Polycyclic aromatic hydrocarbons and digestive tract cancers: a perspective

Long-term atmosphere surveillance (2017-2022) of PM2.5‑bound polycyclic aromatic hydrocarbons and health risk assessment in a typical city in northern China

OBJECTIVE

By analyzing the pollution characteristics of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 in the atmosphere of Hohhot City, we can assess their main sources and evaluate their health hazards.

METHODS

From 2017 to 2022, atmospheric PM2.5 sampling was conducted in Hohhot City. The content of PAHs in the PM2.5 samples was determined using high-performance liquid chromatography. To analyze the sources of PAHs, molecular diagnostic ratios and positive matrix factorization were initially employed to quantify potential PAH sources. Subsequently, the Potential Source Contribution Function was used to analyze the potential emission source areas of PAHs. The recommended health risk assessment model by the United States Environmental Protection Agency was utilized to calculate the lifetime excess cancer risk associated with exposure to PAHs.

RESULT

From 2017 to 2022, the levels of PM2.5 and PAHs showed a decreasing trend year by year, decreasing from 40 μg/m3 to 20 μg/m3 and from 6.92 ng/m3 to 3.60 ng/m3, respectively. The rate of PM2.5 exceeding the Chinese Grade I standard (35 μg/m3) decreased from 65.77% to 24%, and the rate of benzo[a]pyrene concentration exceeding the standard limit (2.5 ng/m3) was 23.88%. Through molecular diagnostic ratios and positive matrix factorization analysis, it was found that biomass/coal combustion (cumulative contribution rate of 56.77%) and traffic emissions (cumulative contribution rate of 36.94%) were the main sources of pollution. The potential pollution source areas in Hohhot City were mainly distributed in Mongolia, western Inner Mongolia, and neighboring provinces and cities. The median incremental cancer risks for children and adults with long-term exposure to PAHs were 5.14 × 10-7 and 1.68 × 10-7, respectively.

CONCLUSION

The overall pollution situation of PM2.5 and PAHs in Hohhot City can be considered acceptable, but it is important to pay attention to pollution sources such as combustion and traffic emissions. The potential pollution source areas are relatively widespread, but the cancer risk remains within an acceptable level.

Transforming beef quality through healthy breeding: a strategy to reduce carcinogenic compounds and enhance human health: a review

The presence of carcinogenic substances in beef poses a significant risk to public health, with far-reaching implications for consumer safety and the meat production industry. Despite advancements in food safety measures, traditional breeding methods have proven inadequate in addressing these risks, revealing a substantial gap in knowledge. This review aims to fill this gap by evaluating the potential of healthy breeding techniques to significantly reduce the levels of carcinogenic compounds in beef. We focus on elucidating the molecular pathways that contribute to the formation of key carcinogens, such as heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs), while exploring the transformative capabilities of advanced genomic technologies. These technologies include genomic selection, CRISPR/Cas9, base editing, prime editing, and artificial intelligence-driven predictive models. Additionally, we examine multi-omics approaches to gain new insights into the genetic and environmental factors influencing carcinogen formation. Our findings suggest that healthy breeding strategies could markedly enhance meat quality, thereby offering a unique opportunity to improve public health outcomes. The integration of these innovative technologies into breeding programs not only provides a pathway to safer beef production but also fosters sustainable livestock management practices. The improvement of these strategies, along with careful consideration of ethical and regulatory challenges, will be crucial for their effective implementation and broader impact.

Polycyclic Aromatic Hydrocarbons (PAHs) in the Environment: Occupational Exposure, Health Risks and Fertility Implications

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds with fused aromatic rings, primarily derived from combustion processes and environmental pollutants. This narrative review discusses the most relevant studies on PAHs, focusing on their sources, environmental and occupational exposure, and effects on human health, emphasizing their roles as carcinogenic, mutagenic, and teratogenic agents. The primary pathways for human exposure to PAHs are through the ingestion of contaminated food (mainly due to some food processing methods, such as smoking and high-temperature cooking techniques), the inhalation of ambient air, and the smoking of cigarettes. Coke oven workers are recognized as a high-risk occupational group for PAH exposure, highlighting the need for appropriate strategies to mitigate these risks and safeguard worker health. PAHs are metabolized into reactive intermediates in the body, which can lead to DNA damage and promote the development of various health conditions, particularly in environments with high exposure levels. Chronic PAH exposure has been linked to respiratory diseases, as well as cardiovascular problems and immune system suppression. Furthermore, this review underscores the significant impact of PAHs on reproductive health. The results of the reported studies suggest that both male and female fertility can be compromised due to oxidative stress, DNA damage, and endocrine disruption caused by PAH exposure. In males, PAHs impair sperm quality, while, in females, they disrupt ovarian function, potentially leading to infertility, miscarriage, and birth defects. Fetal exposure to PAHs is also associated with neurodevelopmental disorders. Given the extensive and detrimental health risks posed by PAHs, this review stresses the importance of stringent environmental regulations, occupational safety measures, and public health initiatives to mitigate exposure and safeguard reproductive and overall health.

Isolation and identification of naphtalene-degrading bacteria and its application in a two-phase partitioning bioreactor

Naphthalene is a persistent environmental pollutant for its potential teratogenic, carcinogenic and mutagenic effects. In this study, 10 strains of bacteria capable of degrading naphthalene were isolated from crude-oil contaminated soil. Among them, Pseudomonas plecoglossicida 2P exhibited prominent growth with 1000 mg/L naphthalene as the sole carbon source and degraded 94.15% of naphthalene in 36 h. Whole genome sequencing analysis showed that P. plecoglossicida 2P had a total of 22 genes related to naphthalene degradation, of which 8 genes were related to the salicylic acid pathway only, 5 genes were related to the phthalic acid pathway only, 8 genes were common in both the salicylic acid and phthalic acid pathways, and 1 gene was related to the gentisic acid pathway. P. plecoglossicida 2P was applied in a two-phase partition bioreactor (TPPB) to degrade naphthalene in wastewater. The optimal operating conditions of the reactor were obtained through response surface optimization: initial naphthalene concentration (C0) =1600 mg/L, bacterial liquid concentration (OD600) = 1.3, and polymer-to-wastewater mass ratio (PWR) = 2%. Under these conditions, the naphthalene degradation rate was 98.36% at 24 h. The degradation kinetics were fitted using the Haldane equation with a high coefficient of determination (R2=0.94). The present study laid foundations for naphthalene degradation mechanism of genus Pseudomonas and its potential application in TPPB.

Associations of coke oven emission exposure with pulmonary function, blood pressure, blood cell parameters, and biochemical indices in coking workers: a cross-sectional pilot study

Background and objective: Coke oven emissions (COEs) are formed in the process of coking production, mainly composed of polycyclic aromatic hydrocarbons (PAHs) and benzene; however, the health impacts of COE exposure in coking workers are not fully clear so far. We aimed to explore the associations of occupational COE exposure with pulmonary function, blood pressure, blood cell parameters, and blood biochemical indices, and to bolster health surveillance and disease prevention and control in coking workers. Methods: We investigated 566 coking workers at a large state-owned enterprise coking plant in Taiyuan, Shanxi, China, measured the concentrations of plasma 16 PAHs and urinary phenol, assessed the health outcomes including pulmonary function, blood pressure, the levels of peripheral hematologic parameters and biochemical indices, and examined the associations of PAH and phenol concentrations with the health outcomes using multiple linear regressions, least absolute shrinkage and selection operator regression (LASSO), and Bayesian kernel machine regression (BKMR). Results: After adjustment for confounders, plasma ∑15PAH concentration was significantly associated with increases in hemoglobin (HGB) and triglyceride (TG) levels in coking workers, and urinary phenol concentration was significantly associated with increases in the diastolic blood pressure (DBP) level, and decreases in platelet (PLT) count. When phenol concentration and PAH concentration were simultaneously included in the multiple linear regression model, both of them were associated with the level of HGB. LASSO and BKMR indicated that the PAHs with four rings and above contributed to the HGB level. Conclusion: PAH exposure could damage hematological parameters and blood lipids, and benzene exposure could increase blood pressure and decrease PLT count.

