Concentrations and dietary exposure to polycyclic aromatic hydrocarbons (PAHs) from grilled and smoked foods

Assessing Cancer Risk Associated with Aquatic Polycyclic Aromatic Hydrocarbon Pollution Reveals Dietary Routes of Exposure and Vulnerable Populations

Polycyclic aromatic hydrocarbon (PAH) exposure is widespread, and many PAHs are considered carcinogenic. The PAH-contaminated AWI Superfund site in Virginia provides a model for studying a complex PAH mixture and its extrapolation to cancer risk and PAH exposure in the general population. We examined cancer risk at the Superfund site due to sediment-derived PAHs and then evaluated PAH sources in the general population and potentially vulnerable subpopulations upon PAH mixture exposure. The PAH mixture was assessed for potential carcinogenicity using the US EPA's OncoLogic™ ranking tool and the US EPA list of priority PAHs. Cancer risk due to PAH exposure was calculated for Superfund site users and compared to the US EPA assessment. Human intake and health endpoints of PAHs within the mixture were extracted from USEtox® chemical fate database, while mean intake exposure was calculated for U.S. adults for select PAHs using NHANES database urinary biomarkers. Eleven PAH compounds within the mixture were of carcinogenic concern, and seven PAHs conveyed significant excess cancer risk at the Superfund site and in the general population, wherein PAH-contaminated seafood ingestion was a main contributor. Other dietary sources of PAHs derived from PAH-contaminated soil or water could also play a role in total exposure. Vulnerable populations to PAH exposure and coinciding increased cancer risk may include, in addition to smokers, children and non-Hispanic blacks, which is a public health concern.

Red meat and processed meat intake and risk for cutaneous melanoma in white women and men: Two prospective cohort studies

BACKGROUND

Red and processed meat consumption has been associated with increased risk for several cancers, but the association with cutaneous melanoma risk has been inconclusive.

OBJECTIVE

To investigate the association between red and processed meat intake and melanoma risk.

METHODS

Dietary information was assessed by using food frequency questionnaires in 2 prospective cohorts: 75,263 women from the Nurses' Health Study (1984-2010) and 48,523 men from the Health Professionals Follow-up Study (1986-2010). Melanoma cases were confirmed by reviewing pathology records. Pooled multivariable hazard ratios and 95% confidence intervals were estimated by using Cox proportional hazards models.

RESULTS

A total of 679 female and 639 male melanoma cases were documented during follow-up. Red and processed meat intake was inversely associated with melanoma risk (P = .002 for trend); the pooled hazard ratios (95% confidence intervals) of the 2 cohorts were 1.00 (reference), 1.00 (0.87-1.14), 0.98 (0.86-1.13), 0.89 (0.77-1.02), and 0.81 (0.70-0.95) for increasing quintiles of intake.

LIMITATIONS

Findings might have limited generalizability, considering that the cohorts were limited to white health professionals.

CONCLUSION

Red and processed meat intake was inversely associated with melanoma risk in these 2 cohorts.

PAHs in Indian diet: Assessing the cancer risk

Food products such as bread, biscuits, tea, coffee, oils, chocolates, grapes, pepper and fishes belonging to different categories represent a significant part of everyday diet in India and other countries having variable cooking techniques. In this study, we evaluated cancer risks of long term exposure to polycyclic aromatic hydrocarbons (PAHs) through consumption of these products for eight societal groups in India. Total concentrations of PAHs in these products from India ranged from 0.18 to 61967 μg kg^-1 and the cancer risk values for the eight sections of Indian population ranged between 7.63E-10 to 5.05E+00, indicating product specific distribution of risk from non-significant to significant levels. Cereals, vegetables and decoctions contributed majorly to cancer risk and the most susceptible group identified was children. The spread of risk estimates followed Burr and Exponential distributions. To the best of our knowledge, this is the first study to develop information on the health risk faced by Indian population through dietary PAHs.

