Carcinogenic Polycyclic Aromatic Hydrocarbons Research Articles

Distribution of polycyclic aromatic hydrocarbons and carcinogenic risk assessment in street-barbecued foods in China

Street-barbecued foods, despite their popularity, produce carcinogenic polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]anthracene (BaA), chrysene (Chr), benzo[b]fluoranthene (BbF), benzo[a]pyrene (BaP) due to incomplete charcoal combustion, direct food-fuel contact, and excessive heating. This study analyzed barbecued foods from high-traffic street vendors using high-performance liquid chromatography. Among five food categories (meat, vegetable, aquatic, starch, and soy products), eight foods exceeded China’s BaP limit (5 µg/kg) and twelve exceeded the EU limit (2 µg/kg). The highest BaP and PAH4 levels were found in barbecued beef and pork belly, respectively. Chr levels were notably high due to open flame exposure. Health risk assessments indicated fourteen foods posed elevated carcinogenic risks. This study highlights the necessity of consumption control to mitigate these risks and provides evidence for improving street food safety and dietary security.

Chemical Fingerprinting, PAHs Characterization and Ecological Risks of Carcinogenic PAHs in Surficial Sediments of Egi Crude Oil Producing Communities, Niger-Delta, Nigeria

In order to do PAHs rings analysis, its source identification, extent to which cPAHs present and what kind of ecological risk they pose, the surface sediments from various freshwaters in the Egi crude oil producing cities in the Niger Delta, Nigeria were analyzed. Sediments collected from the research areas for PAHs loadings (in mg/kg dry weight) ranged from 0.020 to 1.790, 0.050 to 1.880, and 0.020 to 1.640, respectively for Obite, Obagi, and Ibewa cluster areas, as measured by gas chromatography-mass spectrometer. In these clusters, the respective average concentration of the three dominant carcinogenic PAHs were Indeno(1,2,3-cd)pyrene (1.170.0mg/kg), Dibenz[a,h]anthrancene (0.870.0 mg/kg), and Dibenz[a,h]anthrancene (1.3670 mg/kg) for Ibewa, Obagi and Obite cluster areas. The findings showed that dominant PAHs rings are of high molecular weight (HMW) PAHs in these sediments are, 5 member rings, which are benzo(b)fluoranthene, Benzo(k)fluoranthene, and Benzo(a)pyrène, and 6-member ring which are, Indeno(1,2,3-cd)pyrene, Dibenz[a,h]anthrancene, and Benzo[ghi] perylene, respectively. Their fingerprints points majorly to pyrogenic sources, combustion of coal, biomass, petroleum, and other related anthropogenic petroleum activities as the primary source of PAHs in the environment. Notably, the RQNCs and RQMPCs for single PAHs molecule are both less than 1, it means the contamination it generates is considered of low ecological risk. Again, the research area experiences frequent flooding, it is believed that this contributes to the low ecological risk of PAHs chemical pollution. Consequently, the area is deemed to be quite safe.

Toxic effect of polycyclic aromatic hydrocarbons (PAHs) on co-culture model of human alveolar epithelial cells (A549) and macrophages (THP-1)

Polycyclic aromatic hydrocarbons (PAHs) are particulate matter bound environmental contaminants known to cause adverse effects on human health. The toxicity of carcinogenic PAH such as benzo[a]pyrene (BaP) has been extensively investigated, whereas other PAHs have received less attention. The present work investigated the toxic effects of three less investigated PAHs with distinct molecular weights in comparison to BaP on co-culture model of human epithelial lung cells (A549) and macrophages (THP-1). Due to the involvement of more than one cell type in the response to PAH exposure, the new co-culture model is considered to be suitable for the prediction of undesired toxicological effects of PAHs. To do so, the co-culture was established and exposed to 0–400 µM of phenanthrene (PHE), fluoranthene (FLA), and, benzo [ghi] perylene (BghiP) for 24 h. Subsequently, cytotoxicity, micronucleus formation, and cytokine excretion were analyzed. The results revealed that the viability of A549 cells decreased after being exposed to increasing concentrations of PAHs. The formation of micronuclei in binucleated cells (BNC) was found more frequently in cells treated with PAHs in comparison to the untreated group, indicating the genotoxic effect of these compounds. Moreover, an exposure to PAHs enhanced the pro-inflammatory cytokine, i.e., interleukin-6 secretion, while diminished the anti-inflammatory cytokine, i.e., interleukin-10. In summary, PAHs possess negative effects on A549 and THP-1 co-culture model, implying an adverse effect on human health when coming into contact with these chemicals via respiration.

