Search Results (202)

The primary factor in the formation of polycyclic aromatic hydrocarbons (PAHs) in diesel engines, which pose environmental and health risks, is the chemical composition of the diesel fuel. Higher-carbon alcohols have emerged as promising oxygenated blending components for compression ignition engines due to their potential to improve combustion and reduce harmful emissions. However, limited data exist regarding their impact on PAH formation and toxicity characteristics. This study investigates the effects of 15% (v/v) n-propanol, n-butanol, and n-pentanol blends with petroleum diesel (D) and waste cooking oil biodiesel (B) on total PAH emissions, PAH dispersion, and toxicity in a diesel engine under steady-state conditions. Total PAH concentrations and individual species distributions were quantified, and toxicity was evaluated using toxicity equivalency factor (TEF) methodology. Results indicate that the addition of higher alcohols significantly reduces total PAH emissions compared to the respective base fuels. A marked decrease in high-molecular-weight (4–6 ring) PAH compounds was observed, suggesting suppression of heavy PAH formation pathways. Toxicity-weighted PAH emissions also decreased with alcohol blending. Furthermore, total PAH concentrations for all tested blends remained below the Occupational Safety and Health Administration (OSHA) permissible exposure limit (PEL = 0.2 mg/m³) under the examined operating conditions. These findings demonstrate that 15% higher alcohol blends are effective in mitigating PAH emissions without adverse environmental health implications. Full article

Micro- and nanoplastics (MNPs) have emerged as pervasive contaminants in aquatic ecosystems, raising concerns regarding their biological impacts on aquatic organisms. The liver plays a central role in metabolism, detoxification, and immune regulation, making it particularly vulnerable to MNP-induced toxicity. Importantly, MNPs also function as vectors and modulators of co-occurring environmental contaminants, including heavy metals, pesticides, antibiotics, PFASs, algal toxins, and polycyclic aromatic hydrocarbons (PAHs), thereby influencing contaminant bioavailability and hepatic toxicity. This narrative review synthesizes current evidence on hepatic alterations induced by micro- and nanoplastic exposure in zebrafish (Danio rerio), with emphasis on histopathological changes and underlying mechanisms. Relevant peer-reviewed studies were identified through systematic searches of Web of Science, Scopus, PubMed, and ScienceDirect, covering the period 2013–2026, and screened according to predefined inclusion criteria focusing on hepatic endpoints in zebrafish exposed to micro- and nanoplastics. Across the available literature, MNPs consistently accumulate in hepatic tissue and induce structural alterations, including hepatocellular vacuolization, steatosis, inflammatory infiltration, and necrosis. Mechanistically, these pathological changes are closely linked to oxidative stress, impairment of antioxidant defense systems, reprogramming of lipid and glucose metabolism, and activation of inflammatory and regulated cell death signaling pathways. In addition, interactions with co-occurring environmental contaminants—such as heavy metals, pesticides, antibiotics, and algal toxins—frequently exacerbate hepatic injury through synergistic toxicological mechanisms. Disruption of the gut–liver axis and intestinal microbiota has also emerged as an important contributor to systemic metabolic and inflammatory responses. Overall, zebrafish studies demonstrate that the liver represents a critical target organ for MNP toxicity. Future research should prioritize environmentally realistic exposure scenarios, standardized particle characterization, and integrated multi-omics approaches to improve ecological and human health risk assessment. Full article

Polycyclic aromatic hydrocarbons (PAHs)-contaminated soils are often concomitantly polluted with heavy metals, which form combined contamination through cation–π interactions and other mechanisms. However, the mechanism by which bacteria degrade PAHs under combined pollution conditions remains insufficiently studied. In this study, a benzo[a]pyrene (BaP)-degrading bacterial strain, Rhodococcus sp. PDS1, was isolated from the co-contaminated soil of an abandoned coking plant in a steel factory. This strain can not only detoxify arsenic via reductive transformation, but also mediate extracellular arsenic oxidation and efficiently degrade BaP, a high-molecular-weight (HMW) polycyclic aromatic hydrocarbon with low bioavailability and high toxicity. Response surface methodology (RSM) experiments were conducted to optimize the degrading conditions of strain PDS1, considering four factors: pH, temperature, BaP concentration, and trivalent arsenic As(III) concentration. The results showed that the BaP removal by PDS1 would reach 93.59% under the RSM-obtained optimal conditions: pH 7.7, BaP concentration 8.96 mg/L, As(III) concentration 0.82 mM, and culture temperature 36.0 °C. The transcriptome of the strain under the combined stress of arsenic and BaP was further analyzed. The results indicated that the introduction of arsenic induced the upregulated expression of different genes in the arsenic detoxification ars operon and the pcaH/G gene (encoding protocatechuate 3,4-dioxygenase, a key enzyme in BaP degradation) to varying degrees. These findings clarify the mechanism of the degradation of HMW-PAHs such as BaP by strain PDS1 under PAHs–arsenic combined pollution, lay a solid theoretical foundation for subsequent practical applications, and demonstrate the broad prospects of strain PDS1 in the remediation of actual complex contaminated soils. Full article

