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Among environmental contaminants, the rising level of cadmium in freshwater ecosystems is one of the most significant global concerns. The study addresses the current pollution status of cadmium in the middle stretch of River Ganga and explores the potential hazard associated with the consumption of 15 commercially important fish species by the inhabitants. Together 72 water and sediment samples were analyzed from the four representative sampling sites of River Ganga after the surveillance of major anthropogenic stressors. The concentration of cadmium ranges from 0.003 to 0.011 mg/l and 0.2 to 3.48 mg/kg in water and sediment respectively in 2022. The average concentration of cadmium was recorded to be the highest in Channa punctatus (1.35 mg/kg), followed by Rita rita = Johnius coitor (1.15 mg/kg), and the lowest in Labeo bata (0.2 mg/kg). The finding highlights greater exposure duration and feeding preferences of fish species have played a significant role in the bioaccumulation of the metal in the riverine system. Notably, the domestic effluents, agricultural runoffs, and pollutants brought along by the tributaries of River Ganga are identified as the main anthropogenic stressors for the moderate to considerably polluted status of the River Ganga. The target hazard quotient (THQ) and target carcinogenic risk (TCR) have revealed a higher susceptibility to cadmium contamination in children followed by females, and males. In addition, hierarchical cluster analysis (HCA) has noted intake of Rita rita, Channa punctata, Puntius sophore, and Johnius coitor could be more detrimental to children's health than adults. [ABSTRACT FROM AUTHOR]

Fish residing in the aquatic ecosystem are considered the best ecological indicator for monitoring environmental habitat. To evaluate the changes that occurred due to relative restoration in the ecological habitat, a study was conducted in the freshwater zone of the river Ganga between Buxar, Bihar, and Ballia, Uttar Pradesh, between July 2021 and July 2022. In the monitoring, the physico-chemical condition, as well as the food and feeding habits of the fish Gudusia chapra, were monitored with the help of various pollution evaluating indices, namely, the algal pollution index (API) for planktons, the comprehensive pollution index (CPI-WQI), and the National Sanitation Foundation Water Quality Indices (NSF-WQI) for water. The study showed that the relative restoration facilitated the amplification of the fish catch from 5.60 to 98.98% in two consecutive years. The reduction in the API (15 to 4) as well as CPI (0.80 to 0.72) during both years signified the reduction of the pollution status of the river in the region. The NSF-WQI also decreased from 88.27 to 79.27 from 2021 to 2022. The electivity index for the fish showed that fish preferred the groups Cyanobacteria, Rotifera, and Copepoda. The multivariate, as well as univariate analyses, revealed that the fish G. chapra is significantly influenced by multiple abiotic as well as biotic variables, among which the major contributors are riverine velocity, transparency, conductivity, pH, dissolved oxygen, total alkalinity, carbonate, bicarbonate, salinity, total hardness, calcium, silicate, and biochemical oxygen demand. [ABSTRACT FROM AUTHOR]

Water pollution is the most important factor affecting the environment. Appropriate monitoring is a big challenge to make sustainable growth by maintaining it for society. In recent times, water monitoring has turned into a smart monitoring system for water pollution (SMS-wp), with the advances on the Internet of things (IoT), machine learning (ML), and the improvement in current sensors. River Ganga is one of the major sources of water for drinking, irrigation, and industries in the northern part of India. Day by day, Ganga River is getting polluted, due to anthropogenic activities, such as the construction of dams, extensive use of fertilizers in agriculture, and untreated discharges from industries. Contamination in the river water is adversely affecting human health and river biota. Therefore, to improve the river ecosystem and to check infections and diseases, water quality assessment is very much important. The main aim of this study is to determine the Water Quality Index (WQI) of the River Ganges at the upper part of the Indo-Gangetic plain, just downstream of the Himalayan foothill using the last 3 years of data (2017–2019). Trend analysis for River Ganga water at considered locations is also a part of this study. Trend analysis is presenting the water quality of river Ganga in the coming years up to 2025. Twelve physicochemical parameters (TDS, chlorides, alkalinity, DO, temperature, COD, BOD, pH, magnesium, hardness, total coliform, and calcium) were analyzed to determine the water quality of River Ganga. As a result, WQI for next 5 years (from 2020 to 2025) is forecasted as an increment of 17.34% at Haridwar, 4.16% at Roorkee, and 21.63% at Dehradun. Results of the study indicated that WQI values just downstream of the Himalayan foothills in the upper reaches of the Gangetic plain are increasing every year. The authors have concentrated on how the advances in sensor innovation, the Internet of things, and machine learning techniques make water pollution monitoring a genuinely brilliant checking framework. Finally, the system of robust strategies for ML, denoising techniques, and advancement of appropriate guidelines for wireless sensor networks (WSNs) have been recommended. [ABSTRACT FROM AUTHOR]

