Determination of polycyclic aromatic hydrocarbon content in heat-treated meat retailed in Egypt: Health risk assessment, benzo[a]pyrene induced mutagenicity and oxidative stress in human colon (CaCo-2) cells and protection using rosmarinic and ascorbic acids

Occurrence, formation mechanism, and health risk of polycyclic aromatic hydrocarbons in barbecued food

Polycyclic aromatic hydrocarbons (PAHs) show negative impacts on human health. Dietary intake is the predominant way for PAH exposure, of which barbecued food is a crucial contributor. This review aims to provide a comprehensive insight into the formation mechanism, influencing factors, mitigation strategies, and health risks of PAHs in barbecued food. PAHs in barbecued food are formed by Hydrogen abstraction and acetylene addition (HACA) mechanism, Diels-Alder reaction and Maillard reaction, which was influenced by heat source, temperature, cooking time, and the meat type. There are significant differences in PAH concentrations in different barbecued foods, where chrysene dominates among the selected PAH species. To reduce PAHs formation, adding marinades and adopting alternative cooking methods are suggested, which effectively reduce PAH levels by 53 -89 %. In addition, it is estimated that people in countries such as Pakistan has an incremental lifetime cancer risk (ILCR) over 10-5 via barbecued food consumption, indicating potential health risk. This work highlighted that regular monitoring of PAH levels in barbecued food and dynamic modification of relevant safety limits are recommended to ensure food safety.

Determination of 16 European Priority Polycyclic Aromatic Hydrocarbons in Doner Kebab Varieties Cooked Under Different Heating Sources

Doner kebab is a traditional Turkish meat product produced from lamb, beef or poultry meat seasoned with a blend of spices such as salt, black pepper, cumin, thyme and/or sauces. The aim of this study was to determine 16 EU priority polycyclic aromatic hydrocarbons (PAHs) in doner kebabs cooked under four different heating sources (electricity, open gas, wood and charcoal grilling). For this purpose, 200 meat doner and 200 chicken doner kebab samples were obtained randomly from various buffets and restaurants located in Istanbul and analyzed by means of GC-MS. According to the results, benzo[a]pyrene and PAH4 levels, which are important PAH compounds as biomarkers, were significantly higher in chicken doner than in meat doner (p < 0.05). The highest occurrence of benzo[a]pyrene and PAH4 in meat and chicken doner samples was in the charcoal heating source, whereas the lowest occurrence was detected in electric grilling. In terms of all PAH compounds, cooking with an electric heating source caused the formation of fewer PAH compounds in doner kebab samples. Consequently, the fat content of fatty meat products such as doner kebab should be reduced, the contact of fat with the heating source (especially flame) and dripping of fat to the source should be prevented and overcooking of meat should be avoided.

Thymus spp. Aqueous Extracts and Their Constituent Salvianolic Acid A Induce Nrf2-Dependent Cellular Antioxidant Protection Against Oxidative Stress in Caco-2 Cells

The increasing incidence of colorectal cancer and inflammatory diseases poses a major health concern, with oxidative stress playing a significant role in the onset of these pathologies. Factors such as excessive consumption of sugar-rich and fatty foods, synthetic food additives, pesticides, alcohol, and tobacco contribute to oxidative stress and disrupt intestinal homeostasis. Functional foods arise as a potential tool to regulate redox balance in the intestinal tract. Herbs (such as Thymus spp.) have long been screened for their antioxidant properties, but their use as antioxidants for medicinal purposes requires validation in biological models. In this study, we addressed the potential antioxidant protection and preventive effects of extracts from two thyme species at the intestinal level, as well as their molecular mechanisms of action. Caco-2 cells were pre-exposed (4 h) to aqueous (AD) and hydroethanolic (HE) extracts of Thymus carnosus and Thymus capitellatus, followed by a recovery period in culture medium (16 h), and then treated with tert-butyl-hydroperoxide (TBHP; 4 h), before analyzing cell viability. The effect of the extracts' main components was also analysed. Cellular oxidative stress, cell-death markers, and the expression of antioxidant-related proteins were evaluated using flow cytometry on cells pre-exposed to the AD extracts and salvianolic acid A (SAA). Results showed that pre-exposure to AD extracts or SAA reduced TBHP-induced oxidative stress and cell death, mediated by increased levels of nuclear factor erythroid 2-related factor 2 (Nrf2) protein. The protective activity of T. capitellatus AD extract was shown to be dependent on NAD(P)H quinone dehydrogenase 1 (NQO1) protein expression and on increased glutathione (GSH) content. Furthermore, ursolic acid induced cytotoxicity and low cellular antioxidant activity, and thus the presence of this triterpenoid impaired the antioxidant effect of HE extracts. Thus, AD extracts show high potential as prophylactic dietary agents, while HE extracts arise as a source of nutraceuticals with antioxidant potential.