Unpolluted water, both freshwater and saltwater, is essential for achieving several United Nations Sustainable Development Goals, particularly SDGs 6, 3, 2, 14, and 15. This study maps emerging water-quality monitoring technologies at intermediate technological readiness levels (TRLs 4–5) and their potential patent markets (TRL 9). A total of 40,469 patent families were retrieved from the Espacenet worldwide database using IPC G01N33/18 and used to analyze sensing parameters. A subset of 2146 water-pollution-related patents was analyzed in detail. The analysis covered sensing parameters, temporal trends, compound annual growth rates (CAGR), legal status, geographic distribution of patent origins and markets, and the technological landscape, including application domains and niche clusters. The results show pronounced exponential growth in patent filings since 2014 and a high share of active documents, indicating sustained global investment. Innovation leadership is concentrated in China, South Korea, India, the United States, and Japan, with export-oriented patents largely held by transnational corporations, while African participation remains limited. Technological trends prioritize multiparameter environmental and biological sensing, addressing pH, temperature, turbidity, dissolved oxygen, nutrients, heavy metals, polycyclic aromatic hydrocarbons (PAHs), and oxidation–reduction potential. Emerging solutions integrate autonomous platforms, remote sensing, Internet-of-Things architectures, and machine-learning-based analytics. Persistent bottlenecks include sensor robustness in harsh aquatic environments and the reliable discrimination between background variability and early pollution signals. Strengthening low-cost and scalable deployment remains essential to ensure water quality, support environmental sustainability, and minimize risks. Full article

Steroid hormones (SHs) have a high estrogenic potential, and urban wastewater is one of their main ways into the aquatic environment. Constructed wetlands (CWs) are considered one of the most sustainable alternatives for the treatment of wastewater from small communities. However, the use of gravel and sand implies a significant environmental impact associated with their extraction and transport. A more sustainable alternative is the use of plant residues, as they are abundant, inexpensive, and readily available, and they can improve the efficiency of hormone removal through sorption. Thus, the sorption of 15 SHs was studied on conventional, mineral substrates (gravel, sand, and volcanic ash) and alternative vegetal wastes, i.e., mulches from giant reed, palm tree, balsa wood, and pine needles. These materials were characterized by determining their Point of Zero Charge (pH_PZC), ash content, content of leachable polycyclic aromatic hydrocarbons (PAH) and heavy metals, total surface area (BET), and pore characteristics. Results indicated that SH sorption on the mineral substrates was quite low, in most cases less than 10–15%. However, in the mulches it reached between 50 and 95%, except for corticosteroids (11–43%). The pseudo-second-order kinetics provided the best fit in all cases, with R² values between 0.97 and 0.9999. Experiments with a contact time of 7 days showed that the palm tree was the only substrate that completely removed the three corticosteroids studied (cortisone, prednisone, and prednisolone). Additionally, a significant correlation was observed between removal due to sorption (%) and log octanol–water partition coefficient (log Kow). Freundlich isotherm provided a higher number of best fits than Langmuir. Lastly, to compare sand with palm mulch under more realistic experimental conditions, four lab-scale CWs (two with palm mulch and two with sand, with/without plants) were studied. The sand-based CWs achieved faster SH percentage removals, while after 24 h, SH mass removals were significantly higher in the palm mulch-based CWs. Full article

