Rampant industrial growth and urbanization have caused a wide range of hazardous contaminants to be released into the environment resulting in several environmental issues that could eventually lead to ecological disasters. The unscientific disposal of urban and industrial wastes is a critical issue as it can cause soil contamination, bioaccumulation in crops, groundwater contamination, and changes in soil characteristics. This article explores the impact of various industrial and urban wastes, including petroleum hydrocarbons (PHs), coal-fired fly ash, municipal solid waste (MSW) and wastewater (MWW), and biomedical waste (BMW) on various types of soil. The contamination and impact of each of these wastes on soil properties such as compaction characteristics, plasticity, permeability, consolidation characteristics, strength characteristics, pH, salinity, etc is studied in detail. Most of the studies indicate that these wastes contain heavy metals, organics, and other hazardous compounds. When applied to the soil, PHs tend to cause large settlements and reduction in plasticity, while the effect of coal-fired fly ash varies as it mainly depends on the type of soil. From the studies it was seen that the long-term application of MWW improves the soil health and properties for agricultural purposes. Significant soil settlements were observed in areas of MSW disposal, and studies show that MSW leachate also alters soil properties. While the impacts of direct BMW disposal have not been extensively studied, few researchers have concentrated on utilizing certain components of BMW, like face masks and nitrile gloves to enhance the geotechnical characteristics of weak soil. Soil remediation is required to mitigate the contamination caused by heavy metals and PHs from these wates to improve the soil quality for engineering and agricultural purposes, avert bioaccumulation in crops, and pose less environmental and public risks, and ecotoxicity. Coal-fired fly ash and biomedical waste ash contain compounds that promote pozzolanic reactions in soil, recycling and reuse as soil stabilizers offer an effective strategy for their reduction in the environment, thus complying to sustainable practices. In essence, this study offers a contemporary information on the above aspects by identifying the gaps for future research and mitigation strategies of contaminated soils.

Polycyclic aromatic hydrocarbons (PAHs), one of the major environmental pollutants, produced from incomplete combustion of materials like coal, oil, gas, wood, and charbroiled meat, that contaminate the air, soil, and water, necessitating urgent remediation. Understanding the metabolic pathways for PAHs degradation is crucial to preventing environmental damage and health issues. Biological methods are gaining increasing interest due to their cost-effectiveness and environmental friendliness. These methods are particularly suitable for remediating PAHs contamination and mitigating associated risks. The paper also outlines the processes for biodegrading PAHs, emphasizing the function of Pseudomonas spp., a kind of bacterium recognized for its capacity to degrade PAHs. To eliminate PAHs from the environment and reduce threats to human health and the environment, Pseudomonas spp. is essential. Understanding the mechanism of PAH breakdown by means of microbes could lead to effective clean-up strategies. The review highlights the enzymatic capabilities, adaptability, and genetic versatility of the genes like nah and phn of Pseudomonas spp., which are involved in PAHs degradation pathways. Scientific evidence supports using Pseudomonas spp. as biocatalysts for PAHs clean-up, offering cost-effective and eco-friendly solutions.

This work is dedicated to the study and investigation of thermoxidation processes in crude oil and petroleum products. The study of thermoxidation processes in crude oil and petroleum products was carried out using various analytical techniques, including IR, NMR, UV, small-batch reactor, TGA, DSC, DTA, thermochemical luminescence and others. One of the key characteristics of crude oil and petroleum products is their thermo-oxidative stability. During thermoxidation, hydrocarbons in the oil oxidize in an oxygen-rich environment, forming undesirable compounds such as hydroperoxides, alcohols, ketones, and others. These changes lead to increased viscosity and alterations in the chemical and physical properties of the product. The hydroperoxides formed during the process play a critical role as free radical initiators, which accelerate oxidation reactions. At higher temperatures, these reactions can produce solid particles, resins, and even sediments. In engines, such sediments can disrupt the normal flow within the fuel system, leading to improper process management, engine damage, increased operational costs, reduced efficiency, and environmental pollution. Effective management of oxidation processes and the implementation of preventive measures are crucial to addressing environmental issues such as soil and water contamination. In the oil industry, it is essential to enhance the understanding and control of oxidation processes to meet both the increasing global demand and the tightening environmental regulations. This approach not only improves production efficiency but also ensures the protection of the environment

