Polycyclic Hydrocarbons Research Articles

Machine learning models to predict the bioaccessibility of parent and substituted polycyclic aromatic hydrocarbons (PAHs) in food: Impact on accurate health risk assessment

Food intake is the primary pathway for polycyclic aromatic hydrocarbons (PAHs) to enter the human body. Once ingested, PAHs tend to accumulate, posing health risks. To accurately assess the risk of PAHs from food, concentrations of 10 parent PAHs (PPAHs) and 15 substituted PAHs (SPAHs) were detected across 34 commonly consumed foods. Results indicated that SPAHs concentrations (3.89–11.6 ng/g dw) were higher than PPAH concentrations (1.66–3.43 ng/g dw) in shrimp and shellfish and freshwater fish. Four machine learning algorithms were used to predict the bioaccessibility of PAHs in foods, with the random forest model performing the best (R2 =0.987, RMSE=5.99). Feature variable importance analysis revealed that lipid and protein contents in food are critical variables influencing PAH bioaccessibility. Subsequently, the bioaccessibility of 25 PAHs in various foods was predicted to explore its impact on health risk assessment. Consequently, the carcinogenic risks considering bioaccessibility (5.62 ×10−5-7.12 ×10−5) was about an order of magnitude lower than that ignoring bioaccessibility (1.52 ×10−4-1.69 ×10−4), yet it still exceeded 10⁻6, indicating potential carcinogenic risks. Although PPAHs and alkylated PAHs were predominant in foods, 6-nitrochrysene was the main compound inducing both non-carcinogenic and carcinogenic risks owing to its high toxicity. This study developed a novel method for assessing pollutant bioaccessibility and evaluating its impact on health risk assessment, which provides a valuable model for managing massive hazardous pollutants and is essential for improving the accuracy of health risk assessment.

Synergistic enhancement of polycyclic aromatic hydrocarbon degradation by Arthrobacter sp. SZ-3 and Pseudomonas putida B6-2 under high Tween80 concentration: mechanisms and efficiency.

This study investigates the advantages of combined microbial degradation of polycyclic aromatic hydrocarbons (PAHs) in reducing the inhibitory effects of high-concentration eluents commonly used in soil washing. A microbial synergistic strategy was proposed using Arthrobacter sp. SZ-3 and Pseudomonas putida B6-2 as the key bacteria in the presence of Tween 80. The results show that in systems with Tween 80, the SZ-3 strain exhibits a strong capacity to degrade three types of PAH compounds, while the B6-2 strain follows multiple degradation pathways. Mixed bacteria achieved degradation rates 60.70% higher than single bacteria at varying concentrations of Tween 80. Additionally, the average growth rates of mixed bacteria increased by 1.17-1.37 times, aligning with the changes in the functional group. Protein activity detection within each degradation system corresponded with growth quantity and the cyclic variation characteristics of ETS enzyme activity. Notably, the ETS activity of mixed bacteria was 150% higher than that of single bacteria. At a Tween 80 concentration of 500 mg/L, the degradation rates of PAHs (Phe, Flu, Pyr) by mixed bacteria were significantly higher than those by single bacteria. The catechol 1,2-dioxygenase activity of mixed bacteria was 2.30 times higher than that of single bacteria. While Tween 80 did not alter the PAH degradation pathways, it significantly influenced the accumulation amount and duration of the characteristic intermediate product. This provides a reference for the remediation of recalcitrant pollutants under conditions involving high-concentration surfactants.

Ratios of organic mass to organic carbon in fine particulate matter at urban sites in China and Korea during winter and summer.