The Black Sea is highly vulnerable to environmental degradation, making the evaluation of contaminant transfer within its food webs essential for ecosystem protection, sustainable resource management, and human health risk assessment. Marine organisms accumulate contaminants through three main processes: bioconcentration (direct uptake from the abiotic environment), biomagnification (trophic transfer through consumption of contaminated prey), and bioaccumulation, which integrates contaminants from all exposure pathways. Despite numerous studies reporting contaminant concentrations in Black Sea waters, sediments, and biota, integrated analyses of trophic transfer within both pelagic and benthic food webs in the Romanian coastal sector remain limited. This study assessed the bioamplification of heavy metals—HMs, persistent organic pollutants—POPs (OCPs, PCBs) and polycyclic aromatic hydrocarbons—PAHs along the main pelagic and benthic food webs in the Romanian coastal sector, based on concentrations measured in representative invertebrate and fish species. The results revealed a compartment-driven contamination pattern, with the benthic food web functioning as an important reservoir and transfer pathway. Heavy metals showed variable and context-dependent trophic transfer, with selective amplification for Cu and Ni in some benthic links, trophic dilution or neutral transfer for Cd and Pb, and more consistent retention for Cr. In contrast, several PCB congeners showed clear biomagnification, particularly in benthic predator–prey relationships. PAHs displayed compound-dependent trophic transfer, with more pronounced amplification in benthic pathways. Overall, biomagnification was stronger for organic pollutants, particularly PCBs, than for heavy metals. The study contributes to two United Nations Sustainable Development Goals (SDGs): SDG 14 (Life Below Water) and SDG 12 (Responsible Consumption and Production). Full article

This study explores the physicochemical properties and microbiological community structure of oil-contaminated soils from Midrand and Roodepoort, South Africa. Due to sample pooling, the analysis provides a composite profile for investigating site-specific microbial adaptations rather than replicated ecological inference. The soils of Midrand exhibited acidity (pH around 5.5–5.9), elevated levels of heavy metals (e.g., Zn exceeding 1000 mg/kg), and the presence of 5–6 ring polycyclic aromatic hydrocarbons (PAHs). The soils in Roodepoort exhibited a near-neutral pH (about 6.2–7.2), characterized by specific metal concentrations (e.g., Cr exceeding 150 mg/kg) and an elevated presence of four-ring polycyclic aromatic hydrocarbons (PAHs). Metagenomic analysis indicated distinct microbial communities: Pseudomonas spp. were prevalent in Midrand, while Bacillus spp. were dominant in Roodepoort. Correlation analysis suggested connections between pollutants and microbial taxa; however, these findings are tentative. Recovered metagenome-assembled genomes (MAGs) indicated genetic potential for polycyclic aromatic hydrocarbon (PAH) degradation in Midrand and for metal resistance in Roodepoort. The findings suggest that localised pollution profiles are associated with unique microbial community structures and genetic potentials, providing a genomic basis for proposing site-specific bioremediation strategies. The research underscores the necessity for measures that take into account pollutant composition, soil pH, and microbial adaptation. Full article

Petroleum contamination significantly impacts soil microbial communities and vegetation; however, the long-term effectiveness of phytoremediation remains poorly understood. This study evaluated soil microbiological activity, polycyclic aromatic hydrocarbon (PAH) concentrations, and physiological responses five years after the remediation of a petroleum spill site in central Poland. Following a pipeline failure in June 2020 that released diesel fuel and gasoline into the riparian habitat, the contaminated area underwent remediation using Urtica dioica L. as the primary phytoremediator. Soil samples from five plots along a contamination gradient were analyzed for microbial abundance (total bacteria, fungi, fluorescent Pseudomonas sp.), PAH fractions (C6–C12, C13–C16, C17–C35), and physicochemical properties. Chlorophyll fluorescence (JIP test) on two species was used to assess plant photosynthetic efficiency. Results revealed that successful PAH degradation required high fungal abundance rather than optimal soil fertility. Plots with 8–9-fold higher fungal populations achieved 69–81% reduction in heavy PAHs (C17–C35), while the Control plot, despite superior physicochemical properties, maintained high contamination due to low fungal colonization. Urtica dioica exhibited exceptional tolerance (stable maximum quantum yield of PSII (Fv/Fm) and elevated photosynthetic performance index (PIabs)) across all contamination levels, whereas Poa trivialis L. showed significant stress responses. The principal component analysis confirmed that soil texture influences fungal establishment, with sandy soils favoring aerobic degradation despite lower nutrient retention. These findings demonstrate that phytoremediation success depends critically on fungal-mediated biodegradation rather than baseline soil quality alone. Full article

