Remediation Methods Research Articles

Heavy metal toxicity and its human health assessment: A preliminary study from the Perumal Lake sediments, Tamil Nadu, India

The current investigation manifests the heavy metal toxicity and its human health assessment to appraise the environmental deterioration of the sediments within the Perumal Lake, Tamil Nadu, India. Five surface samples were collected from the Perumal Lake in 2023, which undergoes the selective perception of the granulometric analysis, implying supremacy of the clay content and limited sand and silt contents. The organic matter indicates the higher input of waste disposal, and the CaCO3 illustrates the existence of shell fragments in the lake environments. Noteworthy results of the heavy metal concentration as arranged in the devaluation order as Zn > Cu > Fe > Cr > Ni > Mn > Pb > Co > Cd. Followed by the heavy metal concentration, the environmental contamination indices such as Igeo denote that except for Cd metal, other heavy metals indicate moderate to extreme pollution status. The Enrichment Factor (Ef) illustrates Fe, Co, Cd, Zn, Cu, Ni, and Pb, highlighting no metal enrichment. In contrast, Mn and Cr reveal low metal enrichments, and the Cf reveals all the heavy metals, which argues for low to high contamination ranges. The Cd and the mCd are categorized as very high, and PERI underscores the low-risk category. The Hazard Index (HI) of the non-carcinogenic category and carcinogenic demonstrates that children and adults are primarily at risk of ingestion. At the same time, the dermal pathway indicates low jeopardy to children and adults and no risk to humans. The Heavy Metal Toxicity Load (HMTL) poses the sample location three registers a significant accumulation of toxic contagion proposed to remove from the sediments. Realm of heavy metal toxicity and its human health assessment underscores for researchers in environmental quality determination, and the strategies discussed such as phytoremediation, in-situ capping, and biotechnological techniques, may be helpful in evaluation and implement remediation methods of pollution in aquatic environments.

Characteristic features of brain development and remedial methods for autism spectrum disorders and attention deficit hyperactivity disorder: Review of current research

Introduction. Deep understanding of neurobiological processes in normal and abnormal children is crucially important for developing remedial procedures for mental development disorders and using inclusive learning methods. The purpose of this article is to summarize modern and most relevant information about the brain structure and functioning features in connection with disorders of neural structures, pathways and networks, as well as psychosocial and educational remedial methods for children with attention deficit hyperactivity disorder (ADHD) and autism spectrum disorders (ASD). Materials and Methods. The work is based on a comprehensive experimental research results analysis in the field of cognitive sciences and related areas affecting the issues of neurodivergent states. Research articles published between 2003 and 2024, mainly between 2021 and 2024, were used as materials. Results. Within the framework of this study, the authors identified key common and distinctive features of pathogenesis, epidemiology, and the neurobiological foundations of the ASD and ADHD development. Examples of disorders observed at the level of brain anatomical structures and functioning of individual neural networks are demonstrated. The spread of a symptomatic manifestations variety, concomitant disorders (comorbidity), the difficulty in differentiating the concepts of norm and pathology in a wide range of neurodivergent conditions are emphasized. Summarizing the data on various methods of therapy and treatment, the authors justified the key role of psychosocial adaptation within the framework of school education, which requires teachers’ understanding the peculiarities of mental development and techniques for interacting with neurodivergent children. Transmission of carefully selected information about the peculiarities of mental development to children seems to be relevant in order to help them understand their own problems and find solutions to them. These topics can be integrated into in the biology course given by appropriately prepared teachers. Conclusions. Rehabilitation and integration into society of children with ASD and ADHD is the main and practically the only way to solve the problem, requiring an understanding of the neurodevelopment peculiarities, conscious and tolerant attitude on the part of teachers, psychologists, parents and peers. The article is addressed to specialists in the field of psychology, special and inclusive education, pediatricians, educators, teachers, parents.

