Understanding the global water flux is vital to comprehend different hydrological components of the planet. The precise quantification of the global water budget is important to understand the global water cycle. While the first attempts in closing the global water budget date back to the early 1900s, we still have not been able to comprehensively understand the global water cycle. The past few decades have witnessed significant interests among the researchers worldwide in understanding the global water budget considering various ecological, hydrological, and climatic parameters and using data from various sources, such as ground observations or satellite information. However, a certain degree of uncertainty still prevails in the global or regional models developed till date. Here, we discuss some recent advances in this context, taking into account continent-wise analyses of the various significant attempts made by different researchers in varying geographical conditions, and using different tools. These findings will eventually lead to deeper understanding and advancements in the existing approaches aiding in the closure of the global water budget.

Deep marine sediments are rich in microbial diversity, which holds metabolic repertoire to modulate biogeochemical cycles on a global scale. We undertook the environmental microbiome inhabiting the Gulf of Kathiawar Peninsula as a model system to understand the potential involvement of the deep marine sediment microbial community and as a cohort in the carbon, nitrogen, and sulfur biogeochemical cycles. These gulfs are characterized by dynamic tidal variations, diverse sediment textures, and nutrient-rich waters, driven by coastal processes and the interaction between natural coastal dynamics and anthropogenic inputs that shape its microbial community diversity. Our findings suggest that carbon fixation was carried out by Gamma-proteobacteria with CBB cycle-related genes or by microbial participants with Wood-Ljungdahl pathway-related genes. Microbial communities involved in nitrogen metabolism were observed to be rich and diverse, and most microbial communities potentially contribute to the nitrogen cycle via processing nitrogen oxides. Bacteria belonging to the KSB1 phylum were also found to fix nitrogen. The sulfur cycle was spread throughout, with Verrucomicrobiota phylum being a major contributor. The varying napAB genes, significantly lower in the Gulf of Kutch compared to the Gulf of Cambay and the Arabian Sea, mediated nitrate reduction. Dynamics between these pathways were mutually exclusive, and organic carbon oxidation was widespread across the microbial community. Finally, the proteobacteria phylum was highly versatile and conceivably contributed to biogeochemical flux with exceptionally high abundance and the ability to form metabolic networks to survive. The work highlights the importance of critical zones and microbial diversity therein, which needs further exploration

Pesticide poisoning through contaminated water, soil, or food is often linked to the widespread use of chemical pesticides in Indian agriculture. While many studies have reported the association between pesticide exposure and human health impacts, it has been challenging to disseminate this information to a broader population at state and national levels. Consequently, no state-level database exists correlating pesticide use with cancer rates in India. Here, we provide a comprehensive outlook focusing on the challenges of correlating these factors to develop a comprehensive geospatial database at the national level. A data-mining approach can help identify cancer hotspots, supporting informed policymaking

Conventional disinfection methods for drinking water are imperative in removing harmful pathogens. Then again, they often inadvertently give rise to disinfection by-products (DBPs) that are inherently carcinogenic, posing substantial health risks. Hence, exploring innovative and sustainable solutions to counter the side effects of these classical disinfection techniques is inevitable. This chapter thoroughly investigates the global challenges associated with DBPs in treated drinking water and provides a detailed overview of their prevalence globally. Emphasis has been placed on the prevalence and regulatory frameworks of trihalomethanes (THMs), the most predominant DBP species. Additionally, the chapter delves into examining different sustainable water management strategies aimed at reducing the formation of DBPs in treated drinking water, including source water protection, optimum use of disinfectants, and the implementation of advanced treatment technologies. Special attention is given to reducing THMs and their precursors, highlighting the effectiveness of membrane filtration, green adsorbents, and advanced oxidation processes (AOPs). The importance of integrating these strategies with robust monitoring systems and proactive policy measures to safeguard public health in the long term is also highlighted. Additionally, the chapter underscores the need for continuous research and development of innovative DBP control methods while advocating for a holistic and sustainable approach to drinking water management. Ultimately, this chapter aims to contribute to the ongoing dialogue on protecting public health and ensuring long-term water security by emphasizing sustainable DBP minimization strategies