The present study aimed to assess the impact of anthropogenic stressors on the physico-chemical characteristics and water quality of the River Ganga employing a GIS-based approach in the middle Gangetic Plain at Patna, India. After the survey, sand mining, bridge construction, and disposal of untreated domestic and sewage wastes were selected as major anthropogenic stressors. A total of 48 samples were collected in pre-monsoon and post-monsoon seasons of 2022 and were analyzed for 16 physico-chemical parameters, namely water temperature (WT), pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, dissolved oxygen (DO), biological oxygen demand (BOD), total hardness (TH), Ca2+, Mg2+, Na+, K+, Cl- and SO42− ions, following standard protocols. The WQI was calculated using the Weighted Arithmetic Water Quality Index (WAQWI) method and spatial maps were created using ArcGIS software. The result revealed significant seasonal variation in several physico- chemical parameters except for Ca2+, K+ and TA (p > 0.05). ANOVA revealed significant variation for BOD and COD at Ghagha and Triveni, whereas for nitrate at Gai Ghat reference and impact sites, respectively. The Water Quality Index (WQI) revealed a deterioration in water quality by 60% in post-monsoon season. HCA revealed that the WQI was mostly governed by TDS, TH, TA, and EC. HIGHLIGHTS The study highlights the impact of anthropogenic stressors on the River Ganga water quality in Patna India.; Sand mining, sewage disposal and bridge construction activities were selected as major anthropogenic stressors.; Significant seasonal variation was observed for several physico-chemical parameters.; Water quality deteriorated from pre-monsoon to post-monsoon season.; WQI of the River Ganga is primarily governed by TDS, TH, TA and EC.;

Plankton are promising ecological monitoring tool that responds quickly to any sort of aquatic ecological alteration, of which many of them are much susceptible to ecological variations. Therefore, monitoring shifts in plankton composition can indicate changes in water quality and aid to identify potential pollution sources. In the present study, the variation in plankton dynamics in relation to ecological variables were monitored in the freshwater zone of the Hooghly estuary from May 2020 to April 2021. The study was conducted in the interval of every six hours. i.e., at 6 A.M., 12 P.M., 6 P.M., and 12 A.M. The present finding revealed the occurrence of 54 phytoplankton and 20 zooplankton taxa/species. Diel variation revealed that among different time intervals, the highest abundance of phytoplankton was recorded 28,307 cells l−1 at 12 P.M, while the lowest was recorded 10,632 cells l−1 at 6 A.M. However, the highest zooplankton abundance was observed 804 ind l−1 at 6 A.M., and the lowest was recorded 156 ind l−1 at 6 P.M. The ANOVA (p < 0.05) analysis indicated significant diel variation for many planktonic genera. The CCA exhibited that most of the phytoplankton were influenced by multiple water quality variables such as temperature, turbidity, calcium, pH, salinity, DO, and nutrients. However, the majority of the zooplankton were affected by turbidity, total phosphorus, sulphate, calcium and available nitrogen. Significant seasonal variation in plankton composition has also been observed. The present study will help to determine the varying diel pattern of planktons in retort to alterations in the water quality parameters and varying ecological niches. [ABSTRACT FROM AUTHOR]

The River Ganga produces a substantial amount of its fish from small native species, defined here as those with a maximum length of 25 cm. The FiSAT program was utilized to estimate stock assessments of four important small indigenous species from the River Ganga: Johnius coitor, Cabdio morar, Salmostoma bacaila, and Gudusia chapra. Fish samples were collected monthly for a year (April 2020–May 2021) from four predetermined sampling sites along the River Ganga (Farakka, Berhampore, Balagarh, and Tribeni) in West Bengal, India. The estimated exploitation rate for Johnius coitor, Salmostoma bacaila, and Gudusia chapra was relatively lower than the optimum level of 0.5 and considerably lower than Emax values, indicating that their stocks are experiencing low fishing pressure in the region. The FiSAT results indicated that the species Cabdio morar was found to be heavily exploited. The total mortality (Z), natural mortality (M), and fishing mortality (F) rates for all four of the SIF species were examined, and they were contrasted with data from previous studies. On the lower stretch of the River Ganga, all of the fish stocks are optimally exploited (Eopt), except for the species Cabdio morar. The population dynamics of all of the species have been described for the first time on the lower stretch of the River Ganga. According to the findings, all of the fish stocks throughout the lower stretch of River Ganga are optimally exploited (Eopt), except for Cabdio morar. The study also emphasizes the importance of increasing sustainable fishing efforts, focusing on SIFs throughout the lower stretch of the River Ganga in order to safeguard the livelihood and nutritional status of fishermen. [ABSTRACT FROM AUTHOR]

Drift is a phenomenon of dispersion of invertebrates in freshwater lotic systems such as rivers and streams resulting from its water currents. The aquatic organisms living in the stream display drift because of their low buoyancy, which causes them to be dragged into the water column downstream. The said study was carried out for two annual cycles i.e. from December 2019 to November 2021 for studying drifting pattern exhibited by aquatic mites from the river Ganga near Deoprayag. The DBD Index was also calculated to derive actual number of drifting mites from the total population in a unit time. [ABSTRACT FROM AUTHOR]

The river Ganga serves as a lifeline for millions of people by providing water. However, as time passed on, it came under tremendous pressure as a result of the discharge of untreated sewage and industrial waste into the Ganga river at various locations, as well as the direct release and leaching of various pollutant residues into the Ganga River. During the present study, water samples from the Ganga River were taken and tested for temperature, pH, dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS) and electrical conductivity (EC) from several sampling sites during pre-monsoon, monsoon and post-monsoon seasons. The investigation revealed some deterioration in Ganga’s water quality. The Ganga River’s declining water quality is recognized to have an increasingly negative impact on the health of those, who consume it and the organisms that dwell there. [ABSTRACT FROM AUTHOR]