Tailings particle size effects on pollution and ecological remediation: A case study of an iron tailings reservoir

The particle size distribution in tailings notably influences their physical properties and behavior. Despite this, our understanding of how the distribution of tailings particle sizes impacts in situ pollution and ecological remediation in in-situ environment remains limited. In this study, an iron tailings reservoir was sampled along a particle flow path to compare the pollution characteristic and microbial communities across regions with different particle sizes. The results revealed a gradual reduction in tailings particle size along the flow direction. The predominant mineral composition shifts from minerals such as albite and quartz to layered minerals. Total nitrogen, total organic carbon, and total metal concentrations increased, whereas the acid-generating potential decreased. The region with the finest tailings particle size exhibited the highest microbial diversity, featuring metal-resistant microorganisms such as KD4–96, Micrococcaceae, and Acidimicrobiia. Significant discrepancies were observed in tailings pollution and ecological risks across different particle sizes. Consequently, it is necessary to assess tailings reservoirs pollution in the early stages of remediation before determining appropriate remediation methods. These findings underscore that tailings particle distribution is a critical factor in shaping geochemical characteristics. The responsive nature of the microbial community further validated these outcomes and offered novel insights into the ecological remediation of tailings.

The Formulation of a Natural Detergent with a Biosurfactant Cultivated in a Low-Cost Medium for Use in Coastal Environmental Remediation

Green surfactants have significant potential for improving environmental remediation methods. The aim of the present study was to formulate a green natural detergent containing the biosurfactant produced by Starmerella bombicola ATCC 22214 grown in 1.2% canola oil, 10% sucrose, and 0.5% corn steep liquor. The biosurfactant reduced surface tension to 31.84 mN/m and was produced at a yield of 22 g/L. Twelve formulations were proposed using cottonseed oil as the natural solvent and different stabilisers (vegetable wax, hydroxyethyl cellulose, and sodium alginate). The detergent was evaluated for its emulsifying capacity and stability over a 10-day period. Ecotoxicity was investigated using the marine recruitment test on metal plates covered with paint into which the biosurfactant was incorporated as well as tests with a microcrustacean and vegetable seeds. The formulation designated H, consisting of 1% biosurfactant, 40% cottonseed oil, and 2% hydroxyethyl cellulose, achieved the best results. The formulation exhibited both stability and emulsifying capacity (100% of petroleum). The ecotoxicity tests revealed the safety of the natural detergent. The detergent achieved satisfactory oil dispersion and solubilised 98% of the oil impregnated on the rock. The results indicate that the natural detergent holds promise for efficiently cleaning up environmental areas contaminated with oil and petroleum products.

Utilization of Natural Soils as a Remediation Method for Electric Arc Furnace and Ladle Slags

Utilization of Natural Soils as a Remediation Method for Electric Arc Furnace and Ladle Slags

Study on heat and mass transfer characteristics of porous media with different pore structures under continuous wave laser irradiation

The pore structure determined by porosity and particle size will directly affect the remediation efficiency of thermal treatment on contaminated soil. To investigate the remediation capability of continuous wave laser soil remediation technology on soils with different pore structures, this paper establishes a heat and mass transfer model within unsaturated porous media under laser irradiation. Four pore structures were simulated, and the model’s reliability was experimentally validated. Under laser irradiation, energy exchange between the solid and gas phases has a minimal effect on the solid phase temperature. The temperature distribution of the solid phase in the four samples is similar, with the differences primarily arising from moisture content. Interface energy exchange dominated the rise in the temperature of the gas. The intrinsic Nusselt numbers for the four samples were 3.5, 4.4, 4.9, and 6.2, respectively. Laser irradiation causes the Nusselt number to decrease over time, but the relative magnitudes of the Nusselt numbers for the four samples remain unchanged. From the perspective of solid phase temperature, the capability of laser remediation for soils with different pore structures is similar. From the standpoint of gas temperature, the Nusselt number is decisive. However, considering the complex coupling relationship between gas temperature rise and Darcy velocity and evaporation rate, the influence of water saturation and intrinsic permeability cannot be ignored. The research findings can provide a theoretical basis and analytical methods for the efficient laser remediation of soils with different pore structures.

Microbial alchemists: unveiling the hidden potentials of halophilic organisms for soil restoration.

