Cadmium (Cd) contamination in soils poses a serious risk to agricultural production and ecological health. It enters agricultural soils as a result of human activities such as phosphate fertilizer use, industrial discharge, and natural weathering of Cd-enriched parent substrates. After reaching the soil, it interferes with nitrogen (N) cycling by reducing microbial biomass, enzyme activity, and the expression of functional genes (amoA, nirk/nirS, nosZ), affecting N transformations, which ultimately control soil N availability and loss. Moreover, Cd stress downregulates nosZ gene expression, which limits complete reduction of N2O to N2, thus increasing N2O emissions. To reduce Cd stress, biochar (BC) has been recognized as a potential strategy due to its multidimensional role in both Cd immobilization and alleviating Cd-induced disturbances in the soil N cycle. BC, through different mechanisms like ion exchange, precipitation, and surface complexation, decreases Cd bioavailability and nurtures microbial habitats. Furthermore, BC promotes the restoration of N-cycling microbial populations and functional genes, which enhances N retention, lowers N2O emissions, and increases plant-accessible N. The current review summarizes the recent research findings on how Cd toxicity affects N cycling processes and its associated microbes and genes and further emphasizes the dual role of BC in immobilizing Cd and restoring N cycling for sustainable soil remediation, greenhouse gas mitigation, and crop production. Moreover, the review also highlights the critical knowledge gaps, particularly regarding the effect of Cd on gross N transformations using 15N tracing, that need to be addressed in future studies.

Soil nitrogen (N) transformations control N availability and plant production and pose environmental concerns when N is lost, raising issues such as soil acidification, water contamination, and climate change. Former studies suggested that soil N cycling is chiefly regulated by microbial activity; however, emerging evidence indicates that this regulation is disrupted by heavy metal (HM) contamination, which alters microbial communities and enzyme functions critical to N transformations. Environmental factors like soil organic carbon, soil texture, water content, temperature, soil pH, N fertilization, and redox status play significant roles in modulating the response of soil N cycling to HM contamination. This review examines how different HMs affect soil N processes, including N fixation, mineralization, nitrification, denitrification, dissimilatory nitrate reduction to ammonium (DNRA), and immobilization, as well as microbial activities and functional genes related to soil N transformations. The review additionally outlines the impact of HMs on environmental degradation, including the risk of soil N losses (e.g., leaching, runoff, and gaseous emissions) and depletion of soil fertility, thus threatening the sustainability of the ecosystem. The effect of edaphic factors and fertilization on soil N cycling response to HM contamination was also examined. The effect of phytoremediation, a sustainable approach to remediate HM polluted soils, on N cycling was also reviewed. Thus, this review underscores the importance of increasing research and innovative strategies to combat HM pollution’s effects to enhance soil health, boost crop yields, and protect soil stability and productivity.

Aquatic macrophytes play essential roles in freshwater ecosystems, providing services such as habitat creation, nutrient cycling, water quality improvement, and aquatic food supply. However, the overgrowth of aquatic macrophytes, especially free-floating macrophytes, negatively affects the environment, causing reduced oxygen levels, altered water flow dynamics, decreased biodiversity, and nutrient supply to other planktonic species. Various physicochemical technologies have been utilized to regulate macrophytes, including mechanical removal, synthetic herbicides, and biological control methods. However, these methods often have limitations and can pose environmental risks. Aquatic weed biomass disposal is considered another alarming issue for water resource managers. In the past few years, there has been a surge of interest in exploring alternative and sustainable approaches to utilizing weed biomass for renewable bioresource development. One such approach is vermicomposting, which involves bio-conversion of organic waste into value-added products with the aid of earthworms, especially the use of epigeic species of earthworms such as Eisenia fetida. This green technology offers multiple benefits: meaningful biowaste management, nutrient recovery from waste biomass in manure, and protein-rich earthworm biomass as animal feed. This review presents a comprehensive framework on aquatic weed biomass management using earthworm technology and its possible utility in developing a waste-to-wealth system for sustainable development in various waste management and soil fertility development sectors.