Contaminant and residue profiles in Lebanese food: a comparative analysis with global standards

Lebanon's agricultural sector, known for its diverse crop and livestock production, faces challenges in the international market due to the presence of chemical residues and contaminants in its food exports. Recent rejections of these exports have raised global concerns about food safety, increasingly seen as vital for public health and economic prosperity. This review focuses on examining scientific studies about the levels of various chemical residues including pesticides, and veterinary drugs and contaminants like mycotoxins, and polycyclic aromatic hydrocarbons, and heavy metals in Lebanese food products. Findings indicate that these residues and contaminants often exceed both the maximum residue limits (MRLs) and maximum limits (MLs) set by the Codex Alimentarius and the European Union. The review concludes with recommendations for reducing these contaminants and residues to enhance Lebanon's food safety and quality, aligning with international standards, and mitigating the risk of export rejections.

Polycyclic Aromatic Hydrocarbons' Impact on Crops and Occurrence, Sources, and Detection Methods in Food: A Review

Polycyclic aromatic hydrocarbons (PAHs) represent a category of persistent organic pollutants that pose a global concern in the realm of food safety due to their recognized carcinogenic properties in humans. Food can be contaminated with PAHs that are present in water, air, or soil, or during food processing and cooking. The wide and varied sources of PAHs contribute to their persistent contamination of food, leading to their accumulation within these products. As a result, monitoring of the levels of PAHs in food is necessary to guarantee the safety of food products as well as the public health. This review paper attempts to give its readers an overview of the impact of PAHs on crops, their occurrence and sources, and the methodologies employed for the sample preparation and detection of PAHs in food. In addition, possible directions for future research are proposed. The objective is to provide references for the monitoring, prevention, and in-depth exploration of PAHs in food.

Genetic and epigenetic modulations in toxicity: The two-sided roles of heavy metals and polycyclic aromatic hydrocarbons from the environment

This study emphasizes the importance of considering the metabolic and toxicity mechanisms of environmental concern chemicals in real-life exposure scenarios. Furthermore, environmental chemicals may require metabolic activation to become toxic, and competition for binding sites on receptors can affect the severity of toxicity. The multicomplex process of chemical toxicity is reflected in the activation of multiple pathways during toxicity of which AhR activation is major. Real-life exposure to a mixture of concern chemicals is common, and the composition of these chemicals determines the severity of toxicity. Nutritional essential elements can mitigate the toxicity of toxic heavy metals, while the types and ratio of composition of PAH can either increase or decrease toxicity. The epigenetic mechanisms of heavy metals and PAH toxicity involves either down-regulation or up-regulation of some non-coding RNAs (ncRNAs) whereas specific small RNAs (sRNAs) may have dual role depending on the tissue and circumstance of expression. Similarly, decrease DNA methylation and histone modification are major players in heavy metals and PAH mediated toxicity and FLT1 hypermethylation is a major process in PAH induced carcinogenesis. Overall, this review provides the understanding of the metabolism of environmental concern chemicals, emphasizing the importance of considering mixed compositions and real-life exposure scenarios in assessing their potential effects on human health and diseases development as well as the dual mechanism of toxicity via genetic or epigenetic axis.

Development of a highly sensitive method based on QuEChERS and GC-MS/MS for the determination of polycyclic aromatic hydrocarbons in infant foods

Polycyclic aromatic hydrocarbons (PAHs) are environmental contaminants that can be found in various food products, including those intended for infants. Due to their potential health risks, it is crucial to develop sensitive analytical methods for the accurate determination of PAHs in infant foods. This study describes the development and validation of a highly sensitive method for the quantification of European PAH markers, namely benzo[a]pyrene, benzo[a]anthracene, chrysene, and benzo[b]fluoranthene, using gas chromatography-tandem mass spectrometry (GC-MS/MS), in baby food samples. The first step was the optimization of the sample preparation procedure, performed using different methods based on the QuEChERS approach, also testing different extraction solvents. Several factors such as extraction efficiency, selectivity, and recovery were evaluated to choose the most effective procedure for sample preparation. Furthermore, the GC-MS/MS method was optimized, evaluating parameters such as linearity, sensitivity, accuracy, and robustness using spiked infant food samples. The method demonstrated excellent linearities with a correlation coefficient higher than 0.999 over a wide concentration range, and limits of detection and limits of quantification in the range 0.019-0.036 μg/kg and 0.06-0.11 μg/kg, respectively. Extraction recoveries were between 73.1 and 110.7%, with relative standard deviations always lower than 8%. These findings are compliant with the indications of the European Commission (Reg. 836/2011). To assess the applicability of the method to official control activities, a survey was conducted on commercially available infant food products. Four markers were determined in commercial samples belonging to different food categories for infants and young children. The outcome of this monitoring showed that PAH contamination, in all samples, was below the quantification limits. In conclusion, the developed GC-MS/MS method provides a highly sensitive and reliable approach for the determination of PAHs in baby foods. The optimized sample preparation, instrumental parameters, and validation results ensure accurate quantification of 4 PAHs even at trace levels. This method could contribute to the assessment of PAH exposure in infants and it could support regulatory efforts to ensure the safety and quality of infant food products with regular monitoring.