The key results of studies of benzo(a)pyrene in natural and man-made environments of the Southern Baikal region (2016–2024)

The study aims to provide a retrospective review of the results of studies of benz(a)pyrene in the natural and man-made environments of the Southern Baikal region. The study was conducted with staff, students, and postgraduates at the Department of Industrial Ecology and Railways of the Institute of Subsoil Use of Irkutsk National Research Technical University in 2016-2024. The article is devoted to the 75th anniversary of the department. The atmospheric air in the cities of Irkutsk and Krasnoyarsk regions was assessed based on the results of monitoring of the content of benzо(a)pyrene. Its carcinogenic risks to public health were determined. The results of the systematic study of the sources of emissions into the atmosphere of benzо(a)pyrene and its analogues of polycyclic aromatic hydrocarbons were analyzed. Anthropogenic and man-made (aluminum production, low-power heat sources, highways) and natural (forest fires) sources of benzо(a)pyrene release were identified by assessing its mass load. The indicators of sources of atmospheric pollution - snow cover, soils, plants - were identified. Correlations between atmospheric air pollution and health (neoplasms) of the Irkutsk region population were determined found. The distribution of benzо(a)pyrene in the systems of conjugated objects of the biosphere was studied: “source of emissions - atmospheric air - snow cover”, “soil - plant”, “water - hydrobionts”. Patterns indicating a new source of atmospheric pollution with carcinogenic polycyclic aromatic hydrocarbons - natural fires, which can affect the morbidity of the population of the Southern Baikal region - were obtained.

COVID-19 lockdown measures affect polycyclic aromatic hydrocarbons distribution and sources in sediments of Chaohu Lake, China

The COVID-19 pandemic has profoundly impacted human activities and the environment globally. The lockdown measures have led to significant changes in industrial activities, transportation, and human behavior. This study investigates how the lockdown measures influenced the distribution of polycyclic aromatic hydrocarbons (PAHs) in the sediments of Chaohu Lake, a semi-enclosed lake. Surface sediment samples were collected in summer of 2020 (lockdown have just been lifted) and 2022 and analyzed for 16 priority PAHs. The range of ΣPAHs concentrations remained similar between 2020 (158.19–1693.64 ng·g−1) and 2022 (148.86–1396.54 ng·g−1). Among the sampling sites, the west lake exhibited similar PAHs concentrations characteristics over the two years, with higher levels observed in areas near Hefei City. However, the east lake exhibited increased ΣPAHs concentrations in 2022 compared to 2020, especially the area near ship factory. PAHs source analysis using principal component analysis-multiple linear regression (PCA-MLR) revealed an increased proportion of petroleum combustion sources in 2022 compared to 2020. The isotope analysis results showed that organic matter (OM) sources in the western lake remained relatively stable over the two years, with sewage discharge dominating. In contrast, the eastern lake experienced a shift in OM sources from sewage to C3 plants, potentially contributing to the increased PAH levels observed in the eastern lake sediments. Ecological risk assessment revealed low to moderate risk in both 2020 and 2022. Health risk evaluation indicated little difference in incremental lifetime cancer risk (ILCR) values between the two years, with only benzo[a]pyrene (BaP) posing a high risk among the carcinogenic PAHs. Children generally faced higher health risks compared to adults. This study reveals pandemic-induced changes in PAH pollution and sources in lake sediments, offering new insights into the impact of human activities on persistent organic pollutants, with implications for future pollution control strategies.