The environmental impacts of plastic have attracted the interest of the scientists, media, and policymakers, but the impact of microplastics (MPs) on our environment remains largely unknown. These novel pollutants are so widespread that the scientific community has defined the present historical epoch as “The Plasticene”. There is growing concern over the bioaccumulation and entry of these miniature plastic particles released from almost every article of daily use into the food chains, which will ultimately contaminate the human population. Given the presence of these pollutants in almost every strata and biome of the earth, adsorption of other toxic pollutants and generation of novel categories of chemicals, MP pose an eminent challenge to almost every biotic community. At present times, we have very little knowledge about the possible effects of micropollutants as risk assessment and risk management rely on standardized data and reliable methodology adopted, so in present times it is impossible to evaluate the toxic response and deleterious effects on biotic communities. The detailed understanding of origin, exposure pathways, toxic response of biota, remediation options, and precautionary operations are of prime importance for averting the plastic disaster. MPs significant affect rooting ability of plants, reduce photosynthetic ability by dysregulation of chlorophyll a/chlorophyll b ratios and cause imbalance in carbon/nitrogen balance. MPs have most prominent effect on aquatic animals where they cause feeding disruption, alterations in metabolism, hormonal imbalance and henceforth reproductive problems. On cellular levels MPs causes cytotoxicity, nephrotoxicity, immune dysregulation, neurotoxicity and genotoxicity. MPs have been found to affect the microbes which results in replacement of beneficial organisms by harmful organisms at niche areas and MPs acts as vehicle and transport agents for transport and proliferation of harmful organism like Ostreopsis and Coolia and Vibrio genera. Owing to the deleterious effects on environment and biota, various remedial measures proposed by researchers includes biodegradation, coagulation, photo-catalytic degradation and thermal degradation. Therefore, current manuscript attempts to review the status of these pollutants in various biomes of the biosphere, their possible toxic effects on residents of the hydrosphere, atmosphere, and lithosphere, their effect on human health, and various remediation processes with the intention of special and surgical emphasis on future research in the area for fulfillment of the knowledge gap.

Globally, more than 2 billion tonnes of municipal solid waste (MSW) are generated each year, with that amount anticipated to reach around 3.5 billion tonnes by 2050. On a worldwide scale, food and green waste contribute the major proportion of MSW, which accounts for 44% of global waste, followed by recycling waste (38%), which includes plastic, glass, cardboard, and paper, and 18% of other materials. Population growth, urbanization, and industrial expansion are the principal drivers of the ever-increasing production of MSW across the world. Among the different practices employed for the management of waste, landfill disposal has been the most popular and easiest method across the world. Waste management practices differ significantly depending on the income level. In high-income nations, only 2% of waste is dumped, whereas in low-income nations, approximately 93% of waste is burned or dumped. However, the unscientific disposal of waste in landfills causes the generation of gases, heat, and leachate and results in a variety of ecotoxicological problems, including global warming, water pollution, fire hazards, and health effects that are hazardous to both the environment and public health. Therefore, sustainable management of MSW and landfill leachate is critical, necessitating the use of more advanced techniques to lessen waste production and maximize recycling to assure environmental sustainability. The present review provides an updated overview of the global perspective of municipal waste generation, composition, landfill heat and leachate formation, and ecotoxicological effects, and also discusses integrated-waste management approaches for the sustainable management of municipal waste and landfill leachate.

Phosphorus (P) is one of the essential macronutrients for plant metabolism. Regardless of its great quantity in inorganic and organic forms, it is generally inaccessible for plant utility due to bond formation with other ions present in soil. Due to the excessive use of agrochemicals, environmental issues have reached their peak. This has increased the interest of the scientific community in finding a sustainable alternative to chemical fertilisers. Diverse microbes like Rhizobium spp., Serratia spp., Pseudomonas spp., Bacillus spp., Azotobacter spp., Penicillium spp., Rhizopus spp., Fusarium spp., and various actinomycetes have been isolated and screened as phosphorus solubilizing microorganisms (PSMs). The PSMs also act as biological control agents (bioagents) and help to withstand extreme stress circumstances (like heavy metal toxicity) by producing ACC deaminase. With the advent of time, organic farming is gaining attention as this technology is highly eco-friendly, so utilisation of potential microorganisms for solubilisation of phosphorus will improve soil health and crop productivity. PSMs possess significant heavy metal remediation potential; therefore, they can be used in restoration of contaminated soil as well as in enhancing plant health. This review will provide in-depth knowledge about PSMs and their role in sustainable agriculture and bioremediation of toxicants.

