Pesticide application in agriculture has significantly increased to enhance crop productivity. However, its longterm use raises concerns regarding soil microbial communities and water resource contamination. This study examines the prolonged impacts of agropharmaceutic (pesticide category) residues on microbial diversity, soil health, and groundwater pollution. The findings reveal that persistent agropharmaceutic exposure alters microbial community structure, reducing beneficial microorganisms while promoting resistant strains. Additionally, agropharmaceutic leaching into water systems contributes to ecological disturbances and human health risks. This research underscores the urgent need for sustainable pest management practices to mitigate environmental damage while maintaining agricultural efficiency.

Biochar is a solid substance with a charcoal-like appearances. It is highly flammable and is made from the burning of agricultural and forest-based organic wastes by various controlled processes like pyrolysis. Biochar is rich in carbon and storage of the same in soil is highly recommended to ease off climate change by sequestration of carbon along with enhancing agricultural yield and production of energy. According to the World Health Organization, one of the biggest threats to human life in the present century is livestock water contamination. Among different contaminants, microbial contamination is responsible for several harmful diseases many of which are fatal. The current disinfectant methods are quite useful but they produce harmful by-products which can cause more hazards to human health. Magnetic biochar which is a modification of normal biochar is a green, facile, and cost-effective bacteriocide that has immense antimicrobial potential against water-borne pathogens. Magnetic biochar in conjugation with quaternary phosphonium salt produces Magnetic Biochar-Quaternary phosphonium salt [MBQ], which is a further modification of magnetic biochar that holds much better antimicrobial properties than biochar or magnetic biochar. It can successfully undergo inhibition of water-borne pathogens like Escherichia coli and Staphylococcus aureus. MBQ can disrupt the bacterial membrane and induce oxidative damage inside the bacteria, causing their inactivation and inhibition. MBQ also shows biocidal effects. In this review, we will discuss biochar, its properties, various methods of synthesis of biochar, different methods of modification of biochar, antimicrobial and antibacterial properties of biochar, magnetic biochar, and MBQ. Synthesis, Characterization, and antimicrobial properties of MBQ against waterborne microorganisms are also discussed in detail.

Inadequate management of solid waste stands out as a primary cause of environmental contamination, leading to a decline in groundwater quality in the vicinity of landfill sites. Though landfills are required by federal regulation to have liners formed by plastic or clayey layers, these liners tend to have leaks, which can result in landfill leachate percolation into the soil and aquifers, contaminating nearby water sources and further damaging ecosystems. Currently, the elevated nitrate (NO3-) concentration in groundwater spurred by landfill leachates is becoming a growing global concern. Various regions across the world present groundwater NO3- concentrations exceeding the threshold limit (50 mg/L) of WHO for drinking purpose. In this scenario, it is requisite to consider and develop highly efficient and affordable solutions for the long-term management of groundwater resources. Therefore, a bibliographical review was conducted in this paper by searching literature in Web of Science, ScienceDirect, Google Scholar, SpringerLink, PubMed, and Scopus to analyze NO3- pollution in groundwater caused by landfill leachates and explore the impacts of landfills and NO3- pollution on the environment and human health. In addition, this review also presents an overview of the leachate treatment technologies to remove nitrogenous compounds, particularly NO3-. This review entails a worldwide appraisal of groundwater NO3- pollution to comprehend the human health risks and aid in optimizing groundwater quality. A resulting framework developed in this review provides an improved grasp of the link between inadequate landfill management and adverse environmental and health outcomes and urged all stakeholders to address the issue of solid waste to ensure environmental and human health. Overall, the results emphasize the need for immediate action and collaborative efforts to mitigate these impacts and ensure the long-term sustainability of waste management practices.

This study provides prototypical evaluation of groundwater vulnerability to contamination and soil corrosivity in Lokoja region, central Nigeria. By combining the aquifer vulnerability index, integrated electrical conductivity, groundwater confinement overlying strata depth to water table (GOD), and electrical anisotropy coefficient (lambda) derived from lithological composition, resistivity, and layer thickness; the study identifies substantial vulnerabilities in the groundwater resources. Findings indicate that over 70% of the region is moderately to very highly vulnerable to groundwater pollution, especially in the eastern and southern parts, highlighting the need for tailored groundwater management strategies in highly vulnerable areas, covering 40% of the region. Corrosion potential varies spatially, with 80% of the upper layer being minimally corrosive and around 45% of the lower moisture-rich layer showing moderate to significant corrosiveness, emphasizing risks in central and northern zones associated with lithological compositions and moisture content. These accentuate the necessity of rigorous monitoring programs and strict land use regulations to protect aquifers and infrastructure. This research underscores the value of proactive management for safeguarding groundwater resources, providing an invaluable framework for decision-making and resource allocation to tackle contamination and corrosion risks. Importantly, the research addresses a significant research gap in a region with limited scientific exploration.