Meta-analysis identifies key genes and pathways implicated in Benzo[a]pyrene exposure response

IntroductionBenzo[a]pyrene (B[a]P) is a carcinogenic polycyclic aromatic hydrocarbon that poses significant risks to human health. B[a]P influences cellular processes via intricate interactions; however, a comprehensive understanding of B[a]P's effects on the transcriptome remains elusive. This study aimed to conduct a comprehensive analysis focused on identifying relevant genes and signaling pathways affected by B[a]P exposure and their impact on human gene expression. MethodsWe searched the Gene Expression Omnibus database and identified four studies involving B[a]P exposure in human cells (T lymphocytes, hepatocellular carcinoma cells, and C3A cells). We utilized two approaches for differential expression analysis: the LIMMA package and linear regression. A meta-analysis was utilized to combine log fold changes (FC) and p-values from the identified studies using a random effects model. We identified significant genes at a Bonferroni-adjusted significance level of 0.05 and determined overlapping genes across datasets. Pathway enrichment analysis elucidated key cellular processes modulated by B[a]P exposure. ResultsThe meta-analysis revealed significant upregulation of CYP1B1 (log FC = 1.15, 95% CI: 0.51–1.79, P < 0.05, I2 = 82%) and ASB2 (log FC = 0.44, 95% CI: 0.20–0.67, P < 0.05, I2 = 40%) in response to B[a]P exposure. Pathway analyses identified 26 significantly regulated pathways, with the top including Aryl Hydrocarbon Receptor Signaling (P = 0.00214) and Xenobiotic Metabolism Signaling (P = 0.00550). Key genes CYP1A1, CYP1B1, and CDKN1A were implicated in multiple pathways, highlighting their roles in xenobiotic metabolism, oxidative stress response, and cell cycle regulation. ConclusionThe results provided insights into the mechanisms of B[a]P toxicity, highlighting CYP1B1's key role in B[a]P bioactivation. The findings underscored the complexity of B[a]P's mechanisms of action and their potential implications for human health. The identified genes and pathways provided a foundation for further exploration and enhanced our understanding of the multifaceted biological activities associated with B[a]P exposure.

Dual biomarker traceability and ecological risk assessment of centennial organic contamination in South Dongting Lake

Enhanced anthropogenic activity strength has altered the watershed particulate transport and material cycle resulting in organic pollutant deposition changes in Dongting Lake associated with unclear ecological risk. In the present study, dual biomarkers i.e. n-alkanes and polycyclic aromatic hydrocarbon (PAHs) were applied in the 210Pb-dated sediment cores for traceability of centennial organic pollutants in the lake mouth area. The partial least squares path model and risk quotients method were used to explore the controlling pathways and ecological risk. The results show a range of sedimentary organic carbon (C), nitrogen (N), and phosphorus (P) was at 1.76–185.66, 0.97–89.80, and 0.01–0.97 g m−2 yr−1 with total reserves of 51.68, 18.44, and 0.27 t ha−1, respectively, over the past 179 years. The presence of PAHs rapidly increased by 2.47 fold from 535.60 ng g−1, while PAHs and carcinogenic PAHs (ΣCPAHs) burial fluxes increased by about 6 and 5 folds, respectively. Accompanied by anthropogenic activities and climate change, the exotic sources gradually becoming predominant. The n-alkane diagnostic ratios indicated a shift of organic matter (OM) from autotrophic bacteria, algae, and phytoplankton-derived sources to macrophyte and terrestrial plants. The exotic origins rose to approximately 73.61 %, while endogenous sources decreased to 26.39 %. The direct effects of anthropogenic activities and their indirect negative impacts on climate and sedimentary structure are the key ways for sediment material loading. The nutrient accumulation in sediments coincides with the lake's eutrophication history over the past decades. The ΣCPAHs accounted for about 89.37 ± 17.14 % of the total TEQ, reflecting a strong ecological risk. The contribution of anthropogenic activities such as fuel usage, fertilizer application, hard pavement coverage, and OM loss from the ecosystem to the sources of organic pollutants and their component types may be a focus of attention in the middle reaches of the Yangtze River plain lake.

Polycyclic aromatic hydrocarbons in ship breaking area and associated ecological risk assessment: evidence from the Sitakund ship-breaking area in Bangladesh.

