Coal-fired thermal power plant operations significantly impact aquatic environments by releasing fly ash leachate, untreated effluents, and airborne pollutants, thereby deteriorating surface water quality. This study assesses the spatial distribution, pollution load, and ecological risk of potentially toxic elements (PTEs) in surface water collected from the surroundings of coal-based thermal power plant (TPP) in Andhra Pradesh, India. Jupudi Reservoir (JR) showed relatively lower pH levels, indicating mildly acidic conditions possibly resulting from ash pond leachate influence, while the other water bodies maintained a more alkaline nature. The mean concentrations of Chromium (406 µg/L) and Arsenic (214 µg/L) were highest at JR and comparatively elevated relative to other water bodies. Furthermore, the total metal load was significantly higher in JR, TPP, and RC across water, sediment, and plant samples, reflecting the significant influence of coal-based thermal power plant activities on these aquatic ecosystems. Geospatial distribution using ArcGIS-IDW interpolation revealed contamination hotspots near coal ash discharge zones, especially at JR and TPP canal sites. Pollution indices highlighted severe pollution and ecological threats at JR and TPP, with ERI values indicating high ecological risk (> 400). Health risk assessments showed that children are particularly at risk, with elevated non-carcinogenic hazard index (HI > 1) and incremental lifetime cancer risk (ILCR > 1 × 10⁻4) through both ingestion and dermal pathways. Among the studied sites, JR and TPP canal exhibited the highest PTE concentrations, whereas RC served as the least contaminated reference site. statistical analyses, including Pearson correlation and Positive Matrix Factorization (PMF), identified coal combustion by-products, atmospheric deposition, and ash leachate as the dominant sources of contamination, with minor contributions from domestic and agricultural runoff. The findings underscore the urgent need for pollution control, regular monitoring, and site-specific remediation strategies to protect both ecological and human health in coal-affected aquatic systems.

Microplastics (MPs) are impacting coastal and ocean ecosystem and also have been linked with ‘blue economy’, which accounts major portion to the total economy of a nation. The ocean serves as a sink for MPs, receiving them from rivers, runoff, industrial effluents, and direct waste discharge. Consequently, marine organisms are impacted, leading to indirect economic losses, and causing irreparable damage to the blue economy. In addition, the presence of chemicals and microorganisms on MPs is causing detrimental effects on marine organisms, leading to economic repercussions. Coastal tourism, a key aspect of the blue economy, relies on a sustainable and visually appealing environment, which is being threatened by rising marine debris, primarily plastic waste generated by tourists. The clean-up cost is very high, whereas the existing removal technologies do not have higher efficiency and are not that much cost effective. Thus, this study reviews the country wise economic effect of plastic pollution, along with existing policies, regulations and the management strategies to control MPs in marine system considering its potential impacts on sectors associated with marine resources vis-à-vis blue economy.

The continuous release of heavy metals (HMs) from nearby industries leads to the contamination of surrounding agricultural areas. This study employed an integrated approach, combining contamination factor (CF), enrichment factor (EF) and geo-accumulation index (Igeo) for pollution assessment, alongside source apportionment using principal component analysis (PCA) and Geographic Information System (GIS)-based positive matrix factorization (PMF), to evaluate HM contamination in agricultural soils of the northeast Guntur district, India. The mean concentrations of HMs, Cu, Cr, Zn, Ni, Cd and Pb exceeded the Indian natural background soil values by 2.59, 1.21, 2.24, 2.09, 1.15 and 1.4 respectively. Pollution indices revealed high contamination for Ni (CF = 2.21) and Cr (CF = 2.05), with Cr showing moderate enrichment (EF ≈ 1.5) and contamination (Igeo = 0.75). PCA identified three components explaining 78.37% of the total variation while GIS-based PMF identified industrial discharges, waste incineration, agriculture and vehicular and industrial emissions as pollution sources. Ni, Cu and Cr were identified as the primary contaminants, with industrial emissions, vehicular traffic and agricultural activities as key contributors to HM pollution. Cr accounted for ~ 80% of the total hazard index, posing significant non-carcinogenic risks for children via ingestion. Carcinogenic risks through ingestion of Ni and Cr were 2.8 and 1.9 times higher than acceptable levels for adults and 3.9 and 2.6 times higher than acceptable levels for children. Additionally, the high bioconcentration factor (BCF) of Lantana viburnoides (Forssk.) with a BCF of 18.29 for Cd suggests a potential environmental hazard. It is imperative to monitor emissions rigorously to safeguard soil quality and optimize industry standards in this region.

Jharkhand is a mineral-rich state and there are many possibilities in pisciculture. Fish is the staple food of Jharkhand because of its nutritional values. In the present study, water, sediment, and the most favorite fish species (Labeo rohita, Catla catla, Cirrhinus mrigala, Cyprinus carpio, and Ctenopharyngodon idella) were collected from the lentic reservoirs and analyzed for assessing the ecological and human health risk assessment. The mean concentrations of Cd, Cr, Cu, Pb, and Zn in water samples varied within the ranges of 0.001–0.004 mg/L, 0.02–0.04 mg/L, 0.004–0.007 mg/L, 0.023–0.081 mg/L, and 0.003–0.12 mg/L, respectively. In sediment samples, the metal concentrations were recorded within the following ranges: 109.15–411.48 mg/kg for Zn, 0.79–22.87 mg/kg for Cd, 22.71–34.79 mg/kg for Pb, 93.44–581.38 mg/kg for Cr, and 19.61–129.09 mg/kg for Cu. The average concentrations of metals in fish were observed as follows: 82.98 − 91.81 mg/kg of Zn, 20.91 − 31 mg/kg of Cd, 81.48 − 91.81 mg/kg of Pb, 442.68 − 482.50 mg/kg of Cr, and 35.91 − 68.57 mg/kg of Cu. Ecological health assessment based on sediment indices shows the prevalence of Cd in the lentic ecosystems and their bioaccumulation (biota-sediment accumulation factor > 2) in fish species. Among the four reservoirs, HD is the most contaminated site. Local population, especially, children of Ranchi district, consuming fish species are prone to health risk due to the metal contamination. Conclusively, this study provides valuable data on metal concentrations in fish species, supporting future ecotoxicology research and policymaking for any mineral-rich state.