Global occurrence, food web transfer, and human health risks of polycyclic aromatic hydrocarbons in biota

Polycyclic aromatic hydrocarbons (PAHs) are widespread organic pollutants that pose significant health risks due to their bioaccumulation in the biota. This study examines the global distribution of PAHs in biota, identifies key factors influencing using boosted regression tree (BRT) models, analyzes their transfer through trophic magnification factors (TMF), and evaluates health risks using the EPA risk assessment model. Research on PAHs has grown from 1978 to 2023, peaking in 2021, with 171 out of 241 studies (71.1 %) focusing on marine ecosystems. The highest PAH concentrations are observed in the Mediterranean Sea, Red Sea, and North American coastal regions, primarily influenced by industrial and human activities, such as factory emissions and ship transport. BRT analysis shows region factors and feeding habitats significantly influence PAH levels. TMF analysis shows that biodilution is the main mechanism for PAH attenuation, with concentrations decreasing as trophic levels increase. Additionally, health risk assessment further illustrate that toxicity equivalent (TEQ) values are highest in Egypt and Turkey. Across all populations in Egypt, the United States, Turkey, Portugal, and China, as well as children in Portugal and Sweden, there are potential risks from aquatic product consumption (10-6 < CRI < 10-4), with CRI values positively correlated with liver cancer incidence. While hazard quotients (HQ) < 1 suggest overall safety, higher obesity risks are noted, particularly among women and adolescents.

Per- and poly-fluoroalkyl substances exposure and risk of gastrointestinal cancers: a systematic review and meta-analysis

BACKGROUND

Per- and poly-fluoroalkyl substances (PFASs) are a group of synthetic chemicals used since the 1940s in industrial and consumer applications. These substances are known or suspected to cause cancer, particularly kidney and testicular cancer. However, their association with other types of cancer is not well understood. This review aims to investigate the link between PFAS exposure and the risks of other cancers, including gastrointestinal cancers such as esophageal, gastric, colorectal, and pancreatic cancer.

METHODS

We conducted a systematic review of literature from the International Agency for Research on Cancer Monographs, Agency for Toxic Substances and Disease Registry documents, and PubMed (up to January 2024) focusing on the association between PFAS exposure and gastrointestinal cancers. Four independent reviewers screened the studies, extracted the information, and evaluated the quality of the studies using a modified Newcastle-Ottawa Scale. Meta-analyses were performed with random-effects models, including stratified analyses and dose-response assessments.

RESULTS

The meta-analysis included 17 studies. The summary relative risks (RR) of esophageal cancer for perfluorooctanoic acid (PFOA) exposure was 0.75 (95% confidence interval [CI], 0.35-1.60; n = 2), and for perfluorooctane sulfonic acid (PFOS) was 1.76 (95% CI, 0.32-9.68; n = 1). The RR for gastric cancer and PFOA was 0.59 (95% CI, 0.28-1.21; n = 2) and PFAS was 0.96 (95% CI, 0.83-1.12; n = 2). The RR for colorectal cancer and PFOA was 0.83 (95% CI, 0.65-1.06; n = 6) and PFOS was 0.71 (95% CI, 0.22-2.27; n = 4). The RR for pancreatic cancer was 1.02 (95% CI, 0.90-1.15; n = 9) and PFOS was 0.92 (95% CI, 0.76-1.11; n = 2). Stratified analyses by geographical region, study design, quality score, year of publication, gender, and outcome revealed no associations for colorectal and pancreatic cancers. No dose-response trends were identified. Publication bias was suggested for gastric cancer.

CONCLUSION

Our study suggested no association between PFAS exposure and esophageal, gastric, colorectal, or pancreatic cancer. More rigorous research is needed to investigate this relationship in different settings, with precise PFAS quantification, a wider range of compounds, larger sample sizes for specific cancers, and better control for potential confounders. Our meta-analysis suggests inconclusive evidence, highlighting the need for further research.

Common questions and misconceptions about protein supplementation: what does the scientific evidence really show?

Protein supplementation often refers to increasing the intake of this particular macronutrient through dietary supplements in the form of powders, ready-to-drink shakes, and bars. The primary purpose of protein supplementation is to augment dietary protein intake, aiding individuals in meeting their protein requirements, especially when it may be challenging to do so through regular food (i.e. chicken, beef, fish, pork, etc.) sources alone. A large body of evidence shows that protein has an important role in exercising and sedentary individuals. A PubMed search of "protein and exercise performance" reveals thousands of publications. Despite the considerable volume of evidence, it is somewhat surprising that several persistent questions and misconceptions about protein exist. The following are addressed: 1) Is protein harmful to your kidneys? 2) Does consuming "excess" protein increase fat mass? 3) Can dietary protein have a harmful effect on bone health? 4) Can vegans and vegetarians consume enough protein to support training adaptations? 5) Is cheese or peanut butter a good protein source? 6) Does consuming meat (i.e., animal protein) cause unfavorable health outcomes? 7) Do you need protein if you are not physically active? 8) Do you need to consume protein ≤ 1 hour following resistance training sessions to create an anabolic environment in skeletal muscle? 9) Do endurance athletes need additional protein? 10) Does one need protein supplements to meet the daily requirements of exercise-trained individuals? 11) Is there a limit to how much protein one can consume in a single meal? To address these questions, we have conducted a thorough scientific assessment of the literature concerning protein supplementation.

Circadian control of polycyclic aromatic hydrocarbon-induced dysregulation of endothelial tight junctions and mitochondrial bioenergetics

The study evaluates the impact of environmental toxicants, such as polycyclic aromatic hydrocarbons (PAHs), on circadian regulations and functions of brain endothelial cells, which form the main structural element of the blood-brain barrier (BBB). PAH are lipophilic and highly toxic environmental pollutants that accumulate in human and animal tissues. Environmental factors related to climate change, such as an increase in frequency and intensity of wildfires or enhanced strength of hurricanes or tropical cyclones, may lead to redistribution of these toxicants and enhanced human exposure. These natural disasters are also associated with disruption of circadian rhythms in affected populations, linking increased exposure to environmental toxicants to alterations of circadian rhythm pathways. Several vital physiological processes are coordinated by circadian rhythms, and disruption of the circadian clock can contribute to the development of several diseases. The blood-brain barrier (BBB) is crucial for protecting the brain from blood-borne harmful substances, and its integrity is influenced by circadian rhythms. Exposure of brain endothelial cells to a human and environmentally-relevant PAH mixture resulted in dose-dependent alterations of expression of critical circadian modulators, such as Clock, Bmal1, Cry1/2, and Per1/2. Moreover, silencing of the circadian Clock gene potentiated the impact of PAHs on the expression of the main tight junction genes and proteins (namely, claudin-5, occludin, JAM-2, and ZO-2), as well as mitochondrial bioenergetics. Findings from this study contribute to a better understanding of pathological influence of PAH-induced health effects, especially those related to circadian rhythm disruption.

Food process contaminants: formation, occurrence, risk assessment and mitigation strategies - a review

Thermal treatment of food can lead to the formation of potentially harmful chemicals, known as process contaminants. These are adventitious contaminants that are formed in food during processing and preparation. Various food processing techniques, such as heating, drying, grilling, and fermentation, can generate hazardous chemicals such as acrylamide (AA), advanced glycation end products (AGEs), heterocyclic aromatic amines (HAAs), furan, polycyclic aromatic hydrocarbons (PAHs), N-nitroso compounds (NOCs), monochloropropane diols (MCPD) and their esters (MCPDE) which can be detrimental to human health. Despite efforts to prevent the formation of these compounds during processing, eliminating them is often challenging due to their unknown formation mechanisms. It is critical to identify the potential harm to human health in processed food and understand the mechanisms by which harmful compounds form during processing, as prolonged exposure to these toxic compounds can lead to health problems. Various mitigation strategies, such as the use of diverse pre- and post-processing treatments, product reformulation, additives, variable process conditions, and novel integrated processing techniques, have been proposed to control these food hazards. In this review, we summarize the formation and occurrence, the potential for harm to human health produced by process contaminants in food, and potential mitigation strategies to minimize their impact.

Benzo[a]pyrene exposure prevents high fat diet-induced obesity in the 4T1 model of mammary carcinoma

Tumor metastasis is the main cause of death in triple-negative breast cancer (TNBC) patients. TNBC is the most aggressive subtype of breast cancer lacking the expression of estrogen, progesterone, and human epidermal growth factor 2 receptors, thereby rendering it insensitive to targeted therapies. It has been well-established that excess adiposity contributes to the progression of TNBC; however, due to the aggressive nature of this breast cancer subtype, it is imperative to determine how multiple factors can contribute to progression. Therefore, we aimed to investigate if exposure to an environmental carcinogen could impact a pre-existing obesity-promoted cancer. We utilized a spontaneous lung metastatic mouse model where 4T1 breast tumor cells are injected into the mammary gland of BALB/c mice. Feeding a high fat diet (HFD) in this model has been shown to promote tumor growth and metastasis. Herein, we tested the effects of both a HFD and benzo(a)pyrene (B[a]P) exposure. Our results indicate that diet and B[a]P had no tumor promotional interaction. However, unexpectedly, our findings reveal an inhibitory effect of B[a]P on body weight, adipose tissue deposition, and tumor volume at time of sacrifice specifically under HFD conditions.

Could environmental exposure and climate change Be a key factor in the rising incidence of early onset colorectal cancer?