Salinity, resulting from various contaminants, is a major concern to global crop cultivation. Soil salinity results in increased osmotic stress, oxidative stress, specific ion toxicity, nutrient deficiency in plants, groundwater contamination, and negative impacts on biogeochemical cycles. Leaching, the prevailing remediation method, is expensive, energy-intensive, demands more fresh water, and also causes nutrient loss which leads to infertile cropland and eutrophication of water bodies. Moreover, in soils co-contaminated with persistent organic pollutants, heavy metals, and textile dyes, leaching techniques may not be effective. It promotes the adoption of microbial remediation as an effective and eco-friendly method. Common microbes such as Pseudomonas, Trichoderma, and Bacillus often struggle to survive in high-saline conditions due to osmotic stress, ion imbalance, and protein denaturation. Halophiles, capable of withstanding high-saline conditions, exhibit a remarkable ability to utilize a broad spectrum of organic pollutants as carbon sources and restore the polluted environment. Furthermore, halophiles can enhance plant growth under stress conditions and produce vital bio-enzymes. Halophilic microorganisms can contribute to increasing soil microbial diversity, pollutant degradation, stabilizing soil structure, participating in nutrient dynamics, bio-geochemical cycles, enhancing soil fertility, and crop growth. This review provides an in-depth analysis of pollutant degradation, salt-tolerating mechanisms, and plant-soil-microbe interaction and offers a holistic perspective on their potential for soil restoration.

Molecular Basis of Energy Crops Functioning in Bioremediation of Heavy Metal Pollution

Heavy metal pollution is a gradually growing environmental issue that hinders the growth and development of plants, and also destabilizes soil. Consequently, eco-friendly phytoremediation methods have gained traction, with energy crops emerging as a particularly effective solution. Energy crops not only provide high-quality plant materials for detoxification and remediation of heavy metal pollution, but also possess energy properties conducive to biofuel production. Therefore, this paper delves into the tolerance mechanism of energy crops towards heavy metal toxicity, elucidating processes such as root complex-mediated inhibition of metal migration and response to reactive oxygen species (ROS) through heavy metal-related proteins, enzyme systems, reactive nitrogen species (RNS), and hormones. Moreover, it summarizes the heavy metals remediation mechanisms of energy crops, including uptake, translocation, chelation, immobilization, and sequestration. This paper explores applications of energy crops in heavy metal pollution remediation, emphasizing the methods for efficient biochar remediation and biofuel generation. Furthermore, potential challenges in using energy crops for heavy metal pollution remediation are outlined. By systematically examining the function mechanisms and prospective applications of energy crops in heavy metal pollution bioremediation, this paper serves as a valuable reference for both research and practical implementation in this field.

Organic radicals driving polycyclic aromatic hydrocarbon polymerization with peracetic acid activation in soil

The use of peracetic acid (PAA) in advanced oxidation processes has gained significant attention recently, but the knowledge of activating PAA to degrade polycyclic aromatic hydrocarbons (PAHs) is limited due to the variety and selectivity of reactive substances in PAA oxidation system. This paper presented the first systemically study on the degradation of PAHs by PAA activation in soil. It was found that heat-activated peracetic acid (heat/PAA) was capable of degrading phenanthrene (PHE) efficiently with degradation efficiency > 90 % within 30 min. Experimental results demonstrated that a series of reactive oxygen species (ROS) including organic radicals (RO•), hydroxyl radicals (HO•) and singlet oxygen (1O2) were generated, while acetylperoxyl (CH3C(O)OO•) and acetyloxyl (CH3C(O)O•) radicals were primarily responsible for PHE degradation in soil. Further analysis shows that polymerization products such as diphenic acid, 2′-formyl-2-biphenylcarboxylic acid and other macromolecules were dominant products of PHE degradation, suggesting polymerization driving PHE degradation instead of the conventional mineralization process. Toxicity analysis shows that most of the polymerization products had less toxicity than that of PHE. These results indicate that PAA activation was a highly effective remediation method for PAHs contaminated soil, which also provided a novel mechanism for pollutant degradation with the PAA activation process for environmental remediation.