Vermicompost (VC) products have grown in popularity in plant nutrition and are widely used to improve plant growth and suppress plant diseases. In addition, the choice of chemical-free food and increased public concern for human health and the environment due to the impacts of hazardous inorganic fertilizers have motivated farmers to seek safer and more eco-friendly alternatives. The present study aimed to evaluate the plant-growth-promoting and biocontrol potential of macrophyte biomass-based VC products in tomato plants. The results indicated that tomato plants treated with VC + vermicompost tea (VCT) resulted in 30.74% higher plant height, 20.70% more leaves, 29.05% more fruits, and 61.26% higher total yield than the control plants. In addition, VC products significantly reduced disease incidence by 35-60%, whereas the untreated control had the highest wilt incidence (75%). The study concludes that VC products produced from free-floating aquatic weed biomass (Azolla, Lemna, and Salvinia) could be used as a potential alternative to inorganic fungicides to manage Fusarium wilt disease and as bioinoculants to improve the growth and yield of tomato plants for sustainable crop production.

Pharmaceuticals and Personal Care Products (PPCPs) as emerging pollutants have attracted revelatory recognition from research organizations for two decades due to their consistent presence in wastewater. Such ubiquitous contaminants have received alarming apprehension globally for their persistence and potential peril to the health status of organisms and the natural atmosphere. These looming toxins often exist in low concentrations and have complicated structures, making it challenging for wastewater treatment plants to eliminate them; hence, highly efficient and novel eco-friendly technologies are essential for their elimination. This review discusses the source, occurrence, and fate and is followed by a comprehensive analysis of the adverse effects on aquatic biota as well as human well-being.The toxicity analysis with multiple bioassays has also been summarised in this paper. This review covers the multiple remedial technologies, like phytoremediation, and advanced treatment technologies, viz., membrane filtration, adsorption, the photo-Fenton process, and ozonation, that can be adopted in sewage treatment unit processes. We also reviewed the regulatory aspects and risk mitigation policies that are being implemented and are needed now. Thus, the goal of this paper is to provide insight into the aftermath consequences of PPCPs and offer more research that should be focused on the remedial measures of these emerging pollutants and risk-mitigating strategies.

Nanotechnology has fascinated scientists and researchers for exploitation of unparalleled biological, physical, and chemical characteristics of nanoparticles. Nano-formed compounds are developed for utilization in a diverse number of fields from medicine to the space exploration. Because of high surface area to volume ratio, size-dependent attributes and high reactivity, 334nano-compounds are used for the reclamation of soil and wastewater. Nanoremediation technology has proven to be more effective than the conventional remediation technologies due of its high speed of degradation and its ability to be effective across wide range of environmental conditions. Nanoremediation approaches like nanosensors, nanoadsorbent sand nanomaterial-based photocatalysts have shown promising results for remediation of wide range of persistent environmental toxicants. Nanoremediation has also potential for source term treatment as well as the enhancement effect by synergistic action that were very less observed in conventional technologies. These notable advantages make nanotechnology a suitable technology for upcoming future for the reclamation of resources.

Management of food waste is an alarming problem throughout the globe. Around 350 million tons of food waste are generated annually, of which about 60% come from households. The unscientific management of such a massive waste can have long-term deleterious effects on the environment, economy, and society. Landfills are the most common solution worldwide for food waste management. However, landfilling is highly damaging to the environment and poses a risk to human health and global climate. There are several alternatives to landfilling, and one of the potential alternatives is composting. Composting is undeniably a promising eco-friendly approach to managing food waste, promoting economic growth, and reducing our environmental footprint. The idea behind the review is to critically analyze the food waste composting, phases, and parameters affecting composting. It is concluded that composting is a potential benign biotechnique through which not only food waste can be sustainably managed, but it could be utilized as a cost-effective technique for promoting sustainable agriculture and remediation of environmental toxicants.