The emergence of early onset colorectal cancer (EOCRC) is believed to result from the complex interplay between external environmental factors and internal molecular processes. This review investigates the potential association between environmental exposure to chemicals and climate change and the increased incidence of EOCRC, focusing on their effects on gut microbiota (GM) dynamics. The manuscript explores the birth cohort effect, suggesting that individuals born after 1950 may be at higher risk of developing EOCRC due to cumulative environmental exposures. Furthermore, we also reviewed the impact of environmental pollution, including particulate matter and endocrine disrupting chemicals (EDCs), as well as global warming, on GM disturbance. Environmental exposures have the potential to disrupt GM composition and diversity, leading to dysbiosis, chronic inflammation, and oxidative stress, which are known risk factors associated with EOCRC. Particulate matter can enter the gastrointestinal tract, modifying GM composition and promoting the proliferation of pathogenic bacteria while diminishing beneficial bacteria. Similarly, EDCs, can induce GM alterations and inflammation, further increasing the risk of EOCRC. Additionally, global warming can influence GM through shifts in gut environmental conditions, affecting the host's immune response and potentially increasing EOCRC risk. To summarize, environmental exposure to chemicals and climate change since 1950 has been implicated as contributing factors to the rising incidence of EOCRC. Disruptions in gut microbiota homeostasis play a crucial role in mediating these associations. Consequently, there is a pressing need for enhanced environmental policies aimed at minimizing exposure to pollutants, safeguarding public health, and mitigating the burden of EOCRC.

A review on recent advancements in the treatment of polyaromatic hydrocarbons (PAHs) using sulfate radicals based advanced oxidation process

Polyaromatic hydrocarbons (PAHs) are the most persistent compounds that get contaminated in the soil and water. Nearly 16 PAHs was considered to be a very toxic according US protection Agency. Though its concentration level is low in the environments but the effects due to it, is enormous. Advanced Oxidation Process (AOP) is an emergent methodology towards treating such pollutants with low and high molecular weight of complex substances. In this study, sulfate radical (SO4‾•) based AOP is emphasized for purging PAH from different sources. This review essentially concentrated on the mechanism of SO4‾• for the remediation of pollutants from different sources and the effects caused due to these pollutants in the environment was reduced by this mechanism is revealed in this review. It also talks about the SO4‾• precursors like Peroxymonosulfate (PMS) and Persulfate (PS) and their active participation in treating the different sources of toxic pollutants. Though PS and PMS is used for removing different contaminants, the degradation of PAH due to SO4‾• was presented particularly. The hydroxyl radical (•OH) mechanism-based methods are also emphasized in this review along with their limitations. In addition to that, different activation methods of PS and PMS were discussed which highlighted the performance of transition metals in activation. Also this review opened up about the degradation efficiency of contaminants, which was mostly higher than 90% where transition metals were used for activation. Especially, on usage of nanoparticles even 100% of degradation could be able to achieve was clearly showed in this literature study. This study mainly proposed the treatment of PAH present in the soil and water using SO4‾• with different activation methodologies. Particularly, it emphasized about the importance of treating the PAH to overcome the risk associated with the environment and humans due to its contamination.

Development of an effective QSAR-based hazard threshold prediction model for the ecological risk assessment of aromatic hydrocarbon compounds

The insufficient hazard thresholds of specific individual aromatic hydrocarbon compounds (AHCs) with diverse structures limit their ecological risk assessment. Thus, herein, quantitative structure-activity relationship (QSAR) models for estimating the hazard threshold of AHCs were developed based on the hazardous concentration for 5% of species (HC5) determined using the optimal species sensitivity distribution models and on the molecular descriptors calculated via the PADEL software and ORCA software. Results revealed that the optimal QSAR model, which involved eight descriptors, namely, Zagreb, GATS2m, VR3_Dzs, AATSC2s, GATS2c, ATSC2i, ω, and Vm, displayed excellent performance, as reflected by an optimal goodness of fit (R2adj = 0.918), robustness (Q2LOO = 0.869), and external prediction ability (Q2F1 = 0.760, Q2F2 = 0.782, and Q2F3 = 0.774). The hazard thresholds estimated using the optimal QSAR model were approximately close to the published water quality criteria developed by different countries and regions. The quantitative structure-toxicity relationship demonstrated that the molecular descriptors associated with electrophilicity and topological and electrotopological properties were important factors that affected the risks of AHCs. A new and reliable approach to estimate the hazard threshold of ecological risk assessment for various aromatic hydrocarbon pollutants was provided in this study, which can be widely popularised to similar contaminants with diverse structures.

Atmospheric polycyclic aromatic hydrocarbons in India: geographical distribution, sources and associated health risk-a review

Atmospheric distribution of polycyclic aromatic hydrocarbons and associated human health risks have been studied in India. However, a comprehensive overview is not available in India, this review highlights the possible sources, and associated cancer risks in people living in different zones of India. Different databases were searched for the scientific literature on polycyclic aromatic hydrocarbons in ambient air in India. Database searches have revealed a total of 55 studies conducted at 139 locations in India in the last 14 years between 1996 and 2018. Based on varying climatic conditions in India, the available data was analysed and distributed with four zone including north, east, west/central and south zones. Comparatively higher concentrations were reported for locations in north zone, than east, west/central and south zones. The average concentrations of ∑PAHs is lower in east zone, and concentrations in north, west/central and south zones are higher by 1.67, 1.47, and 1.12 folds respectively than those in east zone. Certain molecular diagnostic ratios and correlation receptor models were used for identification of possible sources, which aided to the conclusion that both pyrogenic and petrogenic activities are the mixed sources of PAH emissions to the Indian environment. Benzo(a)pyrene toxicity equivalency for different zones is estimated and presented. Estimated Chronic daily intake (CDI) due to inhalation of PAHs and subsequently, cancer risk (CR) is found to be ranging from extremely low to low in various geographical zones of India.

Sources-attributed contributions to health risks associated with PM2.5-bound polycyclic aromatic hydrocarbons during the warm and cold seasons in an urban area of Eastern Asia

Despite the well-established recognition of the health hazards posed by PM2.5-bound PAHs, a comprehensive understanding of their source-specific impact has been lacking. In this study, the health risks associated with PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) and source-specific contributions were investigated in the urban region of Taipei during both cold and warm seasons. The levels of PM2.5-bound PAHs and their potential health risks across different age groups of humans were also characterized. Diagnostic ratios and positive matrix factorization analysis were utilized to identify the sources of PM2.5-bound PAHs. Moreover, potential source contribution function (PSCF), concentration-weighted trajectory (CWT) and source regional apportionment (SRA) analyses were employed to determine the potential source regions. Results showed that the total PAHs (TPAHs) concentrations ranged from 0.08 to 2.37 ng m-3, with an average of 0.69 ± 0.53 ng m-3. Vehicular emissions emerged as the primary contributor to PM2.5-bound PAHs, constituting 39.8 % of the TPAHs concentration, followed by industrial emissions (37.6 %), biomass burning (13.8 %), and petroleum/oil volatilization (8.8 %). PSCF and CWT analyses revealed that industrial activities and shipping processes in northeast China, South China Sea, Yellow Sea, and East China Sea, contributed to the occurrence of PM2.5-bound PAHs in Taipei. SRA identified central China as the primary regional contributor of ambient TPAHs in the cold season and Taiwan in the warm season, respectively. Evaluations of incremental lifetime cancer risk demonstrated the highest risk for adults, followed by children, seniors, and adolescents. The assessments of lifetime lung cancer risk showed that vehicular and industrial emissions were the main contributors to cancer risk induced by PM2.5-bound PAHs. This research emphasizes the essential role of precisely identifying the origins of PM2.5-bound PAHs to enhance our comprehension of the related human health hazards, thus providing valuable insights into the mitigation strategies.

The Risk of Oral Cancer and the High Consumption of Thermally Processed Meat Containing Mutagenic and Carcinogenic Compounds

The International Agency for Research on Cancer has classified the consumption of heat-processed meat as a direct human carcinogen and the consumption of red meat as a probable carcinogen. Mutagenic and carcinogenic compounds present in meat dishes include, among others, polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HAAs). These compounds can cause the development of gastrointestinal cancer. Oral cancer is one of the world's research priorities due to the ever-increasing incidence rate. However, the effect of diet on oral cancer is still a poorly recognized issue. The aim of this study was to assess the relationship between the risk of oral cancer and dietary ingredients with a particular emphasis on red meat and thermally processed meat. This study was conducted among patients with oral cancer in 2022 and 2023. The shortened standardized Food Frequency Questionnaire (FFQ) and a multivariate regression statistical analysis were used. The high consumption of red meat in general and thermally processed meat, especially smoked, fried, roasted and boiled, increases the risk of oral cavity cancer. Limiting the consumption of meat products and modifying the methods of preparing meat dishes may reduce exposure to carcinogenic compounds from the diet and thus reduce the risk of developing oral cancer.