Polycyclic aromatic hydrocarbons bioaccessibility in seafood: Culinary practices effects on dietary exposure

This work aimed to determine the effect of culinary practices on the contamination level and bioaccessibility of polycyclic aromatic hydrocarbons (PAHs) in seafood. The selected farmed seafood species (marine shrimp, clams and seaweed) were commercially available in Portugal. The mean concentrations of PAHs varied between 0.23 and 51.8 µg kg^-1, with the lowest value being observed in raw shrimp and the highest in dried seaweed. The number of compounds detected in seaweed and clams (naphthalene, acenaphthene, fluorene, phenanthrene, benzo(b)fluoranthene and benzo(j)fluoranthene) were higher than in shrimp (fluorene and pyrene). Among the PAHs measured, fluorene was the predominant one. There was a significant interaction effect between species and culinary treatment (p < 0.05), thus boiled and dried seaweed samples presented the lowest and the highest levels of fluorene (0.13 and 1.8 µg kg^-1), respectively. The daily intake of PAHs decreased with bioaccessibility, varying from 22% for benzo(k)fluoranthene (in raw clam) to 84% for phenanthrene (in steamed clam). According to the potency equivalent concentrations, screening values and bioaccessibility of PAHs, the consumption of marine shrimp, clam and seaweed is considered as safe for consumers.

Reduction of polycyclic aromatic hydrocarbons in common carp meat smoked in traditional conditions

Common carp meat was smoked in traditional conditions without filter and with zeolite, granular activated carbon, and gravel filters. The aim of this study was to determine the influence of using different filters in traditional smoking conditions on 16 polycyclic aromatic hydrocarbons from the Environmental Protection Agency list (16 US-EPA PAHs). Determination and quantification of PAHs were performed by gas chromatography-mass spectrometry (GC-MS). According to the obtained results, all examined samples of common carp meat smoked in traditional conditions were safe for consumers regarding to the European Commission Regulation on PAH content. After statistical analysis, the zeolite filter appeared to be the best one based on food safety of traditional production of smoked common carp meat. Application of any of these filters to produce smoked common carp meat in traditional conditions resulted in a safer product, as lower levels of PAHs were obtained.

Polycyclic aromatic hydrocarbons (PAHs) content of edible vegetable oils in Iran: A risk assessment study

Totally forty samples (23 brands) of different types of edible oils including frying oil (n = 14), blended oil (n = 13), sunflower oil (n = 6), corn oil (n = 5) and canola oil (n = 2) from Iran's market were analyzed for PAHs content by a High-performance liquid chromatography coupled with fluorescence detector. Also, the Health risk assessment in the adults and children consumers were estimated by the calculating margin of exposure (MOE) and the incremental lifetime cancer risk (ILCR) in the Monte Carlo Simulation (MCS) method. Approximately all of the samples contained different amounts of PAHs, while concentrations of BaP, PAH 4, PAH 8 and PAH 13 were reported as 0.90-11.33, 3.51-84.03, 7.41-117.12 and 129.28-19.54 μg/kg, respectively. Light polycyclic aromatic hydrocarbons corresponded to 65% of total PAHs while the remaining 35% belonged to heavy polycyclic aromatic hydrocarbons. Based on BaP content, 12 samples were above the standard limits (2 μg/kg) which set by the Standard Organization of Iran and the European Union, whereas 15 samples exceeded maximum limit 10 μg/kg set for PAH 4 established by EU. Percentile 95% of MOE in the adults due to ingestion of sunflower, corn, frying and blended oils were determined as 4.10E+5; 4.05E+5; , 2.17E+5, 2.33E+5, respectively and in the children due to ingestion of sunflower oil, corn oil, frying oil and blended oil were calculated as 5.38E+4, 4.49E+4, 2.86E+4, 3.37E+4. Regarding the percentile of 95% ILCR in the adults due to ingestion of sunflower oil, corn oil, frying oil and blended oil were reported as 4.5E-6, 4.17E-6l, 5.20E-6, 4.93E-6 and also this value in the children in the same rank order of products can be summarized as 3.43E-5, 3.94 E-5, 3.17E-5, 3.76E-5. The rank order of edible oils investigated based on MOE was sunflower oil > corn oil > blended oil > frying oil; and based on ILCR, frying oil > blended oil > sunflower oil > corn oil. The health risk assessment according to MCS method indicated that adults and children are not at considerable health risk; MOE ≥ 1E+4 and ILCR < 1E-4).