The ability to produce a variety of enzymes enables the fungi to act as bioremediators of xenobiotic compounds. Xenobiotics are extensively used in drugs, medicines, beauty products, hormones, detergents, fire retardants, building materials, etc. Due to their longevity, persistency, and bioavailability, xenobiotics are a source of public outcry. Xenobiotics are resistant to natural degradation processes and hence their persistence in the environment can lead to bioaccumulation in the food chain, disruption of microbial ecosystems, and long-term toxic effects on flora and fauna. Such compounds are when exposed to living beings including human beings, produce several detrimental health effects. It is evident that fungi have the necessary metabolic machinery to remove different types of xenobiotics from different components of environments. This paper discusses about a variety of fungal species that can effectively degrade xenobiotics, their enzymatic potentials as well as possible mycoremediation techniques. Additionally, this paper also discusses about the need for implementing mycoremediation, controlling xenobiotics at their source, and future prospects in this field.

Plastic pollution is a global concern that has recently attracted considerable attention. One type of plastic pollution that has received attention is microplastic (MPs—small plastic particles measuring <5mm). MPs can accumulate in the environment and pose a threat to aquatic and terrestrial ecosystems, as well as human health. The low biodegradable properties of MPs make them persistent. These MPs can get adsorbed into the plant's roots and travel through the food chain. Therefore, removing MPs from environmental matrices like soil, water, and sediments is needed to stop the circulation of the MPs in the food chain. Microbial degradation is an effective method to reduce the MPs concentration from the environments. Microbial degradation of different forms of MP is possible with the application of bacteria such as Bacillus cereus, B. gottheilii, and fungi such as Aspergillus niger and B. adusta. There are many physical factors such as pH and temperature that influence the microbial degradation processes. Microbial degradation is a cost-effective, environment friendly, and polymer-specific process that uses different microbes and microbial enzymes and chemicals. In this context, the present study will summarize the existing knowledge on microbial degradation of MPs.

In order to achieve sustainable waste management solutions, we must integrate computational approaches to meet the challenges posed by escalating waste generation. Waste management and recycling are explored comprehensively in this book chapter with a focus on various computational tools and analyses. This chapter addresses a technologically driven approach to problem-solving based on diverse disciplines, such as Geographic Information Systems (GIS), optimization models, life cycle assessments, artificial intelligence, and sensor technology. This chapter examines GIS applications and explores how spatial analysis and mapping contribute to site selection for waste disposal facilities and route optimization for waste collection. Following this, it discusses optimization models, demonstrating mathematical methodologies used to improve decision-making processes, including linear programming and network optimization. Simulators are discussed in the context of predicting and understanding waste management processes, elucidating their role in this process. Various waste treatment methods are evaluated in detail in relation to the impact of life cycle assessment on the environment, highlighting the importance of this tool in evaluating environmental impacts. In addition, artificial intelligence and machine learning are discussed as tools to analyze data, recognize patterns, and optimize waste management processes. An overview of computational approaches shaping waste management and recycling is presented in this book chapter. It seeks to provide academics, practitioners, and policymakers with a basis for using technology breakthroughs for the creation of sustainable and effective waste management systems by clarifying the uses and advantages of these instruments.

Climate change and environmental degradation require computational environmental engineering. To simulate and optimize complex environmental processes, advanced computer models, big data analytics, and machine learning are used. A holistic assessment of environmental consequences and the design of interdisciplinary solutions that take into account socioeconomic, environmental, and environmental variables can be possible with the creation of integrated modeling frameworks that reflect the interconnected nature of environmental systems. Increasingly high-resolution remote sensing data and sensor networks enable real-time monitoring and decision-making about the environment. The use of these data streams in conjunction with computational models improves environmental predictions, allowing better management of natural resources and risk reduction. The most challenging aspects are improving model validation and uncertainty quantification, developing robust optimization algorithms, and ensuring accessibility for stakeholders of varying backgrounds. Lastly, computational environmental engineering offers significant promise for addressing future environmental problems by incorporating interdisciplinary approaches, using emerging technologies, and addressing important issues. Previous Chapter.

In the past 20-30 years, deterioration in soil quality has become a serious environmental issue. Rapid industrialization and mining activities have triggered the deterioration of soil quality. Owing to these anthropogenic activities, soil is exposed to contaminants, such as heavy metals (HMs) (Xiao et al., Land Degradation & Development 31:1969-1989, 2020; Raj and Maiti, Environmental Monitoring and Assessment 191:566, 2019), which, in turn, result in the degradation of soil quality as well as soil fertility.

Water pollution from Heavy metal (HM) contamination poses a critical threat to environmental sustainability and public health. Industrial activities have increased the presence of HMs in wastewater, necessitating effective remediation strategies. Conventional methods like chemical precipitation, ion exchange, adsorption, and membrane filtration are widely used but possess various limitations. These include high costs, environmental impacts, and the potential for generating secondary pollutants, highlighting the need for sustainable alternatives. Phytoremediation, enhanced by microbial interactions, offers an eco-friendly solution to this issue. The unique physiological and biochemical traits of plants, combined with microbial metabolic capabilities, enable efficient uptake and detoxification of HMs. Microbial enzymes play a crucial role in these processes by breaking down complex compounds, enhancing HM bioavailability, and facilitating their conversion into less toxic forms. Synergistic interactions between root-associated microbes and plants further improves metal absorption and stabilization, boosting phytoremediation efficiency. However, challenges remain, including the limited bioavailability of contaminants and plant resilience in highly polluted environments. Recent advancements focus on improving microbial-assisted phytoremediation through mechanisms like bioavailability facilitation, phytoextraction, and phytostabilization. Genetic engineering facilitates the altering of genes that control plant immune responses and growth which improves the ability of plants to interact beneficially with microbes to thrive in HM rich environments while efficiently cleaning contaminated wastewater. This review examines these strategies and highlights future research directions to enhance wastewater remediation using phytoremediation technologies.