Fishes are poikilothermic animals and are rapid responders to any sort of ecological alteration. The responses in the fish can be easily assessed from their hematological and biochemical responses. To study the variation in the hemato-biochemical parameters in retort to ecological alteration and ecological regime, a study was conducted at six different sampling stations of the middle and lower stretches of river Ganga. Various hematological and biochemical responses of fishes were also monitored in response to multiple ecological alterations. For the assessment of ecological alteration, various indices were calculated such as the water pollution index (WPI), National Sanitation Foundation–water quality index (NSF-WQI), and Nemerow's pollution index (NPI) has been calculated based on various water quality parameters such as dissolved oxygen (DO), pH, total dissolved solids (TDS), total alkalinity (TA), total hardness (TH), electrical conductivity (EC), biochemical oxygen demand (BOD), chlorinity (CL), total nitrogen (TN), and total phosphorus (TP). The hematological parameters such as WBC, RBC, platelet, hemoglobin, and hematocrit were monitored. The serum biochemical parameters such as SGPT, SGOT, ALP, amylase, bilirubin, glucose, triglyceride (TRIG), and cholesterol (CHOL) were investigated. The study revealed that NSF-WQI varied from 45.08 at Buxar to 110.63 at Rejinagar and showed a significantly positive correlation with SGPT, SGOT, ALP, TRIG, CHOL, and WBC, whereas a significantly negative correlation was observed between TRIG and RBC. WPI varied from 19 to 23 and showed a significant positive correlation with SGOT and a negative correlation was observed with total nitrogen. The PCA analysis illustrated the significance of both natural as well as anthropogenic factors on riverine ecology. Strong positive loading was observed with SGPT, SGOT, ALP, and platelet. The study signified the need for monitoring the hemato-biochemical responses of fishes in response to alterations in the ecological regime. [ABSTRACT FROM AUTHOR]

Bacteriophages are key viruses that can kill thousands of harmful microbes generally present at polluted sites. Such bacteriophages are abundantly present in the river Ganga, where millions of people in India and abroad drink its water and take baths every day for spiritual reasons. Besides bacteriophages, several pathogenic and zoonotic microbes are present in the river Ganga. It is interesting to study the diversity and abundance of bacteria and their respective phages present in polluted or non-polluted sites. Thus, the metagenomics study was carried out at the most polluted sites of river Ganga near Kanpur and non-polluted sites at Farakka, which harbors several harmful bacteria and their phages. The results revealed a significantly higher percentage of Microviridae phage family, ssDNA viruses, and Mimiviridae virus family near Kanpur than Farakka. In addition, compared to Kanpur, Farakka has a more significant percentage of Myoviridae, an unidentified phage family, and Retroviridae viral families. Despite heavy drainage of untreated and contaminated effluents from the leather industry, pesticide industry, paper mills, metropolitan cities, and other sources, the vast number of said phages kills several harmful pathogenic microbes in polluted sites to maintain the Ganga water's healing power or natural sterility. In a polluted aquatic environment, the varieties of bacteriophages were identified in the Ganga and their interaction with the microbial host. The taxonomic diversity of several bacteriophages found in pathogenic host systems was investigated to get exceptional knowledge of these small viruses in the aquatic environment. [ABSTRACT FROM AUTHOR]

• River Ganga water contains a wide category of EPs in Varanasi. • A simple and efficient method described for screening EPs, and monitoring the WWTPs. • EPs, mobile resistome, and uncultivable ARB indicate inefficient WWTPs in Varanasi. • Plasmid-borne and MGEs associated ARGs indicate AMR transmission through HGT. An efficient wastewater treatment plant is imperative to limit the entry of emerging pollutants (EPs) and emerging microbial contaminants (EMCs) in the river ecosystem. The detection of emerging EPs in aquatic environments is challenging due to complex sample preparation methods, and the need for sophisticated accurate analytical tools. In Varanasi (India), the river Ganga holds immense significance as a holy river but is consistently polluted with municipal (MWW) and hospital wastewater (HWW). We developed an efficient method for untargeted detection of EPs in the water samples using High-resolution mass spectrometry (HRMS), and identified 577 and 670 chemicals (or chemical components) in the water samples from two major bathing ghats, Assi Ghat (AG) and Dashashwamedh Ghat (DG), respectively. The presence of EPs of different categories viz chemicals from research labs, diagnostic labs, lifestyle and industrial chemicals, toxins, flavor and food additives indicated the unsafe disposal of MWW and HWW or inefficient wastewater treatment plants (WWTPs). Besides, shotgun metagenomic analysis depicted the presence of bacteria associated with MWW viz Cloacibacterium normanse , Sphaerotilus natans (sewage fungi), E. coli , and Prevotella. Also, the presence of human pathogens Arcobacter , Polynucleobacter , Pseudomonas , Klebsiella , Aeromonas , Acinetobacter , Vibrio , and Campylobacter suggests the discharge of HWW. EPs are linked to the development, and transmission of antimicrobial resistance (AMR). Occurrence of antibiotic resistance genes (ARGs), plasmid-borne β-lactamases, aminoglycoside transferases, and ARGs associated with integrons, transposons and plasmids viz mcr -3 gene that confer resistance to colistin, the last resort of antibiotics confirmed the presence of emerging microbial contaminants. Subsequent genome reconstruction studies showed the presence of uncultivable ARB and transmission of ARGs through horizontal gene transfer. This study can be used to monitor the health of aquatic bodies as well as the efficiency of WWTPs and raise an urgent need for efficient WWTPs to safeguard the river, Ganga. [ABSTRACT FROM AUTHOR]