An ultrasensitive biological probe enhanced RT-IPCR assay for detecting benzo[a]pyrene in environmental samples based on the specific polyclonal antibody

Benzo[a]pyrene (BaP), a type of polycyclic aromatic hydrocarbon, is widely distributed in the environment. In this study, BaP immunogen and coating antigen were respectively prepared by different methods, and the specific antibody targeting the BaP analyte was obtained. Moreover, gold nanoparticles modified with the specific polyclonal antibody and thiol-capped DNA were prepared as biological probes. Based on the work above, an ultrasensitive biological probe enhanced real-time immuno-polymerase chain reaction (BP-rt-iPCR) assay was developed to detect BaP in several environmental samples. Under optimal conditions, the proposed method was used to detect BaP with a linearity ranging from 5 pg/l to 50 ng/l. The limit of detection was 1.63 pg/l. The recovery rates of the spiked samples ranged from 92.12% to 109.76% and the coefficients of variation were 7.53%-11.06%. This immunoassay was successfully used to detect BaP in environmental samples, and the BaP detection results were consistent with those obtained using high performance liquid chromatography, indicating that the BP-rt-iPCR method is accurate and reliable, and has great potential to detect trace amounts of BaP.

Residuals, bioaccessibility and health risk assessment of PAHs in winter wheat grains from areas influenced by coal combustion in China

Polycyclic aromatic hydrocarbons (PAHs) contamination in atmospheric and soil was serious, which is mainly due to high level of emission of PAHs in China resulted from the predominating use of coal in energy consumption and continuous development of economy and society for years. However, the status of PAHs in winter wheat grains from the areas influenced by coal combustion in China was still not clear. During harvest season, the winter wheat grains were collected from agricultural fields surrounding coal-fired power plants located in Shaanxi and Henan Provinces. This study found that the mean concentrations of 15 priority PAHs ranged from 69.58 to 557.0μgkg^-1. Three-ring PAHs (acenaphthene, acenaphthylene, fluorene, phenanthrene and anthracene) were dominant in the grains, accounting for approximately 70-81% of the total PAHs. The bioaccessibility of low molecular weight (LMW, 2-3 ring) PAHs (51.1-52.8%), high molecular weight (HMW, 4-6 ring) PAHs (19.8-27.6%) and total PAHs (40.9-48.0%) in the intestinal condition was significantly (p<0.001) higher than that (37.4-38.6%; 15.6-22.5%; 30.7-35.5%) in the gastric condition, respectively. Based on total PAHs, the values of incremental lifetime cancer risk (ILCR) for children, adolescents, adults and seniors were all higher than the baseline value (10^-6) and some even fell in the range of 10^-5-10^-4, which indicated that most grains from the areas affected by coal combustion possessed considerable cancer risk. The present study also indicated that the children were the age group most sensitive to PAHs contamination. The pilot research provided relevant information for the regulation of PAHs in the winter wheat grains and for the safety of the agro-products growing in the PAHs-contaminated areas.

Polycyclic aromatic hydrocarbons in fruits and vegetables: Origin, analysis, and occurrence

Feed intake, for non-smokers, is the first route of contamination to polycyclic aromatic hydrocarbons (PAHs), which are potentially toxic compounds via ingestion. Investigations are focused on the presence of PAHs in fruits and vegetables. Transfer of PAHs can occur from air and soil during cultivation. They can also appear prior to consumption during storage, transport or cooking processes. Rather low amounts of PAHs are usually detected in raw fruits and vegetables. Quantities are between 0.01 and 0.5 μg kg^-1 (wet weight) for compounds classified as priority pollutants by the US Environmental Protection Agency (EPA). However, several studies point out that concentrations of some PAHs can exceed 0.5 μg kg^-1 wet weight in diverse fruits and vegetables and even reach 5 μg kg^-1. Amounts can be very different depending on the surrounding area of the crops, the aromatic hydrocarbon, or even the product itself. PAHs content is usually higher for products grown near roadways or in urban regions than in rural areas. Trace level of compounds such as phenanthrene, fluoranthene and pyrene have been found in quite every raw fruit and vegetable. Relative high amounts of lighter PAHs such as naphthalene, acenaphthylene, and acenaphthene have been found in some of them.