A broad range of artificial or naturally occurring chemicals known as emerging contaminants (ECs) are increasingly found in landfill leachate and provide serious dangers to human health and the environment. This critical analysis investigates the origin, dispersion, and effects of ECs in relation to landfill settings. Landfills serve as EC reservoirs because of the diverse mix of e-waste, industrial compounds, pharmaceuticals, personal care items, and endocrine-disrupting chemicals. Factors including landfill design, waste type, and environmental conditions affect the mobility and permanence of these toxins as they seep into nearby soils, groundwater, and surface water through leachate. ECs have been found in trace amounts in the landfill leachate, and are polar substances having a brief half-life. Concerns over the consequences of newly discovered contaminants on the environment and human health have grown because of their increased detection in the landfill leachate. Additionally, they increase the hazards to human populations by having the ability to pollute agricultural soils and sources of drinking water. The significant finding is that the ECs in landfill leachate can be generated from various sites whether it is from municipal solid wastes, agricultural runoffs, or industrial wastes which become persistent in nature increasing risk to human health and environment. The study identifies important knowledge gaps regarding the development of harmful transformation products, the collective effects of EC combinations, and the inadequacy of traditional treatment techniques in reducing EC pollution. By this it can be concluded that advanced analytical methods, creative leachate treatment approaches, and strong regulatory frameworks are needed to address these issues and successfully stop EC discharge and control its negative effects on the environment and human health. In order to reduce the hazards caused by newly discovered pollutants in landfill leachate and to support environmentally friendly waste management techniques, this analysis emphasizes the necessity of both international and regional initiatives.

Open-cast coal mining operations such as topsoil removal, coal extraction, and coal loading and transportation at site in the South Indian peninsular region significantly endanger water quality by introducing pollutants through mine drainage, airborne particles, and mining-related disturbances, impacting both surface and groundwater. This research evaluates the health hazards linked to potentially toxic elements (PTEs) contamination in water collected from lakes and discharge points adjacent to the Sathupalli open-cast coal mines (SCCL—Singareni Collieries Company Limited) in Telangana, India. The results showed that the pH levels of the collected water samples from the study area varied, with Sathupalli centre mine water (SCW) exhibiting highly acidic conditions (2.2–4.9) with a mean value of 3.8, and other sites ranging from slightly acidic to alkaline (5.6–7.3) with a mean value of 6.6. PTEs such as Cr, Cd, As, Hg, and Pb were found in high concentrations, often exceeding BIS (Indian standard, Drinking water- specification -Second revision, In: IS: 10500. Bureau of Indian Standards, New Delhi, 2012) permissible limits, particularly in SCW and Rajaria cheruvu (RC—Lake). Geospatial analysis identified contamination hotspots, with indices like Heavy metal pollution index (HPI), Nemerov pollution index (NPI) and Heavy metal evaluation index (HEI) indicating severe pollution, and ecological risk index (ERI) values confirming high ecological impact across sites, especially SCW and RC. SCW and RC exhibited the highest non-carcinogenic (HI > 1) and carcinogenic (ILCR > 1 × 10⁻4) risks, particularly for children via dermal and ingestion pathways. In contrast, Tamara Cheruvu (TC—Lake), Veshya Kanthala Cheruvu (VK—Lake), and Drain Discharge Water (DDW) showed lower but notable risks, emphasizing the urgent need for targeted mitigation in coal-impacted zones. Statistical methods such as Positive Matrix Factorization (PMF), correlation coefficients, and Principal Component Analysis (PCA) identified coal mining, especially acidic wastewater discharge, as the primary source of heavy metal pollution, with urban runoff and atmospheric deposition also contributing to contamination. These results emphasize the importance for remediation efforts and continuous monitoring to mitigate environmental degradation and safeguard public health in mining-impacted regions.

Phytoremediation success on coal mine overburden dumps (OBD) largely depends on the selection of suitable plant species adapted to nutrient-poor and metal-contaminated substrates. The present research reported the phytoremediation potential of eight pioneer species (Phyllanthus emblica , Sesbania sp., Tamarindus indica , Pongamia pinnata , Anthocephalus cadamba , Terminalia bellirica , Albizia procera , and Eucalyptus globulus) growing on reclaimed OBD. Rhizosphere soil samples were analyzed for pH (4.2–8.7), electrical conductivity (EC) (271.6 µS/cm), organic carbon (∼0.8 %), and heavy metal (HM) concentrations. Bioconcentration factor for shoot (BCF S ), root (BCF R ) and translocation factor (TF) were used to evaluate HM accumulation and mobility patterns. Phyllanthus emblica showed the highest As accumulation (BCF R = 22.4, TF = 0.3), while Sesbania sp. and Tamarindus indica demonstrated efficient phytoextraction potential for Pb and Cd (TF ≥ 1.0). Anthocephalus cadamba and Terminalia bellirica effectively stabilized Cr, Cu, and Co in roots (BCF R > 3.5; TF < 0.5), indicating phytostabilization potential. Correlation analysis revealed strong positive relationships for Ni–Co (r= 0.86), Cr–Co (r= 0.81), and Cu–Cr (r= 0.71) in roots; Ni–Co (r= 0.93) and Ni–Cr (r= 0.90) in shoots; and Ni–Co (r= 0.90) and Pb-Cd (r= 0.83) in soil, suggesting synchronized uptake and movement. Soil pH significantly influenced HM availability, with acidic conditions enhancing Cd, Ni, and Cr uptake, and neutral pH (> 6.5) favouring As mobility. Soil EC increases the availability of Co, Cr, and Ni, while decreasing that of As (r = -0.24) and Cu (r = -0.40), indicating that alkaline conditions differentially modulate metal mobility in soil. These findings emphasize species-specific and complementary roles of phytoextractors and stabilizers in designing sustainable OBD reclamation strategies.

