Accumulation characteristics and potential risk of PAHs in vegetable system grow in home garden under straw burning condition in Jilin, Northeast China

Dietary exposure to polycyclic aromatic hydrocarbons-contaminated Talinum Triangulare grown along polluted river

The research aims to evaluate the source, dispersion, and human health risk assessment of PAH-contaminated Talinum Triangulare grown along the polluted Ikpoba River. The freeze-dried vegetables were sonicated with dichloromethane for an hour and then concentrated using a rotary evaporator. The extract was purified using a glass column with anhydrous Na2SO4 and silica gel and analyzed using gas chromatography-mass spectrometry (GC-MS). The distribution of the contaminants showed that Pyrene < Benzo(a)anthracene ≤ Fluorene < Phenathrene ≤ Naphthalene ≤ Acenaphthene < Anthracene ≤ Acenaphthylene, while Pyrene < Benzo(a)anthracene < Fluorene < Phenathrene < Acenaphthalene ≤ Naphthalene < Anthracene < Acenaphthylene in wet and dry periods, respectively. The average ∑8 PAHs was 0.85 mg/kg and 0.75 mg/kg in wet and dry periods, respectively, and showed a decrease of 17.64% from wet to dry periods. The daily average dose revealed that the infant male and the adult female consumed the least and highest doses of T. Triangulare (TT), respectively. Furthermore, the hazard quotient and hazard index were < 1 for all the target groups, with adult females having higher values in both seasons. However, the incremental life cancer risk of the target group was between potential and high-potential cancer risk, with adolescent males and adult females more prone to low and high cancer risk, respectively. The isomer ratio and multivariate statistics revealed the sources of the PAH-contaminated TT to be more from pyrolysis.

Uptake of polycyclic aromatic hydrocarbons (PAHs) from PAH-contaminated soils to carrots and Chinese cabbages under the greenhouse and field conditions

Polycyclic aromatic hydrocarbons (PAHs) with the properties of structural stability, semi-volatility, and hydrophobicity are toxic and persistent in environments; thus, their transport and fate in agroecosystems is essential for reducing PAH accumulation in the edible parts of crops. Here, we cultivated cabbages (Brassica pekinensis L.) and carrots (Daucus carota L.) in PAH-contaminated soils under the greenhouse and field conditions. After harvesting, we observed a 9.5-46% reduction in soil ∑PAH concentrations. There were 37% of bioconcentration factors (BCFbs) > 1 and 93% of translocation factors (TFab) > 1, while low-molecular-weight (LMW) PAHs had higher BCFbs than high-molecular-weight (HMW) PAHs. The PAH concentrations showed significant and positive correlations among soils, the belowground parts, and the aboveground parts. The toxicity equivalent concentration (TEQBaP) followed the order of cabbage (greenhouse) > cabbage (field) > carrot (greenhouse) > carrot (field), suggesting potentially higher health risks in cabbage relative to carrot and vegetables under the greenhouse relative to field condition. Our study suggested growing carrots under field conditions as a management strategy for reducing the risks of vegetables grown in PAH-contaminated soils.

Ecological and health risk assessments of polycyclic aromatic hydrocarbons (PAHs) in soils around a petroleum refining plant in China: A quantitative method based on the improved hybrid model

Polycyclic aromatic hydrocarbons (PAHs) are extensively released into the environment by petroleum refining activities, predominantly affecting soil as a major reservoir. This study focuses on an active petroleum refinery in central China and employs a multi-faceted approach, combining geo-statistics, the absolute principal component-multiple linear regression model, and the Monte Carlo simulation, to comprehensively unravel the sources and risks associated with 12 PAHs. The analysis reveals a wide range of PAH concentrations, spanning from 60.23 to 1678.00 μg·kg-1, with an average of 278.91 μg·kg-1. Strikingly elevated PAH levels are primarily concentrated in construction and transportation lands, whereas woodland and grasslands exhibit lower PAH concentrations. In terms of ecological impact, the risk arising from oil-coal combustion significantly surpasses that linked to biomass combustion. meticulous assessments indicate negligible carcinogenic risks for both children and adults within the study area. An innovative hybrid model, which seamlessly integrates risk assessments with source identification, emerges as a pivotal advancement. This hybrid model not only quantifies PAH emission levels from refining activities but also effectively quantifies potential risks from distinct sources. Consequently, this study furnishes a robust theoretical foundation for strategizing PAH pollution risk mitigation. In essence, our research not only contributes a comprehensive understanding of PAH distribution around an active petroleum refinery but also introduces an advanced hybrid model, culminating in valuable insights for devising measures to curtail PAH-related environmental risks.