Owing to the urgent and escalating environmental crisis of water pollution through anthropogenic wastewater generated from various sources, the development of novel and innovative bioremediation strategies that are equally sustainable is highly necessitated. The present study embarks on an integrated omics-based exploration, complemented by a thorough literature synthesis, to critically evaluate and enhance hybrid algal-bacterial systems for effective wastewater treatment. Drawing on case studies and research from diverse geographic regions, we explore how these technologies inform the design and optimization of both engineered and natural treatment systems. The review emphasizes the integration of multi-omics data to support sustainable, targeted bioremediation strategies and underscores the cross-disciplinary convergence of environmental engineering, molecular biology, and systems ecology. This global and holistic perspective positions omics as a cornerstone for advancing the next generation of wastewater treatment solutions. Comprehensive analyses of the efficacies of different treatment methods used to remediate organic pollutants, heavy metals, nutrients, and contaminants of emerging concern (CECs), including antibiotic resistance genes (ARGs), were carried out, thus underscoring the pivotal role of microbial diversity and metabolic activity in the complex process of contaminant elimination. While prior research has predominantly focused on isolated components, the current study presents a holistic approach, merging state-of-the-art high-throughput metagenomics and transcriptomics techniques. This innovative combination illuminates the functional dynamics of microbial communities operating within the hybrid system under a range of operational conditions. The primary critical findings reveal significant shifts in microbial community structure and gene expression patterns, which are intricately linked to enhanced efficiencies in nutrient uptake and contaminant removal. In addition, the study also situates these findings within the expansive framework of omics-based bioremediation research, providing a clear and structured pathway for identifying prevailing knowledge gaps and directing future optimization efforts. Collectively, these contributions not only deepen our understanding of microbial community functions but also pave the way for designing next-generation bio-based wastewater treatment systems driven by the intricate interplay of microbial dynamics.

Protecting wetlands from various human activities requires a deep understanding of their aquatic limnology. This calls for continuous monitoring, which generates extensive and complex datasets. By applying statistical analyses and modelling techniques, these datasets can be effectively interpreted to uncover, define, and gain critical insights into the functions and processes that drive aquatic ecosystems. The present study aims to integrate water quality, sedimentology, aquatic toxicology and modelling techniques to present a detailed and comprehensive assessment of different components of Deepor Beel's (a Ramsar site) ecosystem. Deepor Beel is situated on the banks of the Brahmaputra River in the northeastern region of India and holds immense significance to the city of Guwahati. Originally spanning across more than 40 sq. km area, rampant encroachment and anthropogenic disturbances have not only degraded the wetland ecosystem but also reduced its effective area to now a meagre four sq. km. Large-scale eutrophication due to the discharge of untreated municipal wastewater has played a significant role in the wetland's deterioration. Although several restoration measures were undertaken in the past, they could have been more effective as they lacked prognosis. Hence, we carried out systematic monitoring (the first such extensive monitoring was undertaken) of four components of Deepor Beel's ecosystem, i.e., water, sediment, fish, and aquatic weeds, to understand the governing factors responsible for the wetland's deterioration. We employed different multivariate statistical techniques to understand the sampling site's characterization and behaviour under various environmental and climatic stresses and identify and quantify latent pollution sources contributing to wetland pollution. In addition, a novel water quality index was developed employing Shannon Entropy, which encompasses all essential variables for a comprehensive understanding of the wetland's water quality. We assessed sediment contamination from heavy metals—including chromium (Cr), cadmium (Cd), iron (Fe), manganese (Mn), copper (Cu), lead (Pb), and mercury (Hg)—and conducted fractionation studies, revealing important insights into how these metals interact within the ecosystem. Fish samples from three indigenous species that are locally consumed were collected, and we analyzed the bioaccumulation of heavy metals in various tissues and organs. Our findings indicated significant amounts of heavy metals in the fish organs, making their consumption potentially carcinogenic for humans. Finally, a eutrophication-based ecological model was developed to understand the nutrient dynamics within the wetland. The model was calibrated, and sensitivity analyses were performed and validated using the dataset generated through the laboratory analyses. The model was then simulated for two scenarios: 1) harvesting of aquatic weeds reflecting the current practices, and 2) establishing a treatment unit handling the nitrogen and phosphorus loadings. The results demonstrated that treating the inflow is a more sustainable approach to reducing eutrophication, and this strategy should be implemented promptly. Given the gravity of the situation for Deepor Beel, the findings of this study are significant and call for immediate attention and action