This study evaluates the composition and seasonal characteristics of fine particulate matter (PM2.5) during winter and summer through simultaneous measurements conducted at the Gwangju Institute of Science and Technology in South Korea and the Changping campus of Peking University in China. PM2.5 samples were concurrently collected at both sites, and chemical analyses were conducted to quantify various components, including carbonaceous materials, ionic species, and metals. Although the average PM2.5 concentrations were comparable between the two sites, there were distinct differences in the concentrations of major components. Organic indicator compounds were analyzed to discern the contributions of primary and secondary pollution sources. Changping displayed a mix of primary and secondary pollution, characterized by higher concentrations of primary organic carbon (POC) such as polycyclic aromatic hydrocarbons and hopanes, compared to Gwangju. In contrast, Gwangju demonstrated a higher prevalence of secondary organic carbon (SOC), particularly water-soluble organic carbon not related to biomass burning (WSOCnbb) and various polar organic compounds. The organic mass to organic carbon (OM/OC) ratios estimated using the mass balance method revealed significant differences, with Gwangju showing a higher ratio of 2.3 compared to 1.9 at Changping, indicating a greater influence of secondary pollutants at Gwangju. Additionally, both Changping and Gwangju exhibited higher OM/OC ratios in summer (Changping: 2.0, Gwangju: 2.5) compared to winter (Changping: 1.8, Gwangju: 2.2), indicating seasonal differences in organic mass contributions to PM2.5. These findings underscore the importance of accounting for spatial and seasonal variations in air pollution studies and suggest that updating commonly used OM/OC ratios could enhance the reliability of research outcomes.

Photocatalytic remediation of fluoranthene contaminated soil by eco-friendly GQDs/TiO2/α-FeOOH composite photocatalyst: Efficiency, influence factors, mechanism, and toxicity analysis

Polycyclic aromatic hydrocarbons (PAHs), as a persistent organic pollutant, have adverse effects on soil environment and human health. In this study, a new type of iron-based material graphene quantum dots (GQDs)/TiO2/α-FeOOH was used to construct a photocatalytic system to achieve effective degradation of fluoranthene in soil. The hydrothermal method and sol–gel method were used to synthesize GQDs/TiO2/α-FeOOH composite photocatalyst, which exhibited enhanced photocatalytic activity by promoting charge transfer, increasing specific surface area, and broadening light absorption range. The degradation ratio of fluoranthene in soil suspension by GQDs/TiO2/α-FeOOH was 67.37 % under the condition of 24 h of simulated sunlight irradiation, water/soil ratio of 10:1, and catalyst dosage of 50 mg/g. •O2– and h+ played the major roles in degradation process, and the catalytic mechanism was proposed. The degradation products and degradation pathway of fluoranthene were analyzed by GC–MS detection and DFT calculation, and the toxicity of degradation products was predicted by simulation calculation. The effect of remedial soil on seed germination was investigated through germination test of tomato seeds, and results showed that the productivity of fluoranthene contaminated soil was recovered in a certain extent.

The Toxic Effects of Petroleum Diesel, Biodiesel, and Renewable Diesel Exhaust Particles on Human Alveolar Epithelial Cells.

The use of alternative diesel fuels has increased due to the demand for renewable energy sources. There is limited knowledge regarding the potential health effects caused by exhaust emissions from biodiesel- and renewable diesel-fueled engines. This study investigates the toxic effects of particulate matter (PM) emissions from a diesel engine powered by conventional petroleum diesel fuel (SD10) and two biodiesel and renewable diesel fuels in vitro. The fuels used were rapeseed methyl ester (RME), soy methyl ester (SME), and Hydrogenated Vegetable Oil (HVO), either pure or as 50% blends with SD10. Additionally, a 5% RME blend was also used. The highest concentration of polycyclic aromatic hydrocarbon emissions and elemental carbon (EC) was found in conventional diesel and the 5% RME blend. HVO PM samples also exhibited a high amount of EC. A dose-dependent genotoxic response was detected with PM from SD10, pure SME, and RME as well as their blends. Reactive oxygen species levels were several times higher in cells exposed to PM from SD10, pure HVO, and especially the 5% RME blend. Apoptotic cell death was observed in cells exposed to PM from SD10, 5% RME blend, the 50% SME blend, and HVO samples. In conclusion, all diesel PM samples, including biodiesel and renewable diesel fuels, exhibited toxicity.