A strain of Bacillus licheniformis T5 was isolated from soil contaminated with crude oil due to its efficient degradation of polycyclic aromatic hydrocarbons (PAHs). When subjected to stress metabolism using phenanthrene as a carbon source, significant changes were observed in T5 cells. Infrared spectrum analysis revealed the presence of -C=C- and Ph-O-C (aromatic) groups on the bacterial surface, facilitating the adsorption of PAHs on the phospholipid layer and causing damage to the cell membrane. Scanning electron microscope (SEM) analysis showed the changes of cell morphology, including a large number of folds on the lower surface and the folding of cell membrane. Transmission electron microscope (TEM) observation showed that non-stressed bacteria with adequate nutritional conditions accumulated more lipids. However, the stress group contained more protein. It was found that stress metabolism led to the increase of protein content in T5 cells by 16.4% and the activity of oxidoreductase more than doubled. These physiological and biochemical changes enhance the ability of stressed bacteria to degrade PAHs efficiently, thereby reducing the degradation cycle. The findings offer valuable insights for the remediation of PAHs pollution.

Microplastics (MPs) affect the carbon cycle in coastal salt marsh soils. However, studies on their effects on CHCl3 and CHBr3, which are volatile halohydrocarbons that can damage the ozone layer, are lacking. In this study, indoor simulation experiments were conducted to explore the effects of MPs invasion on the source and sink characteristics of soil CHCl3 and CHBr3. The results showed that different concentrations of polyethylene (PE)MPs promoted CHCl3 and CHBr3 emissions. Emission peaks of the two gases appeared on days 3 and 15 during the culture cycle. CHCl3 and CHBr3 fluxes were mainly affected by soil physicochemical properties and microbial communities. PE-MPs caused changes in soil properties, microorganisms, and related functional genes. Soil total organic carbon, which was significantly and positively correlated with CHCl3. Dissolved organic matter, which was one of the main factors affecting CHBr3, its relative content increased after the addition of PE-MPs. The abundances of Methylocella and Dehalococcoides, which mediate dechlorination reduction, decreased with the addition of PE-MPs. The addition of PE-MPs also significantly varied the abundance of ctrA, which controls dechlorination in soil microorganisms. The gene pceA greatly influenced CHCl3 emissions. In addition, CHBr3 flux was influenced by the interactions between sediment redox and microbial co-metabolic reactions under the control of genes such as TC.FEV.OM and soxB. This study provides theoretical and data support for the source and sink characteristics of volatile halohydrocarbons in coastal salt marshes and highlights the environmental hazards of MPs.

Petroleum pollution in soil is very damaging to the areas affected by the accidental release of petroleum hydrocarbons and has destructive impacts on natural resources and environmental health. Therefore, its monitoring and analysis are critical, however, due to the cost and time associated with chemical approaches, finding a quick and cost-effective analytical method is valuable. This study was conducted to evaluate the potential of using visible near infrared (Vis-NIR) spectroscopy to predict total petroleum hydrocarbons (TPH) in polluted soils around the Shadegan ponds, in southern Iran. One hundred soil samples showing various degrees of pollution were randomly collected from topsoil (0-10 cm). The soil samples were analyzed for TPH using Vis-NIR reflectance spectroscopy in the laboratory and then following application of preprocessing transformation, partial least squares PLS regression as well as two machine learning models including random forest (RF), and support vector machine (SVM) were examined. The results showed that the reflectance values at 1725 nm and 2311 nm, respectively, served as indicative TPH reflectance features, exhibiting weaker reflection with rising TPH. Among the preprocessing methods, the baseline correction method indicated the highest performance than the others. According to the evaluation model criteria in the validation dataset, the efficiency of the three selected models was observed in the following order SVM > RF > PLS regression. The SVM model provided the best performance in the validation dataset with r(2) = 0.85, root mean of square (RMSEP = 1.59 %, and the ratio of prediction to deviation (RPD) = 2.6. Overall, this study provided strong evidence supporting the considerable potential of Visible-NIR spectroscopy as a rapid and cost-effective technique for estimating TPH levels in oil-contaminated soils, surpassing traditional chemical analytical methods. Applying the mid-infrared spectrum (MIR) in combination with Visible-NIR data is expected to provide more comprehensive and accurate results when assessing soils in polluted areas, thereby enhancing the accuracy and reliability of the results across a diverse range of soil types.