Review of the Terminology, Approaches, and Formulations Used in the Guidelines on Quantitative Risk Assessment of Chemical Hazards in Food

This paper reviews the published terminology, mathematical models, and the possible approaches used to characterise the risk of foodborne chemical hazards, particularly pesticides, metals, mycotoxins, acrylamide, and polycyclic aromatic hydrocarbons (PAHs). The results confirmed the wide variability of the nomenclature used, e.g., 28 different ways of referencing exposure, 13 of cancer risk, or 9 of slope factor. On the other hand, a total of 16 equations were identified to formulate all the risk characterisation parameters of interest. Therefore, the present study proposes a terminology and formulation for some risk characterisation parameters based on the guidelines of international organisations and the literature review. The mathematical model used for non-genotoxic hazards is a ratio in all cases. However, the authors used the probability of cancer or different ratios, such as the margin of exposure (MOE) for genotoxic hazards. For each effect studied per hazard, the non-genotoxic effect was mostly studied in pesticides (79.73%), the genotoxic effect was mostly studied in PAHs (71.15%), and both effects were mainly studied in metals (59.4%). The authors of the works reviewed generally opted for a deterministic approach, although most of those who assessed the risk for mycotoxins or the ratio and risk for acrylamide used the probabilistic approach.

Polycyclic aromatic hydrocarbons in cooked (tandoori) chicken and associated health risk

Tandoori cooking is a popular food preparation method in India involving a unique combination of grilling, baking, barbecuing, and roasting processes. This study determined the levels of 16 polycyclic aromatic hydrocarbons (PAHs) in tandoori chicken and assessed the associated health risk. The sum of 16 PAHs concentration ranged from 25.4 to 3733 μg/kg with an average of 440 ± 853 μg/kg. Analyzed samples demonstrated major contribution of 2, 3, and 4 ring PAHs. Diagnostic ratios identified combustion and high-temperature processes as the main source favoring PAHs generation in these samples. Benzo(a)pyrene equivalents and incremental lifetime cancer risk (ILCR) estimates for different population groups (boys, girls, adult males, adult females, elderly males, elderly females) associated with dietary intake of these products ranged from 6.88E-05 to 4.13E-03 and 1.63E-08 to 1.72E-06, respectively. Since the ILCR values fell within the safe limits (1E-06, i.e., nonsignificant), the consumption of tandoori chicken may be considered as safe. The study emphasizes the need for extensive studies on PAHs formation in tandoori food products.

Genotoxicity of chlorinated hydrophobic organic compounds extracted from a source of drinking water

As precursors of disinfection by-products (DBPs), sediment hydrophobic organic compounds (HPOCs) derived from six reservoirs along the Dongjiang River were chlorinated (Cl-WS) and then fractionated into two polar components (hydrophobic organic compounds (Cl-HOCs) and hydrophilic organic compounds (Cl-HICs)) by solid phase extraction. Based on Caco-2 cell exposure study, the genotoxicity of Cl-WS, Cl-HOCs and Cl-HICs was analyzed by reactive oxygen species (ROS) analysis, comet assay and ethoxyresorufin-O-deethylase assay. Protective effects of antioxidants (catalase, vitamin C and epigallocatechin 3-gallate (EGCG)) on genotoxicity of the chlorinated samples were investigated. The results showed that Cl-WS and its two fractions (Cl-HOCs and Cl-HICs) induced ROS, DNA damage and dioxin-like toxicity (TEQbio), and Cl-HICs were a major contributor to oxidative damage and TEQbio compared with Cl-HOCs. Antioxidants significantly reduced Cl-HOCs- and Cl-HICs-induced ROS, but had insignificant effect on DNA oxidative damage and TEQbio. In addition, EGCG showed higher efficacy in reducing DNA damage induced by Cl-HICs than by Cl-HOCs. To our knowledge, this is the first study to investigate the genotoxicity of Cl-WS and its two polar components in Caco-2 cells, as well as the protective effects of antioxidants on Cl-HOCs and Cl-HICs-induced ROS, DNA damage, and TEQbio. This study provides important toxicity information for water treatment industries in differentiating DBPs of different polarity.

Evaluation of the Impact of BaP Exposure on the Gut Microbiota and Allergic Responses in an OVA-Sensitized Mouse Model

BACKGROUND

Exposure to environmental pollutants, including benzo[a]pyrene (BaP), has been implicated in allergic diseases and intestinal microbiota homeostasis, but the environment-microbiota-immunity triangular relationship and to what extent BaP-induced remodeling of the gut microbiota contributes to intestinal allergic inflammation remain to be established.

OBJECTIVES

We investigated the impact of BaP on intestinal allergic inflammation and examined the relationship between this effect and gut microbiota dysbiosis. We explored the potential ability of intestinal bacteria to degrade BaP and alleviate cytotoxicity as a detoxification strategy to counteract the effects of BaP exposure.

METHODS

We combined microbiome shotgun metagenomics with animal histological and intestinal allergic inflammatory responses to assess the effects of BaP (50μg/mouse per day) in a 23-d toxicity test in antigen-induced allergic female mice. In addition, genome annotation, quantitative analysis of BaP, and in vitro cytotoxicity-tests using CaCo-2 cells were conducted to infer the role of intestinal bacteria in BaP detoxification.