Regulation mechanism of exogenous nitric oxide on phenanthrene uptake by ryegrass roots

Polycyclic aromatic hydrocarbons (PAHs) constitute a category of persistent organic contaminants that possess the potential to induce carcinogenic, teratogenic, and mutagenic consequences. Our previous findings have revealed that plant roots actively take up PAHs through co-transport with protons, and auxin can promote PAHs uptake by wheat roots. It remains unclear whether nitric oxide (NO), a signaling molecule involved in numerous physiological processes in plants and downstream of auxin, can affect PAHs uptake by plant roots. In our study, 50 μmol/L sodium nitroprusside (SNP) significantly enhanced phenanthrene uptake after 4 h of exposure. After the addition of SNP (50 μmol/L), the H+ flux on root surface increased, and H+-ATPase activity was activated, indicating that exogenous NO promotes phenanthrene uptake by plant roots via activating H+-ATPase. By studying the effects of 50 μmol/L cyclic guanosine monophosphate (cGMP), 5 mmol/L Ca2+, and 50 μmol/L adenosine monophosphate (AMP) on phenanthrene uptake by ryegrass roots and measuring root calcium-dependent protein kinases (CDPK) activity, we demonstrated that exogenous NO promotes phenanthrene uptake through the signaling pathway of NO, cGMP, Ca2+, CDPK, 14-3-3 protein and H+-ATPase. The results contribute significant insights into elucidating the underlying mechanisms of NO modulating PAHs absorption by plant roots, thereby offering crucial strategies for advancing food safety measures and enhancing the phytoremediation potential of soils and waters contaminated with PAHs.

The mechanisms of effects of oil-derived polyaromatic hydrocarbons on cardiac electrical activity in navaga cod (Eleginus nawaga)

The intensive development of oil and gas industries in the Arctic threatens Arctic aquatic ecosystems. The toxic and primarily lethal cardiotoxic effects of oil in living organisms are believed to be associated with polyaromatic hydrocarbons (PAHs), and previous works revealed the electrophysiological mechanisms of action of individual oil-derived PAHs. However, the physiological effects of a complex PAHs mixture in oil water-soluble fraction (WSF) have not been previously studied. This study is focused on the effects of oil WSF on electrical activity and major ionic currents in the working myocardium of navaga (Eleginus nawaga), which is one of the most important commercial fish species in the Arctic. We found that 1% and 10% solutions of oil WSF cause a marked increase in the duration of action potentials (APs) in navaga cardiomyocytes. This effect appears to be due to the suppression of rapid delayed rectifying current IKr (IC50 about 3% in ventricular and atrial myocardium). At higher concentrations, oil WSF also suppressed calcium current ICaL (IC50 = 10.6%), which led to a decrease in the contractile activity in isolated myocardial preparations. Unlike individual tricyclic PAHs, oil WSF did not affect fast sodium current INa and AP upstroke velocity. An assessment of the content of tricyclic PAHs in 10% solution of oil WSF showed that their total concentration is relatively low and does not exceed 100 nM. Thus, oil WSF also has a powerful cardiotoxic effect in fish myocardium, but its effects differ from the previously studied effects of tricyclic PAHs and suggest the presence of yet unexplored oil compounds that have a more powerful toxic potential against ERG channels.

Effects of simulated smoke condensate generated from combustion of selected military burn pit contents on human airway epithelial cells.