Drinking water sources with groundwater arsenic (As) contamination face multifaceted challenges in the removal and supply of fresh drinking water resources. To eradicate this problem, bioremediation has evolved to become more effective than other chemical and physical removal processes in its cost-effectiveness, high removal efficiency, and lesser production of secondary by-products or waste. Thus, this study aimed to treat As from aqueous media and to detoxify highly toxic forms of As by the isolated bacteria from As-affected areas. We isolated two new Gram-positive bacteria, which are reported here (Bacillus sp. and Bacillus cereus), with As5+ minimum inhibitory concentrations (MICs) of 4500 mg/L for the Bacillus sp. and 1000 mg/L for Bacillus cereus; meanwhile, for As3+, the MICs are 600 mg/L for both isolates. Bacillus sp. and Bacillus cereus can also effectively convert the highly toxic and easily mobile As3+ to As5+ in aqueous media. This study also demonstrates that these bacteria can remove a significant proportion of As3+ and As5+ (averaging 50% for both) from aqueous media. These As-resistant bacteria from the As-affected area can be used and upscaled for the treatment of As for a safer drinking water supply.

Microplastics, small sized plastic particles having size <5 mm are formed through primary process including production of beauty products, microbeads and microfibres as well as secondary process including mechanical weathering, friction, aberration and fragmentation of large plastics. The major sources of microplastics are land-based and ocean-based sources. Microplastic pollution is a serious concern due to the persistent, low biodegradability and bio-accumulative behaviour. Microplastics can bioaccumulate in the food chain and can cause ecological and human health risk. Hence, it is important to remove from the aquatic ecosystems. Microplastics are removed from aquatic systems and wastewater through a series of processes such as physical, chemical and biological treatments. In the present articles, >250 articles are reviewed to collect the information regarding the various physical, chemical and biological methods for the removal of microplastics. Also, the probable control strategies to combat with plastic pollution were assessed. It was concluded that recent water treatment methods are efficient in removing microplastic pollution. The efficiencies to remove microplastic from the water ranged between 74 %-99.2 %, 65 %-99.20 % and 77 %-100 % for physical, chemical and biological treatment methods, respectively. Among the three treatment methods, physical methods especially the filtration of water from biochar is the most efficient way (efficiency up to 100 %) to remove microplastics. It was also concluded that creating public awareness, promoting reusing, recycling and reducing, and application of bioplastics can control the production of microplastics from plastic wastes. This review will be useful to add current knowledge regarding the abatement of microplastic pollution, and finding novel solution to control microplastics. This review will also help the policymakers to implement most effective and cost-efficient method to remove microplastics, and to find out new methods to reduce, reuse and recycle plastic wastes.

Extraction of coal through opencast mining leads to the buildup of heaps of overburden (OB) material, which poses a significant risk to production safety and environmental stability. A systematic bibliometric analysis to identify research trends and gaps, and evaluate the impact of studies and authors in the field related to coal OB phytostabilization was conducted. Key issues associated with coal extraction include land degradation, surface and groundwater contamination, slope instability, erosion and biodiversity loss. Handling coal OB material intensifies such issues, initiating additional environmental and physical challenges. The conventional approach such as topsoiling for OB restoration fails to restore essential soil properties crucial for sustainable vegetation cover. Phytostabilization approach involves establishing a self-sustaining plant cover over OB dump surfaces emerges as a viable strategy for OB restoration. This method enhanced by the supplement of organic amendments boosts the restoration of OB dumps by improving rhizosphere properties conducive to plant growth and contaminant uptake. Criteria essential for plant selection in phytostabilization are critically evaluated. Native plant species adapted to local climatic and ecological conditions are identified as key agents in stabilizing contaminants, reducing soil erosion, and enhancing ecosystem functions. Applicable case studies of successful phytostabilization of coal mines using native plants, offering practical recommendations for species selection in coal mine reclamation projects are provided. This review contributes to sustainable approaches for mitigating the environmental consequences of coal mining and facilitates the ecological recovery of degraded landscapes.

Plastic is ubiquitously present in the environment due to its low biodegradability. Microplastics (MPs) are the degraded form of plastic having a diameter ranging from 0.1 µm to 5 mm. The present review aims to sum up the MP pollution in aquatic ecosystems of India to assess the probable effects of the MPs in organisms, and to find out the possible remedies to remove MPs. In India, MP concentrations were found maximum in the surface sediment of the estuarine ecosystem and water sample of the Hooghly River. Maximum MPs-based works focused on the ocean, sea, and estuarine aquatic systems of the southern states of India. Once entering the soil and sediment, MPs cause detrimental health effects on living beings. Generally, combined MP remediation methods exhibited better removal efficiency. Some microbial bioremediators are effectively being used for MP removal from aquatic systems. This study will be useful in making precise decisions regarding strengthening the law to control MP pollution, promoting the regular monitoring of MPs in Indian aquatic systems, and implementing a better MP removal process. It will not only save our environment from MP exposure but also improve the living standards and health status of people in developing countries.

The article focuses on the abundance of microplastics (MPs) in various environmental matrices, such as sediment and water, and their potential impacts. MPs can be considered as plastic particles that are less than 5 mm in dimension. The article presents an overview of the methods used for detecting and quantifying MPs in environmental samples, including spectroscopic techniques, microscopy, and chemical digestion. It also summarizes the current understanding of the distribution and abundance of MPs in various environmental compartments highlighting their importance in different environmental compartments. This article further discusses the potential impacts of MPs on different biota, such as marine organisms and terrestrial animals, and their ability to act as carriers for pollutants and other harmful substances. The review emphasizes the need for further research to better understand the impacts of MPs and to develop effective management strategies to mitigate their environmental effects.