RESULTS

BaP exposure impacted the taxonomic composition and the functional potential of the gut microbiota and aggravated antigen-induced intestinal allergic inflammatory responses. The level of inflammatory cytokines correlated with the abundance of specific bacterial taxa, including Lachnospiraceae bacterium 28-4 and Alistipes inops. We identified 614 bacteria harboring genes implicated in the degradation of BaP, and 4 of these bacterial strains were shown to significantly reduce the cytotoxicity of BaP to CaCo-2 cells in vitro.

DISCUSSION

Using allergic female mice as a model, we investigated the relationship between BaP, microbiota, and host immune reactions, highlighting the role of gut bacteria in BaP-aggravated allergic reactions. Our findings offer novel insight toward establishing the causal relationship between BaP exposure and the occurrence of allergic disorders. Identifying gut bacteria that degrade BaP may provide new strategies for ameliorating BaP cytotoxicity. https://doi.org/10.1289/EHP11874.

Arabinogalactan ameliorates benzo[a]pyrene-induced intestinal epithelial barrier dysfunction via AhR/MAPK signaling pathway

Benzo[a]pyrene (B[a]P), a kind of pollutant, can disrupt the gut microbiota, but its effects on the function of intestinal epithelial barrier (IEB) is still unclear. Arabinogalactan (AG), a natural polysaccharide, can protect intestinal tract. Thus, the purpose of this study was to evaluate the effect of B[a]P on IEB function and the mitigation effect of AG on the IEB dysfunction induced by B[a]P using a Caco-2 cell monolayer model. We found B[a]P could damage the IEB integrity by inducing cell cytotoxicity, increasing lactate dehydrogenase leakage, decreasing the transepithelial electrical resistance, and increasing fluorescein isothiocyanate-dextran flux. The mechanism of B[a]P-induced IEB damage may through induction of oxidative stress, including increasing reactive oxygen species levels, decreasing glutathione levels, reducing the activity of superoxide dismutase, and increasing malonaldehyde levels. Moreover, it can be due to increasing secretion of pro-inflammatory cytokines (interleukin [IL]-1β, IL-6, and tumor necrosis factor [TNF]-α), down-regulated expression of tight junction (TJ) proteins (claudin-1, zonula occludens [ZO]-1, and occludin), and induced activation of aryl hydrocarbon receptor (AhR)/mitogen activated protein kinase (MAPK) signaling pathway. Remarkably, AG ameliorated B[a]P-induced IEB dysfunction through inhibited oxidative stress and pro-inflammatory factor secretion. Our study demonstrated B[a]P could damage the IEB and AG could alleviate this damage.

Benzo[a]pyrene induces epithelial tight junction disruption and apoptosis via inhibiting the initiation of autophagy in intestinal porcine epithelial cells

Ingestion of food contaminated with benzo[a]pyrene (B[a]P) poses health risks to animals and humans. However, the toxicity of B[a]P exposure on the intestinal barrier function and underlying mechanisms remain obscure. In the present study, intestinal porcine epithelial cells (IPEC-1) were challenged with different doses of B[a]P and its deleterious effects were determined. We found that B[a]P exposure led to impaired intestinal tight junction function as evidenced by reduced transepithelial electric resistance, increased permeability, and downregulated intestinal tight junction protein levels. Further study demonstrated that B[a]P treatment induced cell cycle arrest, and resulted in oxidative damage-related apoptosis in IPEC-1 cells. Intriguingly, we observed an inhibition of autophagy and an activation of unfolded protein response (UPR) in B[a]P-challenged cells, when compared with controls. To investigate the role of autophagy on B[a]P-induced epithelial tight junction disruption and apoptosis, cells were cotreated with B[a]P and rapamycin, and rapamycin dramatically improved intestinal tight junction and reduced apoptosis, indicating a protective effect of autophagy for the cells in response to B[a]P treatment. We also explored the role of UPR in B[a]P-induced cellular damage by using 4-phenylbutyric acid, an antagonist of UPR. Interestingly, B[a]P-induced apoptosis and dysfunction of the intestinal tight junction were exacerbated by 4-phenylbutyric acid, and the 4-phenylbutyric acid didn't ameliorate the inhibitory effects of B[a]P on microtubule-associated protein 1 light chain 3 (LC3-II) and lysosomal-associated membrane protein 2 (LAMP2) in IPEC-1 cells. These novel findings provided herein indicated that B[a]P induces intestinal epithelial tight junction disruption and apoptotic cell death via inhibiting autophagy in IPEC-1 cells.