Exposure to military burn pit smoke during deployment is associated with different respiratory and non-respiratory diseases. However, information linking smoke exposure to human pulmonary health is lacking. This study examined the effects of simulated burn pit smoke condensates on human airway epithelial cells (HAECs) from twelve donors (smokers/non-smokers, biological female/male) cultured at an air-liquid interface and exposed to condensates from three simulated burn pit waste materials (cardboard, plywood, and plastic) incinerated at two combustion conditions: smoldering and flaming. Cellular gene expression was analyzed using bulk RNA sequencing, and basolateral media cytokine levels were assessed using multiplex immunoassay. Flaming smoke condensates caused more significant differentially expressed genes (DEGs) with plywood flaming smoke being the most potent in altering gene expression and modulating cytokine release. Cardboard and plywood flaming condensates primarily activated detoxification pathways, whereas plastic flaming affected genes related to anti-microbial and inflammatory responses. Correlation analysis between smoke condensate chemicals and gene expression to understand the underlying mechanism revealed crucial role of oxygenated polycyclic aromatic hydrocarbons (PAHs) and aluminum, molybdenum, and silicon elements; IL6 expression was positively correlated with most PAHs. Stratification of data based on HAEC donor demographics suggests that these affect gene expression changes. Enrichment analysis indicated similarity with several deployment-related presumptive and reported diseases, including asthma, emphysema, and cancer of different organs. This study highlights that simulated burn pit smoke exposure of HAECs causes gene expression changes indicative of deployment-related diseases with more pronounced effects seen in smokers and females. Future studies are needed to further characterize how sex and smoking status affect deployment-related diseases.

Feeding of the crab Eriphia gonagra (Fabricius, 1781) (Decapoda: Brachyura: Eriphiidae) as a tool to assess the impacts of oil spills

ABSTRACT This study aimed to observe changes in the diet of crab Eriphia gonagra due to the oil spill that occurred in 2019 on two beaches on the Pernambuco coast (Gaibu and Carneiros Beach) Northeastern, Brazil. Changes in the species feeding were investigated considering the periods before, during, and after of the spill and correlated with the analysis of sediment contamination Polycyclic Aromatic Hydrocarbons (PAHs) and Trace Metals (TM). 160 specimens were analysed. 24 food items were found, with a prevalence of Mollusca (fragment) and Macroalgae in the diet. There was no detection of oil fragments in the stomachs of animals, however, different patterns were observed in the feeding of the species studied in the BEF, DUR, and AFT periods of the spill. A generalist habit, it was possible to observe changes in captured items, thus we observed a diet with low nutritional levels caused mainly in impacted environments. Two factors may be prevalent in explaining the impacts caused by the feeding of E. gonagra in Carneiros Beach. The first was the decrease in prey that died after the arrival of the oil, the second was the lasting effects of contaminants on the predation capacity of the species.

Benzo(a)anthracene Targeting SLC1A5 to Synergistically Enhance PAH Mixture Toxicity.

Human exposure to polycyclic aromatic hydrocarbons (PAHs) as mutagenic and carcinogenic pollutants in the environment often occurs in the form of mixtures. Although the mixture effects of PAHs have been previously recognized, the toxicological mechanisms to explain them still remain quite unclear. This study combined metabolomics and chemical proteomics methods to comprehensively understand the mixture effects of a PAH mixture including benzo(a)anthracene (BaA), benzo(b)fluoranthene (BbF), benzo(a)pyrene (BaP), and chrysene (CHR). Among them, BaA has shown a strong synergistic effect with other PAHs. Interestingly, BaA alone is not a potent oxidative stress inducer in liver cells but dose-dependently amplifies oxidative damage caused by the PAH mixture. Global metabolomics analysis results revealed damage to the antioxidant glutathione synthesis, which was caused by the glutamine depletion caused by BaA in the mixture. Subsequently, the label-free chemical proteomics and cellular thermal shift analysis (CETSA) demonstrated that the PAH mixture altered the thermal shift of glutamine transporter SLC1A5. Furthermore, Western blotting and the isothermal titration calorimetry (ITC) interaction measurements showed nanomolar KD values between BaA and SLC1A5. Overall, this study showed that BaA synergistically contributed to PAH mixture induced oxidative damage by targeting SLC1A5 to inhibit glutamate transport into cells, resulting in the inhibition of glutathione synthesis.

Interstellar Formation of Nitrogen Heteroaromatics [Indole, C8H7N; Pyrrole, C4H5N; Aniline, C6H5NH2]: Key Precursors to Amino Acids and Nucleobases.