Water pollution is an inextricable problem that stems from natural and human-related factors. Unfortunately, with rapid industrialization, the problem has escalated to alarming levels. The pollutants that contribute to water pollution include heavy metals (HMs), chemicals, pesticides, pharmaceuticals, and other industrial byproducts. Numerous methods are used for treating HMs in wastewater, like ion exchange, membrane filtration, chemical precipitation, adsorption, and electrochemical treatment. But the remediation through the plant, i.e., phytoremediation is the most sustainable approach to remove the contaminants from wastewater. Aquatic plants illustrate the capacity to absorb excess pollutants including organic and inorganic compounds, HMs, and pharmaceutical residues present in agricultural, residential, and industrial discharges. The extensive exploitation of these hyperaccumulator plants can be attributed to their abundance, invasive mechanisms, potential for bioaccumulation, and biomass production. Post-phytoremediation, plant biomass can be toxic to both water bodies and soil. Therefore, the circular bioeconomy approach can be applied to reuse and repurpose the toxic plant biomass into different circular bioeconomy byproducts such as biochar, biogas, bioethanol, and biodiesel is essential. In this regard, the current review highlights the potential strategies for the phytoremediation of HMs in wastewater and various strategies to efficiently reuse metal-enriched biomass material and produce commercially valuable products. The implementation of circular bioeconomy practices can help overcome significant obstacles and build a new platform for an eco-friendlier lifestyle.

The qualitative and quantitative assessment of groundwater is one of the important aspects for determining the suitability of potable water. Therefore, the present study has been performed to evaluate the groundwater quality for Achhnera block in the city of Taj, Agra, India, where groundwater is an important water resource. The groundwater samples, 50 in number were collected and analyzed for major ions along with some important trace element. This study has further investigated for the applicability of groundwater quality index (GWQI), and the principal component analysis (PCA) to mark out the major geochemical solutes responsible for origin and release of geochemical solutes into the groundwater. The results confirm that, majority of the collected groundwater samples were alkaline in nature. The variation of concentration of anions in collected groundwater samples were varied in the sequence as, HCO3− > Cl− > SO42− > F− while in contrast the sequence of cations in the groundwater as Na > Ca > Mg > K. The Piper diagram demonstrated the major hydro chemical facies which were found in groundwater (sodium bicarbonate or calcium chloride type). The plot of Schoellar diagram reconfirmed that the major cations were Na+ and Ca2+ ions, while in contrast; major anions were bicarbonates and chloride. The results showed water quality index mostly ranged between 105 and 185, hence, the study area fell in the category of unsuitable for drinking purpose category. The PCA showed pH, Na+, Ca2+, HCO3− and fluoride with strong loading, which pointed out geogenic source of fluoride contamination. Therefore, it was inferred that the groundwater of the contaminated areas must be treated and made potable before consumption. The outcomes of the present study will be helpful for the regulatory boards and policymaker for defining the actual impact and remediation goal.

Microplastics (MPs) have already been detected in various environmental matrices like soil, sediment, and surface water, and recently in groundwater also. The occurrence of MPs in groundwater depends up on the transportation through recharge and may controlled by source and local hydrogeology, and partly on the process of surface water-groundwater interaction (SW-GW). Based on the available studies, we intended to establish a hypothetical overview on the source and process-dependent occurrence of MPs in groundwater across terrestrial and coastal aquifers. Groundwater recharge from agricultural stagnant water, losing streams near dumping sites and agricultural fields, effluents from wastewater treatment plants, septic system failure etc. are the potential sources of MPs in groundwater. The factors like sea level rise and tidal pumping are among the major factors which may control the migration of MPs in coastal aquifer along with the physical and chemical properties of the aquifer media. These MPs have another ecological concern as they can adsorb persistent organic pollutants as well as heavy metals and transfer them to animal tissues through food chain. Studies are being conducted mainly focusing the MP contamination in surface water, marine environment and soil, and very limited studies are available to address the source of MPs in groundwater. However, no such study has been done on the existence, profusion, or environmental factors that contribute to MP pollution in the groundwater in relation to the present climate change scenario. Understanding the extent of MP contamination in groundwater systems is necessary for developing effective management strategies and minimizing their impact on the environment and human health. This study focusses on the source along with the controlling factors of the migration of MPs towards groundwater including the effect of climate change.

The mismanagement of consumer-discarded plastic waste (CDPW) has raised global environmental concerns about climate change. The COVID-19 outbreak has generated ∼1.6 million tons of plastic waste per day in the form of personal protective equipment (masks, gloves, face shields, and sanitizer bottles). These plastic wastes are either combustible or openly dumped in aquatic and terrestrial environments. Open dumping upsurges emerging contaminants like micro-nano plastics (MNPs) that directly enter the ecosystem and cause severe impacts on flora and fauna. Therefore, it has become an utmost priority to determine sustainable technologies that can degrade or treat MNPs from the environment. The present review assesses the sources and impacts of MNPs, various challenges, and issues associated with their remediation techniques. Accordingly, a novel sustainable circular model is recommended to increase the degradation efficiency of MNPs using biochemical and biological methods. It is also concluded that the proposed model does not only overcome environmental issues but also provides a sustainable secondary resource to meet the sustainable development goals (SDGs).

Mining activities in the opencast coal mines contaminate the surrounding soil by releasing coal dust containing heavy metals (HMs). The objective of the present study was to quantify the concentration of HMs like Fe, Cu, Mn, Ni, Cr, Zn, and Co in soil on profile and distance basis in the vicinity of the coal mines. This research also proposed the synthesis application of positive matrix factorization (PMF) model for the quantitative assessment of pollution sources. The results showed that the soil was more affected due to the presence of Cr in mining areas., and the contamination factor (Cf) of Cr was high at the edge of coal mine. It was observed from the study that Cfof the HMs was decreased with the increase in distance from the mine edge. The application of PMF model demonstrated that the contributions of Zn (4.2%), Ni (16.8%), and Mn (100%) were maximum in the pollution. The study concluded that soil contamination is inexorable due to opencast coal mining activities, and it can be mitigated by developing a green belt or through the process of ecological restoration and phytoremediation.