Effects of biodegradable and non-biodegradable microplastics on bacterial community and PAHs natural attenuation in agricultural soils

Anthropogenic activities such as in situ straw incineration and the widespread use of agricultural film led to the accumulation of polycyclic aromatic hydrocarbons (PAHs) and microplastics (MPs) in agricultural soils. In this study, four biodegradable MPs (BPs), including polylactic acid (PLA), polybutylene succinate (PBS), poly-β-hydroxybutyric acid (PHB) and poly (butylene adipate-co-terephthalate) (PBAT) and non-biodegradable low-density polyethylene (LDPE) were selected as representative MPs. The soil microcosm incubation experiment was conducted to analyze MPs effects on PAHs decay. MPs did not influence PAHs decay significantly on day 15 but showed different effects on day 30. BPs reduced PAHs decay rate from 82.4% to 75.0%- 80.2% with the order of PLA < PHB < PBS < PBAT while LDPE increased it to 87.2%. MPs altered beta diversity and impacted the functions to different extents, interfering in PAHs biodegradation. The abundance of most PAHs-degrading genes was increased by LDPE and decreased by BPs. Meanwhile, PAHs speciation was influenced with bioavailable fraction elevated by LDPE, PLA and PBAT. The facilitating effect of LDPE on 30-d PAHs decay can be attributed to the enhancement of PAHs-degrading genes and PAHs bioavailability, while the inhibitory effects of BPs were mainly due to the response of the soil bacterial community.

PAHs, PCBs and OCPs in olive oil during the fruit ripening period of olive fruits

Because of their possible carcinogenic effects, it is crucial to determine levels of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in olive oils. However, there are a few studies about these pollutants' levels in olive oils and no other studies reported PAHs, PCBs and OCPs at the same time and during the ripening period of olives in olive oils. A modified clean-up technique was successfully applied for eliminating lipidic components. Additionally, this study does not just report the concentrations of these pollutants but also inspects the sources depending on the actual sampling site. Also, PCBs and OCPs carcinogenic risks in olive oil were reported for the first time in the literature. This study aims to present levels, carcinogenic risks, sources and concentration changes during the ripening period of these pollutants in olive oil. For this purpose, fruit samples for oil extraction were collected between the beginning of the fruit ripening and harvest period. Obtained olive oils from the fruits were extracted and cleaned up using the QuEChERS method. GC-MS and GC-ECD were used for the quantitative analysis of the targeted pollutants. The average concentrations for ∑₁₆PAHs, ∑₃₇PCBs and ∑₁₀OCPs were 222.48 ± 133.76 μg/kg, 58.26 ± 21.64 μg/kg and 25.48 ± 19.55 μg/kg, respectively. During the harvest period, the concentrations were in a decreasing trend. Calculated carcinogenic risks were above acceptable limits for all groups and traffic, wood-coal burning, atmospheric transport and previous uses were the main sources. Results of the source determination indicated that some possible sources could be prevented with regulations and precautions.

Level and risk assessment of selected polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and organochlorine pesticides in walnut and soil

It is unknown how hydrophobic organic contaminants (HOCs) are distributed and how they affect the environment in high-fat nuts and their planted soil. The profile of HOCs in walnut/soil system was investigated in this study. Polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), and organochlorine pesticides (OCPs) were found in walnuts at concentrations of 0.67, 127, and 116 μg/kg, respectively. The target hazard quotients (THQ) of 17 PCBs, 16 PAHs, and 21 OCPs from walnut consumption by human were 0.06, 0.01, and 0.11, respectively. The highest concentrations of HOC in the soil were found in Nap and toxaphene, with concentrations of 2580 and 902 μg/kg, respectively. Bioaccumulation factors (BAF) and biota-sediment accumulation factors (BSAF) in walnuts were ranged from <0.01 to 7.04 and <0.01 to 3.83, respectively. Concentrations of most individual HOCs in soil samples were significantly correlated with soil organic matter (SOM) (p < 0.01) and minerals (p < 0.01), with maximum correlation coefficients of 0.70 (OM-PCB81) and -0.84 (P-BaP). According to this study, high-fat walnuts do not have a high bioaccumulation of HOCs from soil, and the risk of consumption is within the safe range.