The River Ganga basin is home to over 520 million people and 2500 species of flora and fauna, including several fish species. This study determines the bioaccumulation factors of fish for five trace metals, namely Cu, Fe, Zn, Mn, and Cr, in a stretch of the River Ganga in the upper Gangetic alluvial plain with limited industrial activities. The abundance of different trace metals in the water follows the order Fe > Zn > Mn > Cu > Cr. The concentrations in fish show a slightly different pattern and follow the relative quantitative order as Zn >≈ Fe >Mn > Cu >Cr. The trace metal levels in fish are well below the permissible limits set by various regulatory agencies. The bioaccumulation factor values are in order Zn>Cr>Mn>Cu>Fe. This stretch of the Ganga has not been extensively investigated for bioaccumulation by aquatic organisms. These values, therefore, represent site-specific baseline data for future anthropogenic activities that may affect the trace metal profile in this part of the Gangetic aquatic system. The study is also significant due to the presence of the Narora nuclear power plants, as the bioaccumulation factors of stable elements help predict the behavior of their radioactive counterparts and homologous elements in the environment.

Aquatic mites scientifically termed Hydrachnidia is one of the major group of macroinvertebrates, which are highly sensitive towards environmental disturbances and hence rightly act as a bio-indicator. The subject study was performed for two annual cycles on the snow-fed river Ganga near Deoprayag to assess the abundance and variety of aquatic mites. Overall 25 species of seven genera under five families were recorded and identified. Torrenticolidae was the most dominant family with a total of eleven species. The abundance of aquatic mites was found to be maximum during winter in the month of December and minimum during monsoon in the month of July. Overall the study area showed a high diversity of aquatic mites throughout the study period. [ABSTRACT FROM AUTHOR]

Escherichia coli strain, AKS1GF ICAR-CIFRI, was isolated from a thermally contaminated water with average water temperatures of 45°C ± 2.5°C in river Ganga, India. The draft genome sequence is of 4.7 MB consisting of 44 contigs. The strain contains 4,314 protein coding genes and 96 RNA genes., Competing Interests: The authors declare no conflict of interest.

The perennial river Ganga is recognized as one of India's largest rivers of India, but due to continuous anthropogenic activities, the river's ecosystem is under threat. Next-generation sequencing technology has transformed metagenomics in the exploration of microbiome and their imperative function in diverse aquatic ecosystems. In this study, we have uncovered the structure of community microbiome and their functions in sediments of river Ganga at Kanpur, India, at three polluted stretches through a high-resolution metagenomics approach using Illumina HiSeq 2500. Among the microbes, bacteria dominate more than 82% in the three polluted sediment samples of river Ganga. Pseudomonadota (alpha, beta, and gamma) is the major phylum of bacteria that dominates in three sediment samples. Genes involved in degradation of xenobiotic compounds involving nitrotoluene, benzoate, aminobenzoate, chlorocyclohexane, and chlorobenzene were significantly enriched in the microbiome of polluted stretches. Pathway analysis using KEGG database revealed a higher abundance of genes involved in energy metabolism such as oxidative phosphorylation, nitrogen, methane, sulfur, and carbon fixation pathways in the sediment metagenome data from the river Ganga. A higher abundance of pollutant degrading enzymes like 4-hydroxybenzoate 3-monooxygenase, catalase-peroxidase, and altronate hydrolase in the polluted microbiome indicates their role in degradation of plastics and dyes. Overall, our study has provided bacterial diversity and their dynamics in community structure and function from polluted river microbiome, which is expected to open up better avenues for exploration of novel functional genes/enzymes with potential application in health and bioremediation. [ABSTRACT FROM AUTHOR]

Presently, sustainability of floodplain, a diverse element of the riverine landscape, provides an ideal research setting for investigating complex interaction between anthropogenic disturbance and eco-environmental degradation. Nowadays, these floodplains are continually degraded and fragmented on account of unsustainable land use. To analyse the spatial and temporal changes of landuse/landcover, a supervised classification (maximum likelihood algorithm) method has been made for the period 1998 to 2018. Present research simulates and predicts landuse/landcover dynamics of lower stretch of the Ganges river up to 2038 to analyse future riverine landscape dynamics stressed by various natural and socio-economic factors based on Cellular Automata-Artificial Neuron Network (CA-ANN) model clubbed with Modules for Land Use Change Evaluation (MOLUSCE) plugin of QGIS software. Outcome of research reveals that the trend of agriculture land, sand, and inland waterbody areas is reduced by 15.75, 5.71, and 1.95%, whereas, for orchard, agricultural fallow and bare land areas increased by 7.94, 7.92, and 5.69% for the period from 1998 to 2018. The simulation model predicted a continuation of the similar trend till 2038. The significant reduction of agricultural land and sand areas is largely an attribute to floodplain degradation in an altered hydrological regime. Ultimately, hydro-morphological changes, increasing population pressure, and agriculture intensification in floodplain landscape were identified as main driving forces in temporal landuse/landcover changes. The prediction of future forecast indicates that if the present rate of landuse/landcover trend persists in the study stretch of Ganges river without appropriate sustainable development practice, severe floodplain degradation will ensue. This study provides a holistic measure for understanding long-term environmental degradation related to anthropogenic activities and impact of climate changes in floodplain landscape at local and regional scale.