Microplastics (MPs) are the contaminants of growing concern due to their persistent properties in the environment. This review compares the global data on MPs concentration in soil, sediment, salt, sand, biosolids, and water. Previous studies have also developed various methods to estimate MPs for different environmental matrices, which were generally based on salt-based density separation, physical (microscopy), chemical characterization (spectroscopy), and visual counting for extraction, identification, and quantification, respectively. In most of the existing field-based studies, MPs are usually identified and detected by microscopic observation and Fourier transform infrared (FTIR) analysis, which maximize the probability of error in the estimation process. A combination of thermogravimetric analysis-FTIR spectroscopy, Raman microspectroscopy, optical photothermal infrared, and pyrolysis/gas chromatography–mass spectrometry are used for the identification, recognition, and quantification of MPs in the heterogeneous solid and liquid matrices for minimizing the interference and misinterpretation of the other constituents (organic matter) present in the samples, especially soil, sediments, and biosolids.

This paper reviews research on phytoremediation (2002–2021), particularly for the estimation of plant efficiency and soil pollution indices, examining the extraction of metals from soil and plants growing under both artificial (spiked with specific metal) and natural conditions. From the analysis of >200 published experimental results, it was found that contamination factor and geo-accumulation index as well as translocation and bioconcentration factors are the most important soil pollution and plant efficiency metrices, respectively, which are gaining importance to assess the level of metal pollution and its transfer from soil to plant to find a better metal clean-up strategy for phytoremediation. To access the metal concentration, it was found that the most widely accepted extractants to dissolve and extract the metals from the soil and plant were HNO3 and HClO4 (mainly in 5:1; v/v or 4:1; v/v), which are used both in natural and artificial metal contamination studies. Moreover, plants such as Pteris vittata, Monochoria korsakowi, Lolium perenne, Festuca rubra, Poa pratensis, Ricinus communis, and Siegesbeckia orientalis can act as hyperaccumulators under both natural and artificial experiments and can be directly implemented into the fields without checking their further efficiency in phytoremediation.

Coal mine activities lead to the release of potentially toxic elements (PTEs) to the surrounding areas. The present study concerns the health risk caused due to the exposure of PTEs (Hg, As, Cd, Cr, and Pb) in the children residing in the areas around coal mines. The PTEs content and bioaccumulation coefficient (BAC) in the plant, viz., Albizia lebbeck and Madhuca longifolia growing on the nearby soils of the coal mine affected areas were also estimated. The results demonstrated that the hazard quotient (HQ) for Cr (0.211) in the roadside soil (RSS) was higher than other PTEs. The hazard index (HI) was also at the maximum in the RSS (0.553) followed by the core zone soil (0.541). In RSS, Cr contributed the maximum for the HI value (38%) which elucidated that Cr might cause health problem in the long term. The Cr concentration (5.49 mg kg−1) was also higher than other PTEs in the plant leaves of M. longifolia and was two-fold higher than A. lebbeck. Except Cd, the accumulation of other PTEs in the leaves of both the species were low, which could be due to their low availability in soils. The BAC for Cr in M longifolia was comparatively higher than A. lebbeck and was found at the maximum for Cd (0.29) in M longifolia. The outcomes of the study elucidated that although there is no severe health risk in children, the data indicated that the prolonged exposure to PTEs might lead to serious health issues.

In India, about 75% of the electricity is generated from coal-based thermal power plants and they produce approximately 210 million tons of fly ash (FA). High ash content of Indian coal (30%-40%) produces large volumes of FA of which 68% has been successfully utilized in various activities. FA is stored in the earthen FA lagoons (embankment), where colonization of vegetation (grasses, herbs, and shrubs) is very common. This vegetation is established as a process of ecological succession and many toxic metals are bioaccumulated and transferred to aerial parts. During phytoremediation of FA, these naturally grown plant species can be used. In this chapter two field studies on bioaccumulation of metals in naturally colonizing vegetation are discussed, while one case study on bioaccumulation of metals in FA-filled coal mine opencast voids blanketed with topsoil is also discussed.

Soil contamination caused by the deposition of mercury (Hg) is a global problem. Hg is released to the environment through the coal burning in thermal power plant and various anthropogenic sources and contaminates soil. Hg is taken up by plant roots from contaminated soil and transferred to aerial parts. Through bioaccumulation in the plant, Hg moves into the food chain, resulting in potential health and ecological risks. Coal combustion in thermal power plants is the major anthropogenic source of Hg in environment and India emits approximately 240 tonnes/year (in year 2010--2013). Indian coals are reported to have higher Hg contents than coals from other countries, with values ranging from 0.11 to 0.80 mg/kg. The world average Hg concentrations reported in coal and fly ash are 0.01--1 and 0.62 mg/kg, respectively. The mass of Hg accumulated globally in the soil is estimated to be 250--1000 Gg (1 Gg = 1000 tonnes). Phytoremediation method has been proved to be the best approach for removal of Hg from soil because this method is environmentally friendly and cost effective. The objective of this study was to investigate the efficiency of Brassica juncea plant for the removal of Hg from contaminated soil. A laboratory-scale pot study was conducted by spiking the Hg using solution of HgCl2 in three different concentrations (10, 50, and 100 mg Hg/kg of soil). B. juncea was grown for 90 days and plant samples were collected after the exposure of 30th, 60th, and 90th days. Hg uptakes in plant (roots, shoots and leaves) and soil were digested as per USEPA standard methods and measured in Coal Vapor AAS.

The release of potentially toxic metal(loid)s (PTMs) such as As, Cd, Cr, Pb and Hg has become a serious threat to the environment. The anthropogenic contribution of these PTMs, especially Hg, is increasing continuously, and coal combustion in thermal power plants (TPPs) is considered to be the highest contributor of PTMs. Once entered into the environment, PTMs get deposited on the soil, which is the most important sink of these PTMs. This review centred on the sources of PTMs from coal and flyash and their enrichment in soil, chemical behaviour in soil and plant, bioaccumulation in trees and vegetables, health risk and remediation. Several remediation techniques (physical and chemical) have been used to minimise the PTMs level in soil and water, but the phytoremediation technique is the most commonly used technique for the effective removal of PTMs from contaminated soil and water. Several plant species like Brassica juncea, Pteris vittata and Helianthus annuus are proved to be the most potential candidate for the PTMs removal. Among all the PTMs, the occurrence of Hg in coal is a global concern due to the significant release of Hg into the atmosphere from coal-fired thermal power plants. Therefore, the Hg removal from pre-combustion (coal washing and demercuration techniques) coal is very essential to reduce the possibility of Hg release to the atmosphere.