Low-disturbance land remediation using vertical groundwater circulation well technology: The first commercial deployment in an operational chemical plant

Soil and groundwater contamination by organic pollutants from chemical plants presents significant risks to both environmental and human health. We report a significant field trial where a chemical plant in operation showed soil and groundwater pollution, as verified by sampling and laboratory tests. While many remediation methods are effective, they often require the temporary shutdown of plant operations to install necessary equipment. This paper introduces a novel combination of low-disturbance contaminant remediation technologies, including groundwater circulation well (GCW), pump and treat (P&T), and in-situ chemical oxidation (ISCO) technologies, that can be applied on the premises of an active plant without halting production. The groundwater with dissolved contaminants is removed through P&T and GCW, while GCW enhances ISCO that focus on eliminating the remaining hard-to-pump contaminants. Results show: (1) after two years of remediation effort, the contaminant levels in soil and groundwater were significantly reduced; (2) the average concentration reduction rate of four contaminants, including 1,2-dichloroethane, methylbenzene, ethylbenzene, and M&P-xylene, exceeds 98 %; (3) the presented remediation strategy results in the improvement of remediation efficiency. Specifically, the concentration of 1,2-dichloroethane in observation wells dropped from 40,550.7 μg/L to 44.6 μg/L. This study offers a first-of-its-kind commercial deployment of a GCW-based remediation strategy in an active plant setting. Moreover, the combined remediation approach presented here can serve as a model for designing contaminant remediation projects that require minimal operational disruption.

Remediation of Saline Soils Using Halo-Tolerant Plant Growth Promoting Rhizobacteria

Soil salinization poses a significant threat to global agriculture, affecting approximately 6.73m Ha land area in India. Salinity stress impacts plant growth and soil health negatively, leading to reduced crop yields and soil degradation. This review examines the sources and effects of soil salinity, highlighting the intricate interplay between salinity and soil nutrients and its remediation. Traditional methods for soil remediation often have detrimental long-term effects, prompting the exploration of alternative strategies such as the use of halo-tolerant plant growth-promoting rhizobacteria. HT-PGPR offer a promising solution for sustainable agriculture by enhancing soil fertility and plant resilience to salinity stress through various mechanisms. Furthermore, this review identifies research gaps in understanding the metabolic pathways and strain selection of HT-PGPR, as well as their interactions with soil microbiota. Future research directions include field-scale experiments to validate the effectiveness and economic viability of HT-PGPR inoculation for large-scale application in saline soils. Overall, leveraging the potential of HT-PGPR represents a critical step towards mitigating the global challenge of soil salinity and ensuring food security in the face of climate change.

Assessment of Landfills and their Impact on the Soil: a Local Study in Ukraine

Landfills are widely utilised for waste disposal due to their economic advantages and ease of implementation compared to alternative methods. However, landfills exert significant environmental and health impacts on adjacent agricultural land. Accumulation of heavy metals in soil is a risk to ecological and food safety. Methodological approaches to assess and mitigate the impact of landfills on agricultural land are essential for ensuring sustainable land use practices and safeguarding human health. In this study, landfills were assessed at the local level, and the hazard level was classified according to it. A set of priority measures for restoring technogenic disturbed areas and minimising their impact on agricultural land was determined. The need to select a set of innovative, ecologically oriented methods for remediation of landfills, depending on the type and degree of soil contamination, was identified in context of ensuring environmental and food security.

Enhanced Natural Attenuation Technique, Edaphic and Microbiological Changes in Oil-Impacted Soil of Odhiaje Community, Rivers State

Oil spills in the Niger Delta could exert environmental pressures on the soil component. We investigated the impacts of oil spills and the effect of the Enhanced Natural Attenuation (ENA) remediation method on contaminated soil and resident microbial populations in the Odhiaje community in Rivers State, Nigeria. Soil samples for microbiological studies were collected weekly during a 17-week remediation period, while those for edaphic parameters were taken before and after remediation, all at 4 sampling points (SPs). Serial dilution of the oil-impacted soils for microbial density enumeration was carried out according to standard methods. Results revealed that mean concentrations of Total Petroleum Hydrocarbon Contents (THC) (Sig.value = 0.009), SO42- ions (Sig.value = 0.001), and sand compositions (Sig.value = 0.045) all differed markedly across the sampling points at p<0.05. Mean levels of EC (Sig.tvalue = 0.039) and ΣN (Sig.tvalue = 0.058) & K+ ions (Sig.tvalue = 0.004) differed significantly before and after the remediation exercise at the 95% confidence interval. Application of nutrients was rapidly accompanied by microbial population increases, leading to the consumption of oil contaminants in soils to levels comparable to control over the remediation period. Total Heterotrophic Bacteria counts correlated with pH (r = 0.501) and SO42- ions (r = 0.500) (p<0.05), and K+ ions (r = -0.800) (p<0.01); Total Heterotrophic Fungi correlated with pH (r = 0.520) (p<0.05), and Mg2+ ions (r = 0.820) (p<0.01); Hydrocarbon Utilizing Bacteria correlated with available P (r = 0.530) and silt composition (r = -0.504) (p<0.05), and K+ (r = 0.626) and Mg2+ ions (r = 0.733) (p<0.01); and Hydrocarbon Utilizing Fungi correlated with K+ (r = 0.500) & Mg2+ ions (r = 0.506) (p<0.05). Results indicate improvement in C/N ratios and effectiveness of the current cost-effective bioaugmentation technique in the restoration of arable soil productivity in the Odhiaje community.

