluate borehole water quality. Groundwater was analysed for pH, dissolved oxygen (DO), temperature, electrical conductivity (EC), total dissolved solids (TDSs), turbidity, chemical oxygen demand (COD), nitrogen (N), sulphate (SO42−), fluoride (F−), chloride (Cl−), calcium (Ca2+), magnesium (Mg2+), potassium (K+), and sodium (Na+) using a multi-parameter device, spectrophotometer, turbidity meter, and inductively coupled plasma optical emission spectrophotometer. Total coliforms and Escherichia coli were quantified using the Colilert system. The water quality index (WQI) was calculated using the arithmetic weighting method. The parameters ranged as follows: pH (6.71–7.94), DO (2.19–7.79 mg/L), EC (379.67–1317.33 µS/cm), TDSs (190–659 mg/L), temperature (16.75–22.31 °C), turbidity (0.17–3.21 NTU), COD (9–50 mg/L), F− (0.17–2.09 mg/L), Cl− (36.1–184.55 mg/L), N (0.64–28.56 mg/L), SO42− (27.18–112.13 mg/L), K+ (1.71–21.77 mg/L), Ca2+ (29.59–134.59 mg/L), Mg2+ (16.72–110.78 mg/L), and Na+ (38.52–170.63 mg/L). One borehole was polluted with E. coli (9 MPN/100 mL) and 25% were contaminated with coliforms beyond 10 MPN/100 mL. The WQI ranged from 50.430 to 190.220. The results underscore the importance of regular monitoring of groundwater.

An Analysis of Springwater Parameter Status for Different Locations in the Rural Hilly Garhwal Region of Uttarakhand

Uttarakhand boasts significant spring, groundwater, and surface water resources, particularly in the Garhwal and Kumaon regions, where year-round waterfalls and springs are abundant. However, efficient utilization of these resources remains limited. Reports from the Uttarakhand Pollution Control Board and Water Commission highlight that many remote villages face issues with high mineral content, particularly calcium hardness, in their water. Nine samples revealed total dissolved solids (TDS) above 500 mg/l and hardness exceeding 300 mg/l, with some containing coliform bacteria. Water quality index (WQI) values showed four samples in the ‘Good’ category, while two indicated poor quality.

Polyaromatic hydrocarbons of small reservoirs of the Tomsk region

Relevance. The assessment of the state of natural waters includes the determination of a number of physico-chemical indicators, on the basis of which various indices and classifications are developed. However, they do not take into account a number of pollutants that have a significant impact on the state of the reservoir, for example, polyaromatic hydrocarbons. The article considers some aspects of determining priority pollutants, which include polyaromatic hydrocarbons, according to environmental hazard criteria: toxicity, carcinogenicity, prevalence, frequency of occurrence, source of origin (anthropogenic or natural). Hydrochemical parameters such as pH, dissolved oxygen content, biological oxygen consumption (BPK5), and ion content are taken into account to determine water quality. An attempt was made to assess the impact of polyaromatic hydrocarbons on the ecological state of water bodies and to take into account their contribution to changes in the values of the water pollution index. All these data prove the relevance of the study. Aim. To establish the composition of polyaromatic hydrocarbons in the surface waters of small reservoirs of the Tomsk region to assess anthropogenic load and to show the relationship with the indices of natural water quality. Methods. Extraction, liquid adsorption chromatography, high-performance liquid chromatography, capillary electrophoresis, amperometry, titrimetry. Results. Small lakes of the Tomsk region were studied for the content of 13 polyaromatic hydrocarbons. The authors have carried out the identification by high-performance liquid chromatography with fluorimetric detection. The total content of polyaromatic compounds in the studied surface water samples varies from 0.37 to 0.54 mcg/l. In the polyaromatic hydrocarbons mixture in aqueous samples, there is an increased content of light 2–3 nuclear polyarenes with better solubility (naphthalene, fluorene and phenanthrene), as well as benz[a]anthracene. The content of inorganic components represented by cations and anions does not exceed the maximum permissible concentrations. The water pollution index was calculated; all lakes are moderately polluted, closer to polluted. The paper demonstrates the dependence of the water pollution index coefficient on the content of high-molecular polyaromatic hydrocarbons and the ratio of high-molecular to low-molecular polyaromatic hydrocarbons. It is shown that the higher the value of the water pollution index coefficient, the higher the proportion of difficult-to-oxidize components in surface waters.