Ship-breaking yards are recognized for releasing hazardous polycyclic aromatic hydrocarbons (PAHs), leading to severe environmental pollution in the sediment of ship-breaking areas. This study assessed the concentrations of 16 priority PAHs in surface sediments collected from the intertidal zone adjacent to the Sitakund ship-breaking yards. The samples underwent Soxhlet extraction and detection using PerkinElmer GC-Clarus 690 and MS-Clarus SQ8C with an Elite-5MS capillary column (30m × 0.25mm ID × 0.25µm). The study utilized PAH concentrations to reveal spatial distribution patterns, identify point sources, and assess potential toxicity. The total PAH concentration ranged from 1899.2 to 156,800.08ngg-1 dw, while the concentration of 7 carcinogenic PAHs ranged from 822.03 to 1899.15ngg-1 dw. High molecular weight PAHs dominated among the 16 PAHs, whereas low molecular weight PAHs, such as 2-ring PAHs, were negligible. Source characterization based on different molecular ratios suggested that PAHs in the area originated from pyrolytic processes related to ship dismantling, fishing activities, and water transportation for people. The observed PAH concentrations exceeded both national and international standards for sedimentary PAH levels, indicating significant ecological risks. The total TEQcarc values of sediment samples varied from 564.41 to 10,695.12ngg-1, with a mean value of 3091.25ngg-1. The study's findings underscore the immediate biological damage that PAH contamination in the Sitakund ship-breaking area could cause, emphasizing the need for effective control measures to ensure ecological and human safety.

Determination of persistent organic pollutants in urban and peri-urban wastewater sludge: environmental and carcinogenic human risk assessment in the case of land application.

The management of digested sludge derived from treatment water plants is a problem worldwide due to the possible transfer of contamination from sludge to amended soil and, in turn, to humans. Within this work, through a chemometric experimental design, a robust GC-MS method for the simultaneous determination of two classes of micropollutants of concern (polycyclic aromatic hydrocarbons-PAHs-and polychlorinated biphenyls-PCBs-including dioxin-like compounds) was developed using microwave-assisted extraction (MAE). The method, which showed interesting greenness features in compliance with the 12 principles of Green Chemistry, allowed PCB and PAH extraction with recoveries higher than 75% (RSD < 14%) with method detection limits between 4.6 and 11.5µgkg-1 (PAHs) and between 6.9 and 13.7µgkg-1 (PCBs), without preconcentration. The matrix effect was below 20%. The validated protocol allowed the characterization of two digested sludges sampled in an urban and a peri-urban district, representative models of two scenarios of different anthropic impacts. This study highlighted higher contamination for the sludge derived from the urban area, accounted for by the 4-ring PAHs. In addition, since carcinogenic PAHs were detected, the environmental risk (by mean of the comparison of predicted vs predicted no-effect concentrations) and the carcinogenic human risk from dermal contact (through the calculation of the adsorbed lifetime average daily dose) were assessed in the case of soils amended with the sludges considered, pointing out that the measured concentrations do not pose a risk.

Rapid removal of polycyclic aromatic hydrocarbons from water using sulfonated mesoporous polymeric adsorbents

Polycyclic aromatic hydrocarbons (PAHs) are potential hazards and are often found in aquatic environments through industrial effluents. Herein, we report sulfonated modified mesoporous thermoplastic polymers to remove potentially carcinogenic PAHs from water rapidly. Mesoporous structures of the thermoplastics (polystyrene, polysulfone, and polycarbonate) were attained using nano-crystallization induced phase separation by flash-freezing route. Sulfonation reactions carried out hydrophilic surface modifications of the polymers. Their ion exchange capacity (IEC) values determined the degree of sulfonation. The sulfonated mesoporous polymers were characterized using Fourier-Transform Infra-Red spectroscopy (FT-IR) for functional groups, Field-Emission Scanning Electron Microscopy (FE-SEM) for mesoporous structures, Brunauer-Emmet-Teller method for specific surface area, and Barrett-Joyner-Halenda method for pore size distributions. The IEC values for the sulfonated mesoporous polymers range from 1.13 – 1.15 × 10-2 meq. g−1. The sulfonated mesoporous polymers showed high specific surface areas (176–185 m2/g) with pore sizes ranging from 5 nm to 9 nm. The sulfonated mesoporous polymers rapidly adsorb PAHs from nearly saturated water solutions within 60 min with % removal of over 98 %. The adsorbents can also be easily regenerated by simple washing with methanol and are found to be recycled up to 10 cycles with only a marginal reduction in adsorption capacities.

Polycyclic Aromatic Hydrocarbons (PAHs) in Grilled Marshmallows.