Wastewater treatment plants (WWTPs) are major contributors to the release of volatile organic chemicals (VOCs), many of which pose significant risks to human health through both non-carcinogenic and carcinogenic pathways. These chemicals, along with plastic-derived compounds, pesticides, and pharmaceuticals and personal care products (PPCPs), have emerged as critical environmental pollutants. Their widespread release through urban wastewater systems, combined with their hydrophilic nature and limited removal efficiency in conventional WWTPs, allows these pollutants to persist throughout the water cycle, often contaminating drinking water supplies. Despite increasing global awareness of the environmental and health risks associated with these contaminants, data on their occurrence, transport, and fate in Mexico's wastewater systems are still limited. To address this knowledge gap, the present study analyzed 54 VOCs in wastewater samples collected from 17 WWTPs across different provinces of Mexico. Among these, 38 VOCs were detected at significant levels, with the highest concentrations recorded for Toluene (21.39 µg/L), 1,1,2,2-Tetrachloroethane (28.02 µg/L), followed by p-Isopropyltoluene (27.24 µg/L), and Trichloromethane (17.56 µg/L). Additionally, pesticides and related chemicals such as 2-Chlorotoluene, Naphthalene, 1,2-Dichlorobenzene, and n-Butylbenzene were prevalent, underscoring the extensive use of these compounds in agricultural practices. These chemicals not only bioaccumulate in soil but can also leach into groundwater systems, exacerbating contamination risks and increasing their persistence in the environment. Furthermore, many of the detected compounds, such as Toluene, its derivatives, and Trichloromethane, are known endocrine disruptors (EDCs) capable of causing hormonal imbalances, drug resistance, and reduced primary productivity in ecosystems. Their bioaccumulation in organisms and persistence in water further exacerbate their environmental impact, making them critical candidates for regulatory scrutiny. Therefore, this study underscores the urgent need for enhanced regulatory monitoring and management strategies targeting VOCs and EDCs in Mexico’s wastewater systems. By providing valuable insights into the prevalence and distribution of these hazardous pollutants, the findings highlight the importance of incorporating pesticides and PPCPs into comprehensive monitoring frameworks. Such efforts are essential for mitigating the environmental and health impacts of these contaminants and ensuring the sustainable management of water resources. The results also offer a foundation for developing targeted interventions aimed at reducing pollutant loads in wastewater and preventing their long-term accumulation in aquatic ecosystems

The present study aims to investigate the influence of fly ash leachate (FL) on the hydraulic and mechanical behaviour of two Indian bentonites with discrete mineralogical and chemical compositions. The investigation revealed that both bentonites with different mineralogical and physical properties noticeably affected free swelling, Atterberg limits, swelling potential, swelling pressure, and hydraulic conductivity. However, a comparative assessment for both types of bentonites shows that swelling capability, liquid limit, cation exchange capacity, and the specific surface area experience a directly proportionate variation to the free swell (80% decline), liquid limit (74% decline), swelling potential (61% decline), and swelling pressure (59% decline) when permeated with FL. In addition, a rise in hydraulic conductivity (28 and 38 times rise at a void ratio of 1.1) was observed with leachate presence for both bentonites. The research findings would therefore prove constructive to engineers for deciding on bentonite types for liner application in landfills.

Disinfection by-products (DBPs) are one of the significant emerging contaminants that have caught the attention of researchers worldwide due to their pervasiveness. Their presence in drinking water, even in shallow concentrations (in levels of parts per billion), poses considerable health risks. Therefore, it is crucial to understand their kinetics to understand better their formation and persistence in the water supply systems. This manuscript demonstrates different aspects of research carried out on DBPs in the past. A systematic approach was adopted for the bibliographical research that started with choosing appropriate keywords and identifying the most relevant manuscripts through the screening process. This follows a quantitative assessment of the extracted literature sample, which included the most productive and influential journal sources, the most widely used keywords, the most influential authors active in the research domain, the most cited articles, and the countries most actively engaged in the research field. Critical observations on the literature sample led to the qualitative assessment, wherein the past and current research trends were observed and reported. Finally, we identified the essential gaps in the available literature, which further led to recommending the course ahead in the research domain. This study will prove fruitful for young and established researchers who are or wish to work in this emerging field of research.