Nitrogen-substituted polycyclic aromatic hydrocarbons (NPAHs) are not only fundamental building blocks in the prebiotic synthesis of vital biomolecules such as amino acids and nucleobases of DNA and RNA but also a potential source of the prominent unidentified 6.2 μm interstellar absorption band. Although NPAHs have been detected in meteorites and are believed to be ubiquitous in the universe, their formation mechanisms in deep space have remained largely elusive. Here, we report the first bottom-up formation pathways to the simplest prototype of NPAHs, indole (C8H7N), along with its building blocks pyrrole (C4H5N) and aniline (C6H5NH2) in low-temperature model interstellar ices composed of acetylene (C2H2) and ammonia (NH3). Utilizing the isomer-selective techniques of resonance-enhanced multiphoton ionization and tunable vacuum ultraviolet photoionization reflectron time-of-flight mass spectrometry, indole, pyrrole, and aniline were identified in the gas phase, suggesting that they are promising candidates for future astronomical searches in star-forming regions. Our laboratory experiments utilizing infrared spectroscopy and mass spectrometry in tandem with electronic structure calculations reveal critical insights into the reaction pathways toward NPAHs and their precursors, thus advancing our fundamental understanding of the interstellar formation of aromatic proteinogenic amino acids and nucleobases, key classes of molecules central to the Origins of Life.

Inhibitory Effects of Fruit Powders on the Formation of Polycyclic Aromatic Hydrocarbons in Charcoal-Grilled Pork

Polycyclic aromatic hydrocarbons (PAHs), carcinogenic substances primarily formed through pyrolysis and oxidation of fat at high cooking temperatures, are commonly found at high levels in grilled meats. Reducing PAHs formation by incorporating natural antioxidants, such as through marination, has been demonstrated to be effective. However, the inhibitory effect of fresh phenolic-rich fruit powders on PAHs formation in charcoal-grilled meats remains unknown. To clarify the application of the fruit powders, 15 experimental groups were conducted. All pretreatment techniques (spraying, marinating, and mixing) were applied across all four freeze-dried fruit powders (lemon, guava, papaya, and mango). Each method was systematically tested with each fruit powder to evaluate its effect on inhibiting the formation of the four PAHs (BaA, CHR, BbF, and BaP) in charcoal-grilled pork belly and loin. Firstly, guava powder exhibited the highest phenolic content and antioxidant activity compared to the lemon, papaya, and mango powders (p < 0.05), among which the main phenolic compounds were ellagic acid, quercetin, and epigallocatechin gallate (EGCG). Further, marination of pork belly with guava powder exhibited the highest inhibition rate of PAHs (94.8%), followed by lemon (91.1%), papaya (89.8%), and mango (89.0%), with a statistically significant difference at p < 0.05. The reduction in estimated daily intake (EDI) and the increase in the margin of exposure (MOE) indicate that consuming grilled meat treated with these fruit powders poses no safety concerns and may potentially reduce health risks. Finally, the sensory evaluation showed that marinating with guava powder did not perceptibly affect the sensory attributes of the meat. Overall, this study provides a potent strategy for inhibiting the formation of PAHs in meat during charcoal grilling by incorporating fruit powder while preserving sensory qualities.

Determination of PCB and PAH tissue levels in bottlenose dolphins that stranded in the Mississippi sound before and after the unusual mortality event in 2019

Cetaceans are regarded as a sentinel species because their health and population changes can serve as indicators of effects on marine ecosystems. We characterized levels of 24 polycyclic aromatic hydrocarbons (PAHs) and 7 polychlorinated biphenyls (PCBs) in blubber, kidney, liver, and muscle of 138 bottlenose dolphins (Tursiops truncatus) that stranded in the Mississippi Sound (MSS) between 2010 and 2021. The samples were divided into four time periods: 2010–2018, 2019, 2020, and 2021, to assess whether there was a significant association between chemical levels in dolphin tissues and the 2019 unusual mortality event (UME) in the MSS resulting from the unprecedented freshwater incursion from 2 openings of the Bonnet Carré Spillway (BCS). We found 7 PCBs were readily detected in all tissues across time, and the major PAH was naphthalene, with detection of biphenyl and acenaphthene at lower levels and frequency. There was little change in tissue PCB levels over time; only naphthalene in the blubber was higher in tissues from dolphins that stranded before 2019. However, there were not significant changes in chemical levels in tissues from stranded bottlenose dolphins in the MSS before or after the UME in 2019.