Co-exposure health risk of benzo[a]pyrene with aromatic VOCs: Monoaromatic hydrocarbons inhibit the glucuronidation of benzo[a]pyrene

Occupational workers and residents near petrochemical industry facilities are exposed to multiple contaminants on a daily basis. However, little is known about the co-exposure effects of different pollutants based on biotransformation. The study examined benzo[a]pyrene (BaP), a representative polycyclic aromatic hydrocarbon related to the petrochemical industry, to investigate changes in toxicity and co-exposure mechanism associated with different monoaromatic hydrocarbons (MAHs). A central composite design method was used to simulate site co-exposure scenarios to reveal biotransformation of BaP when co-exposed with benzene, toluene, chlorobenzene, or nitrobenzene in microsome systems. BaP metabolism depended on MAH concentration, and association of MAH with microsome concentration/incubation time. Particularly, MAH co-exposure negatively affected BaP glucuronidation, an important phase Ⅱ detoxification process. BaP metabolite intensities decreased to 43%-80% for OH-BaP-G, and 32%-71% for diOH-BaP-G in co-exposure system with MAHs, compared with control group. Furthermore, glucuronidation was affected by competitive and time-dependent inhibition. Co-exposure significantly decreased gene expression of UGT 1A10 and BCRP/ABCG2 in HepG2 cells, which are involved in BaP detoxification through metabolism and transmembrane transportation. Therefore, human co-exposure to multiple contaminants may deteriorate toxic effects of these chemicals by disturbing metabolic pathways. This study provides a reference for assessing toxic effects and co-exposure risks of pollutants.

Measurement of polycyclic aromatic hydrocarbons in edible oils and potential health risk to consumers using Monte Carlo simulation, southwest Iran

Persistent organic pollutants, such as polycyclic aromatic hydrocarbons, are hazardous trace contaminants frequently observed in food ingredients, such as edible oils. This study aimed to measure PAHs in forty brands of edible oils marketed in southwest Iran. Additionally, we characterized the daily intake of MOE and ILCR using Monte Carlo simulation. To analyze the content of PAHs, the liquid-liquid extraction method followed by GC-MS was utilized. The average concentration of PAHs was mostly lower than the maximum value for individual PAH (2 μg/Kg); however, the average concentration of fluorene (3.86 μg/Kg) and benzo(a)anthracene (3.13 μg/Kg) was more than the permitted level. The highest residual concentrations of PAHs were mostly observed in canola and corn oils. The daily intake of BaP and 4-PAH for 95% of consumers was 0.01 ng/kg BW/day and 0.04 ng/kg BW/day, respectively. Also, MOE was more than 10,000 for the percentiles of 5%, 50%, and 95%. The modeled ILCR showed that consumption of oil does not currently pose a cancer risk for Iranian consumers due to PAHs exposure. Concerning potential health risks, consumption of edible oils is safe; however, regular monitoring and assessment are required.

Effects of aflatoxin B1 on human breast cancer (MCF-7) cells: cytotoxicity, oxidative damage, metabolic, and immune-modulatory transcriptomic changes

Aflatoxin B1 (AFB1) is a potent mycotoxin that is commonly produced by molds such as Aspergillus (A.) flavus and A. parasiticus. AFB1 is associated with several health adverse effects in humans including mutagenesis and carcinogenesis. Aflatoxin is commonly secreted in the milk leading to deleterious effects on breast tissue and potential nursing infants. However, the effects of aflatoxins, particularly AFB1, on the breast cells are less investigated. In this study, AFB1-associated effects on human breast cancer cell lines (MCF-7) were investigated. AFB1 caused significant cytotoxicity on MCF-7 cells. Such cytotoxicity had a positive correlation with the induction of oxidative stress. In addition, AFB1 caused significant transcriptomic alterations in xenobiotics and drug-metabolizing enzymes, transporters, and antioxidant enzymes. Besides, AFB1 upregulated pro-inflammatory markers such as tumor necrosis factor-α and cyclooxygenase-2 with a significant reduction of mRNA expressions of the immunity-related genes including interleukins 8 and 10.

Formation and mitigation of acrylamide in oven baked vegetable fries

Investigation into oven baked sweet potato and carrot fries at various temperatures and times demonstrated the in situ formation of acrylamide in an exponential manner. High levels of acrylamide were found in these food items: up to 327 µg/kg for sweet potato baked at 190 °C for 14 min, and 99 µg/kg for carrot baked at 190 °C for 13 min. Risk assessment via Margin of Exposures estimation showed that consumption of these fries might pose adverse health effects to consumers from toddlers to adults, especially when the fries were prepared at high temperatures above 175 °C and for a long time. Raw ingredient blanching and immersion in acetic acid prior to preparation have been proven to greatly reduce acrylamide formation, up to 99%. It is recommendable to apply these techniques either at industrial or domestic cooking scales to ensure minimal health risk from dietary exposure to acrylamide.

Bubble Column Bioreactor using native non-genetically modified organisms: a remediation alternative by hydrocarbon-polluted water from the Gulf of Mexico

Notwithstanding the benefits that oil provides as a source of energy, society also recognizes the environmental problems caused by its use. We evaluated eight coastal sites in the central area of the Gulf of Mexico. At these sites, 14 hydrocarbons were detected which belong to compounds formed by carbons ranging from C9 to C27. The hydrocarbons with the highest concentrations were n-nonane (3.07 ± 1.60 mg L−1), carbazole (0.93 ± 0.12 mg L−1) and benzo [a] pyrene (1.33 ± 0.71 mg L−1). The hydrocarbons found belong mostly to medium fraction hydrocarbons, which are mostly found in fuels such as diesel. Therefore, this fuel was used as a carbon source or substrate in bubble column bioreactors. The capacity of non-genetically modified organisms to degrade microbial hydrocarbons was evaluated using a mineral medium for a period of 14 days. Suspended solids increased from 0.8 to 2.94 g L−1. Diesel consumption was achieved in 12 days of operation.