Apart from Hg mining, coal and its by-products were also recognised as one of the major sources of Hg contamination for the environment causing severe health hazard for human and wildlife. Present study investigates phytoremediation potential (PRP) of Hg from flyash (FA) using Brassica juncea. The plants were grown under five different combinations: garden soil (GS) (0% FA + 100% GS), FA25 (25% FA + 75% GS), FA50 (50% FA + 50% GS), FA75 (75% FA + 25% GS) and FA100 (100% FA + 0% GS), and their biometric growth and Hg accumulation in different tissues were observed every month upto 90 days of exposure duration. With increase in time duration, Hg accumulation also increased and mainly accumulated in root followed by stem > leaf however, for FA50 it was root > leaf > stem. Among FA treated combinations, the relative elongation ratio of root and shoot, and their dry biomass increased with increase in time and were significantly higher for FA25 and FA50 combinations. With increase in percentage of FA and exposure duration, the Hg accumulation also increased (R2 > 0.964) and thus Hg content in substrate decreased (R2 > 0.852). The bioconcentration factor of root was enhanced with exposure duration however no changes were observed for TF suggesting maximum phytostabilization potential (0.58 mg Hg kg−1 plant−1). Non-detrimental effect of Hg and higher PRP of 2.62 mg Hg kg−1 plant−1 suggests Indian mustard as a promising accumulator species for phytoremediation of FA-contaminated sites when grown on equal proportion of FA and GS, and can show higher PRP if exposed for longer duration.

A Phytoremediation experimental set up was established by spiking the soil with varying concentrations of mercury (Hg) (Treatment: T1:10; T2:50; T3:100; T4:500 and T5:1,000 mg Hg/kg soil). Hg removal ability of the Indian mustard plant was determined after 30, 60 and 90 days of exposure. Hg accumulation trend in second and third month of exposure was root > leaf > stem, while for the 1st month it was root > stem > leaf. The highest percentage of Hg accumulation (81%) and glutathione (14 mg/kg) was observed in the plants of T4 and T5 treatment, respectively at 90 days of exposure indicating a high level of Hg stress tolerance. At 90 days of exposure the chlorophyll a content in leaves grown on Hg-free soil (control soil) was 1.8, 2.4, 2.8, 3.6 and 4.4 fold higher than T1, T2, T3, T4 and T5 treatment respectively. With increase in exposure duration, translocation factor decreased whereas bioconcentration factor increased signifying Hg is mainly accumulated in the roots. The study suggests that Brassica juncea can withstand under high Hg contamination and can show great potential to phytostabilize Hg when grown under 100 mg/kg of soil Hg without showing any significant detrimental effect on the plant.

The present study was intended to determine the potentially toxic elements (PTEs) concentration in fly ash (FA), soil, plant, and vegetable to assess the impacts of pollution on the nearby areas of coal-fired thermal power plant (TPP). The PTEs concentrations (mg/kg) in FA were Cr (48–74) > Pb (41–65) > Cd (7.4–9.7) > As (3.19–4.43) > Hg (0.518–0.598). The contamination factor (Cf) for Cd was highest in agricultural soil (Cf = 22) followed by roadside soil (Cf = 20), and forest soil (Cf = 15), which showed that the soil was strongly polluted due to the presence of Cd. The ecological risk index (ERI) in the topsoil of roadside area was also very high (1130), due to the high value of ecological risk factor of Cd (898) and Hg (213). The health risk associated with the intake of soil containing PTEs were also estimated by calculating hazard index (HI), and the values showed that the risk posed to children was minimum (HI < 1). But in case of roadside area, the HI was very close to one (0.975) indicating that the prolong exposure may pose severe health risk. The bioaccumulation coefficient of all PTEs for Albizia lebbeck and Madhuca longifolia were < 1, indicating less PTEs accumulation in the plant species. The hazard quotient of all PTEs (except of Hg) through vegetable consumption (Allium cepa and Raphanus sativus) was > 1, which signifies that the long-time consumption of contaminated vegetables may cause severe risk to the people.

A descriptive research was conducted seasonally for divulging the impact of deposition and contamination of selected heavy metals (HMs) like Cd, Ni, Cu, Pb, Zn and Cr) in roadside soil (RSS) and grass (Cynodon dactylon) of a National Highway (Dhanbad - Raniganj; NH 2, India). The contamination factor for Cd was found maximum among all the HMs during pre-monsoon season and the highest geo-accumulation index was also found for Cd. The ecological risk index (ERI) was calculated and compared with two control sites which showed elevated risk of HMs in the RSS. The highest ERI value (596) was observed in the pre-monsoon. The general trends of bio-concentration factor, bio-accumulation factor, and translocation factor were Zn > Ni > Cr > Cu > Pb > Cd, Zn > Ni > Cu > Cr > Pb > Cd, and Ni > Zn > Pb > Cr > Cu > Cd, respectively. Potential health risk (non-cancer) for children and adults was also assessed, and the highest hazard indices in pre-monsoon were found for children (4.80 × 10−1) and adults (6.33 × 10−2). The total cancer risk in pre-monsoon for adults was 0.324 × 10−4 while for children was 0.295 × 10−4. This study demonstrates the occurrence of HMs in the road side soil causing the increase in the health risks problems for the nearby residents. The findings of the present study can be further interpreted to assess the health risk posed due to the exposure of HMs near RSS of the highways covering the industrial areas elsewhere in the world.