The Ganga River is the major source of drinking water for humans over the decades. It is also the ecological niche for millions of relict species, i.e., for a variety of planktons, benthic organisms, fish, and various other aquatic organisms. The blasting population resulted in an enhanced rate of pollution in the river system emanating from various anthropogenic activities and industrialization in the bank of river Ganga. The study was made in the middle and lower stretch of the river to monitor the decadal changes in the water quality of river Ganga from 1960 to 2019 at six different study sites. In the present study, various water quality parameters such as dissolved oxygen, pH, free carbon dioxide, total alkalinity, conductivity, total dissolved solids (TDS), hardness, chloride, and nitrate have been studied during 2015–2019. The data for 1960 to 2006 were taken from ICAR-CIFRI publications. Based on the studied parameters, National Sanitation Foundation (NSF)—water quality index (WQI) was calculated. In the present study, it was found that the calculated NSF-WQI was 69.24 in 1960–1961 which increased up to 113.39 during 2001–2006. But, with the implementation of various rejuvenating strategies, the WQI of the river got reduced to 106.48 during 2015–2019. This reflected the positive changes in the riverine system. Different water quality parameters such as dissolved oxygen, pH, and hardness were observed mostly within the permissible range as based on the drinking water guidelines for humans and survival of the aquatic organisms as well, except a few location-specific observations. [ABSTRACT FROM AUTHOR]

Hydrachnidia commonly known as aquatic mites are a significant group of aquatic macroinvertebrates, which act as potential bio-indicator due to their high vulnerability towards contamination and environmental changes. The present study has been conducted on the river Ganga near Haridwar city for two years with the aim to provide an account of the density and diversity of aquatic mites in river Ganga near Haridwar city, Uttarakhand. A total of 411 individuals m-2 of aquatic mites belonging to 11 species under six genera of four different families i.e. Torrenticolidae, Spherchontidae, Hygrobatidae and Feltriidae were recorded. Family Torrenticolidae was observed as the most diversified family. The maximum density and diversity of aquatic mites were recorded in the month of December (winter) and the minimum in the month of July (monsoon). [ABSTRACT FROM AUTHOR]

Ganga river is one of the important water bodies harbouring different aquatic communities especially sedentary benthic organisms. We determined several macrobenthic molluscan faunas including 24 species comprising of 18 gastropods and 6 bivalves. The maximum species diversity with a value of 2.08 was recorded during monsoon, whereas the species richness was found to be highest (0.809) during winter. To determine the correlation between the physicochemical parameters of water, sediment and macrobenthic organisms, we have employed the canonical correspondence analysis (CCA) for middle, lower and estuarine stretches of river Ganga. The water CCA components, CCA1 and CCA2, explained 48.64%, 47.01%, 45.11% (p = 0.568, 0.019 and 0.417) and 18.11%, 26%, 23.9% (p = 0.98, 0.292 and 0.978) between the environmental parameters and macrobenthos correlation, respectively. Similarly, the CCA components for soil showed a percentage of 41.82%, 41.58%, 24.73% in CCA1 (p = 0.156, 0.026 and 0.922) and the CCA2 revealed a percentage value of 24.23%, 25.58%, 23.59% (p = 0.446, 0.174 and 0.488) of the mentioned parameters. The present study explored a dual relationship between the organisms and environmental factors according to their abundance and distribution pattern. [ABSTRACT FROM AUTHOR]

Present study was carried out to determine the concentration and bioaccumulation of pesticide residues in two commonly edible fishes: bagrid fish, Rita rita and common carp, Cyprinus carpio collected from river Ganga at Narora, India. The human health risk via consumption of these fishes was also assessed. The n-hexane extract of the muscle tissues was characterized by gas chromatography coupled to mass spectrometry and quantified by electron capture detector for pesticide residues. Bioaccumulation factor (BAF) in bagrid fish for detected pesticides was found to be higher than those in common carp. Estimated daily intake (EDI) values in our study were insignificantly higher than Average daily intake (ADI) values. Target hazard quotient (THQ) via consumption of selected fishes was found to be lower than the set 1.0, inferring non-carcinogenic risk. With regard to contaminants carcinogenic effects the total risk ratio (R) values of each pesticide was found lower than threshold risk limit except of heptachlor which indicates carcinogenic risk. The results justify pesticide pollution in river Ganga at Narora and thus more attention is required in order to help improve the health status of this ecosystem and reduce contamination of fishes.

This is the first study conducted on the food and feeding habits of the yellowtail mullet (Minimugil cascasia), in the Ganga River (India). The gut contents of 276 individuals (TL: 45.32–89.79 mm) were investigated. Dominant food items of the yellowtail mullet included three diatoms, namely Cyclotella sp., Amphora sp., and Aulacosiera sp.; one green alga, Scenedesmus sp.; two blue-green algae, Merismopedia sp. and Nostoc sp. The food composition varied according to the size class of fish, with small individuals feeding on the blue-green algae and large one feeding on the diatoms and green algae. Sand and detritus comprising 84.16% and 81.87% by frequency and 48.83% and 20.31% by volume, respectively, dominated in the gut contents of the yellowtail mullet. The relative gut length (RGL) of the yellowtail mullet suggested an omnivorous iliophagous feeding habit, where foods items are picked up from the bottom mud layer known as the iliotrophic layer. [ABSTRACT FROM AUTHOR]

Abstract Ganga River water is very much stressed with the rapidly increasing population, climate change and water pollution that increase domestic, agricultural and industrial needs. This study assesses the surface water quality of the River Ganga in India, using NSFWQI, OIP and multivariate techniques. During the current study, water samples from Ganga River were collected for the assessment of 19 physico-chemical determinants from 20 sampling locations. Water quality indices (WQIs) is used to classify the overall impact of different variables of water. Multivariate techniques were utilized to assess the water conditions for productive management of fresh water quality. The WQI results showed that surface water quality varied at the selected sampling sites among medium and good categories. The PCA generates the 6 principle components which highly contributes (80.3%) in influencing the hydro-chemistry of river water. Agricultural waste runoff, untreated effluents and many other anthropogenic activities were identified as main contributor in decreasing the water quality of the River Ganga. To maintain and protect this fresh water resources against contamination, the usage of stringent policies and rules are expected to preserve fresh water resources for people in the future.