Elimination of microplastic from soil by pyrolysis and potential hazard analysis: Effects of pyrolysis temperature and holding time

AbstractEfficient and harmless treatment of microplastics in soil is the current focus of microplastic pollution management. In this study, the pyrolysis effect of soil microplastics at different temperatures and holding times was analyzed. The results showed that temperature and holding time significantly affected the morphology and compositional structure of soil. Pure microplastics and product adhesion after pyrolysis at low temperature (400°C) were not easy to remove. Interestingly, compared with pure polyethylene (PE), direct pyrolysis of microplastics in soil could obtain better results, and the content of organic matter and polycyclic aromatic hydrocarbons (PAH) could be significantly reduced. However, the pyrolysis performance was very unsatisfactory even if the action time was prolonged at 400°C. Prolonged high‐temperature treatment accelerated the fragmentation of the alkane main chain of PE, thus generating more PAH, and the temperature was not high enough (400°C) for further effective degradation of PAH into carbon dioxide and water. Therefore, higher temperature and longer holding time need to be selected to ensure the pyrolysis performance. This study revealed the role and mechanism of pyrolysis in soil microplastic mixed systems, aiming to provide a basis for the treatment of microplastics in terrestrial ecosystems.

Decoupling study of municipal solid waste gasification: Effect of pelletization on pyrolysis and gasification of pyrolytic char

To explore the influence of pelletization on the thermal conversion of municipal solid waste (MSW), pyrolysis characteristics and gasification reactivity of MSW pellet and powder were investigated in this study. Besides, the physicochemical properties of internal char and external char within the char pellet were separately characterized. Moreover, the relationship between the physicochemical properties of char pellet and its gasification reactivity was clarified. Results showed that the pyrolytic gas yields of MSW pellets were increased by 15.47 % and 11.55 % at 700 °C and 800 °C, respectively, compared to powder MSW. It was mainly attributed that the conversion of monocyclic aromatic hydrocarbons to polycyclic aromatic hydrocarbons was promoted by the longer residence time within the pellets. Meanwhile, the physicochemical properties of pyrolytic char pellets exhibited a significant heterogeneity. Specifically, the number of ordered aromatic rings of char pellet was reduced, while the order degree of carbon structure was enhanced, particularly the internal char. However, the difference magnitude between internal and external char was diminished with temperature. This was due to the higher temperature resulting in a larger surface specific area and pore volume of the char pellet, especially the internal char, thereby enhancing the pyrolysis process. Furthermore, an increase in pore volume within the char pellet improved gasification reactivity when the conversion rate > 0.4. These findings provide a reference for the pyrolysis and gasification process of MSW pellets.

Production and Characterization of Duckweed Bio-Oil via Pyrolysis: A Renewable Alternative to Fossil Fuels

Duckweed bio-oil has gained significant interest due to its exceptional benefits in raw material utilization and eco-friendliness. Research on microalgae cultivation and pyrolysis production lines is vital to enhancing the efficiency of duckweed biomass consumption for renewable energy. In this work, the pyrolysis process was applied to create bio-oil from duckweed. A fixed-bed reactor was connected to condensers, with heat delivered via a gas burner, and a thermocouple used to measure the reactor’s temperature. A stopwatch was used to track the elapsed time until the last drop of product was visible from the system. The results show that both duckweed oils are heavy oils, with an API gravity of 8.73, densities of 1.079 g/cm³ and 1.006 g/cm³, high viscosities of 8.24 mm²/s and 9.32 mm²/s, respectively, a specific gravity of 1.01, a high flash point of 96 °C, and a pour point of 16 °C. The research confirms that duckweed biomass can be pyrolyzed to produce bio-oil. GC/MS analysis was conducted on the generated bio-oil, revealing the presence of multiple polyaromatic hydrocarbons. Consequently, carbon chain elements (C8-C28) are present in duckweed bio-oils. According to the findings, duckweed-derived bio-oil shows great promise as a fossil fuel alternative. This study suggests that, since microalgae have the potential to be a viable replacement for fossil fuels, efforts should be made to scale up microalgae production from the laboratory to industrial levels.