Analysis of groundwater and surface water quality using modelled water index and multivariate statistics in Kampala and Mbarara Districts, Uganda

The demand for domestic, public and industrial use of water increases with population growth. However, activities from humans and natural environment have resulted into decline in water quality. The aim of this study was to evaluate the quality of groundwater and surface water collected from Kampala and Mbarara districts of Uganda using water quality index and multivariate statistics. A total of 10 physicochemical parameters (pH, water temperature, chloride, sulphate, nitrate, electrical conductivity, total dissolved solids, total suspended solids, total solids, and phosphate) were measured monthly to evaluate the quality of water in the study districts. Results showed that sulphate, electrical conductivity and total dissolved solids were observed with significantly high values in surface water than the groundwater for both seasons. Among all the parameters measured, electrical conductivity was observed with the highest value (2129.67 ± 1.41 µS/cm) while nitrate concentration (0.57 ± 0.02 mg/L) was observed with the lowest during the wet season in surface water. In addition, the mean values of nitrate, electrical conductivity, total dissolved solids and sulphate detected in the groundwater and surface water were within the recommended limits, while phosphate and chloride were observed with mean concentrations above the regulatory limits in 50% of the samples. The correlation analysis revealed strong and positive association between electrical conductivity and total dissolved solids in groundwater and surface water for both seasons. Also, the chemical make-up of groundwater and surface water within the study districts revealed that the determination of water quality rests on two major indices (conductivity and anthropogenic-pollutants) based on the factor analysis. The two indices accounted for 0.619% in groundwater and over 0.70% in surface water, indicating more pollution in surface water. Moreover, the water quality index (WQI) values obtained ranged from 14.81 to 115.73 in dry season and 7.77 to 108.24 during the wet season. According to WQI classification, 42% of the samples collected fell within the “excellent” and “good” categories while others fell within “poor” and “unfit” categories (58%) during the dry season. Based on these findings, appropriate treatment methods, proper sanitation and waste management should be implemented in locations with critical water conditions. Also, frequent monitoring of groundwater and surface water quality by environmental protection agency is highly recommended.

A comprehensive assessment of gold leaching wastewater through pollution and water quality indices. Case study: Small scale extraction facilities in the department of Caldas—Colombia

This study introduced a comprehensive methodology (the Six-Indices method for Water Pollution Assessment) to evaluate the quality of gold leaching effluents. Sampling was conducted for 14 months in small-scale gold mining facilities in the department of Caldas, Colombia. 23 physicochemical parameters were selected based on environmental regulations, standards of use for agricultural purposes and WHO recommendations. They covered general characteristics of effluents and critical inputs of the leaching process. 15 (pH, COD, TSS, CN−, Cl−, SO42−, S2−, Cd, Zn, Cu, Cr, Fe, Ni, Ag, and Pb) of them exceeded permissible limits. Multivariate statistical analysis (Person's correlation and hierarchical clustering analysis) and six Wastewater Quality Indices (WWQIs: Arithmetic Weighted Water Quality Index, WAWQI, Synthetic Pollution Index, SPI, Index of Water Pollution, WPI, Comprehensive Pollution Index, CPI, Heavy Metal Pollution Index, HPI, and Degree of Pollution, Cd) were used to comprehensively assess the effluent contamination. Key pollutant interactions (hydrocarbons & fats and oils, Zn & CN−, Cu & Cl−, as well as CN− & COD & SO42−) were revealed guiding targeted mitigation strategies. CN− and heavy metals were the main pollutants, posing serious environmental risks due to their high levels. The calculated HPI value was above the critical level of 100, indicating that the artisanal gold leaching operations in the studied area could be hazardous to human health. This study provides a starting point for developing effective and sustainable strategies to manage wastewater in mining regions in Colombia and other areas with similar mining practices.