Water quality assessment relies mostly on physico-chemical-based characterization; however, eutrophication and climate change advocate the abundance of toxic microcystins (MCs) producing cyanobacteria as emerging bio-indicator. In the present study, a spatial-temporal analysis was carried out at ten sampling sites of Prayagraj and Varanasi during June 2017 and March 2018 to determine the Ganga River water quality using physico-chemical parameters, cyanobacteria diversity, detection of MCs producing strains and MC-LR equivalence. Coliform bacteria, COD, NO3-N, and phosphate are the significant contaminated parameters favoring the growth of putative MCs producing cyanobacteria. National Sanitation Foundation WQI (NSFWQI) indicates water quality, either bad or medium category at sampling points. The morphological analysis confirms the occurrence of diverse cyanobacterial genera such as Microcystis, Anabaena, Oscillatoria, and Phormidium. PCR amplification affirmed the presence of toxic microcystin (mcy) genes in uncultured cyanobacteria at all the sampling sites. The concentration of MC-LR equivalence in water samples by protein phosphatase 1 inhibition assay (PPIA) and high-performance liquid chromatography (HPLC) methods was observed in the range of 23.4–172 ng/L and 13.2–97.5 ng/L respectively which is lower than the harmful exposure limit by World Health Organization (WHO). Ganga isolate 1 was identified as Microcystis based on partial 16S rDNA sequence and its toxicity was confirmed due to presence of mcy genes and MCs production potential. These findings suggest the presence of MCs producers as new emerging parameter to monitor water quality index and identification up to species level will be valuable for restoration strategies of river Ganga. [ABSTRACT FROM AUTHOR]

The banks of the lower stretch of River Ganga are home to several towns and megapolis representing high density of human population. A stretch of 50 km represented by prefixed stations of the lower part of Ganga (Ganga Environmental Time Series- GETS) was monitored spatiotemporally using eDNA metagenome-based Nanopore sequencing to elucidate structure of microbial communities along with mapping of antibiotic-resistant genes (ARGs), metal resistance genes (MRGs) and mobile genetic elements (MGEs). Besides, in situ environmental parameters, concentration of dissolved nutrients, metals and metalloids were measured. The concentration of dissolved oxygen ranged from 3.4–6.2 mg l ^−1 , indicating deteriorating water quality corresponding to high population density. Dissolved nitrate concentrations were higher in some stations reflecting direct release of untreated municipal sewage into the river. In particular, concentration of metals such as Cd (2.34–38.52 ppb) and metalloids such as As (0–218.7 ppb) were found to be alarmingly high in surface water. Gammaproteobacteria was encountered ubiquitously while rare bacterioplankton represented by eleven classes showed site specificity. Several genes belonging to ARGs were identified and multidrug resistance genes (MDR) were found in all the studied stations exhibiting high abundance. The ‘hotspots’ of ARGs were widespread, possibly owing to rampant usage of personal health care products that may have contributed to observed ARG abundances. High abundance of MRGs comprising arsenic (∼12%) and copper (∼12%) were also identified showing strong correlations with the abundance of ARGs. Correlation and network analysis revealed the potential role of MGEs in the dissemination of ARGs. ANOSIM and cluster analyses supported patchy distribution patterns of microbial communities. The RDA plot showed possible influences of environmental parameters in shaping the microbial community structure and towards dissemination of functional genes such as ARGs and MRGs in the lower stretch of the River Ganga.

We studied spatial and temporal variation of Pb (lead), Cd (cadmium), and Cr+6 (chromium) in abiotic and biotic components of the Ganga River at Varanasi, which is situated in the river's lower-middle stretch. River water, bottom sediment, and fish were collected seasonally at two sampling locations. Inductively coupled plasma emission spectroscopy (ICP-ES) was used for metal analysis. Cadmium and lead in the river water exceeded the permissible limit for drinking water prescribed by the World Health Organization. The geo-accumulation index (Igeo), contamination factor (CF), and ecological risk assessment (Er) revealed that Cd followed by Pb caused moderate to heavy contamination and posed potential ecological risk to the Ganga River system at Varanasi. The pollution load index (PLI) values were above "1," indicating deterioration of sediment quality. Heavy metal concentration was determined in fish muscle tissues, and estimated daily intake (EDI) was calculated to evaluate potential health risk to consumer resulting from daily consumption of contaminated fish and the target hazard quotient (THQ). We also looked into the work of other researchers to observe temporal trend of heavy metals. Through this communication, we present a holistic status of metal contamination in the Ganga River system. [ABSTRACT FROM AUTHOR]

Quarterly field sampling was conducted from 2016 to 2020 to understand the distribution and current status of IUCN Red-listed fish species along the entire stretch of River Ganga. During the study, 18 fish species belonging to 8 orders and 12 families were recorded under the IUCN Red list. Fishes belonging to the family Synodontidae contributed highest among the threatened group. The status of fish species have been categorized on the basis of IUCN Red list. Among 18 fish species, Clarias magur and Tor putitora were categorized as endangered, whereas Wallago attu and Schizothorax richardsonii were categorized as vulnerable. The present study suggests the necessary management plans and conservation strategies for these IUCN Red-listed fish species of River Ganga. [ABSTRACT FROM AUTHOR]