The aim of this study was to assess potential health risks among children and adolescents consuming various grilled marshmallows using a survey and to determine polycyclic aromatic hydrocarbons (PAHs) in these food products. PAH analysis in grilled marshmallows included a dilution stage with deionized water and liquid-liquid extraction with cyclohexane and solid-phase extraction (SPE). PAH fractions were initially analyzed via high-performance thin-layer chromatography, and PAH concentrations were determined via gas chromatography with a tandem mass detector using the selective reaction monitoring (SRM) mode. This study on the consumption of grilled marshmallows was conducted among approximately 300 children and adolescents. The preliminary results indicated that "raw" marshmallows did not contain PAHs. However, the obtained data suggested the exposure of young people to carcinogenic PAHs from grilled marshmallows (63.5% of them consumed marshmallows). Carcinogenic benzo(a)pyrene (BaP) was determined in all samples. The profile of PAH concentrations in the extracts isolated from various grilled types of marshmallows was similar (r2 > 0.8000), regardless of the grilling method. Compared to the white sugar confection, higher concentrations of PAHs were determined in multicolored marshmallows. The lack of social awareness about exposure to carcinogenic substances is alarming.

Assessment of polycyclic aromatic hydrocarbon (PAH) profiles in heat-processed meat and fish: a study on health risk evaluation

The profiles of polycyclic aromatic hydrocarbons (PAHs) in selected heat-processed meat and fish were evaluated to determine the potential health risk associated with consumption. The samples were analysed using a gas Chromatography-Mass spectrometer. Different concentrations of individual PAHs were detected in the samples, with the smoked samples having the highest concentrations. The total PAHs (mg/kg) in smoked samples were 2.763 ± 0.185 (game meat), 1.618 ± 0.102 (mackerel fish), and 1.718 ± 0.129 (catfish), whereas levels (mg/kg) in grilled samples were 0.771 ± 0.049 (chicken) and 0.911 ± 0.053 (fish). The total carcinogenic PAH (PAH7) concentrations (mg/kg) in grilled chicken and fish and smoked (game meat, mackerel fish, and catfish) samples were 0.231, 0.294, 0.440, 0.309, and 0.332, while their total PAH8 concentrations were 0.356, 0.371, 0.537, 0.465, and 0.476 respectively. The non-carcinogenic PAH risk estimations, both individually (hazard quotient) and cumulatively (hazard index), were below 1 in all the samples. The mean concentrations of PAH markers B[a]P and the PAH4 were above the EU limits in both the smoked and the grilled samples tested. This implies that exposure to high levels of these PAHs through regular consumption of these products may increase the risk of developing certain types of cancer and other health issues. The smoked fishes has the lowest MOE values for the PAH8 compared to the other samples. The margin of exposures (MOEs), carcinogenic toxic equivalent (TEQ), and excess cancer risk (ECR) also indicated that frequent consumption of smoked fish (mackerel or catfish) by an adult of 70 kg body weight above the reported intake rate of 0.0019 kg/AME/day for a prolonged period may have higher cancer risks than in other samples. Smoked game meat had the highest PAH16 level, but indicated a relatively lower risk level, possibly because of its relatively low intake rate (0.0004 kg/AME/day).

The seasonal variation of Asian dust, anthropogenic PM, and their sources in Dushanbe, Tajikistan

Central Asia's arid climate and growing population make it susceptible to air pollution from mineral dust and anthropogenic sources. To assess the impact of these pollution sources on local air quality, the chemical composition of PM10 aerosol particles was collected within a year at Dushanbe, Tajikistan. Primary sources of the pollutants, their impact on PM10 composition, and their seasonal trends were assessed. The measurement approach employed analysis of trace metals, ions, organic compounds, laboratory investigations, diagnostic ratio calculations, all complemented by positive matrix factor analysis. The results reveal that for about 70% of the year, PM10 levels (80 ± 55 μg m−3 as the annual average) in Dushanbe were higher than the WHO limits, with varying levels during the seasons. Summer concentrations peaked up to 434 μg m−3 due to a combined mineral and road dust influence. Interestingly, winter concentrations reached 152 μg m−3 due to strong contributions (about 64%) from residential heating and fossil fuel combustion, often triggered during sub-10 °C temperatures. Mineral dust events were associated with elevated concentrations of trace metals, including Zn and Pb, alongside organic carbon and high-chain n - alkanes. During such events, Ca/Fe, Ca/Al ratios exceeded those of Saharan dust, suggesting a high salt content in Asian dust, potentially influenced by dried-off lake emissions. It was striking to observe that winter periods exhibited concerning levels of carcinogenic PAHs, such as benzo(b)fluoranthene (<25 ng m−3) and benzo[a]pyrene (<12 ng m−3, BaP), with average values of 4.1 ± 5.9 ng m−3 (BaP) that significantly exceed WHO recommendations. The high PM10 and PAH exposure could pose severe health risks, necessitating collective attention from the local authorities in developing new mitigation strategies concerning the reduction of emissions from residential heating of coal and wood in winter to curb combustion emissions and reduce exposure.