Risk Assessment of Polycyclic Aromatic Hydrocarbons and Heterocyclic Aromatic Amines in Processed Meat, Cooked Meat and Fish-Based Products Using the Margin of Exposure Approach

Background

The objective of this study is to assess the risk of exposure of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HCAs) in meat and fish-based products marketed in Malaysia using the margin of exposure (MOE) approach.

Methods

Benchmark Dose (BMD) software was used to model the BMD at a lower end of a one-sided 95% confidence interval with a 10% incremental risk (BMDL10) of PAHs and HCAs from different target organ toxicities. The MOEs of PAHs and HCAs in meat and fish-based products were determined by utilising the calculated BMDL10 values and estimated daily intake of meat and fish-based products from published data.

Results

The calculated BMDL10 values of PAHs (i.e. benzo[a]pyrene [BaP] and fluoranthene [FA]) and HCAs (i.e. 2-amino-3,8,dimethylimidazo[4,5-f]quinoxaline [MeIQx] and 2-amino-1-methyl-6-phenylimidazo[4,5,6]pyridine [PhIP]) ranged from 19 mg/kg bw/day to 71,801 mg/kg bw/day. The MOE of BaP ranged from 41,895 to 71,801 and that of FA ranged from 19 to 1412. As for MeIQx and PhIP, their MOEs ranged from 6,322 to 7,652 and from 2,362 to 14,390, respectively.

Conclusion

The MOEs of FA, MeIQx and PhIP were lower than 10,000, indicating a high concern for human health and therefore demanding effective risk management actions.

Acceleration of benzo(a)pyrene-induced colon carcinogenesis by Western diet in a rat model of colon cancer

Colorectal cancer (CRC) is the third leading cause of cancer-related mortalities in the USA and around 52,550 people were expected to die from this disease by December 2023. The objective of this study was to investigate the effect of diet type on benzo(a)pyrene [B(a)P]-induced colon cancer in an adult male rat model, the Polyposis In the Rat Colon (PIRC) kindred type. Groups of PIRC rats (n = 10) were fed with AIN-76A regular diet (RD) or Western diet (WD) and received 25, 50 and 100 µg B(a)P/kg body wt. via oral gavage for 60 days. Rats fed diets alone, but no B(a)P, served as controls. After exposure, rats were euthanized; colon and liver samples were analyzed for activation of drug metabolizing enzymes (DMEs) CYP1A1, CYP1B1, SULT and GST. Plasma and tissue samples were analyzed by reverse phase-HPLC for B(a)P metabolites. In addition to these studies, DNA isolated from colon and liver tissues was analyzed for B(a)P-induced DNA adducts by the 32P-postlabeling method using a thin-layer chromatography system. Western diet consumption resulted in a marked increase in DME expression and B(a)P metabolite concentrations in rats that were administered 100 µg/kg B(a)P + WD (p < 0.05) compared to other treatment groups. Our findings demonstrate that WD accelerates the development of colon tumors induced by B(a)P through enhanced biotransformation, and the products of this process (metabolites) were found to bind with DNA and form B(a)P-DNA adducts, which may have given rise to colon polyps characterized by gain in tumor number, sizes, and dysplasia.

Environmental impact and human health effects of polycyclic aromatic hydrocarbons and remedial strategies: A detailed review

Polycyclic Aromatic Hydrocarbons (PAHs) profoundly impact public and environmental health. Gaining a comprehensive understanding of their intricate functions, exposure pathways, and potential health implications is imperative to implement remedial strategies and legislation effectively. This review seeks to explore PAH mobility, direct exposure pathways, and cutting-edge bioremediation technologies essential for combating the pervasive contamination of environments by PAHs, thereby expanding our foundational knowledge. PAHs, characterised by their toxicity and possession of two or more aromatic rings, exhibit diverse configurations. Their lipophilicity and remarkable persistence contribute to their widespread prevalence as hazardous environmental contaminants and byproducts. Primary sources of PAHs include contaminated food, water, and soil, which enter the human body through inhalation, ingestion, and dermal exposure. While short-term consequences encompass eye irritation, nausea, and vomiting, long-term exposure poses risks of kidney and liver damage, difficulty breathing, and asthma-like symptoms. Notably, cities with elevated PAH levels may witness exacerbation of bronchial asthma and chronic obstructive pulmonary disease (COPD). Bioremediation techniques utilising microorganisms emerge as a promising avenue to mitigate PAH-related health risks by facilitating the breakdown of these compounds in polluted environments. Furthermore, this review delves into the global concern of antimicrobial resistance associated with PAHs, highlighting its implications. The environmental effects and applications of genetically altered microbes in addressing this challenge warrant further exploration, emphasising the dynamic nature of ongoing research in this field.

Using machine learning methods to analyze the association between urinary polycyclic aromatic hydrocarbons and chronic bowel disorders in American adults

The etiology of chronic bowel disorders is multifaceted, with environmental exposure to harmful substances potentially playing a significant role in their pathogenesis. However, research on the correlation between polycyclic aromatic hydrocarbons (PAHs) and chronic bowel disorders remains limited. Using data from the National Health and Nutrition Examination Survey (NHANES) conducted in 2009-2010, we investigated the relationship between 9 PAHs and chronic diarrhea and constipation in U.S. adults. We employed unsupervised methods such as clustering and Principal Component Analysis (PCA) to identify participants with similar exposure patterns. Additionally, we used supervised learning techniques, namely weighted quantile sum (WQS) and Bayesian kernel machine (BKMR) regressions, to assess the association between PAHs and the occurrence of chronic diarrhea and chronic constipation. PCA identified three principal components in the unsupervised analysis, explaining 86.5% of the total PAH variability. The first component displayed a mild association with chronic diarrhea, but no correlation with chronic constipation. Participants were divided into three clusters via K-means clustering, based on PAH concentrations. Clusters with higher PAH exposure demonstrated an increased odds ratio for chronic diarrhea, but no meaningful connection with chronic constipation. In the supervised analysis, the WQS regression underscored a positive relationship between the PAH mixture and chronic diarrhea, with three PAHs significantly impacting the mixture effect. The mixture index showed no correlation with chronic constipation. BKMR analysis illustrated a positive trend in the impact of four specific PAHs on chronic diarrhea, given other metabolites were fixed at their 50th percentiles. Our results suggest a clear association between higher PAH exposure and an increased risk of chronic diarrhea, but not chronic constipation. It also underscores the potential role of specific PAHs in contributing to the risk of chronic diarrhea.

Hazards of polycyclic aromatic hydrocarbons: a review on occurrence, detection, and role of green nanomaterials on the removal of PAH from the water environment

Organic pollutant contamination in the environment is a serious and dangerous issue, especially for developing countries. Among all organic pollutants, polycyclic aromatic hydrocarbons (PAHs) are the more frequently discovered ones in the environment. PAH contamination is caused chiefly by anthropogenic sources, such as the disposal of residential and industrial waste and automobile air emissions. They are gaining interest due to their environmental persistence, toxicity, and probable bioaccumulation. The existence of PAHs may result in damage to the environment and living things, and there is widespread concern about the acute and chronic threats posed by the release of these contaminants. The detection and elimination of PAHs from wastewater have been the focus of numerous technological developments during recent decades. The development of sensitive and economical monitoring systems for detecting these substances has attracted a lot of scientific attention. Using several nanomaterials and nanocomposites is a promising treatment option for the identification and elimination of PAHs in aquatic ecosystems. This review elaborated on the sources of origin, pathogenicity, and widespread occurrence of PAHs. In addition, the paper highlighted the use of nanomaterial-based sensors in detecting PAHs from contaminated sites and nanomaterial-based absorbents in PAH elimination from wastewater. This review also addresses the development of Graphene and Biofunctionalized nanomaterials for the elimination of PAHs from the contaminated sites.