Halogenated and parent polycyclic aromatic hydrocarbons in vegetables: Levels, dietary intakes, and health risk assessments

Halogenated polycyclic aromatic hydrocarbons (HPAHs) are attracting increasing concern because of their greater toxicity than their corresponding parent PAHs. However, human exposure to HPAHs via food consumption is not fully understood. In this study, daily intake via vegetable ingestion of 11 HPAHs and 16 PAHs and subsequent cancer risk were assessed for population in Beijing. A total of 80 vegetable samples were purchased from markets, including five leafy vegetables and three root vegetables. The concentrations of total HPAHs (∑HPAHs) were 0.357-0.874ng/g in all vegetables, lower than that of total PAHs (∑PAHs, 10.6-47.4ng/g). ∑HPAHs and ∑PAHs concentrations in leafy vegetables were higher than those in root vegetables, suggesting that the atmospheric deposition might be the dominant source of PAHs and HPAHs in leafy vegetables. Among the HPAH congeners, 2-BrFle and 9-ClFle were the predominant compounds and frequently detected in the vegetable samples. HPAHs and PAHs were also found in certificated vegetables at the concentrations of 0.466-0.751ng/g and 10.6-38.9ng/g, respectively, which were lower than those in non-certificated vegetables except for spinach. For leafy vegetables from local farms, the ∑PAHs and ∑HPAHs levels in the rape and Chinese cabbage samples significantly decreased with increasing the distance away from the incineration plant. The incremental lifetime cancer risks of HPAHs were below the acceptable risk level (10^-6), suggesting that there might be little or no risk to consumers from these compounds in vegetables. For all population groups, children were the most sensitive population to PAHs and HPAHs, and their health issues should be paid more attention.

Street foods exacerbate effects of the environmental burden of polycyclic aromatic hydrocarbons (PAHs) in Nigeria

Polycyclic aromatic hydrocarbons (PAHs) are a large group of well-known toxicants with carcinogenic potential and other health effects including on the immune system. The high health risks of non-communicable diseases and relevant comorbidities in Africa, particularly in contaminated areas like e-waste and crude oil and gas exploration areas and for high consumers of food commodity groupings which are most critical for PAH exposure, are exacerbated by dietary exposure due to unsafe practices in commonly consumed foods, like those street vended.In February 2016, 20 commonly consumed street foods were purchased directly from vendors at major bus stops in Benin City and Umunede in Nigeria. The concentration of 16 priority PAHs was determined. The dietary intake of B[a]P, ∑PAH, PAH4, PAH8, and ∑B(a)P_eq was estimated for children, peripubertal children/adolescent, and adult using the total diet study (TDS) method. Among the analyzed PAHs, there was a predominance of chrysene (17.42 μg/kg). Roasted yam (14.15 μg/kg) and fried fish (1.40 μg/kg) had the highest levels of ∑PAH and B[a]P, respectively. The mean concentration of B[a]P, ∑PAH, PAH4, PAH8, and ∑B(a)P_eq ranged from 0.65-1.40 μg/kg, 0.20-14.15 μg/kg, 0.43-5.22 μg/kg, 0.13-7.88 μg/kg, and 0.002-2.123 μg/kg, respectively. The mean concentration of B[a]P and PAH4 reported in this study was below the maximum allowable levels of 5 and 12 μg/kg for adults and above the maximum levels for young children set at 1.0 μg/kg for both B[a]P and PAH4 in food. The estimated dietary intake of B[a]P, ∑PAH, PAH4, PAH8, and ∑B(a)P_eq for adult, adolescent, and children was 0.56, 0.37, and 0.31 μg/day; 17.6, 10.7, and 8.81 μg/day; 5.78, 4.01, and 3.26 μg/day; 9.22, 6.19, and 5.09 μg/day; and 1.72, 0.97, and 0.82 μg/day, respectively.Street foods represent one important source of PAHs. The exposure occurring through street food compounds with that from home-made foods, environmental pollution, and lifestyle (tobacco smoke) is making up an aggregate daily exposure in the general population.The incremental lifetime cancer risk for adults and children from the consumption of street food was 7.6 × 10^-8 and 2.1 × 10^-8, respectively. Along with initiatives to manage environmental contamination and promote healthier lifestyle, people should be empowered on healthy cooking practices and safe food cookery environments.