Edible insects: Understanding benzo(a)pyrene toxicokinetics in yellow mealworms for safe and sustainable consumption

The global interest in edible insects as sustainable protein sources raises concerns about the bioaccumulation of contaminants, including polycyclic aromatic hydrocarbons (PAHs), to problematic levels. Understanding the accumulation dynamics of PAHs in edible insects is highly relevant due to the widespread sources and toxicological profiles; however, the bioaccumulative potential of PAHs in edible insects is unexplored. This study examined the uptake and elimination dynamics of benzo(a)pyrene (B(a)P), a representative and carcinogenic PAH, in yellow mealworm larvae (YMW, Tenebrio molitor). Larvae were exposed to feeding substrate with varying B(a)P concentrations (0.03, 0.3, and 3 mg kg−1), and uptake (21 days in B(a)P-contaminated substrate) and elimination (21 days in B(a)P-free substrate) kinetics were subsequently assessed. The results showed that YMW can eliminate B(a)P, revealing dose-dependent B(a)P bioaccumulation in these insects. Larvae fed on a substrate with 0.03 mg kg−1 accumulated B(a)P over 21 days, presenting values of 0.049 (Standard deviation - 0.011) mg kg−1 and a kinetic-based (BAFkinetic) of 1.93 g substrate g organism−1, exceeding the EU regulatory limits for food. However, with a B(a)P half-life (DT50) of 4.19 days in the larvae, an EU legislation safety criterion was met after a 13-day depuration period in clean substrate. Larvae exposed to substrates with 0.3 and 3 mg kg−1 showed B(a)P accumulation, with BAFkinetic values of 3.27 and 2.09 g substrate g organism−1, respectively, not meeting the current legal standards for food consumption at the end of the exposure to B(a)P. Although the B(a)P half-life values after 35 days were 4.30 and 10.22 days (DT50s), the larvae retained B(a)P levels exceeding permitted food safety limits. These findings highlight a significant oversight in regulating PAHs in animal feed and the need for comprehensive safety evaluations of PAH hazards in edible insects for improved PAH feeding guidelines.

Residues of atrazine and diuron in rice straw, soils, and air post herbicide-contaminated straw biomass burning

This study investigates the environmental impact of burning herbicide-contaminated biomass, focusing on atrazine (ATZ) and diuron (DIU) sprayed on rice straw prior to burning. Samples of soil, biomass residues, total suspended particulate (TSP), particulate matter with an aerodynamic diameter ≤ 10 µm (PM10), and aerosols were collected and analyzed. Soil analysis before and after burning contaminated biomass showed significant changes, with 2,4-dichlorophenoxyacetic acid (2,4-D) initially constituting 79.2% and decreasing by 3.3 times post-burning. Atrazine-desethyl, sebuthylazine, and terbuthylazine were detected post-burning. In raw rice straw biomass, terbuthylazine dominated at 80.0%, but burning ATZ-contaminated biomass led to the detection of atrazine-desethyl and notable increases in sebuthylazine and terbuthylazine. Conversely, burning DIU-contaminated biomass resulted in a shift to 2,4-D dominance. Analysis of atmospheric components showed changes in TSP, PM10, and aerosol samples. Linuron in ambient TSP decreased by 1.6 times after burning ATZ-contaminated biomass, while atrazine increased by 2.9 times. Carcinogenic polycyclic aromatic hydrocarbons (PAHs), including benzo[a]anthracene (BaA), benzo[a]pyrene (BaP), and benzo[b]fluoranthene (BbF), increased by approximately 9.9 to 13.9 times after burning ATZ-contaminated biomass. In PM10, BaA and BaP concentrations increased by approximately 11.4 and 19.0 times, respectively, after burning ATZ-contaminated biomass. This study sheds light on the environmental risks posed by burning herbicide-contaminated biomass, emphasizing the need for sustainable agricultural practices and effective waste management. The findings underscore the importance of regulatory measures to mitigate environmental contamination and protect human health.