Association between urinary concentrations of polycyclic aromatic hydrocarbons and risk of endometriosis in the NHANES 2003-2006

To explore the association between exposure to polycyclic aromatic hydrocarbons (PAHs) and endometriosis risk. Data were obtained from the 2003-2006 National Health and Nutrition Examination Survey database. Urinary concentrations of PAHs were divided into quartiles, and weighted multivariate logistic regression, restricted cubic spline, and subgroup analyses were performed. An extreme gradient boosting (XGBoost) algorithm was used to screen the most important PAHs. After multivariable adjustments, 9-fluorene, 1-phenanthrene, 2-phenanthrene, and 4-phenanthrene exposure were significantly associated with a risk of endometriosis. Specifically, compared with the reference group, the odds ratios (ORs) of endometriosis for the fourth quartile were 3.52 (95% confidence interval (CI): 1.15, 10.77), 3.10 (95% CI: 1.37, 6.97), 4.86 (95% CI: 1.93, 12.21), and 2.67 (95% CI: 1.02, 7.01) for 9-fluorene, 1-phenanthrene, 2-phenanthrene, and 4-phenanthrene, respectively. In terms of continuous exposure, each one-standard-deviation increase in the urinary concentration of 9-fluorene, 1-phenanthrene, 2-phenanthrene, and 4-phenanthrene was independently associated with a 66% (OR: 1.66, 95% CI: 1.15, 2.40), 62% (OR:1.62, 95% CI: 1.19, 2.20), 68% (OR: 1.68, 95% CI: 1.24, 2.28), and 56% (OR: 1.56, 95% CI: 1.11, 2.19) increase in the risk of endometriosis, respectively, in the fully adjusted model. A significant association between the urinary concentration of 9-fluorene and the risk of endometriosis was also observed in participants who had a high body-mass index (≥25 kg/m2), with a corresponding OR of 2.61 (95% CI: 1.37, 5.00; P for interaction = 0.006). Our findings show that high urinary concentrations of PAHs were associated with a high risk of endometriosis in participants and that the urinary concentration of 9-fluorene was related with a high susceptibility of endometriosis in participants with overweight.

An overview of the impacts of coal mining and processing on soil: assessment, monitoring, and challenges in the Czech Republic

Coal mining activities are causing an extensive range of environmental issues at both operating and abandoned mine sites. It is one of the most environmentally destructive practices, with the capability to eliminate fauna and flora, impact the groundwater system, and pollute the soil, air, and water. The Czech Republic relies almost exclusively on coal as its primary domestic source of energy. The combined reserves of hard and brown coals in this country are 705 million tons. About 50 million tons of coal is produced annually, making it the 14th biggest producer in the world. Soil degradation is an inevitable outcome of the coal production from surface coal mining procedures in the Czech Republic. Significant changes have taken place in soil productivity, hydraulic characteristics, horizon, and texture as a result of soil pollution, bioturbation, compaction, and weathering. The current review has evaluated the impact of reclamation and coal mining on soil characteristics, including biological, chemical, and physical properties. Additionally, the study has outlined the process of soil formation in reclamation areas in the Czech Republic. In nutshell, research gaps and future directions in understanding coal mining areas and their influences on soils in the Czech Republic are identified.

Aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) play both distinct and common roles in the regulation of colon homeostasis and intestinal carcinogenesis

Both aryl hydrocarbon receptor (AhR) and pregnane X receptor (PXR) belong among key regulators of xenobiotic metabolism in the intestinal tissue. AhR in particular is activated by a wide range of environmental and dietary carcinogens. The data accumulated over the last two decades suggest that both of these transcriptional regulators play a much wider role in the maintenance of gut homeostasis, and that both transcription factors may affect processes linked with intestinal tumorigenesis. Intestinal epithelium is continuously exposed to a wide range of AhR, PXR and dual AhR/PXR ligands formed by intestinal microbiota or originating from diet. Current evidence suggests that specific ligands of both AhR and PXR can protect intestinal epithelium against inflammation and assist in the maintenance of epithelial barrier integrity. AhR, and to a lesser extent also PXR, have been shown to play a protective role against inflammation-induced colon cancer, or, in mouse models employing overactivation of Wnt/β-catenin signaling. In contrast, other evidence suggests that both receptors may contribute to modulation of transformed colon cell behavior, with a potential to promote cancer progression and/or chemoresistance. The review focuses on both overlapping and separate roles of the two receptors in these processes, and on possible implications of their activity within the context of intestinal tissue.

Association of exposure to polycyclic aromatic hydrocarbons with thyroid hormones in adolescents and adults, and the influence of the iodine status

Some studies of endocrine-disrupting polycyclic aromatic hydrocarbon (PAH) exposure and thyroid hormones (THs) are inconclusive. To assess the associations between PAHs and THs, and the influence of the iodine status on PAHs-THs, we employed 648 adolescents (12-19 years old) and 2691 adults from the National Health and Nutrition Examination Survey 2007-2008 and 2011-2012. PAH metabolites [1-hydroxynaphthalene (1-NAP), 2-NAP, 1-hydroxyphenanthrene (1-PHE), 2-PHE, 3-PHE, 2-hydroxyfluorene (2-FLU), 3-FLU, 9-FLU, and 1-hydroxypyrene (1-PYR)], THs [total and free thyroxine (TT4 and FT4), total and free triiodothyronine (TT3 and FT3), thyroid stimulating hormone (TSH), and thyroglobulin (Tg)], peripheral deiodinase activity (GD) and thyroid's secretory capacity (GT) were involved. Multiple linear regression and weighted quantile sum (WQS) regression models were used to assess PAH-TH associations and the interaction between PAHs and the iodine status. Stratification analyses were conducted based on sex, smoking and iodine status. For adolescents, in a multivariable-adjusted regression model (β; 95% CI), 1-PHE (4.08%; 1.01%, and 7.25%), 2-PHE (3.98%; 0.70%, and 7.25%) and 9-FLU (3.77%; 1.10%, 7.47%) were positively correlated with TT3; 3-PHE and 1-PYR interacted with the iodine status (P-int < 0.05); 9-FLU was positively correlated with GD in both sexes. Combined exposure to PAHs was positively associated with Tg (0.137; 0.030, and 0.243), and negatively correlated with TSH (-0.087; -0.166, and -0.008). For adults, 2-NAP was positively correlated with FT3 (0.90%; 0.20%, and 1.61%), FT4 (1.82%; 0.70%, and 2.94%), TT3 (1.31%; 0.10%, and 2.63%), TT4 (2.12%; 0.90%, and 3.36%) and GT (2.22%; 1.01%, and 3.46%), but negatively correlated with TSH (-4.97%; -8.33%, and -1.49%); 1-NAP interacted with the iodine status (P-int < 0.05); 1-PHE was inversely correlated with TT3 in males; 2-PHE was positively correlated with TT3 in females. Combined exposure to PAHs was positively associated with FT3 (0.008; 0.001, and 0.014). Combined exposure to PAHs was positively associated with FT3, TT3 and GD, and negatively correlated with FT4, TT4 and GT in non-smoking adults; but positively associated with Tg (β = 0.140; 95% CI: 0.042, 0.237) in smoking adults. Our results indicated that combined and individual PAH exposure might be related to THs, and the iodine status had an influence on PAH-TH associations. These associations were not identical between adolescents and adults, and there were sex and smoking status differences.

Development and validation of an HPLC-MS/MS method for the simultaneous analysis of volatile organic compound metabolites, hydroxylated polycyclic aromatic hydrocarbons, and 8-hydroxy-2'-deoxyguanosine in human urine

Humans are widely and concurrently exposed to volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs). However, few studies have reported the internal co-exposure levels of these chemicals in occupational and general populations. Specifically, the associations revealed between the urinary levels of metabolites of VOCs (mVOCs), hydroxylated PAHs (OH-PAHs), and oxidative stress biomarkers for humans remain limited. In this study, a method based on solid-phase extraction (SPE) and liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) was developed for the simultaneous analysis of 22 mVOCs, 12 OH-PAHs, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in human urine samples. The method was validated with all target analyte accuracies and precisions in the range of 76 %-120 % and 1 %-14 % at three levels of spiked urine samples, respectively. The limit of detection (LOD) and limit of quantification (LOQ) of the target analytes were 0.01-0.34 ng/mL and 0.01-7.57 ng/mL, respectively. And the method was applied to measure urinary levels of target analytes from 38 petrochemical workers in Guangzhou, South China. Except for 3-hydroxy-benzo[a]pyrene, all target analytes were detected in the urine samples. The average levels were 0.05-12.6 ng/mL for individual OH-PAHs, 0.20-73620 ng/mL for individual mVOCs, and 1.00 ng/mL for 8-OHdG. Additionally, 3-hydroxy-phenanthrene, 1-hydroxy-pyrene, 6-hydroxy-chrysene, N-acetyl-S-(trichlorovinyl)-L-cysteine, 2-methylhippuric acid, thiodiacetic acid, trans, trans-Muconic acid, and N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine had statistically significant positive effects on 8-OHdG levels, while 1-hydroxy-naphthalene, 1,2-dihydroxybenzene, and hippuric acid showed a negative effect on 8-OHdG, indicating these metabolites could lead to synergistic or antagonistic oxidative DNA damage. This study provides a robust analytical method that permits a comprehensive assessment of co-exposure to PAHs and VOCs and their potential adverse health effects.