Analysis of real pharmaceutical wastewater and proposed novel remediation methods

Analysis of real pharmaceutical wastewater and proposed novel remediation methods

Photocatalytic degradation properties

Photocatalysis, an innovative technology, holds promise for addressing industrial pollution issues across aqueous solutions, surfaces, and gaseous effluents. The efficiency of photodegradation is notably influenced by light intensity and duration, underscoring the importance of optimizing these parameters. Furthermore, temperature and pH have a significant impact on pollutant speciation, surface chemistry, and reaction kinetics; therefore, process optimization must consider these factors. Photocatalytic degradation is an effective method for treating water in environmental remediation, providing a flexible and eco-friendly way to eliminate organic contaminants from wastewater. Selectivity in photocatalytic degradation is achieved by a multidisciplinary approach that includes reaction optimization, catalyst design, and profound awareness of chemical processes. To create efficient and environmentally responsible methods for pollution removal and environmental remediation, researchers are working to improve these components.

Occurrence, analysis and removal processes of emerging pharmaceuticals from waters for the protection and preservation of a sustainable environment: A review

Pharmaceuticals are a group of man-made commercial and synthetic products and an important mainstay of modern society. However, their presence in aquatic environments is identified as a potential risk, causing harm to living things even at low concentrations ranging from ng L−1 to μg L−1. Due to their pseudo-persistence, bio-accumulation, and low elimination rate by conventional treatments, the majority of these xenobiotic contaminants and their metabolites are routinely released into the environment by sewage treatment plants and last longer in an aquatic environment. This review aims to provide an extensive report and a current state of knowledge concerning various classes of pharmaceutical compounds (PCs). It also discusses the occurrence, the analytical methods for the determination of PC micro-pollutants, and the remediation methods noted in recent literature focusing on the most recent advances. In this context, this review highlights the statistical data regarding the status of PCs in detection, analysis, and removal methods in aqueous media. In addition, this review provides an overview of the conventional and advanced technologies for the removal of PCs from water sources, offering critical comments, and discussing the challenges related to improving existing technologies for sustainable and eco-friendly management of water resources. It likewise emphasizes the importance of the combination of different treatment methods to reach up to 100% PC removal.Finally, gaps in the literature were found, and recommendations for further research were also cited in accordance with this paper. To the best of our knowledge, this review paper is among the rare works that deal with both: i) the analysis of large varieties of PCs in different water matrices, ii) the removal and identification of target analytes and their by-products generated during the elimination processes, and iii) the possible degradation pathways proposed by different studies.

Synthesis and photocatalytic properties of Cerium(IV) oxide graphene oxide composites

Semiconductor photocatalytic technology is a simple, efficient, and low-cost method for environmental pollution remediation. Cerium dioxide (CeO2), as a promising oxidative degradation photocatalyst, can solve the problems of energy shortage and environmental pollution. In this paper, cerium dioxide/graphene oxide composites were successfully synthesized by a one-pot hydrothermal method, achieving a degradation rate of 88.96 % for rose red dye in 150 min, and the introduction of reduced graphene oxide effectively improves the photocatalytic performance of pure cerium oxide.