Benzo(a)pyrene-induced cytotoxicity, cell proliferation, DNA damage, and altered gene expression profiles in HT-29 human colon cancer cells

In the US alone, around 60,000 lives/year are lost to colon cancer. In order to study the mechanisms of colon carcinogenesis, in vitro model systems are required in addition to in vivo models. Towards this end, we have used the HT-29 colon cancer cells, cultured in Dulbecco's Modified Eagle Medium (DMEM), which were exposed to benzo(a)pyrene (BaP), a ubiquitous and prototypical environmental and dietary toxicant at 1, 10, 100 nM and 1, 5, 10, and 25 μM concentrations for 96 h. Post-BaP exposure, growth, cytotoxicity, apoptosis, and cell cycle changes were determined. The BaP metabolite concentrations in colon cells were identified and measured. Furthermore, the BaP biotransformation enzymes were studied at the protein and mRNA levels. The BaP exposure-induced damage to DNA was assessed by measuring the oxidative damage to DNA and the concentrations of BaP-DNA adducts. To determine the whole repertoire of genes that are up- or downregulated by BaP exposure, mRNA transcriptome analysis was conducted. There was a BaP exposure concentration (dose)-dependent decrease in cell growth, cytotoxicity, and modulation of the cell cycle in the treatment groups compared to untreated or dimethylsulfoxide (DMSO: vehicle for BaP)-treated categories. The phase I biotransformation enzymes, CYP1A1 and 1B1, showed BaP concentration-dependent expression. On the other hand, phase II enzymes did not exhibit any marked variation. Consistent with the expression of phase I enzymes, elevated concentrations of BaP metabolites were generated, contributing to the formation of DNA lesions and stable DNA adducts, which were also BaP concentration-dependent. In summary, our studies established that biotransformation of BaP contributes to cytotoxicity, proliferation of tumor cells, and alteration of gene expression by BaP. • Benzo(a)pyrene (BaP) is an environmental and dietary toxicant. • BaP causes cytotoxicity in cultured HT-29 colon cancer cells. • mRNA transcriptome analyses revealed that BaP impacts cell growth, cell cycle, biotransformation, and DNA damage.

Chemical hazards in smoked meat and fish

This review aims to give an insight into the main hazards currently found in smoked meat and fish products. Literature research was carried out on international databases such as Access to Global Online Research in Agriculture (AGORA) database, Science direct, and Google scholar to collect and select 92 relevant publications included in this review. The smoking process was described and five hazards mostly found in smoked fish and meat were presented. The heat-induced compounds such as polycyclic aromatic hydrocarbons, heterocyclic amines, and nitrosamines were found in smoked fish and meat. Other hazards such as biogenic amines and heavy metals were also present in smoked fish and meat. The levels of these hazards reported from the literature exceeded the maximal limits of European Union. A brief description of risk assessment methodology applicable to such toxic compounds and risk assessment examples was also presented in this review. As most of the hazards reported in this review are toxic and even carcinogenic to humans, actions should be addressed to reduce their presence in food to protect consumer health and to prevent public health issue.

Levels of polycyclic aromatic hydrocarbons in edible and fried vegetable oil: a health risk assessment study

Polycyclic aromatic hydrocarbons (PAHs) are environmental chemicals that are formed due to incomplete combustion of the organic matters, or during heat treatment of the food. The objectives of the present study were first to estimate levels of the 15-priority PAHs in the edible vegetable oil (corn oil, sunflower oil, olive oil, and canola oil) collected from Egypt. Furthermore, the effect of heat treatment on the formation of PAHs in the canola oil was further examined. In addition, dietary intakes and cancer risk among Egyptian consumers were additionally calculated. The achieved results indicated presence of 15-priority PAHs in all examined oil samples. Canola oil had the highest residual concentrations of PAHs compared with the other tested oil species. Heat treatment of canola oil led to a drastic increase in the formed B[a]P (316.55%), total 2-PAHs (322.47%), total 4-PAHs (297.42%), total 8-PAHs (285.26%), and total 15-PAHs (443.32%), respectively. The incremental lifetime cancer risk among the Egyptian population is considered safe when was calculated for all examined oil samples.

The physiological response of Ectomycorrhizal fungus Lepista sordida to Cd and Cu stress

Ectomycorrhizal fungi (ECMF) can develop the resistance of host plants to heavy metal stress. However, little is known about the response of ECMF to heavy metal exposure. In this study, the growth and physiological indices of Lepista sordida under Cd and Cu stress were studied. The growth of L. sordida on PDA medium under Cd and Cu stress was observed using scanning electron microscopy (SEM). After the addition of Cd and Cu to the medium, the mycelium started twisting, breaking, sticking together, and even dissolving. In the control group, a good and luxuriant mycelium growth of L. sordida along with the numerous clamp connections was observed. The mycelial biomass decreased with increasing concentrations of heavy metals in a liquid medium. The catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and ascorbate peroxidase (APX) activities were also investigated, and the results showed that the Cd and Cu treatments caused a significant increase in the antioxidant enzyme activities. The contents of soluble protein, soluble sugar, and free proline in L. sordida were investigated, and it was found that the contents initially increased and then decreased with the increasing concentrations of Cd and Cu. However, the content of malondialdehyde (MDA) increased with the increasing concentrations of Cd and Cu. In conclusion, the present study provides a theoretical basis for the better utilization of Ectomycorrhizal fungal resources for the remediation of soil contaminated with heavy metal.