Assessment of the Quality of Borehole Water Collected Around Unlined Solid Waste Dumpsites within Awka Metropolis

Groundwater is an important natural resource that is essential to man and other living things. However, it can become polluted resulting from natural and anthropogenic conditions. The quality of selected groundwater samples collected from boreholes around abandoned and active dumpsites in Awka metropolis, Nigeria between January and March 2023, was assessed using water quality index (WQI) method. The samples were analyzed for their physico-chemical properties and some selected heavy metals using atomic absorption spectroscopy. The results of the physico-chemical analysis showed that the mean pH ranged from 5.75 – 6.71 in January as compared to 5.92 – 6.98 in February and 5.94 – 6.84 in March indicating slight acidity. Calcium and magnesium content ranged from 8 – 20mg/l of Ca2+ and 96 – 314 mg/l of Mg2+ ion. The concentration of heavy metals in the samples were all seen to be within the standard limits for potable water (Fe (0.057 – 2.384 ppm), Cu(0.00 – 0.185 ppm) except for mercury, lead and cadmium(Hg (0.00 – 0.248 ppm), Pb (0.00 – 0.051 ppm), Cd (0.006 – 0.39 ppm) for the month of February whereas heavy metal concentration for the month of March ranged from Fe (1.432 – 2.908 ppm), Cu (0.00 – 0.008 ppm), Hg (0.00 – 0.016 ppm), Pb (0.00 – 0.003 ppm), Cd (0.00 – 0.01ppm). Pollution Index of the sampled borehole water from the different locations shows that some were potable and can be consumed without treatment. The study shows that solid wastes contribute to the level of contamination caused by Heavy metals and some physico-chemical parameters in groundwater matrix.

Dissolved Oxygen Concentration Prediction in the Pearl River Estuary with Deep Learning for Driving Factors Identification: Temperature, pH, Conductivity, and Ammonia Nitrogen

Predicting the dissolved oxygen concentration and identifying its driving factors are essential for improved prevention and management of anoxia in estuaries. However, complex hydrodynamic conditions and the limitations in traditional methods result in challenges in the identification of the driving factors for the low dissolved oxygen (DO) phenomenon. The objective of our study is to develop a robust deep learning model using four-year in situ data collected from an automatic water quality monitoring station (AWQMS) in an estuary, for accurate identification and quantification of the driving factors influencing DO levels. Mitigations in hypoxia were observed during the initial two years, but a subsequent decline in DO concentrations was witnessed recently. The periodicity of DO concentrations in the Pearl River Estuary reduced with the increase in the hypoxic intensity. Maximal information coefficient (MIC) and extreme gradient boosting (XGBoost) were employed to determine the significance of input variables, which were subsequently validated by using the long- and short-term memory networks (LSTMs). The driving factors contributing to the hypoxia problem were shown as temperature, pH, conductivity, and NH4+-N concentrations. Notably, the evaluation index values of the hybrid model are MAPE = 0.0887 and R2 = 0.9208, which have been improved compared with the LSTM model by about 99.34% in MAPE reduction and 16.56% in R2 improvement, indicating that the MixUp-LSTM model was capable of effectively capturing nonlinear relationships between DO and other water quality indicators. Based on existing literature, three traditional statistical methods and four machine learning models were also performed to compare with the proposed MixUp-LSTM model, which outperformed other models in terms of prediction accuracy and robustness. Overall, the successful identification of the driving factors for the deoxygenation phenomenon would have important implications for the governance and regulation of low DO in estuaries.

Assessment of water quality in the piped water supply system by using Water Quality index method

Background Drinking water of the right and approved quality is a basic requirement for the development of any civilization. According to SDG 6 it is crucial to provide every citizen with equitable water quality and quantity. Methods The study area is the smart city of Bhubaneswar with 67 wards and three zones: the north zone, south-west zone, and south-east zone with around 12.4 lakh population. To maintain the water quality in the supply pipeline in this city, which is always assumed to be safe, it needs to be examined within certain time intervals to check the contamination. In this context, studies on water quality parameters in the supply pipeline network from different anticipated vulnerable areas have been collected for testing. In this context, water samples were collected from areas near industries, market complexes, educational institutions, and construction sites of each ward of Bhubaneswar. Nearly 10 water quality parameters were tested and analyzed using the weighted arithmetic water quality index method. This method takes input of all the parameters and provides the overall water quality index value, which classifies the water in different grades like excellent, good, poor, and very poor quality. Results According to the WHO (2011) guidelines, the study found that there is a deviation in the parameters like 10.78% in pH, 19.48% in dissolved oxygen, 43.88% in conductivity, and 22.95% in hardness from the standard limit, but the overall water quality index indicates the water is not in the poor and very poor range. Also, water quality index values identify that the water in the south-east zone is excellent compared to the north and south-west zones. The reason for the slight deterioration is due to the underground cable works, road works and also some areas where the old pipeline system is still existing due to personal encroachment of people as per Public health Engineering department.