Riparian soils co-contaminated with heavy metals and organic pollutants present a formidable environmental challenge; conventional single-target remediation strategies are frequently insufficient due to the synergistic interactions between contaminant classes. This review offers a systematic synthesis of phytoremediation as an integrative and ecologically sustainable paradigm for addressing these complex multi-pollutant scenarios. Through a critical examination of underlying mechanisms—namely phytoextraction, rhizodegradation, phytostabilization, and phytovolatilization—we evaluate the efficacy of selected hyperaccumulator and pollution-tolerant species in simultaneously mitigating inorganic (e.g., Pb, Cd, As) and organic (e.g., PAHs, pesticides) contaminants. Furthermore, the discussion highlights emerging strategic integrations, including genetic engineering for enhanced metal accumulation, the application of engineered nanomaterials to modulate pollutant bioavailability and plant stress tolerance, rhizosphere amendment with low-molecular-weight organic acids, and biochar-mediated immobilization coupled with microbial stimulation. The analysis posits that phytoremediation, particularly when augmented by these advanced synergies, constitutes a viable, multifunctional, and environmentally benign strategy for the holistic restoration of riparian ecosystems. Future inquiries should prioritize the mechanistic elucidation of combined technologies, the development of predictive performance models, and rigorous long-term field validation to guarantee operational efficacy and environmental safety. Full article

The main objective of this research was to evaluate the seasonal variability of PM₁₀-bound polycyclic aromatic hydrocarbons (PAHs), their sources, and analyse their health impacts We confirmduring the COVID-19 pandemic period. The chemical composition of PM₁₀ in terms of PAH content was carried out using the gas chromatography-mass spectrometry (GC-MS) technique. PM₁₀ samples were collected in Krakow from 2020 to 2021. A total of 92 samples of particulate matter (PM₁₀ fraction) were analysed. The analyses contained 16 basic PAHs identified by the United States Environmental Protection Agency (U.S. EPA) as the most harmful. The information obtained on the concentrations of PAHs was used to determine the profiles of pollution sources, exposure profiles, and the values of toxic equivalency factors recommended by the EPA: mutagenic equivalent to B[a]P (ang. mutagenic equivalent, MEQ), toxic equivalent to B[a]P (ang. toxic equivalent, TEQ), and carcinogenic equivalent to 2,3,7,8-tetrachlorodibenzo-p-dioxin (ang. carcinogenic equivalent, CEQ). In Kraków, heavy PAHs accounted for over 90% of the total PAHs detected in the PM₁₀ samples. In addition, air trajectory frequency analysis was performed to obtain information on the possibility of transporting pollutants from selected areas in the vicinity of the studied site. Interpreting the trajectory results provided information on the nature of air pollution sources. Analysis of Kraków’s air mass trajectory showed that the highest daily concentration of PM₁₀ in the air flow was from the southwest and east for days. Full article

Floods and wildfires are two extreme environmental events with significant yet different impacts on soil health and on two particularly important soil pollutants, heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs), which are directly associated with ishytoxic properties and their ability to enter the food chain. The present study includes a methodological approach that was based on a literature review of published studies conducted worldwide regarding these two phenomena. The main forms of both pollutants, their possible sources and inevitable deposition onto the soil surface, along with their behavior–transport–mobility, and their residence time in soil were investigated. Furthermore, the changes that both HMs and PAHs induce in the physicochemical properties of post-flood and post-fire soils (in soil pH, Cation Exchange Capacity (CEC), organic matter content, porosity, mineralogical alterations, etc.), are investigated after a literature review of various case studies. Wildfires, in contrast to floods, can more easily remove large quantities of heavy metals into the soil ecosystem, most likely due to the intense erosion they cause. At the same time, floods appear to significantly burden soils with PAHs. In wildfires, the largest mean increases were observed for Mn (386%), Zn (300%), and Cu (202%). In floods, Pb showed the highest mean increase (534%), with Cd also rising substantially (236%). Regarding total PAHs, mean post-event concentrations reached 482.3 μg/kg after wildfires, compared to 4384 μg/kg after floods. Changes in the structure and chemical composition of flooded and burned soils may also affect the mobility and bioavailability of the pollutants under study. Overall, these two phenomena significantly alter soil quality, affecting both ecological processes and potential health impacts. Full article

The production and use of Li-ion batteries (LIBs) is steadily increasing each year, leading to a growing number of battery-powered products. Consequently, the number of chemical hazards associated with the operation and other stages of the life cycle of this type of cell is increasing as well. Therefore, this study examined the impact of selected extinguishing agents for extinguishing Li-ion battery fires—namely, a dedicated extinguishing granulate, a natural sorbent (exfoliated vermiculite), and quartz sand—on the level of heat and released substances. The study determined the emission of heavy metals and polycyclic aromatic hydrocarbons (PAH) into the air during a cell fire, the concentration of the inhalable aerosol fraction, and the concentration of hazardous substances in the extinguishing agent residue. The analysis concluded that quartz sand provides the most effective heat removal and insulation of the battery from the external environment, which also reduces the amount of pollutants released into the environment. Full article