Occurrence of polycyclic aromatic hydrocarbons in fried and grilled fish from Shandong China and health risk assessment

Diet is the main way for the human body to ingest polycyclic aromatic hydrocarbons (PAHs). In this study, the occurrence, dietary exposure, and health risks of 15 PAHs in 31 fried and grilled fish samples were investigated, which were collected from the Shandong Province of China. The results showed that benzo[a]pyrene (BaP) of 5 samples exceeded the European Union (EU) limit value. Naphthalene (NaP) and fluorene (Fle) were present in all samples, and the average concentration of ∑15PAHs was 91.1 μg/kg, with light PAHs dominated. The average contamination level of ∑15PAHs in fried and grilled fish was distributed differently, and there seemed to be more PAH contamination in the grilled samples. The results of the margin of exposure (MOE) suggested that PAH ingestion through fried and grilled fish did not imply significant toxicological concern for consumers in Shandong. The incremental lifetime cancer risk (ILCR) values for the consumption of fried and grilled fish were higher than 1 × 10-6, indicating a potential health risk in the adult population. The study provides baseline health information on PAH intake by residents due to dietary exposure to fried and grilled fish food products, suggesting that health risk monitoring of PAHs in such foods should be continually performed.

Mediation of the association between polycyclic aromatic hydrocarbons exposure and telomere attrition by oxidative stress: A prospective cohort study

Previous studies have reported associations between polycyclic aromatic hydrocarbons (PAHs) exposure and telomere attrition, but the underlying mechanisms remain to be elucidated. This study aimed to explore the mediation role of oxidative stress on the effects of PAHs exposure on telomere attrition in a cohort study of 1180 coke-oven workers. We determined baseline urinary concentrations of ten urinary PAH metabolites, two oxidative stress biomarkers [8-hydroxydeoxyguanosine (8-OHdG) and 8-iso-prostaglandin-F2α (8-isoPGF2α)] and peripheral leukocytes telomere length (TL) in both baseline and follow-up visits. Mediation analysis was applied to assess effects of oxidative stress biomarkers on the PAHs-TL attrition associations. The baseline 8-OHdG had a significant dose-response relationship with TL decline [β(95 %CI) = 0.07(0.03-0.12), P = 0.001] and TL ratio [β(95 %CI)]=0.07 (0.02-0.12), P = 0.003]. Mediation analyses indicated that 8-OHdG mediated a separate 39.1 %, 47.0 %, 43.3 %, and 58.0 % of the associations between 1-hydroxynaphthalene (1-OHNa), 2-OHNa, ΣOHNa, 1-hydroxypyrene (1-OHP) and TL decline (P = 0.016, 0.008, 0.012, and 0.014, respectively). Additionally, 8-OHdG mediated a separate 44.8 %, 49.4 %, 49.2 %, and 35.5 % of the associations between 1-OHNa, 2-OHNa, ΣOHNa, 1-OHP and TL ratio (P = 0.012, 0.008, 0.012, and 0.046, respectively). Our study proposed the positive association of 8-OHdG with TL attrition and revealed the mediation roles of 8-OHdG in PAHs-TL attrition associations.

The occurrence and levels of polycyclic aromatic hydrocarbons (PAHs) in African environments-a systematic review

In the African continent, several studies have been conducted to determine PAH pollution levels with their associated health risks in the environment. However, these studies are very much disconnected. The objective of this study is to conduct a systematic review that serves as a comprehensive report on the PAH-related studies conducted in the African continent. Data sources are from Google Scholar and PubMed. English language studies that reported on PAH levels in smoked fish and meat, soils and dust, aquatic environments, indoor and outdoor air, and ready-to-eat food items were selected. Specific PAHs included the following: 33 PAHs comprising of the 16 USEPA PAHs, non-alkylated PAHs, non-alkylated PAHs, oxygenated PAHs (OPAHs), and azaarenes (AZAs). Study appraisal and synthesis methods: The Newcastle-Ottawa Scale (NOS) was adapted to assess the quality of the selected studies basing on their sampling methods, analytical techniques, and results. A total of 121 studies were reviewed, with the majority (56) being from Nigeria. PAH levels in smoked fish and meat, soils and dust, aquatic environments, indoor and outdoor air, and ready-to-eat food items recorded total concentrations of PAHs ranging from 5 to 3585 μg/kg, BDL to 6,950,000 μg/kg, 0 to 10,469,000 μg/kg, 0 to 7.82 ± 0.85 μg/m³, and 2.5 to 7889 ± 730 μg/kg respectively. Carcinogenic risk assessment for children and adults ranged from very low to very high levels when compared to the ILCR range (10^-6 to 10^-4) defined by the USEPA. Out of 54 African countries, only 19 were represented. The majority of selected studies failed to apply any standard protocols for sample collection and analysis. The low to very high PAH levels reported in studies calls for effective actions on environmental health. Similar systematic reviews are expected to be performed in other continents for a global assessment of PAH pollution.