Mercury (Hg) is one of the most toxic global pollutants of continuing concern, posing a severe threat to human health and wildlife. Due to its mobility, Hg is easily transported through the atmosphere and directly deposited onto water, sediments and soils or incorporated in biota. In groundwater, Hg concentrations can be influenced by either geogenic or anthropogenic sources, causing critical health effects such as damage to the respiratory and nervous systems. The geogenic sources of Hg include rocks and minerals containing Hg (cinnabar, organic-rich shales, and sulfide-rich volcanic) and geothermal fluids. The anthropogenic Hg sources include the combustion of fossil fuels, gold mining, chemical discharges from dental preparation, laboratory activities and legacy sites. In groundwater, the average background concentration of Hg is < 0.01 mu g/L. Mercury can be mobilized into groundwater from geogenic or anthropogenic sources due to changes in redox potential (Eh), with concentrations reaching above the WHO drinking water standard of 1 mu g/L. Under reducing conditions, microbial activity facilitates the reductive dissolution of FeOOH, causing the release of sorbed Hg2+ into groundwater. The released Hg2+ may be reduced to Hg-0 by either dissolved organic matter or Fe2+. The stability of Hg species (Hg-0, Hg-2(2+), Hg2+, MeHg) in groundwater is controlled by Eh and pH. While high Eh and low pH conditions can mobilize Hg from the solid into aqueous phases, the soil binding ability can sequestrate the mobilized Hg via adsorption of Hg2+ by goethite, hematite, manganese oxides, hydrous ferric oxides, or organic matter restricting it from leaching into groundwater. During groundwater contamination, remediation using nanomaterials such as pumice-supported nanocomposite zero-valent iron, brass shavings, polyaniline-Fe3O4-silver diethyldithiocarbamate, and CoMoO/gamma-Al2O3 has been documented. These promising emerging technologies utilize the principle of adsorption to remove up to 99.98 % of Hg from highly contaminated groundwater. This study presents an overview of groundwater contamination, remediation, complex biogeochemical processes, and a hydrogeochemical conceptual model concerning Hg's mobility, fate, and transport.

Currently, the cultivation and harvesting of mollusks is a crucial activity worldwide. However, this industry generates a large amount of mollusk shell waste disposed of in landfills, causing environmental pollution. In addition, the companies linked to this item allocate large sums of money to depositing the shells in authorized landfills. In South America, Chile is one of the leading producers worldwide of scallop shell (Argopecten purpuratus) waste, creating a growing environmental and financial problem in the country, especially considering that there has yet to be progress in the development of new technologies that may reuse this waste in Chile. This study used different techniques to completely characterize the northern Chile scallop shell waste's physical and chemical properties for the first time. The XRD result corresponded with calcite crystal structures (CaCO3), and the XFR showed 97.68% purity. Three particle sizes were obtained: BS (595-100 mu m), MS (250-595 mu m), and SS (<250 m). In addition, the potential use of these wastes to remove contaminants present in water from the wine industry (caffeic acid) and some drinking water (arsenic(III)) was evaluated. The powder with the smallest particle size (SS), which has a surface area of 1 m(2)/g, 0.0050 m(3)/g of pore volume and pore diameter of 18.0 nm, removed 100.0% of CA and 23.0% As(III) in a pH condition of 4.6. The results show that scallop shell waste can be used to treat water and reinforce polymeric matrix composite materials to improve mechanical properties.

The groundwater flow and the transport of solutes and contaminants in fractured geologic media play a very important role in various hydrogeological and geological processes. Fractures are discontinuities that occur in practically all types of rocks, consolidated and semi-consolidated sediments, in which groundwater flows at different scales of space and time. This article reviews more than 20 years of research in the CGEO of different selected examples in Mexico, from local to regional scales, associated with 1) gravitational Groundwater Flow Systems, 2) hydrogeochemical interaction of groundwater with fractured rocks through which it circulates, 3) instrumentation and coupled numerical analysis of flow parameters and time -varying geomechanics, during consolidation associated with pumping, 4) analysis of fracture generation with the development and application of coupled flow and geomechanical equations, 5) formation of new minerals, 6) sustenance of ecosystems, 7) artificial fracturing of soils for their conservation and infiltration of rainwater improvement; and on the issue of transport of natural solutes, 8) used as a tracers, 9) toxic elements to health and environment, 10) spills of hydrocarbon derivatives in low permeability and double porosity media due to fracturing and 11) heat. The results show the importance of the physical -chemical interaction between fractured and granular geological media at both local and regional scales, where groundwater residence times range from a few days to thousands of years; which implies modifying the criteria for water management and the permanence of ecosystems in the country. The complexity of these processes requires different methodologies for their evaluation, among them the instrumentation and calibration of numerical models from 1D to 3D for analysis, predictions and the proposal of restoration, sustainability and management solutions; they also help to prevent, control and mitigate the negative impacts on health and the environment caused by the induction of geogenic elements and by various types of pollutants; fractured geologic media also support numerous terrestrial and marine ecosystems; in the case of damaged agricultural soils, artificial fracturing allows increasing rainwater infiltration and improving productivity in adaptation to climate change and reducing the extraction in aquifers where safe capacity has been exceeded; unfortunately, excessive extraction in closed basins is causing fracturing of the aquitards, both hydraulic and due to differential settlement, which favors the migration of pore water rich in elements harmful to human health and the environment, whose natural function was its protection. All this requires designing mechanisms for the transfer of scientific knowledge to society and decision makers to propose novel restoration and sustainability strategies, under the new paradigm of Gravitational Groundwater Flow Systems.