Micro and nano-plastics (MNPs) have been considered one of the major emerging contaminants that require immediate attention. Their potential impact on the natural ecosystems is yet to be understood, especially their associations with other contaminants like heavy metals and organisms essential for the sustenance of life, i.e., microbes. Microplastics (MPs) also act as sources and carriers of pollutants, similar to macro and mesoplastics, that leach harmful chemicals such as Polybrominated Diphenyl Ethers (PBDEs), Pharmaceutical and Personal Care Products (PPCPs), Endocrine Disruptive Chemicals (EDCs), etc. They also behave like super sponge materials which adsorb microbes such as antibiotic resistance bacteria (ARBs), and coronavirus, making their concentration much higher than the ambient environment. Among these microbes, heavy metal-resistance (MRGs) and antibiotic-resistance genes (ARGs) carry immense significance. The present study provides an in-depth review analysis of the works published related to the association of MPs to heavy metals and ARGs. 1526 articles were investigated after the dataset was subjected to a three-stage screening process. A scientometric analysis revealing details about the most productive and influential journals, co-authorship details, most influential publications, most cited keywords, and most active countries in the research domain was conducted. This provided significant information regarding various aspects of the published works of literature. Subsequently, a qualitative discussion was carried out wherein a detailed discussion with regard to the trends in research on sub-areas in the broad domain was conducted. This resulted in identifying the gaps in the available literature, which paved the way for providing a framework for future research. Through this study, it is expected that the readers will be exposed to a summary of the overall research that has been conducted to date, and the manuscript will act as a guide for future research.

To meet the United Nations' Sustainable Development Goals, agricultural soil which is a non-renewable natural resource must be carefully managed. Heavy metals present in agricultural soil may imperil food security and instigate extreme risks to human health. Organic wastes have been long known for valuable amendments to soil thereby, improving overall soil health. In the present study, Echhornia crassipes, Hydrilla verticillata, and vegetable waste, was utilized to prepare compost amendments. Lycopersicum esculentum was used to metal uptake from compost amended soils. 5%, 10%, 15%, 25%, and 35% compost: soil (w/w) were studied to understand metal translocation in plants. Potential Ecological risk indices showed that while the degree of risk was medium for the natural soil, it reduced to slight for the soil amended with WHC and VWC for all compositions. The non-carcinogenic risks associated with the human health reduced on application of the composts, however, they still remained substantial for Fe, As, and Pb for WHC, HVC, and VWC composts at higher application ratios, especially among children. On the other hand, the carcinogenic health index values which were calculated to estimate the risk associated with ingestion of L. esculentum, showed a decrease in risk for all the metals studied, upon soil amendment. Soil amended with HVC compost showed an increase in carcinogenic risk for As, Pb, and Cr. Finally, we conclude that biological soil remediation is economical and a sustainable land management strategy that may lead to green and clean remediation solutions for metal contaminated soil.

The present study provides a scientific investigation of a detailed review of the published works in the domain of eutrophication-based ecological modelling till the year 2020. A total of 399 articles were extracted for final analyses, which were subjected to a three-step hierarchical procedure; Bibliographic examination, scientometric investigation, and qualitative assessment. The bibliographic test filtered 320 samples, based on which the article samples were subjected to several scientometric analyses, such as identifying the most influential and productive journals, researchers, articles, and countries. Keyword analysis revealed the most frequently used keywords in the research domain and amongst scholars around the world. The scientometric studies were followed by a qualitative assessment wherein the current trends in research were discussed. This was followed by identifying the critical gaps in research to provide future direction. Thus, this research offers a more comprehensive and holistic approach towards the critical review of the published literature, thereby providing essential insights to the researchers regarding the existing practices of developing eutrophication-based ecological models and the future prospects lying ahead.

Water serves numerous purposes besides drinking, such as irrigation and industrial usage. Most water quality indices developed have primarily focused on drinking water quality. However, assessing other functionalities of water bodies is also equally essential. The present study proposes a novel technique to measure water quality for two highly specific water use, i.e., assessing heavy metal contamination and irrigation suitability. The ambiguities in the current practice of entropy weights were identified, and a novel method was proposed, considering a three-dimensional approach instead of the conventional two-dimensional procedure. Weights to different parameters were assigned based on the probability estimates obtained from the frequency of observed values within acceptable limits. The proposed method’s reliability, correctness, and applicability were tested using Deepor Beel’s water quality dataset. Results were highly consistent with the experimental values and correlated well with other established methods. The efficacy of the method was determined by employing sensitivity analyses. Both indices showed high reliability and correctness, as no single parameter was found to be highly sensitive compared to others. Therefore, the proposed methodology proved to be the most reasonable, incorporating all the factors required for a reliable water quality monitoring program.