Presently, sustainability of floodplain, a diverse element of the riverine landscape, provides an ideal research setting for investigating complex interaction between anthropogenic disturbance and eco-environmental degradation. Nowadays, these floodplains are continually degraded and fragmented on account of unsustainable land use. To analyse the spatial and temporal changes of landuse/landcover, a supervised classification (maximum likelihood algorithm) method has been made for the period 1998 to 2018. Present research simulates and predicts landuse/landcover dynamics of lower stretch of the Ganges river up to 2038 to analyse future riverine landscape dynamics stressed by various natural and socio-economic factors based on Cellular Automata-Artificial Neuron Network (CA-ANN) model clubbed with Modules for Land Use Change Evaluation (MOLUSCE) plugin of QGIS software. Outcome of research reveals that the trend of agriculture land, sand, and inland waterbody areas is reduced by 15.75, 5.71, and 1.95%, whereas, for orchard, agricultural fallow and bare land areas increased by 7.94, 7.92, and 5.69% for the period from 1998 to 2018. The simulation model predicted a continuation of the similar trend till 2038. The significant reduction of agricultural land and sand areas is largely an attribute to floodplain degradation in an altered hydrological regime. Ultimately, hydro-morphological changes, increasing population pressure, and agriculture intensification in floodplain landscape were identified as main driving forces in temporal landuse/landcover changes. The prediction of future forecast indicates that if the present rate of landuse/landcover trend persists in the study stretch of Ganges river without appropriate sustainable development practice, severe floodplain degradation will ensue. This study provides a holistic measure for understanding long-term environmental degradation related to anthropogenic activities and impact of climate changes in floodplain landscape at local and regional scale. [ABSTRACT FROM AUTHOR]

The Ganga is the largest river in India, serves as a lifeline for agriculture, drinking water, and religious rites. However, it became highly polluted due to the influx of industrial wastes and untreated sewages, leading to the decline of aquatic biodiversity. This study investigated the microbial diversity and plastic-xenobiotic degrading enzymes of six sediment metagenomes of river Ganga at Prayagraj (RDG, TSG, SDG) and Devprayag (KRG, BNG, BRG). The water quality parameters, higher values of BOD (1.8–3.7 ppm), COD (23–29.2 ppm) and organic carbon (0.18–0.51%) were recorded at Prayagraj. Comparative analysis of microbial community structure between Prayagraj and Devprayag revealed significant differences between Bacteroidetes and Firmicutes, which emerging as the predominant bacterial phyla across six sediment samples. Notably, their prevalence was highest in the BRG samples. Furthermore, 25 OTUs at genus level were consistent across all six samples. Alpha diversity exhibited minimal variation among samples, while beta diversity indicated an inverse relationship between species richness and diversity. Co-occurrence network analysis established that genera from the same and different groups of phyla show positive co-relations with each other. Thirteen plastic degrading enzymes, including Laccase, Alkane-1 monooxygenase and Alkane monooxygenase, were identified from six sediment metagenomes of river Ganga, which can degrade non-biodegradable plastic viz. Polyethylene, Polystyrene and Low-density Polyethelene. Further, 18 xenobiotic degradation enzymes were identified for the degradation of Bisphenol, Xylene, Toluene, Polycyclic aromatic hydrocarbon, Styrene, Atrazene and Dioxin etc. This is the first report on the identification of non-biodegradable plastic degrading enzymes from sediment metagenomes of river Ganga, India. The findings of this study would help in pollution abatement and sustainable management of riverine ecosystem. [Display omitted] • Metagenomic study of microbial communities in sediments of river Ganga stretches. • Highest concentrations of Mn, Fe, and Cr were observed in the polluted sites. • Bacteroidota and Chloroflexota were predominant in all sediment samples. • First report reveals the presence of 13 plastic & 18 xenobiotic degradation enzymes. [ABSTRACT FROM AUTHOR]

Pesticides consumption along with its impact on different matrices of the environment has increased over past. Monitoring and risk assessment is important to know the exact scenario of pesticide toxicity of aquatic environment. The article compiles the number of studies on different stretches of river Ganga over past years. Risk quotient (RQ) method was used for the determination of potential risk of reported pesticides. Based on general (RQm) and worst-case (RQex) DDT and aldrin in the middle stretch of river Ganga show high risk. Regular monitoring along with compartmental studies is important to assess the pesticide pollution load and persistence in the river. Because hundreds of formulations are being used in the basin for agricultural purposes, detailed analysis and bio-magnification of all the pesticides should be appreciated.

Sugar industry in India has imparted significant contribution in the growth of agriculture and socio-economic status of the country. However, continuation of conventional practices owing to lack of awareness for environmentally sustainable technologies has led to the pollution in water resources resulting in degradation of environmental quality. Considering this, Central Pollution Control Board of India took initiative for minimizing the pollution load in rivers by formulating a charter and invoking environmental compensation for sugar industries. Present assessment of environment related reforms through national policy like charter implementation and environmental compensation is one of the primary baseline studies done so far. These reforms were implemented in 85 sugar industries situated along the main stem of River Ganga for validation. The analysis depicted that the implementation of charter and environmental compensation resulted in significant reduction in freshwater consumption (56.4%), effluent generation (13.8%), and biochemical oxygen demand load (34.6%). Thus, similar reforms may be adopted in other sugar industries as well in order to improve the environmental quality and sustained growth of the economy.