Reducing the Risk of Acrylamide and Other Processing Contaminant Formation in Wheat Products

Wheat is a staple crop, consumed worldwide as a major source of starch and protein. Global intake of wheat has increased in recent years, and overall, wheat is considered to be a healthy food, particularly when products are made from whole grains. However, wheat is almost invariably processed before it is consumed, usually via baking and/or toasting, and this can lead to the formation of toxic processing contaminants, including acrylamide, 5-hydroxymethylfurfural (HMF) and polycyclic aromatic hydrocarbons (PAHs). Acrylamide is principally formed from free (soluble, non-protein) asparagine and reducing sugars (glucose, fructose and maltose) within the Maillard reaction and is classified as a Group 2A carcinogen (probably carcinogenic to humans). It also has neurotoxic and developmental effects at high doses. HMF is also generated within the Maillard reaction but can also be formed via the dehydration of fructose or caramelisation. It is frequently found in bread, biscuits, cookies, and cakes. Its molecular structure points to genotoxicity and carcinogenic risks. PAHs are a large class of chemical compounds, many of which are genotoxic, mutagenic, teratogenic and carcinogenic. They are mostly formed during frying, baking and grilling due to incomplete combustion of organic matter. Production of these processing contaminants can be reduced with changes in recipe and processing parameters, along with effective quality control measures. However, in the case of acrylamide and HMF, their formation is also highly dependent on the concentrations of precursors in the grain. Here, we review the synthesis of these contaminants, factors impacting their production and the mitigation measures that can be taken to reduce their formation in wheat products, focusing on the role of genetics and agronomy. We also review the risk management measures adopted by food safety authorities around the world.

Recent Evidence on Polycyclic Aromatic Hydrocarbon Exposure

This review provides a comprehensive conclusion of the relationship between the intake of various polycyclic aromatic hydrocarbons (PAHs) and different dietary patterns, pointing to the accompanying potential health risks. To achieve this, existing pertinent research was collected and analyzed. The collation revealed that the concentration of PAHs in food and their dietary patterns were diverse in different regions. Specifically, the concentration of PAHs in food was found to be related to the level of pollution in the area, including soil, air, and water pollution, which is then accumulated through the food chain into food that can be ingested directly by the human body, resulting in malformations in offspring, increased risk of cancer, and gene mutation. Guidebooks and dietary surveys were consulted to uncover disparities in dietary patterns, which indicated regional variations in taste preferences, traditional foods, and eating habits. Different regions are spatially categorized in this assessment by cities, countries, and continents. Notably, smoking and grilling are two of the food processing methods most likely to produce high levels of PAHs. To prevent excessive intake of PAHs from food items and attain a higher quality of life, more health education is urgently needed to promote healthy eating patterns.

Integrating Microbiome Analysis, Metabolomics, Bioinformatics, and Histopathology to Elucidate the Protective Effects of Pomegranate Juice against Benzo-alpha-pyrene-Induced Colon Pathologies

Polycyclic aromatic hydrocarbons, e.g., benzo[a]pyrene (BaP), are common dietary pollutants with potential carcinogenic activity, while polyphenols are potential chemopreventive antioxidants. Although several health benefits are attributed to polyphenol-rich pomegranate, little is known about its interaction with BaP. This study integrates histochemical, microbiomic, and metabolomic approaches to investigate the protective effects of pomegranate juice from BaP-induced pathologies. To this end, 48 Sprague-Dawley rats received, for four weeks, either pomegranate, BaP, both, or neither (n = 12 rats per group). Whereas histochemical examination of the colon indicated tissue damage marked by mucin depletion in BaP-fed animals, which was partially restored by administration of pomegranate juice, the fecal microbiome and metabolome retained their resilience, except for key changes related to pomegranate and BaP biotransformation. Meanwhile, dramatic microbiome restructuring and metabolome shift were observed as a consequence of the elapsed time (age factor). Additionally, the analysis allowed a thorough examination of fecal microbiome-metabolome associations, which delineated six microbiome clusters (marked by a differential abundance of Lactobacillaceae and Prevotellaceae, Rumincococcaceae, and Erysipelotrichaceae) and two major metabolome clusters (a sugar- and amino-acids-dominated metabotype vs. a cluster of fatty acids and hydrocarbons), with sugar alcohols maintaining a unique signature. In conclusion, using paired comparisons to minimize inter-individual animal variations allowed the dissection of temporal vs. treatment-derived variations. Microbiome-metabolome association clusters may be further exploited for metabotype prediction and gut-health biomarker discovery.

Long-Term Atmosphere Surveillance (2016-2021) of PM2.5-bound Polycyclic Aromatic Hydrocarbons and Health Risk Assessment in Yangtze River Delta, China

Long-term atmospheric quality monitoring of fine particulate matter (PM2.5) and PM2.5-bound polycyclic aromatic hydrocarbons (PAHs) was performed in Wuxi from 2016 to 2021. In total, 504 atmospheric PM2.5 samples were collected, and PM2.5-bound 16 PAHs were detected. The PM2.5 and ∑PAHs level decreased annually from 2016 to 2021, from 64.3 to 34.0 μg/m3 and 5.27 to 4.22 ng/m3, respectively. The benzo[a]pyrene (BaP) levels of 42% of the monitoring days in 2017 exceeded the recommended European Union (EU) health-based standard of 1 ng/m3. Five- and six-ring PAHs were found, including benz[a]anthracene, benzo[k]fluoranthene (Bkf), BaP, and benzo[g,h,i]perylene, which were the dominant components (indicating a prominent petroleum, biomass, and coal combustion contribution) using molecular diagnostic ratios and positive matrix factorization analysis. Moreover, PM2.5 and PAHs were significantly negatively associated with local precipitation over a period of six years. Statistically significant temporal and spatial distribution differences of PM2.5, and ∑PAHs were also found. The toxicity equivalent quotient (TEQ) of total PAHs was 0.70, and the TEQ of BaP (0.178) was the highest, followed by that of Bkf (0.090), dibenz[a,h]anthracene (Dah) (0.048), and indeno[1,2,3-cd]pyrene (0.034). The medians of the incremental lifetime cancer risk for long-term exposure to PAHs were 2.74E-8, 1.98E-8, and 1.71E-7 for children, teenagers, and adults, respectively, indicating that the carcinogenic risk of PAHs pollution in air was acceptable to local residents in this area. Sensitivity analysis revealed that BaP, Bkf, and Dah significantly contributed to carcinogenic toxicity. This research provides comprehensive statistics on the local air persistent organic pollutants profile, helps to identify the principal pollution source and compounds, and contributes to the prevention of regional air pollution.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12403-023-00572-x.

Detection of polycyclic aromatic hydrocarbons using a high performance-single particle aerosol mass spectrometer

The real-time detection of the mixing states of polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs in ambient particles is of great significance for analyzing the source, aging process, and health effects of PAHs and nitro-PAHs; yet there is still few effective technology to achieve this type of detection. In this study, 11 types of PAH and nitro-PAH standard samples were analyzed using a high performance-single particle aerosol mass spectrometer (HP-SPAMS) in lab studies. The identification principles 'parent ions' and 'mass-to-charge (m/z) = 77' of each compound were obtained in this study. It was found that different laser energies did not affect the identification of the parent ions. The comparative experiments of ambient atmospheric particles, cooking and biomass burning emitted particles with and without the addition of PAHs were conducted and ruled out the interferences from primary and secondary organics on the identification of PAHs. Besides, the reliability of the characteristic ions extraction method was evaluated through the comparative study of similarity algorithm and deep learning algorithm. In addition, the real PAH-containing particles from vehicle exhaust emissions and ambient particles were also analyzed. This study improves the ability of single particle mass spectrometry technology to detect PAHs and nitro-PAHs, and HP-SPAMS was superior to SPAMS for detecting single particles containing PAHs and nitro-PAHs. This study provides support for subsequent ambient observations to identify the characteristic spectrum of single particles containing PAHs and nitro-PAHs.

Chronic Exposure to Low-Molecular-Weight Polycyclic Aromatic Hydrocarbons Promotes Lipid Accumulation and Metabolic Inflammation

2-naphthol is a low-molecular-weight (LMW) polycyclic aromatic hydrocarbon (PAH) and air pollutant associated with childhood obesity. There has been a recent emergence of studies on the consequences of PAHs on human health. Current epidemiological reports suggest LMW-PAHs may contribute to obesity incidences in children, yet most studies focus on high-molecular-weight PAHs. This study explores 2-naphthol's impact on obesity and obesity-associated metabolic disorders. To investigate 2-naphthol's effect on lipid metabolism and inflammation, we employed 3T3-L1 and BAT1 cell lines to model white and brown adipocytes, respectively, alongside a murine macrophage cell line (RAW264.7). We found that 2-naphthol increased the expression of key adipogenic and lipogenic genes while decreasing lipolytic gene expression in chronically treated 3T3-L1 and BAT1 adipocytes. In addition, chronic 2-naphthol treatment also suppressed adrenergic-stimulated thermogenic gene expression in BAT1 brown adipocytes. In consistence, an increase in lipid accumulation was demonstrated in BODIPY and Oil Red O-stained adipocytes. Additionally, 3T3-L1 adipocytes and RAW264.7 macrophages chronically exposed to 2-naphthol showed upregulated mRNA expression of major inflammatory cytokines (e.g., tumor necrosis factor α (Tnfα), interleukin-1β (Il-1β), and Il-6). In summary, chronic exposure to 2-naphthol stimulates lipid accumulation in adipocytes and inflammation in adipocytes and macrophages. These findings support previous research that demonstrates 2-naphthol has obesogenic potential.