A Chemical Synthesis of Benzo[a]pyrene Hapten and Its Application in a Streptavidin-Horseradish Peroxidase-Based Enzyme-Linked Immunological Analysis

A specific BaP hapten was synthesized and BaP antigens (immunogen, coating antigen) were prepared using diverse methods. Based on these works, a streptavidin-horseradish peroxidase-based enzyme-linked immunological analysis was developed and firstly used to detect BaP. Several physiochemical factors that may influence the assay performance were optimized in the assay. Under optimal conditions, a detection limit of 0.0094 ng mL−1 was obtained and good linearity was achieved within a range of 0.03–35.40 ng mL−1. Satisfactory recovery of spiked samples (91.12–109.23%) was obtained and the coefficient of variation was acceptable. Finally, the detection results of BaP in environmental and food samples were consistent with those obtained using high-performance liquid chromatography. The proposed immunoassay is reliable and has great potential for detecting trace amounts of BaP.

Presença de hidrocarbonetos policíclicos aromáticos em produtos alimentícios e a sua relação com o método de cocção e a natureza do alimento

Resumo Hidrocarbonetos Policíclicos Aromáticos (HPA) podem estar associados à carcinogênese em humanos. Tais compostos penetram no organismo pelo trato gastrointestinal, o que faz da dieta uma importante via de contaminação. O objetivo desta revisão é analisar a relação entre a formação/ingestão desses compostos e a alimentação. Foi encontrada associação direta do método de cocção empregado com o aumento dos níveis de HPA nos alimentos e a formação de novos compostos. A fonte térmica aplicada, a composição do alimento, o tipo de óleo utilizado, especialmente nos processos de fritura, bem como o tipo de tratamento empregado ao alimento antes da cocção, são fatores que influenciam o teor de HPA no produto final. A legislação brasileira é pouco abrangente em relação a esses compostos e a necessidade de ampliação das normas nacionais se torna ainda mais evidente quando este tema é visto como uma questão de Segurança de Alimentos.

Tracing biomarker of PAH-exposure and susceptibility factor (GSTM-polymorphism) among cancer patients in Pakistan

We studied cancer patients for possible PAH exposure, using urinary concentration of 1-hydroxypyrene (1-OHP) as a biomarker of internal dose of polycyclic aromatic hydrocarbons (PAHs). The subjects included in this study belonged to various socio-demographic backgrounds, and were diagnosed with cancer (i.e. lung, head and neck or digestive tract cancer). In general, we observed high concentration of urinary 1-OHP among digestive tract cancer patients, compared with the controls (CN) (mean 1.06, median 1.03 and mean 0.62, median 0.63 μmol/mol-Cr in digestive tract cancer patients and controls respectively). The concentrations of urinary 1-OHP were higher than the background level of PAHs; therefore, these groups could have been exposed to PAHs. Highest urinary 1-OHP concentration was observed in digestive tract cancer patients (median 1.25 μmol/mol-Cr) with GSTM-1 genotype. The results of PCA were consistent with qualitative and quantitative data analysis. The contribution of urinary 1-OHP eigenvector revealed a relatively high PAH-exposure among cancer patients compared with CN, while diet and age were influential parameters among cancer patients, which could have a strong link in cancer etiology in the selected exposure groups.