We have done a qualitative and quantitative analysis of Ganga River water in two areas namely Palta and Diamond Harbour, in the state of West Bengal, India. Anthropogenic activity is very high in these regions. Restriction of human activity near river basins due to the prolonged COVID-19 lockdown has brought remarkable changes in the environment. A comparison of the pre-lockdown period and the lockdown period was done. The study covered the years from March 2019 to May 2020. Results demonstrate improvement in surface water quality of River Ganga, during the lockdown period as there was less anthropogenic activity. The water quality test revealed that turbidity has reduced to <94% during the lockdown. River Ganga was one of the polluted rivers, unfit for a bath but physicochemical properties like turbidity, total suspended solids, and total dissolved solids have improved enormously during the lockdown. The chemical oxygen demand, biochemical oxygen demand has changed from 12 and 3 mg/L to <6 and 1.2 mg/L, respectively. Consecutively, dissolved oxygen level has increased from 6 to 12 mg/L. Low total coliform and fecal coliform counts indicated improvement in the bacteriological quality of water. The results of the present investigation establish a significant improvement in water quality. [ABSTRACT FROM AUTHOR]

Consumption of toxic metal contaminated fish is a significant risk to human health. The Ganga river is one of the vital river systems in India, and it nurtures a rich biodiversity of flora and fauna. In the present study, screening of potential toxic metal elements (Cd, Cr, Mn, Cu, Pb, Ni, Zn, and As) was undertaken in 31 food fishes, especially the small indigenous fishes (SIFs) from the lower stretch of river Ganga by inductively coupled plasma mass spectrometry (ICP-MS). The concentration of toxic metal elements varied among different fish species. Among the toxic metal elements studied, Cr, Zn, and As were found to be dominant in Eleotris fusca; Cd, Ni, and Pb were highest in Securicula gora; Cu was highest in Cabdio morar; and Mn was highest in Coilia dussumieri. The average pollution load index values (APLI) for all the fishes analyzed were less than one except for Eleotris fusca, which indicated no serious toxic metal element pollution load. The estimated daily intake values (EDI) for the toxic metal elements were found to be within the permissible maximum tolerable daily intake (MTDI). Among the fishes studied, only a few species showed hazard index (HI) greater than one, indicating non-carcinogenic health risks. Similarly, the target carcinogenic values (TCR) for most of the toxic metal elements were below the permissible limit (10 -4 ) in the fishes that assures minimal cancer risk. This study provides a comprehensive data on the composition of potential toxic metal elements of 31 food fishes from the lower stretch of the river Ganga, the first of its kind, and suggests the necessity of periodic monitoring of these in the aquatic ecosystem., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: Chlorophyll a concentration proxies the phytoplankton biomass which directly involves in signifying the production functions of aquatic ecosystem. Thus, it is imperative to understand their spatio-temporal kinetics in lotic environment with reference to regional climatic variabilities in the tropical inland waters. Objective: In-situ studies were conducted to examine the changes in phytoplankton biomass in lower Ganga basin as influenced by various environmental parameters under regional climatic variability during 2014-2016. Methods: Firstly, the most key influential environmental parameters on riverine Chl-a concentration were determined. Then the direct cascading effect of changing climatic variables on key environmental parameters were derived through modeling and quantified probable changes in mean Chl-a concentration in the lower stretch of river. Results: Only five environmental parameters namely water temperature, total dissolved solid, salinity, total alkalinity and pH were key factors influencing Chl-a (Multiple R²: 0.638, P < 0.05). Present estimates indicate that if the present rate of regional climatic variability over the last 3 decades (mean air temperature + 0.24 °C, total annual rainfall -196.3 mm) remain consistent over the next three decades (2015-2045), an increase in mean Chl-a by + 170 µgL-1 may likely be expected grossly reaching about 475.94 µg L-1 by the year 2045 or more. Conclusions: The present study is first such comprehending a gross hint towards the probable ecosystem response with an alternative model based methodology in data-deficient situations. Subsequently, the output would also be of great benefit for increase water governance and developing strategy protocol for sustainable water management for greater ecosystem services. [ABSTRACT FROM AUTHOR]

The Ganga, most holy river in the Indian sub-continent crosses from the Himalayas to the Indian Ocean, source for endurance for many individuals, serve water to 40% of the country’s population of 11 Indian states. This study was done with the support of United Nations Development Program with the objectives of understanding the factors influencing attitude and behaviour of the community concerning waste management by studying 78 riverbank villages of Ganga at Shaibganj, Jharkhand. The study revealed that more than three-fifth of the family dumped their waste in open space, one-fourth burn the waste openly, one of ten households throw the waste directly into the river and dumped the waste near the river, only few of the families were availing door to door collection/common bin facilities. Chi-Square test indicates a significant association between waste management with religion, caste, type of family, age at marriage and SLI of the respondents. The study revealed that in comparison to Hindus, other are significantly more likely to dispose wastewater to the river. Odds Ratio of General Caste, Scheduled Tribe, Other Backward Caste are significantly more likely to have waste disposal system at place compare to Scheduled Caste community. Regression analysis showed people from joint family are more likely to have proper waste disposal system than nuclear family. Finding suggests relation among information, knowledge, and proper waste management, hence relevant knowledge will lead to positive attitude and actions of the community towards proper waste management for creating a safe environment and better health. [ABSTRACT FROM AUTHOR]