Pollution from crude oil and its derivatives poses a serious threat to human health and ecosystems, with accidental spills causing substantial damage. Biodegradation, using microorganisms to break down these contaminants, presents a promising and cost-effective solution. Exploring and utilizing new bacterial strains from underexplored habitats could improve remediation efforts at contaminated sites. This study aimed to evaluate the hydrocarbon biodegradation capacity of bacteria isolated from agricultural soils in Huamachuco, Peru. Soil samples from Oca crops were collected and bacteria were isolated. Biodegradation assays were conducted using diesel as the sole carbon source in the Bushnell Haas Mineral medium. Molecular characterization of the 16S rRNA gene identified four strains. Diesel biodegradation assays at 1% concentration were performed under agitation conditions at 150 rpm and 30 degrees C, and monitored on day 10 by measuring cellular biomass (OD600), with hydrocarbons analyzed by gas chromatography. The results showed Pseudomonas protegens (PROM2) achieved the highest efficiency in removing total hydrocarbons (91.5 +/- 0.7%). Additionally, Pseudomonas citri PROM3 and Acinetobacter guillouiae ClyRoM5 also demonstrated high capacity in removing several individual hydrocarbons. Indigenous bacteria from uncontaminated agricultural soils present a high potential for hydrocarbon bioremediation, offering an ecological and effective solution for soil decontamination.

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants that pose significant environmental and health risks. These compounds originate from both natural phenomena, such as volcanic activity and wildfires, and anthropogenic sources, including vehicular emissions, industrial processes, and fossil fuel combustion. Their classification as carcinogenic, mutagenic, and teratogenic substances link them to various cancers and health disorders. PAHs are categorized into low-molecular-weight (LMW) and high-molecular-weight (HMW) groups, with HMW PAHs exhibiting greater resistance to degradation and a tendency to accumulate in sediments and biological tissues. Soil serves as a primary reservoir for PAHs, particularly in areas of high emissions, creating substantial risks through ingestion, dermal contact, and inhalation. Coastal and aquatic ecosystems are especially vulnerable due to concentrated human activities, with PAH persistence disrupting microbial communities, inhibiting plant growth, and altering ecosystem functions, potentially leading to biodiversity loss. In plants, PAH contamination manifests as a form of abiotic stress, inducing oxidative stress, cellular damage, and growth inhibition. Plants respond by activating antioxidant defenses and stress-related pathways. A notable aspect of plant defense mechanisms involves plant-derived extracellular vesicles (PDEVs), which are membrane-bound nanoparticles released by plant cells. These PDEVs play a crucial role in enhancing plant resistance to PAHs by facilitating intercellular communication and coordinating defense responses. The interaction between PAHs and PDEVs, while not fully elucidated, suggests a complex interplay of cellular defense mechanisms. PDEVs may contribute to PAH detoxification through pollutant sequestration or by delivering enzymes capable of PAH degradation. Studying PDEVs provides valuable insights into plant stress resilience mechanisms and offers potential new strategies for mitigating PAH-induced stress in plants and ecosystems.

The distribution of integral indicators of the soil-plant system components contamination with polycyclic aromatic hydrocarbons in the urban area has been considered. An anthropogenically modified natural complex of the RUDN University campus and the adjacent South-Western Forest Park (Moscow) was the object of study. Soils (Albic Retisols (Ochric)) and common plant species were studied. Traffic load was the main pollution source. Emissions from five sections of roads, around and across the territory, formed a specific pattern of pollutants, which was demonstrated by the example of marker compounds, namely, polycyclic aromatic hydrocarbons. Background concentrations of individual polyarenes in the environment, determined by the method of dynamic phase portraits, have been calculated as an approximate safe level of contamination of soils and vegetation. A local redistribution of contamination zones was revealed owing to the migration of polyarenes from snow into soils, and then into root systems, and the above-ground parts of plants distribution. The proposed methodological approach, based on the use of integral indicators, allows us to assess the degree of damage to ecosystems caused by a complex of priority pollutants.

Kerosene is widely used in various types of anthropogenic activities. Its environmental safety is mainly discussed in the context of aerospace activities. At all stages of its life cycle, aerospace activity impacts the environment. In aviation, the pollution of atmospheric air and terrestrial ecosystems is caused, first of all, by jet fuel and the products of its incomplete combustion and is technologically specified for a number of models in the case of fuel leak during an emergency landing. In the rocket and space activities, jet fuel enters terrestrial ecosystems as a result of fuel spills from engines and fuel tanks at the crash sites of the first stages of launch vehicles. The jet fuel from the second and third stages of launch vehicles does not enter terrestrial ecosystems. The fuel components have been studied in sufficient detail. However, the papers with representative data sets and their statistical processing not only for the kerosene content, but also for the total petroleum hydrocarbons in the soils affected by aerospace activity are almost absent. Nevertheless, the available data and results of mathematical modeling allow us to assert that an acceptable level of hydrocarbons, not exceeding the assimilation potential, enters terrestrial ecosystems during a regular aerospace activity. Thus, the incoming amount of jet fuel disappears rapidly enough without causing any irreversible damage.