Meat consumption and colorectal cancer risk in Japan: The Takayama study

Compared with the abundant data from Western countries, evidence regarding meat consumption and colorectal cancer is limited in the Japanese population. We evaluated colorectal cancer risk in relation to meat consumption in a population-based prospective cohort study in Japan. Participants were 13 957 men and 16 374 women aged ≥35 years in September 1992. Meat intake, assessed with a validated food frequency questionnaire, was controlled for the total energy intake. The incidence of colorectal cancer was confirmed through regional population-based cancer registries and histological identification from colonoscopy in two main hospitals in the study area. From September 1992 to March 2008, 429 men and 343 women developed colorectal cancer. After adjustments for multiple confounders, a significantly increased relative risk of colorectal cancer was observed in the highest versus lowest quartile of the intake of total and red meat among men; the estimated hazard ratios were 1.36 (95% CI: 1.03, 1.79) for total meat (P for trend = 0.022), and 1.44 (95% CI: 1.10, 1.89) for red meat (P for trend = 0.009). A positive association between processed meat intake and colon cancer risk was also observed in men. There was no significant association between colorectal cancer and meat consumption in women. These results suggest that the intake of red and processed meat increases the risk of colorectal or colon cancer among Japanese men. Abstaining from excessive consumption of meat might be protective against developing colorectal cancer.

Polycyclic aromatic hydrocarbons in commercial brands of dry whole soybeans for direct human consumption

A total of 13 polycyclic aromatic hydrocarbons (PAHs) were surveyed in dry whole soybeans (Glycine max L.) sold for human consumption. The analysed samples were commercialised in vegetarian shops and food stores in Southern Brazil regions. The determination of PAHs levels was carried out by high performance liquid chromatography (HPLC)with fluorescence detection. PAHs were present in 89.7% of the samples. Chrysene (Chy) and 5 methyl chrysene (5MeChy) were the main PAHs detected (76.9% and 71.8%, respectively) followed by dibenzo(ai)pyrene (DaiP), however in a much less percentage of samples (23.1%). Apart from those PAHs, also benzo(a)antracene (BaA), benzo(b)fluoranthene (BbF), benzo(k)fluoranthene (BkF) and benzo(a)pyrene(BaP) were found. The ΣPAH levels in the positive samples ranged from 0.80 to 38.78 µg kg-1, with exception of one sample that reached 204.46 µg kg-1 (ΣPAHs of six compounds). Despite the present contamination there are no maximum limits set for PAHs in soybeans.

Effects of cooking methods and tea marinades on the formation of benzo[a]pyrene in grilled pork belly (Samgyeopsal)

We investigated the effects of different grilling tools, temperatures, and tea marinades on the formation of benzo[a]pyrene in grilled pork belly as well as the antioxidant capacities of tea marinades. The least amount of benzo[a]pyrene was detected in modified charcoal-grilled pork belly (1.28μg/kg). The highest risk factors for the formation of benzo[a]pyrene are direct contact with flames and fat excess on the heating source. A modified charcoal grill can be used as an alternative grilling tool to meet consumer needs for safety and taste. The marination of pork bellies with tea increased radical-scavenging activity and prevented lipid oxidation in proportion to the concentration of tea infusion and marinating time. The yerba mate tea marinade significantly increased the radical-scavenging activity and prevented benzo[a]pyrene formation more than the green tea marinade. Tea marinade can be applied to seasoning or sauce as pretreatment to preserve the quality of meat and to decrease benzo[a]pyrene formation during cooking.

Characteristics of polycyclic aromatic hydrocarbons in food oils in Beijing catering services

The concentrations and characteristics of 16 polycyclic aromatic hydrocarbons (PAHs) in 48 oil samples randomly collected from 30 catering services that employ six cooking methods were quantified via high-performance liquid chromatography (HPLC). These 16 PAHs were detected in almost all of the samples. The levels of Σ16PAHs, Σ4PAHs, benzo[a]pyrene (BaP), and total BaP equivalents (ΣBaP_eq) for the six cooking methods exceeded the legal limit. The concentrations of Σ4PAHs were approximately 9.5 to 16.4 times the legal limit proposed by the European Commission (Off J Eur Union 215:4-8, 2011), and the level of BaP exceeded the national standard in China by 4.7- to 10.6-fold, particularly in oil from fried foods. Low molecular weight PAHs (LMW PAHs) were predominant in fried food oil from different catering services and accounted for 94.8 % of these oils, and the ΣBaP_eq of the high molecular weight PAHs (HMW PAHs) was 11.5-fold higher than that of the LMW PAHs. The concentrations of Σ16PAHs (3751.9-7585.8 μg/kg), Σ4PAHs (144.6-195.7 μg/kg), BaP (79.7-135.8 μg/kg), and ΣBaP_eq (231.0-265.4 μg/kg) were highest in the samples from fast food restaurants/buffets (FB), followed by those from fried food stalls (FS) and then cooking restaurants/cafeterias (RC). The results of this study suggest that the government should strengthen control and supervision of PAH contamination in food and edible oils.