The Presence of Polycyclic Aromatic Hydrocarbons (PAHs) in Grilled Beef, Chicken and Fish by Considering Dietary Exposure and Risk Assessment

Polycyclic aromatic hydrocarbons (PAHs) are dangerous chemical compounds that can be formed by cooking foods at high temperatures. The aim of this study is to determine the level of contamination of PAH compounds with high performance liquid chromatography (HPLC) on heat treated meat samples and the consumption of PAH compounds in meat samples, as well as the dietary exposure status and possible health risk estimation. In five different heat treated meat samples (meat doner, chicken doner, meatballs, grilled chicken, and fish), the total PAH (Σ16PAH) contamination level was 6.08, 4.42, 4.45, 4.91, and 7.26 μg/kg, respectively. Benzo[a]pyrene (BaP) in meatballs and grilled fish samples had a level 0.70 and 0.73 μg/kg. All of the samples analyzed were found to be below the EU permitted limit (5 μg/kg) in terms of BaP. Estimates of daily intake (EDI) for a total of 16PAH in heat treated meat doner, chicken doner, meatballs, grilled chicken and fish samples were 3.41, 3.71, 2.49, 4.12, and 1.77 ng/kg bw/day, respectively. In this study, the average margin of exposure (MOE) value calculated was found in the range of 179.487 and 425.000 for BaP and PAH4. This study is the first study to provide important information in terms of evaluating the possible health risk that PAH compounds can create in people's diets due to heat treatment of meat and meat products in Sivas, Turkey.

Reduced graphene oxide-based magnetic composite for trace determination of polycyclic aromatic hydrocarbons in cosmetics by stir bar sorptive dispersive microextraction

This work describes a sensitive and rapid analytical method for trace determination of polycyclic aromatic hydrocarbons (PAHs) in cosmetic samples. The proposed method is based on stir bar sorptive-dispersive microextraction (SBSDME). A magnetic composite made of CoFe₂O₄ magnetic nanoparticles embedded into reduced graphene oxide sheets is used as sorbent phase. After the extraction, the target analytes are desorbed in toluene and then analyzed by gas chromatography-mass spectrometry (GC-MS). The main parameters involved in the extraction procedure (i.e., composite amount, extraction time and desorption time) were evaluated and optimized to provide the best extraction efficiency. The method was successfully validated under the selected conditions, showing a linear range of at least up to 125 ng mL^-1, instrumental and method limits of detection from 0.02 to 2.50 ng mL^-1 and from 0.15 to 24.22 ng g^-1, respectively, and relative standard deviations (RSD) below 10 % for all the target analytes. Standard addition combined with internal standard calibration was employed for quantification. The proposed method was successfully applied to the analysis of ten PAHs in four cosmetic products of different matrix. Several analytes between 14 and 464 ng g^-1 were found, some of them prohibited in cosmetic products. This work expands the analytical potential of SBSDME technique to other analytes and to the use of new sorbent phases, showing the great versatility of this approach depending on the characteristics of the analytes.

Deoxynivalenol-induced alterations in the redox status of HepG2 cells: identification of lipid hydroperoxides, the role of Nrf2-Keap1 signaling, and protective effects of zinc

Deoxynivalenol (DON) is a type B trichothecenes that is widely contaminating human and animal foods, leading to several toxicological implications if ingested. Induction of oxidative stress and production of lipid peroxides were suggested to be the reasons for DON-induced cytotoxicity. However, detailed and comprehensive profiling of DON-related lipid hydroperoxides was not identified. Furthermore, the mechanisms behind DON-induced cytotoxicity and oxidative stress have received less attention. Zinc (Zn) is an essential element that has antioxidant activities; however, the protective effects of Zn against DON-induced adverse effects were not examined. Therefore, this study was undertaken to investigate DON-induced cytotoxicity and oxidative damage to human HepG2 cell lines. Furthermore, a quantitative estimation for the formed lipid hydroperoxides was conducted using LC-MS/MS. In addition, DON-induced transcriptomic changes on the inflammatory markers and antioxidant enzymes were quantitatively examined using qPCR. The protective effects of Zn against DON-induced cytotoxicity and oxidative stress, the formation of lipid hydroperoxides (LPOOH), and antioxidant status in HepG2 cells were investigated. Finally, the effects of DON and Zn on the Nrf2-Keap1 pathway were further explored. The achieved results indicated that DON caused significant cytotoxicity in HepG2 cells accompanied by significant oxidative damage and induction of the inflammatory markers. Identification of DON-related LPOOH revealed the formation of 22 LPOOH species including 14 phosphatidylcholine hydroperoxides, 5 triacylglycerol hydroperoxides, and 3 cholesteryl ester hydroperoxides. DON caused significant downregulation of Nrf2-regulated antioxidant enzymes. Zn administration led to significant protection of HepG2 cells against DON-induced adverse effects, probably via activation of the Nrf2-Keap1 pathway.