Assessing health risks of polycyclic aromatic hydrocarbons (PAHs) in cooked fish using monte carlo simulation: a global review and meta-analysis.

Cooking food at high temperatures can lead to the formation of harmful chemical compounds called polycyclic aromatic hydrocarbons (PAHs). The purpose of this study was to conduct a systematic review and meta-analysis to evaluate the concentrations of 16 PAHs in cooked fish using roasting, barbecuing, or grilling techniques. The Monte Carlo simulation method was employed to accurately assess and quantify the uncertainties associated with risk estimation. This study compiled data on PAH levels in cooked fish using gas or charcoal from 57 original published articles in the PubMed, Science Direct, Scopus, Google Scholar, and Web of Science databases between January 1, 2010 to December 30, 2023. The investigation showed that 55.1% of cooked fish was made by grilling, 35.1% by barbecuing, and 9.8% by roasting. Based on the 95th percentile Hazard Quotient (HQ) from fish consumption, the ranking of 8 PAHs was as follows: Benzo[a]pyrene (BaP = 14.10) > Pyrene (Pyr = 0.29) > Fluorene (Flu = 0.23) > Naphthalene (Nap = 0.22) > Fluoranthene (Flrt = 0.12) > Acenaphthene (Ace = 0.11) > Acenaphthylene (Acy = 0.04) > Anthracene (Anth = 0.02). However, the non-carcinogenic risk ratio for other PAH compounds in fish consumption, excluding BaP, was found to be less than one (HQ < 1). The 95th percentile lifetime excess cancer risk (LTCR) values for 8 PAH compounds (BaP (4.35E- 9) > Anth (6.10E- 11) > Flrt (9.35E- 12) > Pyr (7.04E- 12) > Ace (6.56E- 12) > Flu (4.97E- 12) > Nap (4.39E- 12) > Acy (2.57E- 12)) from fish consumption were negligible and can be disregarded (LTCR < 10- 6). Based on the analysis of the findings, it can be concluded that the consumption of cooked fish using various methods worldwide does not present a carcinogenic risk linked to PAHs.

8054 Temporal Trends In Thyroidal Endocrine Disruptor Exposure Among United States Reproductive-Age And Pregnant Women Over 20 Years And Differences By Socioeconomic Status

Abstract Disclosure: C. Han: None. S. Lee: None. E.N. Pearce: None. Background: Widespread exposure to endocrine disrupting chemicals (EDCs) poses a risk to public health and environmental safety. Women of reproductive age and pregnant women may be uniquely vulnerable to adverse thyroidal effects of EDCs. A better understanding of thyroidal EDCs exposure is needed to inform public health strategies. Objective: To examine temporal trends in EDC exposure and their effects on thyroid function among reproductive-age and pregnant women in the U.S. over the last two decades, with a focus on the impact of socioeconomic status. Methods: We analyzed data from the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2020 in 25,320 reproductive-age women and 2,525 pregnant women to assess the levels of exposure to thyroid-disrupting chemicals, including dioxins, organochlorides, polyfluoroalkyl substances (PFAS) from serum samples, and polyaromatic hydrocarbons, perchlorates, and metabolites from personal care products, phthalates, and plasticizers from urine samples. We used Kruskal-Wallis tests to analyze changes in EDC exposures over the past 20 years and multivariate linear regression models to identify factors influencing these levels. Results: We found a significant decline in exposures to 20 types of dioxins, 7 organochlorides, 6 PFAS, 5 personal care product chemicals, 6 phthalate metabolites, perchlorate, and thiocyanate, but substantial increases in exposure to 2 polyaromatic hydrocarbons among reproductive-age women. Among pregnant women, trends were similar, with declines in exposures to dioxins, organochlorides, PFAS, and phthalate metabolites; whereas exposure to 3 Polyaromatic hydrocarbons, 1 personal care product chemical, nitrates, and thiocyanates increased. Linear regression indicated a significant positive association between socioeconomic status and the levels of dioxin and PFAS in both reproductive-age and pregnant women, and a negative association between socioeconomic status and perchlorate and polyaromatic hydrocarbons in the participants. Conclusion: The past two decades have witnessed a general decline in the levels of most thyroidal EDCs in U.S. reproductive-age and pregnant women; however, some, particularly polyaromatic hydrocarbons, exposures have increased, especially among women with lower socioeconomic status. This has the potential to worsen disparities in health outcomes. These findings highlight the necessity for targeted public health interventions to reduce the impact of EDCs on thyroid health and address socioeconomic health disparities. Presentation: 6/3/2024