Water Quality Changes in the Xingkai (Khanka) Lake, Northeast China, Driven by Climate Change and Human Activities: Insights from Published Data (1990–2020)

Water quality degradation and eutrophication of lakes are global ecological and environmental concerns, especially shallow lakes. This study collected hydrochemical data from 2935 samples of the Chinese part of Xingkai (Khanka) Lake, based on 40 published papers spanning the period from 2001 to 2023. Using the water quality index (WQI), improved geo-accumulation index (Igeo), and redundancy analysis (RDA), we analyzed the overall contamination characteristics of the water environment in Xingkai Lake. Additionally, we explored the impact of climate change and human activities on the lake’s water quality. The results showed that the annual WQI for Xingkai Lake ranged from 47.3 to 72, with a general downward trend, indicating improving water quality. Notably, the average WQI in May and total nitrogen (TN) content decreased significantly, signaling further improvement in water quality. The average concentration of TN in sediments was 1401.3 mg/kg, reflecting mild contamination. The Igeo values for the heavy metals Hg and Cr were greater than 1, indicating moderate contamination, while the Igeo values for Cd and Pb were between 0 and 1, which is in the range of uncontaminated to moderately contaminated. Land use and climate change (average annual temperature and annual precipitation) were key factors influencing water quality, with cumulative explanatory ratios of 67.3% and 50.1%. This study utilized land-use change as a metric for human activities, highlighting the potential impacts of climate change and human activities on the water quality of Xingkai Lake. It offers vital insights for the sustainable management of Xingkai Lake and provides valuable references into the management of similar transboundary lakes.

In-vitro and in-vivo assessment of the bactericidal potential of peracetic acid and hydrogen peroxide disinfectants against A. hydrophila infection in Nile tilapia and their effect on water quality indices and fish stress biomarkers

This study aimed to assess the in vitro and in vivo disinfectant potential of peracetic acid (PAA) (1 mg/L) and hydrogen peroxide (H2O2) (20 mg/L) on the physicochemical and microbiological water quality parameters of fish aquaria, the microbial density of Nile tilapia muscular tissue, fish hepatic cortisol levels, and antioxidant biomarkers. In vitro, PAA and H2O2 reduced A. hydrophila colony viability by 5 log units after 30 and 5 min of contact time, respectively. PAA and H2O2 were added to aquaria water twice a week for the three-week experiment. Increased fish escape reflexes were observed only in the PAA group, which returned to normal within 10 min. No mortalities were reported in either the PAA or H2O2 groups. An in vivo experimental challenge with a pathogenic strain of A. hydrophila revealed a 20% reduction in mortality in the PAA group, with no mortalities in the H2O2 group. Cortisol levels and antioxidant markers were measured to assess the impact of PAA and H2O2 on fish health. Cortisol levels in the PAA and H2O2 groups were significantly higher than in the control group after disinfectant exposure, but they progressively returned to normal. A significant reduction in superoxide dismutase (SOD) and catalase (CAT) activity, along with considerably higher glutathione peroxidase (GPx) and malondialdehyde (MDA) enzymatic activity, was observed in the PAA and H2O2 groups compared to the control group. A substantial increase in total antioxidant capacity (TAC) was recorded in the PAA group. Physicochemical analyses revealed reduced pH and increased dissolved oxygen levels in the PAA and H2O2 groups. Microbiological analyses showed a significant reduction in bacterial density in water by 64% and 76% after 30 min of exposure to PAA and H2O2, respectively, with a non-significant increase in microbial count after bacterial challenge. Additionally, aerobic bacterial count, Aeromonas spp., and psychotropic bacterial count in fish muscle showed a significant reduction in the H2O2 group compared to the PAA and control groups before and after infection. The study concludes that regular application of PAA and H2O2 can temporarily reduce bacterial load in aquaria and fish muscle, regulate stress responses, and improve fish health by reducing A. hydrophila-induced infections and improving survival.