Bibliometric analysis of global research on polycyclic aromatic hydrocarbons and health risk between 2002 and 2021

During the last 20 years, the association between polycyclic aromatic hydrocarbons (PAHs) and health risk has become one of the hotspots in the fields of public health and the environment. A bibliometric study of 1392 research articles retrieved from the Web of Science Core Collection (WoSCC) published between 2002 and 2021 was performed to give an in-depth statistical evaluation of research progress and future trends on PAHs and health risk (PHR). According to the findings, the annual output of significant scientific papers increased exponentially. China ranked first among the 86 nations in terms of the number of publications (NP), followed by the USA and India. Logistic regression analysis showed that there was a positive relationship between the second tertile of 180-day usage count (AOR = 1.62; 95% CI: 1.16-2.26) and increased odds of open access publishing after adjustment for the confounders, indicating that open access papers on PHR were more preferred over the preceding 6 months than non-open access articles. The most popular terms were "PAHs," "risk assessment," and "source identification." According to the bibliometric study, the research hotspots that require more exploration include identifying PAH sources in media such as soil, water, dust, and food and evaluating their linkages to health hazards using appropriate risk models. Understanding the environmental behavior, bioavailability, and health concerns of PAHs and their derivatives in various media is critical for environmental and public health protection. This paper provides an overview of current research status and future perspectives for PHR research.

Association between dietary fat intake and colorectal cancer: A multicenter case-control study in Iran

The evolving trends in colorectal cancer (CRC) as one of the most common malignancies worldwide, have likely been influenced by the implementation of screening programs and changes in lifestyle habits. Changing lifestyle, including the shift in diet composition with higher fat, sugar, and animal-source foods intake, led to an increasing burden of CRC in countries undergoing rapid socioeconomic improvement. Results for the link between specific fatty acids (FAs) and CRC are generally inconclusive and more limited in developing countries than elsewhere. This study aims to investigate the association between FA intakes and CRC and its anatomical subsites in a large Iranian case-control study. A food frequency questionnaire was used to collect information on dietary intake in 865 cases and 3206 controls. We conducted multivariate logistic regression models to calculate the odds ratio (OR) and 95% confidence interval (CI). We found positive association between CRC and high intake of dietary total fat (OR highest quartile Q4 = 1.77, 95% CI = 1.32-2.38), cholesterol (ORQ4 = 1.58, 95% CI = 1.22-2.05), and palmitoleic acid (ORQ4 = 2.16, 95% CI = 1.19, 3.91), and an inverse association with high intake of dietary heptanoic acid (ORQ4 = 0.33, 95% CI = 0.14, 0.79) and low intake of palmitic acid (OR lowest quartile Q2 = 0.53, 95% CI = 0.31-0.88). None of the fat variables were associated with rectal cancer. Our study suggests that the recommendation of limited consumption of fats may decrease the risk of CRC among the Iranian population.

Urinary polycyclic aromatic hydrocarbon metabolites, plasma p-tau231 and mild cognitive impairment in coke oven workers

BACKGROUND

As a group of environmental pollutants, polycyclic aromatic hydrocarbons (PAHs) may be neurotoxic，especially in high-exposure occupational populations. However, the effect of PAHs on mild cognitive impairment (MCI) is still unclear.

OBJECTIVE

We aimed to investigate the relationship between PAH metabolites and MCI and to explore whether plasma p-tau231 can be used as a potential biomarker to reflect MCI in coke oven workers.

METHOD

A total of 330 workers were recruited from a coke oven plant as the exposure group, and 234 workers were recruited from a water treatment plant as the control group. The concentrations of eleven PAH metabolites and plasma p-tau231 were determined by high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) and ELISA. Cognitive function was measured by the Montreal Cognitive Assessment (MoCA) questionnaire. A multivariate logistic regression model and multiple linear regression model were used to analyze the associations of urinary PAH metabolites with the detection rate of MCI, MoCA scores and plasma p-tau231. The dose-response relationships were evaluated using restricted cubic spline models.

RESULTS

We found 146 MCI-positive workers in coke oven plant (44.24%), and 69 MCI-positive workers in water treatment plant (29.49%). In addition, the urinary sum of PAH metabolites (Ʃ-OH PAHs) was significantly associated with MCI (OR, 1.371; 95% CI:1.102-1.705). Each one-unit increase in ln-transformed Ʃ-OH PAHs was associated with a 0.429 decrease in the sum of MoCA, a 0.281 reduction in the visuospatial/executive function and a 9.416 increase in the level of plasma P-Tau231. We found a negative association between plasma P-Tau231 and visuospatial/executive function (β = -0.007, 95% CI: -0.011, -0.003).

CONCLUSION

Our data indicated that urinary Ʃ-OH PAHs levels of workers were positively associated with MCI and the level of plasma P-Tau231.

Preparation of Monoclonal Antibody against Pyrene and Benzo [a]pyrene and Development of Enzyme-Linked Immunosorbent Assay for Fish, Shrimp and Crab Samples

Polycyclic aromatic hydrocarbons (PAHs) are significant environmental and food pollutants that can cause cancer. In this work, a specific monoclonal antibody (mAb) to identify pyrene (PYR) and benzo [a]pyrene (BaP) was prepared, and an indirect competitive enzyme-linked immunoassay (ic-ELISA) was established to detect PYR and BaP residues in living aquatic products for the first time. The effects of complete antigens with different coupling ratios on the production of high-sensitivity mAb was explored. Under the optimal conditions, the IC₅₀ value was 3.73 ± 0.43 µg/L (n = 5). The limits of detection (LODs) for PYR and BaP in fish, shrimp, and crab ranged from 0.43 to 0.98 µg/L. The average recoveries of the spiked samples ranged from 81.5–101.9%, and the coefficient of variation (CV) was less than 11.7%. The validation of the HPLC-FLD method indicated that the ELISA method set up in this experiment provided a trustworthy tool for PAHs residues detection in aquatic products.

Colorectal Cancer and Microbiota Modulation for Clinical Use. A Systematic Review

Colorectal cancer (CRC) is one of the top contributors to the global burden of cancer incidence and mortality, with both genetic and environmental factors contributing to its etiology. Environmental factors may be the cause of up to 60% of the risk of developing CRC, with gut microbiota being a crucial modifiable risk factor. The microbial ecosystem plays a vital role in CRC prevention and antitumoral response through modulation of the immune system and production of short-chain fatty acids. Numerous approaches have been followed to modify the gut microbiota in order to reduce the risk of cancer development, improve treatment efficacy, and reduce side effects. This study aims to perform a systematic analysis of the published literature to elucidate whether microbiota modulation through pre-, pro-, and symbiotic treatment and/or nutritional intervention can be beneficial for patients diagnosed with CRC. Our analysis finds that some prebiotics, mainly in the form of oligo- and polysaccharides, probiotics such as lactic strain producers of short-chain fatty acids, and consumption of a Mediterranean plant-based diet may be beneficial for patients diagnosed with CRC. However, there is a need for clinical data which evaluate the modulation of gut microbiota in a safe and effective manner.

Filamentous fungi from textile effluent and their potential application for bioremediation process

The inappropriate disposal of toxic compounds generated by industrial activity has considerably impacted the environment. Microbial communities inhabiting contaminated sites may represent ecological alternatives for the decontamination of environments. The present work aimed to search the potential of fungi isolated from wastewater treatment plant of a textile industry for bioremediation processes. Twenty-three fungi previously isolated from textile effluent were evaluated for their abilities to degrade pollutants using heavy metal and hydrocarbon tolerance assays. One isolate was subjected to pyrene degradation due its ability to tolerate hydrocarbon. The majority of isolates were resistant to at least two metals tested, i.e. chrome, copper, lead and aluminum. Isolates Penicillium sp. ITF 2, Penicillium rubens ITF 4, Penicillium sp. ITF 12 and ITF 20 (not identified) showed tolerance to tested heavy metals in all concentrations. ITF 12 and ITF 20 were able to tolerate benzene, toluene and hexane, separately. ITF 12 was able to degrade 24.9% of pyrene after 5 days of cultivation. The results encourage future studies to optimize the tolerance and degradation assay using the isolates that showed the best results, as well as studies on the treatment of environments contaminated with heavy metals and hydrocarbons, including industrial textile effluents.