Facile Synthesis of N-Doped Carbon Dots as a New Matrix for Detection of Hydroxy-Polycyclic Aromatic Hydrocarbons by Negative-Ion Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

N-doping carbon dots (N-CDs) were prepared by microwave-assisted pyrolysis of dl-malic acid and ethanolamine as precursors. The material served as an excellent matrix for the detection of the environmental pollutants hydroxy-polycyclic aromatic hydrocarbons (OH-PAHs) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) in negative ion mode. The obtained N-CDs exhibited good UV absorption capacity and favorable solubility. The use of the N-CDs matrix exhibited low matrix background interference and was beneficial to improve the signal response due to the specific π-conjugated polyaromatic structure and the doping of nitrogen atoms. The developed method was found to have good reproducibility and sensitivity. The N-CDs as a new matrix also were employed for the detection of OH-PAHs in real PM2.5 samples. The mass concentrations of Σ-hydroxy-pyrene, Σ-dihydroxy-anthraquinone, and Σ-dihydroxy-benzo(a)pyrene on the collected PM2.5 samples ranged from 0.125 to 0.136 ng/m(3), 0.039 to 0.052 ng/m(3), and 0.053 to 0.072 ng/m(3), respectively. This work extends the application field of N-CDs and provides a good candidate of matrix for MALDI-TOF MS detection of environmental pollutants.

A Critical Review about the Health Risk Assessment of PAHs and Their Metabolites in Foods

Polycyclic aromatic hydrocarbons (PAHs) are a family of toxicants that are ubiquitous in the environment. These contaminants generate considerable interest, because some of them are highly carcinogenic in laboratory animals and have been implicated in breast, lung, and colon cancers in humans. Dietary intake of PAHs constitutes a major source of exposure in humans. Factors affecting the accumulation of PAHs in the diet, their absorption following ingestion, and strategies to assess risk from exposure to these hydrocarbons following ingestion have received very little attention. This review, therefore, focuses on concentrations of PAHs in widely consumed dietary ingredients along with gastrointestinal absorption rates in humans. Metabolism and bioavailability of PAHs in animal models and the processes, which influence the disposition of these chemicals, are discussed. Finally, based on intake, disposition, and tumorigenesis data, the exposure risk to PAHs from diet is presented. This information is expected to provide a framework for refinements in risk assessment of PAHs.

Prediction of the bioaccumulation of PAHs in surface sediments of Bohai Sea, China and quantitative assessment of the related toxicity and health risk to humans

Assessing the health risk of PAHs in sediments was quite difficult because sediment occurred in sea floor, and it was very hard to contact with them directly for humans. This study was attempted to reveal the relationship between concentrations of PAHs in surface sediments and health risk of seafood consumers. The transfer (bioaccumulation) of PAHs from surface sediment into benthic organisms was predicted. Source contributions to PAHs and related toxicity and health risks (from intake of PAHs-contaminated benthic organisms) were studied based on PMF model and Monte Carlo simulation, respectively. Total concentrations of PAHs (TPAHs) ranged from 149.40 to 1211.97 ng g(-1) in sediments of Bohai Sea (BS), China. Petroleum and vehicular emission, coal combustion and coke oven constituted 40.0%, 32.2% and 27.8% of PAHs, respectively, but contributed 53.0%, 22.8% and 24.2% of toxicity posed by PAHs in sediment. For children, teens and adults, the 95th percentile carcinogenic and non-carcinogenic risks were below the threshold values of 10(-6) and 1.0, respectively, suggesting no potential health risk. Sensitivity analysis suggested that exposure duration (ED) and PAH concentrations (CS) were the two most sensitive parameters in risk assessment. The results provided a method to evaluate the quality of sediments and the potential health risk related to PAHs in marine sediments.