As China’s industrialization progresses, the transformation of site properties across various regions has become increasingly common. Concurrently, with the relocation and market exit of some enterprises, the land occupied by the original factory sites has been developed for other uses. This study provides a comprehensive evaluation of soil and groundwater contamination levels and the associated ecological and health risks in abandoned industrial lands. The investigation focused on analyzing heavy metal and polycyclic aromatic hydrocarbon (PAH) contamination using various assessment methods, including the single-factor pollution index, Nemerow composite pollution index, and potential ecological risk index. These methods were used to assess the contamination levels of 11 heavy metals in both soil and groundwater. Additionally, health risk assessments for PAHs were conducted using the Incremental Lifetime Cancer Risk (ILCR) and Carcinogenic Risk (CR) models, considering both direct and indirect exposure pathways. The results indicated that the average concentration of each heavy metal in the soil did not exceed the screening thresholds, with all Nemerow index values falling below 1, suggesting that the site is not significantly polluted. Ecological risk assessment further revealed that most heavy metals posed minor risks, while some localized areas showed slight enrichment. Health risk assessments for PAHs indicated that, although the risks for both adults and children were within acceptable limits, the ingestion pathway for children showed a slightly higher risk compared to adults. The groundwater quality met Class IV standards, indicating no significant pollution. These findings provide data support and reference for future land-use planning, environmental management, and remediation strategies for abandoned industrial sites. Full article

The increasing presence of microplastics (MPs) in terrestrial ecosystems, particularly when combined with organic pollutants and heavy metals, presents a considerable environmental challenge. This review examines the intricate interactions between MPs, co-contaminants (both organic and inorganic), and plants involved in phytoremediation processes. A literature search was performed across the databases Scopus, ScienceDirect, and Google Scholar, covering the timeframe from 2015 to 2025. The studies selected specifically addressed the synergistic and antagonistic effects of microplastics in conjunction with heavy metals or organic pollutants (such as PAHs and pesticides) within plant–soil systems. The findings reveal that MPs influence pollutant mobility, bioavailability, and toxicity through adsorption and desorption mechanisms, leading to varied implications for plant growth, microbial communities, and contaminant uptake. Depending on the physicochemical characteristics of MPs and co-pollutants, the effects can range from increased phytotoxicity to diminished contaminant accumulation in plants. Additionally, physiological and molecular disruptions, including oxidative stress, hormonal imbalances, and impaired enzymatic activity, were frequently noted in co-contamination scenarios. Recent developments, such as the creation of genetically modified hyperaccumulator plants and the use of nanotechnology and microbial consortia, demonstrate potential to enhance phytoremediation efficiency in complex polluted soils. This review underscores the pressing need for integrated, multidisciplinary strategies to overcome the limitations of existing phytoremediation methods in co-contaminated environments. Future research should focus on standardized methodologies, a mechanistic understanding, and the safe implementation of emerging biotechnologies for sustainable soil remediation. Full article

The presence of vanadium compounds in heavy oils poses a significant challenge by poisoning and deactivating refining catalysts, making their removal an essential processing step. However, this process is challenged by the competitive adsorption of abundant polycyclic aromatic hydrocarbons (PAHs) in heavy oils, due to the similar conjugated π-electron structure of PAHs and vanadyl porphyrins. In the presented study, the adsorption behaviors of vanadyl octaethylporphyrin (VOOEP) and 1-methylpyrene (1-MP) on various solid adsorbents were investigated. Among the adsorbents studied, the primary secondary amine adsorbent (PSA) demonstrated superior performance, achieving high VOOEP adsorption capacity and exceptional selectivity, even in the presence of a large excess of 1-MP. The adsorption kinetics, isotherms, and thermodynamics of VOOEP and 1-MP onto PSA were studied. Four common kinetic models (pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion) were used for data fitting. The adsorption isotherms were modeled using Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherms. The adsorption kinetics for both VOOEP and 1-MP on PSA were best described by the pseudo-second-order model, while equilibrium data were well fitted by the Freundlich isotherm. Thermodynamic analysis confirmed that the adsorption of VOOEP and 1-MP on PSA is a spontaneous and exothermic process. The practical applicability of PSA was confirmed with a heavy deasphalted oil (HDAO), where it efficiently removed vanadium with high selectivity, with lower co-adsorption of desirable oil components. The results indicate that PSA is a promising adsorbent for effectively removing vanadium compounds from heavy oils. Full article