Associations between exposure to multiple environmental chemicals and metabolic syndrome: A mixture analysis

Exposure to environmental chemicals is prevalent. While previous studies reported associations between multiple chemical exposures and metabolic syndrome (MetS), they did not comprehensively account for correlations among exposures. We used machine learning methods including Boruta algorithm and least absolute shrinkage and selection operator (LASSO) regression, combined with weighted quartiles sum (WQS) regression to investigate the associations of phenols, polycyclic aromatic hydrocarbons (PAHs), metals, and phthalates with MetS and its components. Data were drawn from the 2005–2012 National Health and Nutrition Examination Survey (NHANES). The mean (standard deviation (SD)) age of 2596 participants was 48.4 (17.9) years. After adjusting for age, sex, body mass index, race/ethnicity, marital status, education, poverty income ratio, physical activity, smoking, and alcohol, higher 2-Phenanthrene (2-PHE) and mono-(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP) concentrations were associated with a higher odds of the MetS (odds ratio (OR) = 4.26, 95 % confidence interval (CI) 2.40–7.58 per ng/mL, and 3.24, 1.75–6.02 per ng/L, respectively). WQS index for environmental chemicals was positively associated with the MetS (OR = 1.31, 95 % CI 1.09–1.57). Moreover, we observed consistent and stronger positive associations with MetS (OR = 1.54, 95 % CI 1.04–2.30) in current smokers. Exposure to phenols, PAHs, metals, and phthalates was positively associated with an increase in metabolic syndrome and its components, which was more pronounced in current smokers.

High temperature and hyperkalemia increase vulnerability of navaga cod (Eleginus nawaga) cardiomyocytes to the ecotoxicant 3-methyl-phenanthrene

Oil and gas mining and transportation in the Arctic can lead to release of polycyclic aromatic hydrocarbons (PAHs) in the ocean and freshwater basins. PAHs are known for their toxic effects in fish hearts, including the inhibition of main ionic currents (IKr, INa and ICaL) in fish cardiac myocytes. The present study is the first one to assess the effect of a particular PAH abundant in crude oil and diesel, namely 3-methyl-phenanthrene (3-MP), on the electrical excitability (EE) of cardiomyocytes from navaga cod (Eleginus nawaga), commercial fish species from the Arctic. Action potentials (APs) were elicited in current-clamp experiments at 9, 15 and 21 °C, and AP characteristics and the current needed to elicit APs were examined. Also, the effects of 3 μM 3-MP were tested at 3 temperatures and in normal (3.5 mM) and high (8 mM) extracellular K+ concentrations.Elevation of temperature leads to hyperpolarization of resting membrane potential and AP shortening, but does not decrease EE. 3-MP was found to suppress EE in cardiomyocytes at 9 and 15 °C, but not at 21 °C. High extracellular K+ itself drastically decreases EE, although it does not worsen the effect of 3-MP. However, combination of hyperthermia and high K+ leads to augmentation of depressive effect of 3-MP on EE. We hypothesize that hyperthermia rescues Na+ channels from inactivation due to membrane hyperpolarization, thereby compensating for the partial inhibition of INa by 3-MP. However, elevation of extracellular K+ nullifies this protective mechanism by depolarizing the resting potential and aggravates the effect of 3-MP.