Characterization of Wildland Firefighters' Exposure to Coarse, Fine, and Ultrafine Particles; Polycyclic Aromatic Hydrocarbons; and Metal(loid)s, and Estimation of Associated Health Risks.

Firefighters' occupational activity causes cancer, and the characterization of exposure during firefighting activities remains limited. This work characterizes, for the first time, firefighters' exposure to (coarse/fine/ultrafine) particulate matter (PM) bound polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s during prescribed fires, Fire 1 and Fire 2 (210 min). An impactor collected 14 PM fractions, the PM levels were determined by gravimetry, and the PM-bound PAHs and metal(loid)s were determined by chromatographic and spectroscopic methodologies, respectively. Firefighters were exposed to a total PM level of 1408.3 and 342.5 µg/m3 in Fire 1 and Fire 2, respectively; fine/ultrafine PM represented more than 90% of total PM. Total PM-bound PAHs (3260.2 ng/m3 in Fire 1; 412.1 ng/m3 in Fire 2) and metal(loid)s (660.8 ng/m3 versus 262.2 ng/m3), distributed between fine/ultrafine PM, contained 4.57-24.5% and 11.7-12.6% of (possible/probable) carcinogenic PAHs and metal(loid)s, respectively. Firefighters' exposure to PM, PAHs, and metal(loid)s were below available occupational limits. The estimated carcinogenic risks associated with the inhalation of PM-bound PAHs (3.78 × 10-9 - 1.74 × 10-6) and metal(loid)s (1.50 × 10-2 - 2.37 × 10-2) were, respectively, below and 150-237 times higher than the acceptable risk level defined by the USEPA during 210 min of firefighting activity and assuming a 40-year career as a firefighter. Additional studies need to (1) explore exposure to (coarse/fine/ultrafine) PM, (2) assess health risks, (3) identify intervention needs, and (4) support regulatory agencies recommending mitigation procedures to reduce the impact of fire effluents on firefighters.

Amplified adsorption and photocatalytic degradation of polycyclic aromatic hydrocarbons using biocompatible nanocrystalline reduced graphene oxide quantum dots

Carcinogenic polycyclic aromatic hydrocarbons (PAHs) have been broadly recognized as significant organic pollutants in the environment, which pose a serious threat to both humans and animals. Therefore, there is an urgent need to develop a solution that effectively removes and reduces PAHs present in the environment. In the present work, we synthesized biocompatible nanocrystalline reduced graphene oxide quantum dots in powdered form (rGOQDTs) of crystallite size 2 nm through hydrothermal method and subsequently used for efficient adsorption and degradation of PAHs for the first time. We noticed that the adsorption of PAHs onto rGOQDTs was faster and more efficient as compared to adsorption on graphene oxide (GO). A 40-fold giant enhancement in the adsorption efficiency of Anthracene and Pyrene on rGOQDTs has been observed as compared to that of graphene oxide. We attribute this enormous enhancement in adsorption efficiency to the stacking of PAHs with rGOQDTs and stronger π-π interactions between rGOQDTs and PAHs. Interestingly, rGOQDTs also exhibit efficient photo-degradation of adsorbed PAHs under visible light irradiation and it degrades almost all PAHs after 80 min of visible light illumination. The degradation efficiency of PAHs is also higher for rGOQDTs as compared to GO. Our work paves the way for efficient removal and degradation of polycyclic aromatic hydrocarbons from the environment.

Impact of Photo-remediation on Anthracene PAHs in treated wastewater using ZnO/TiO2/H2O2 Catalysis