Variations in Water Quality Index and Physicochemical Properties of Surface Water and Bottom Sediments of Selected Coastal Beaches of Niger Delta, Southern Nigeria

Variations in Water Quality Index and Physicochemical Properties of Surface Water and Bottom Sediments of Selected Coastal Beaches of Niger Delta, Southern Nigeria

Research on Water Quality for Evaluation Using the Water Quality Index and Multivariate Statistical Approach of Evrenye Stream (Kastamonu, Türkiye)

Research on Water Quality for Evaluation Using the Water Quality Index and Multivariate Statistical Approach of Evrenye Stream (Kastamonu, Türkiye)

Water Quality and Prevalence of Extended Spectrum Beta Lactamase Producing Escherichia coli (ESBL E. coli) in Sungai Terengganu, Malaysia

Antimicrobial resistance (AMR) is a significant global issue impacting human, animal, and environmental health, as well as economic security. Water bodies, especially, are now recognized for their role in the spread of antimicrobial-resistant pathogens, though standardized monitoring methods are lacking. This study investigates the presence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli in the Sungai Terengganu River in Malaysia, focusing on water quality and ESBL E. coli monitoring. Sampling was conducted twice in 2023 at 13 locations along the river. Overall, the water quality index (WQI) classified the river as Class II (WQI = 81), with upstream regions rated as Class I, indicating minimal anthropogenic impact. Higher Biological Oxygen Demand (BOD), Chemical Oxygen Demand (COD), and Total Suspended Solids (TSS) in downstream areas suggested organic pollution from anthropogenic activities. Four metal elements exceeded the National Water Quality Standards (NWQS): Al (0.88 mg/L), Fe (3.45 mg/L), Cu (0.102 mg/L), and Hg (2.525 mg/L). No Pb, Cr, Se, Sn, or As were detected. Statistical analysis showed better water quality correlates with lower microbial contamination. ESBL E. coli was found in 8 of 13 sampling sites (61.5%), with the highest concentration at 800 CFU/100 mL. From 40 presumptive ESBL isolates tested, 87.5% (35 isolates) were positive for ESBL and carried additional drug resistance genes, including mcr-1, tetW, sul-1, and sul-2. These findings indicate a concerning presence of multidrug-resistant E. coli in the river, representing a potential public health risk.

Characteristics of Water Environment and Intestinal Microbial Community of Largemouth Bass (Micropterus salmoides) Cultured Under Biofloc Model

To investigate the effects of biofloc mode on the water environment and intestinal microbial community structure of largemouth bass, a 60-day culture experiment was conducted without water replacement in 300-L glass tanks. The experiment included a control group and a biofloc group, each with three replicates. The results showed the following: (i) the richness and diversity of the water environment and fish intestinal microbial community increased under the biofloc model; (ii) Proteobacteria, Patescibacteria, and Bacteroidota were the dominant phyla in the water environment of largemouth bass, while Proteobacteria, Firmicutes, Bacteroidota, Patescibacteria, and Actinobacteriota were the dominant phyla in the gut of largemouth bass. However, differences in the relative abundance and community structure of microorganisms were observed between the two groups, suggesting that the biofloc system impacts both the water environment and intestinal microbial community structure in largemouth bass culture. (iii) A correlation analysis between water quality indices and enzyme activity with microbial abundance revealed that microbial community composition could effectively reflect water quality and fish physiological health. Based on the analysis of microbial community structure, this study offers a theoretical foundation for integrating largemouth bass culture with the biofloc system, and provides valuable data for future health management and water quality control in largemouth bass production.

Appraisal of groundwater suitability for drinking and irrigation utilities in the Cooum River basin, South India: Implications from uranium, nitrate, and fluoride health risks

The study reveals that 6% of groundwater samples exceed the WHO's recommended fluoride limit of 1.5 mg/L, and 15% surpass the nitrate standard of 45 mg/L, rendering the water unsuitable for drinking. Gibbs plot analysis identifies evaporation as the dominant factor affecting groundwater chemistry, while the Piper diagram classifies the water into mixed Ca–Mg–Cl and NaCl types, indicating natural processes and potential seawater intrusion. Cation exchange processes are observed in 75.5% of samples, as shown by Schoeller's indices. The hydrochemical facies evolution suggests freshening from recharge in most samples, with signs of salinity intrusion in others. Between 2010 and 2023, land use and land cover (LULC) changes show a significant increase in built-up areas, resulting in reduced groundwater recharge and heightened pollution risks. The classification accuracy is high, with an overall accuracy of 82.20% and a Kappa coefficient of 83.06%. Water Quality Index (WQI) assessment reveals that 47% of the groundwater samples are excellent for drinking, while 20.6% are suitable. Although 80% of the groundwater remains appropriate for agriculture, the study highlights the need for targeted groundwater management to address urbanization impacts and mitigate health risks from elevated nitrate ingestion, particularly for vulnerable populations such as children.