Reduction of the polycyclic aromatic hydrocarbon (PAH) content of charcoal smoke during grilling by charcoal preparation using high carbonisation and a preheating step

Charcoal-grilling may lead to contamination of food with carcinogenic polycyclic aromatic hydrocarbons (PAHs) during the grilling process. The objective of this work was to determine the effect of charcoal preparation on 16 USEPA priority PAHs in the smoke produced during the grilling process. Firstly, mangrove charcoal was prepared at carbonisation temperatures of 500, 750 and 1000 °C. The charcoal were then preheated by burning at 650 °C. This preheating step is usually used to prepare hot charcoal for the grilling process in the food industry. In this study, charcoal was preheated at different burning times at 5, 20 min and 5 h, at which time partial and whole charcoal glowed, and charcoal was completely burnt, respectively. Finally, PAHs in the smoke were collected and determined by GC/MS. The result showed that charcoal prepared at a carbonisation temperature of 500 °C had higher levels of PAHs released into the smoke. In contrast, charcoal produced at 750 and 1000 °C had lower PAHs released for all burning times. In addition, PAHs released for 5, 20 min and 5 h of burning time were about 19.9, 1.2 and 0.7 µg g(-1) dry charcoal for charcoal produced at 500 °C, and about 0.9-1.4, 0.8-1.2 and 0.15-0.3 µg g(-1) dry charcoal for charcoal produced at 750 and 1000 °C, respectively. Therefore, this research suggests that food grilled using charcoal carbonised at a high temperature of about 750 °C presents a lower risk of PAH contamination. In addition, in the preheating step, whole charcoal should fully glow in order to reduce the PAH content in charcoal before grilling.

Dietary intake polycyclic aromatic hydrocarbons (PAHs) and associated cancer risk in a cohort of Chinese urban adults: Inter- and intra-individual variability

Dietary intake is one of the major exposure pathways of polycyclic aromatic hydrocarbons (PAHs), especially in Chinese people because foods are often prepared with grilling and/or frying that would produce high levels of PAHs. In this paper, we assessed daily dietary intakes (DDI) of PAHs, using a "duplicate plate method", among 100 Chinese urban residents. The DDI of benzo(a)pyrene ranged from 0.06 µg per day to 13.5 µg per day with a median of 0.69 µg per day, varying largely across subjects. The median Incremental Lifetime Cancer Risk (ILCR) attributable to PAH dietary intake was 6.65 × 10(-5) (4.41 × 10(-5) to 1.02 × 10(-4) as inter-quartile range). The contribution of several high-PAH containing foods like barbecued, smoked or deep-fried meats to the overall DDIs was about 13%. The use of raw foods may underestimate dietary intake of PAHs and associated exposure risk considerably. Results from foods sampled in different seasons suggested that seasonal variability within an individual may contribute notably to overall variability measured in a population and more future studies with longer-term investigation on food ingestion and pollutant exposure are needed. The study indicates that measuring actually consumed foods is more appropriate for dietary intake exposure assessment, and intra-individual variance should be taken into account during study design and data analysis.

Quantitatively assessing the health risk of exposure to PAHs from intake of smoked meats

Smoked meat and meat products represent a significant part of the daily diet in south-west China and many other parts of the world. In this study, we evaluated the health risks of long-term exposure to polycyclic aromatic hydrocarbons (PAHs) in a daily low dose exposures (from intake of PAH-containing smoked meats) in south-west China for eight groups of people based on a Monte Carlo simulation. Total concentrations of PAHs in smoked meats from south-west China ranged from 14.4 to 56.3μgkg(-1). The 95th percentile carcinogenic risk (CR) values of eight groups in four cities and provinces were lower than the acceptable value (1.00E-5), indicating no significant risk. The 95th percentile Hazard Index (HI) values were below 1, suggesting no obvious non-carcinogenic effects developed. This study was the first attempt to provide information on the potential health risk for daily intake of PAH-containing smoked meat.