Mercury (Hg), arsenic (As), cadmium (Cd), and lead (Pb) are the major toxic metals released by coal mining activities in the surrounding environment. These metals get accumulated in the soils. The plants grown on the contaminated soil uptake these toxic metals in their roots and aerial parts. This study monitored the bioaccumulation of Hg and other three toxic metals in coal mine soil. The pot study of Hg accumulation in Brassica juncea showed that the extent of Hg uptake by roots and shoots of the plants grown on was high in the mature plant and Hg content in root was higher than the shoot. In the soil of unreclaimed overburden (OB) dump, the toxic metal content was higher than that of reclaimed OB dump which posed high ecological risk in the soil of unreclaimed OB dump. Bioaccumulation coefficient (BAC) value showed that Hg was not accumulated in the leaves of Dalbergia sissoo L., Gmelina arborea, Peltaphorum inerme L., Cassia seamea L, and Acacia mangium L grown on coal mine soil.

Mercury (Hg) is a pollutant that poses a global threat, and it was listed as one of the ten leading ‘chemicals of concern’ by the World Health Organization in 2017. The review aims to summarize the sources of Hg, its combined effects on the ecosystem, and its remediation in the environment. The flow of Hg from coal to fly ash (FA), soil, and plants has become a serious concern. Hg chemically binds to sulphur-containing components in coal during coal formation. Coal combustion in thermal power plants is the major anthropogenic source of Hg in the environment. Hg is taken up by plant roots from contaminated soil and transferred to the stem and aerial parts. Through bioaccumulation in the plant system, Hg moves into the food chain, resulting in potential health and ecological risks. The world average Hg concentrations reported in coal and FA are 0.01–1 and 0.62 mg/kg, respectively. The mass of Hg accumulated globally in the soil is estimated to be 250–1000 Gg. Several techniques have been applied to remove or minimize elevated levels of Hg from FA, soil, and water (soil washing, selective catalytic reduction, wet flue gas desulphurization, stabilization, adsorption, thermal treatment, electro-remediation, and phytoremediation). Adsorbents such as activated carbon and carbon nanotubes have been used for Hg removal. The application of phytoremediation techniques has been proven as a promising approach in the removal of Hg from contaminated soil. Plant species such as Brassica juncea are potential candidates for Hg removal from soil.

The working of thermal power plant (TPP) in an area is the primary source of pollution, because it releases potentially toxic elements (PTEs) laden fly ash (FA), which may lead to serious health and ecological risks. This study assessed the current status of pollution in the nearby areas of TPP by measuring the concentration of PTEs (As, Cd, Cr, Hg, and Pb) in FA, soils (roadside, forest, agricultural, and residential areas), tree leaves (Albizia lebbeck and Madhuca longifolia), and vegetables (Raphanus sativus and Allium cepa). Hg concentration in FA was found to be lower (0.449 mg/kg) than global average Hg content (0.62 mg/kg). PTEs content in topsoil (0–15 cm) of the roadside area was comparatively higher (As, 4.56; Cd, 12.68; Cr, 72.53; Hg, 2.77; Pb, 46.05 mg/kg) than other areas. Bioaccumulation coefficient and transfer factor of As in M. longifolia and A. cepa were 1.03 and 0.30, respectively, which showed high accumulation of PTE. The ecological risk index (1561) was found to be very high in the roadside area, due to high values ecological risk factor of Cd (1268) and Hg (277) in the area. The total hazard quotients (THQs) posed by As, Cd, Cr, and Pb in vegetables were exceeding the safe limits (THQ > 1), suggesting that long-term consumptions of these vegetables may pose serious health risks. Therefore, the remediation measures are needed to minimize the pollution level in soil to reduce the health risk due to the exposure of PTEs.

Open-cast coal-mining activities release a substantial amount of potentially toxic metal(loid)s or metals which contaminates soil in its vicinity. A total of 75 soil samples were collected from an open-cast coal-mining area (North Karanpura area, India), representatives of five land-use sites, namely roadside soil (RSS), reclaimed mine soil (RMS), forest soil (FS), residential land soil (RS), and agricultural soil (AS) from three profiles (0–10, 10–20, and 20–30 cm). The samples were analyzed for five USEPA recognized potentially toxic metals, mercury (Hg), arsenic (As), cadmium (Cd), chromium (Cr), and lead (Pb). Ecological and health risks were assessed to study the impact of metals pollution on ecological ecosystem and children. Hg concentrations were found above the maximum permissible limit and highest in RSS (0.90 mg kg−1) which was 13-, 12-, and 4-fold higher than AS, RS, and FS, respectively. Among all soil samples, a high concentration of Hg was found in topsoil profile (0–10 cm) which indicates anthropogenic sources of Hg due to coal dust deposition and transport activities in the mining region. In addition, the increased concentration of Cd was also observed for most of the sites (RSS: 1.35 mg kg−1; RMS: 1.25 mg kg−1). For all the metals in all the sites, the concentration decreased along the depth. Contamination factor and ecological risk index suggested that roadside and reclaimed area had very high ecological risk due to major contribution of Hg and As contamination in soil. The pollution load index was also found to be very high from the threshold limit, which suggests the possibility of transfer of contaminant from soil to children in coming future, and causes severe health risk.

Mercury (Hg) and other heavy metals, such as arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), and zinc (Zn), were analyzed in coal (bituminous), roadside soil, reclaimed mine soil, core zone soil, and reference soil (agriculture soil) along three soil profiles (0–10, 10–20, and 20–30 cm) in a coal mining area (Jharkhand, India) inhabited by economically marginalized dense population. Higher toxic metal concentrations in coal (0.47 mg Hg/kg, 2.81 mg As/kg, and 13 mg Pb/kg, 2.61 mg Cd/kg) can cause ecological hazard in the area. Roadside soil has the highest Hg (2.32 mg/kg), and core zone soil has the highest Pb (15.7 mg/kg) concentration. Hg concentration in roadside soil indicates high potential ecological risk, while Cd contamination in mining area can be put under moderate ecological risk. Roadside soils shows highest Ecological Risk Index (ERI) value of 339, indicating considerable ecological risk, and Hg alone contributes 64% of ERI value. Higher ERI and (Formula presented.) (Hg) were due to the deposition of coal dust from mining activities and transportation.