The remediation of carcinogenic Polycyclic Aromatic Hydrocarbons )PAHs( such as Anthracene (3 Rings) in different sources of wastewater was examined using a mix of Zink Oxide, Titanium Oxide, and Hydrogen peroxide (ZnO/ TiO2/H2O2). Eleven wastewater sources were collected from different industrial wastewater and treated wastewater (5 Farms, Main treatment plant, Tanning factory treated wastewater, Tanning factory non-treated wastewater, Carton factories, Factories Lake, and Grease refining plants. Anthracene was extracted by QuEChERS methodology and Analyzed by GCMSMS/TQD. Remediation techniques were applied by using different UV wavelengths irradiation on photolysis of PAHs under two wavelengths (254 and 306 nm) UV irradiation with ZnO + TiO2+ H2O2catalysts for 10 h. Also, the influence of remediation time and several parameters on Anthracene photolysis have been studied. The results indicate that Tanning factory non-treated wastewater had the highest concentration of Anthracene PAHs. The average recovery of Anthracene ranged from 92-96% and Detection Limit (DL) was 5 µg/l. The results of Anthracene concentration in tested wastewater ranged from 21.09 -223.69 µg/l. Also, the results show the anthracene was not detected after 5, 8, and 10h after the remediation using UV 254nm ZnO + TiO2+ H2O2. On the other side, the Anthracene was not detected after 3, 5, and 8h after the remediation using UV 254nm/ZnO + TiO2+ H2O2. Generally, the results of Photoremediation were effective and sufficient for the Anthracen. The impact of photocatalytic illumination of ZnO + TiO2 + H2O2yields valence band holes and conduction band electrons, which interact with the surface adsorbed molecular oxygen to give superoxide radical anions, and finally, the water produces radicals of HO•. These radicals oxidize the target molecule (Anthracene) to Anthraquinone.

Diesel Particulate Matter Permeation into Normal Human Skin and Intervention Using a Topical Ceramide Formulation

Introduction: Diesel particulate matter (DPM) emitted from diesel engines is a major source of air pollutants. DPM is composed of elemental carbon, which adsorbs organic compounds including toxic polycyclic aromatic hydrocarbons (PAHs). The skin, as well as airways, is directly exposed to DPM, and association of atopic dermatitis, psoriasis flares, and premature skin aging with air pollutant levels has been documented. In skin, the permeation of DPM and DPM-adsorbed compounds is primarily blocked by the epidermal permeability barrier deployed in the stratum corneum. Depending upon the integrity of this barrier, certain amounts of DPM and DPM-adsorbed compounds can permeate into the skin. However, this permeation into human skin has not been completely elucidated. Methods: We assessed the permeation of PAHs (adsorbed to DPM) into skin using ex vivo normal (barrier-competent) organ-cultured human skin after application of DPM. Two major PAHs, 2-methylnaphthalene and triphenylene, and a carcinogenic PAH, benzo(a)pyrene, all found in DPM, were measured in the epidermis and dermis using liquid chromatography electrospray ionization tandem mass spectrometry. In addition, we investigated whether a topical formulation can attenuate the permeation of DPM into skin. Results: 2-Methylnaphthalene, triphenylene, and benzo(a)pyrene were recovered from the epidermis. Although these PAHs were also detected in the dermis after DPM application, these PAH levels were significantly lower than those found in the epidermis. We also demonstrated that a topical formulation that has the ability to form more uniform membrane structures can significantly suppress the permeation of PAHs adsorbed to DPM into the skin. Conclusion: Toxic compounds adsorbed by DPM can permeate even barrier-competent skin. Hence, barrier-compromised skin, such as in atopic dermatitis, psoriasis, and xerosis, is even more vulnerable to air pollutants. A properly formulated topical mixture that forms certain membrane structures on the skin surface can effectively prevent permeation of exogenous substances, including DPM, into skin.

Study on migration behavior and mechanism of strong carcinogenic PAHs in oil to fume during frying using stable isotope method

The migration and distribution of four strong carcinogenic polycyclic aromatic hydrocarbons (PAH4) in oil to fume during frying were characterized by the stable isotope-labeled PAH4-d12. The results indicated that PAH4-d12 mainly migrated to heterogeneous oil fume, and their mobilities increased significantly with the increase in heating time and frying temperature, which were 0.48−1.08%, 0.96−1.21%, and 2.98−3.60% at 160, 180, and 200 °C, respectively. The established linear models proved that PAH4-d12 migrated through the carrying of heterogeneous fume, and the carrying ability of fume produced at 200 °C was significantly stronger than at 160 and 180 °C. For morphology, ultrafine fume (<1 μm) at 200 °C had the most emission and the strongest carrying ability for PAH4-d12. For components, the heterogeneous fume produced at 200 °C contained more unsaturated fatty acids and conjugated heterocyclic compounds, which could bind with PAH4-d12 in electrostatic force and π-π conjugate force for migration. This study explained the potential mechanism of oil fume components binding to PAH4 from molecular interaction.