Study on Plant-blanket to reduce heavy metal migration caused by precipitation and to improve the soil environment of pyritic tailings

The increasing demand for mineral resources due to industrial development has led to significant tailings pollution during the mineral extraction process. In the southwestern region of China, a large amount of pyritic tailings containing pyrite cinder easily leaches heavy metals and other pollutants when exposed to precipitation, resulting in widespread soil contamination. Effective remediation methods are urgently needed to address this issue. This study utilized naturally occurring Plant-blanket formed by the symbiosis of moss and herbaceous plants on pyritic tailings as restoration material. Through leaching experiments and staining tracer techniques, the study investigated the ability of Plant-blanket to reduce the migration of heavy metals from pyrite cinder to soil under the influence of precipitation and its role in improving the soil environment. The results showed that within 12 h, the Plant-blanket could absorb water equivalent to 206.9 % of its own weight and had good water retention ability. It reduced the stained area ratio of soil horizontal and vertical profiles after precipitation leaching by a maximum of 76.08 % and 46.41 %, respectively, and improved the pH, cation exchange capacity (CEC), bulk density, and water content of soil at different depths. In addition, after being covered by Plant-blanket, the migration of Cd and Cu was reduced by a maximum of 44.35 % and 55.77 % respectively, and it increased the diversity and abundance of bacterial communities, promoting the recovery of soil microbial ecological functions. These findings indicate that Plant-blanket can regulate water and improve soil environment, and has certain control ability on the migration of Cd and Cu produced by pyritic tailings. Meanwhile, Plant-blanket plays an important role in improving the soil environment in mining areas and promoting ecosystem restoration, providing valuable reference for further exploration of ecological restoration of tailings.

Phytoremediation of soils contaminated as a result of military and anthropogenic impact

Military conflicts and anthropogenic accidents cause significant soil contamination with heavy metals, oil products, pesticides, and other toxic substances. The purpose of this study was to highlight the factors of influence of military-anthropogenic load on soils and to analyse the available methods of their remediation. The study summarised the available and promising phytoremediation methods with an assessment of their impact on soil contamination by chemicals that are typical pollutants during military conflicts. The study summarised, classified, and compared the groups of pollutants that are most common during military operations; analysed the impact of pollutants on the fertile soil layer and their mobility; and analysed the available remediation methods. It was found that the available soil remediation technologies, which can be used individually or in combination, provide the necessary tools to address the problem of chemical contamination of soils due to toxic products such as explosive derivatives and heavy metals. The degree of economic feasibility was considered, which, accordingly, suggested that soil phytoremediation may be the most economically feasible under certain conditions. This opens wide possibilities for further investigations, where the synergy of ecology, economics, and agrobiology will enable the development of mechanisms for optimising soil phytoremediation methods, considering their type, profile, and intended use. An algorithm of actions for remediation of soils as a result of military-anthropogenic load was proposed, which includes a related set of related actions on zoning, demining, assessment, and return of land to industrial use. The findings of this study can be used to clean industrial areas that have been contaminated during production processes or accidents

Biochar-bacteria-plant combined potential for remediation of oil-contaminated soil.

Oil pollution is a common type of soil organic pollution that is harmful to the ecosystem. Bioremediation, particularly microbe-assisted phytoremediation of oil-contaminated soil, has become a research hotspot in recent years. In order to explore more appropriate bioremediation strategies for soil oil contamination and the mechanism of remediation, we compared the remediation effects of three plants when applied in combination with a microbial agent and biochar. The combined remediation approach of Tagetes erecta, microbial agent, and biochar exhibited the best plant growth and the highest total petroleum hydrocarbons degradation efficiency (76.60%). In addition, all of the remediation methods provided varying degrees of restoration of carbon and nitrogen contents of soils. High-throughput sequencing found that microbial community diversity and richness were enhanced in most restored soils. Some soil microorganisms associated with oil degradation and plant growth promotion such as Cavicella, C1_B045, Sphingomonas, MND1, Bacillus and Ramlibacter were identified in this study, among which Bacillus was the major component in the microbial agent. Bacillus was positively correlated with all soil remediation indicators tested and was substantially enriched in the rhizosphere of T. erecta. Functional gene prediction of the soil bacterial community based on the KEGG database revealed that pathways of carbohydrate metabolism and amino acid metabolism were up-regulated during remediation of oil-contaminated soils. This study provides a potential method for efficient remediation of oil-contaminated soils and thoroughly examines the biochar-bacteria-plant combined remediation mechanisms of oil-contaminated soil, as well as the combined effects from the perspective of soil bacterial communities.