Inflammatory potential of diet and colorectal carcinogenesis: a prospective longitudinal cohort

BACKGROUND

Acknowledging the role of inflammation in colorectal carcinogenesis, this study aimed to evaluate the associations between diet-associated inflammation, as measured by the energy-adjusted dietary inflammatory index (E-DIITM), and distinct stages of colorectal carcinogenesis.

METHODS

The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial enrolled participants without a colorectal cancer history, who were asked to complete baseline questionnaires and food frequency questionnaires. To estimate the associations between the E-DII and risks of newly incident colorectal adenoma, recurrent adenoma, and colorectal cancer, multivariable-adjusted Cox proportional hazards regression models were employed.

RESULTS

Among 101,680 participants, with an average age of 65 years, a total of 1177 incident colorectal adenoma cases, 895 recurrent adenoma cases and 1100 colorectal cancer cases were identified. Higher E-DII scores from food and supplement (HRQ5 vs Q1: 0.86 [0.69-1.06], Ptrend: 0.27) or from food only (HRQ5 vs Q1: 0.82 [0.64-1.05], Ptrend: 0.06) were not associated with higher risks of incident adenoma. However, the elevated risk of recurrent adenoma was found in the highest category of E-DII from food plus supplement (HRQ5 vs Q1: 1.63 [1.28-2.03], Ptrend: < 0.001) when compared with the lowest category. A significant association between colorectal cancer risk and E-DII from food plus supplement (HRQ5 vs Q1: 1.34 [1.09-1.65], Ptrend: 0.009) was found, where this association was only pronounced in distal colorectal cancer.

CONCLUSION

Higher E-DII scores from diet plus supplement but not from diet only were associated with a higher risk of recurrent adenoma and distal colorectal cancer. The role of nutrient supplements on cancer risk, especially when combined with diet, needs to be elucidated in future studies.

Polycyclic aromatic hydrocarbon and its effects on human health: An overeview

Polycyclic aromatic hydrocarbons (PAHs) are a class of chemicals of considerable environmental significance. PAHs are chemical contaminants of fused carbon and hydrogen aromatic rings, basically white, light-yellow, or solid compounds without color. Natural sources of pollution are marginal or less significant, such as volcanic eruptions, natural forest fires, and moorland fires that trigger lightning bursts. The significant determinants of PAH pollution are anthropogenic pollution sources, classified into four groups, i.e., industrial, mobile, domestic, and agricultural pollution sources. Humans can consume PAHs via different routes, such as inhalation, dermal touch, and ingestion. The Effect of PAHs on human health is primarily based on the duration and route of exposure, the volume or concentration of PAHs to which one is exposed, and the relative toxicity of PAHs. Many PAHs are widely referred to as carcinogens, mutagens, and teratogens and thus pose a significant danger to human health and the well-being of humans. Skin, lung, pancreas, esophagus, bladder, colon, and female breast are numerous organs prone to tumor development due to long-term PAH exposure. PAH exposure may increase the risk of lung cancer as well as cardiovascular disease (CVD), including atherosclerosis, thrombosis, hypertension, and myocardial infarction (MI). Preclinical studies have found a relationship between PAH exposure, oxidative stress, and atherosclerosis. In addition, investigations have discovered a relationship between PAH exposure at work and CVD illness and mortality development. This review aims to explain PAH briefly, its transportation, its effects on human health, and a relationship between environmental exposures to PAHs and CVD risk in humans.

Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Smoked Sardinella sp. in Ghana: Impact of an Improved Oven on Public Health Protection

An improved fish smoking oven called FAO-Thiaroye Technique (FTT) has been introduced in Ghana and other countries in the Global South as a technical intervention for the high levels of polycyclic aromatic hydrocarbons (PAHs) in traditionally smoked fish produced in those regions. This study evaluated the extent to which the intervention reduces consumer exposure to PAHs (considering benzo(a)pyrene [BaP] as a marker) in smoked fish, using Ghana as a case. Smoked Sardinella sp. were sampled from two traditional ovens (Chorkor smoker and metal drum oven) and the FTT and their PAH levels were determined by gas chromatography-mass spectrometry. Samples of the product were also purchased from informal markets in three selected regions of Ghana and analyzed for their PAH levels. Cross-sectional consumer surveys were conducted in the selected regions to determine intakes of the commodity. A probabilistic risk assessment of PAH was then done by the margin of exposure (MoE) approach. BaP MoE as low as 1,060 and 752 were obtained for products from the traditional ovens and the informal markets, respectively, whereas the lowest value for FTT products was approximately 161,000. MoE values less than 10,000 were considered to denote a serious public health concern requiring risk management action. Therefore, the findings suggest that there is a potential health concern of high consumer exposure to PAHs in traditionally smoked fish in Ghana, and that the FTT is a technically viable intervention for the problem.

Consumption of Thermally Processed Meat Containing Carcinogenic Compounds (Polycyclic Aromatic Hydrocarbons and Heterocyclic Aromatic Amines) versus a Risk of Some Cancers in Humans and the Possibility of Reducing Their Formation by Natural Food Additives-A Literature Review

(1) Background: Thermal treatment of high-protein food may lead to the formation of mutagenic and carcinogenic compounds, e.g., polycyclic aromatic hydrocarbons and heterocyclic aromatic amines. Frequent consumption of processed meat was classified by the International Agency for Research on Cancer as directly carcinogenic for humans. (2) Methods: A literature review was carried out based on a search of online databases for articles on consuming thermally processed meat containing carcinogenic compounds versus a risk of cancers in humans published between 2001 and 2021. (3) Results: A review of the current literature on the participation of PAHs and HAA in the formation of certain neoplasms indicates a positive relationship between diet and the incidences of many cancers, especially colon cancer. A simple way to obtain dishes with reduced contents of harmful compounds is the use of spices and vegetables as meat additives. These seasonings are usually rich in antioxidants that influence the mechanism of HAA and PAH synthesis in food. (4) Conclusions: As there is a growing risk of a cancer tendency because of exposing humans to PAHs and HAAs, it is extremely vital to find a simple way to limit carcinogenic compound synthesis in a processed proteinaceous food. Disseminating the knowledge about the conditions for preparing dishes with a reduced content of carcinogenic compounds could become a vital element of cancer prevention programs.

Quantification and health impact assessment of polycyclic aromatic hydrocarbons (PAHs) emissions from crop residue combustion

Emission of Polycyclic Aromatic Hydrocarbon compounds from combustion of crop residue was investigated. Crop residues comprising maize cobs, maize husks, rice husks and bean chaff were burnt in a furnace at a temperature of 400 °C and the emissions from the combustion process were characterized using standard methods. Health risk through inhalation was assessed using toxic equivalent factors and excess lifetime cancer risk. The results showed the detection of 16 PAH compound which included: Benzo[ghi]perylene, Naphthalene, Acenaphthene, Anthracene, Phenanthrene, Fluorene, Fluoranthene, Acenaphthylene, Pyrene, Benzo[a]anthracene, Dibenzo[a,h]anthracene, Benzo[b]fluoranthene, Chrysene, Benzo[a]pyrene, Indene[1,2,3-cd]pyrene and Benzo[k]fluoranthene. Benzo[b]fluoranthene had highest mean concentration of 1.30 μg/mg while Dibenzo[a,h]anthracene had the lowest mean concentration of 0.01 μg/mg. It was also revealed that the toxicity of PAHs was due to the presence of Benzo[b]fluoranthene for all the samples except for sample 4 for which the main contribution to toxicity was emission from benzo(a)pyrene, while the cancer risk assessment estimated to be 1.2 × 10^-1 was far above the acceptable carcinogenic risk limit of 1 × 10^-6. This study concluded that, more efforts are needed to reduce emission of PAHs from the combustion of crop residues into the ambient air otherwise, human health could be under threat especially if exposed for a long period.

Association among urinary polycyclic aromatic hydrocarbons and depression: a cross-sectional study from NHANES 2015-2016

Polycyclic aromatic hydrocarbons (PAHs) are a group of chemicals produced from incomplete combustion of carbon-containing products. PAH exposure is associated with pulmonary disease, cardiovascular disease, liver disease, and cancer. However, studies on the exposure to PAHs and depression are limited. The aim of this study is to investigate the relationship between seven types of urinary PAH exposure and depression in the adult population using the National Health and Nutrition Examination Survey (NHANES)2015-2016 dataset. The nine-item Patient Health Questionnaire (PHQ-9) was used to assess for depression; a PHQ-9 score ≥ 10 was considered depressed. Multivariate logistic regression analysis for complex survey procedures was used to assess the relationship between seven types of PAH exposure and depression. A total of 4,123 adults aged ≥20 years were included in the study sample. All forms of urinary PAHs studied, including 1-hydroxynaphthalene, 2-hydroxynaphthalene, 3-hydroxyfluorene, 2-hydroxyfluorene, 1-hydroxyphenanthrene, 1-hydroxypyrene, and 2 and 3-hydroxyphenanthrene, were positively associated with depression.