Analysis of the Artistic Effect of Garden Plant Landscaping in Urban Greening

At present, China is at an essential stage in the progress of social civilisation. At the same time, China's current economic level is developing rapidly and the level of urbanisation is also increasing. However, the uncontrolled development of urban space and excessive consumption of land resources have led to many urban ecological and environmental problems. As a result, there is an urgent need to improve the urban habitat. Plant landscaping is an important part of the urban environment. In addition, plant landscaping is also a crucial part of the visual arts and plays a key role in the shaping of urban spaces. In the context of the urban construction boom, people are increasingly demanding quality in the urban environment. Spatial scale, as a vital factor influencing the visual effect of planting, is gradually becoming a focus of landscape design. Urban greening based on plant landscape can not only improve the urban ecological environment and enhance people's quality of life but also resolve the contradiction between the demand for urban green space and the continuous reduction of urban greening land. Therefore, plant landscaping is recognised as a key step towards global sustainable development. However, according to current research and application practice, the development of urban greenery is limited and hindered by the value of plant landscaping and its applications. In addition, no comprehensive theoretical system has yet been established at the plant scale. In other words, there are still problems of scale in plant landscaping, such as unreasonable density, disproportion, and unclear hierarchy. Therefore, this paper begins with the definition of plant spatial scale in the city and analyses plant spatial types and scale characteristics from multiple perspectives, so as to establish an overall knowledge of plant landscaping. After that, through a study of the current situation of plant landscaping in cities, a quantitative analysis of the visual scale of plant space in urban squares is carried out to address the issues of plant scale design in this research. The focus of the analysis is on the scale of plants in relation to related elements. Furthermore, this study explores the influence of visual aesthetic scale and psychological scale on planting based on the functional scale of plant elements. Finally, the above quantitative analyses are applied to derive some relative data criteria and to summarise the design strategies for the spatial scale of planting in the city. The findings of this study can provide some guiding suggestions and references for the future construction of urban greenery, thus promoting the orderly development of plant landscaping in cities.

Effectiveness of plants and green infrastructure utilization in ambient particulate matter removal

Air pollution is regarded as an increasingly threatening, major environmental risk for human health. Seven million deaths are attributed to air pollution each year, 91% of which is due to particulate matter. Vegetation is a xenobiotic means of removing particulate matter. This review presents the mechanisms of PM capture by plants and factors that influence PM reduction in the atmosphere. Vegetation is ubiquitously approved as a PM removal solution in cities, taking various forms of green infrastructure. This review also refers to the effectiveness of plant exploitation in GI: trees, grasslands, green roofs, living walls, water reservoirs, and urban farming. Finally, methods of increasing the PM removal by plants, such as species selection, biodiversity increase, PAH-degrading phyllospheric endophytes, transgenic plants and microorganisms, are presented.

Developing an integrated framework for source apportionment and source-specific health risk assessment of PAHs in soils: Application to a typical cold region in China

Here, a new integrated methodology framework has been proposed for source apportionment and source-oriented risk evaluation, and applied to identify the characteristics, sources and health risks of PAHs in the soils of a typical cold region in Northeastern China. To this end, a large-scale data set containing 1780 soil samples and 16 priority PAHs has been collected from the study area. Two advanced receptor models, positive matrix factorization (PMF) and multivariate curve resolution-weighted alternating least-squares (MCR-WALS), have been comparatively employed to apportion the pollution sources of soil PAHs, with the help of a set of modified literature PAH source fingerprints. Further, the apportionment results have been incorporated into a probabilistic incremental lifetime cancer risk model for assessing the source-specific health risk of soil PAHs. Notably, the PMF and MCR-WALS models have apportioned essentially same results. The coal combustion and gasoline engine are identified as the main contributors of soil PAHs, with contributions of 57.9-58.1% and 25.2-22.2%, respectively. The health risks posed by PAHs in the soils are negligible for both adult and children; relatively, source-oriented risk assessment shows coal combustions make the largest contribution to the total risk of PAHs (56.1%), followed by gasoline engine (22.5%) and coke oven (21.4%).

Evaluation of Polycyclic Aromatic Hydrocarbons (PAHs) in Bamboo Shoots from Soil

The toxicity, carcinogenicity and persistence of polycyclic aromatic hydrocarbons (PAHs) pose a great threat to the ecological system and human health. The contamination levels, translocation and source analysis of 16 PAHs in bamboo shoot and its planted soil were investigated. The average concentrations of total PAHs were 18.80 ± 1.90 µg/kg and 123.98 ± 113.36 µg/kg in bamboo shoots and soils, respectively. The most abundant PAH was Phenanthrene (PHE), with the detected average concentrations of 5.85 µg/kg in bamboo shoots and 19.28 µg/kg in soils. The highest detected types of PAHs were 3 rings and 4 rings, with the proportions of 80.69% (bamboo shoots) and 35.23% (soils). The transfer factors of PAHs were ranged from 0.011 to 0.895, in which PAHs with 3 rings showed the strongest transfer ability. The combustion of biomass and petroleum might be the main source of PAHs in the planted soils of bamboo shoots.

Ecological risk and early warning of soil compound pollutants (HMs, PAHs, PCBs and OCPs) in an industrial city, Changchun, China

Soil ecological risk caused by compound pollutants is a topic that deserves increasing attention, and soil risk early warning is a more in-depth discussion on this topic. In this study, we collected soil samples from Changchun, a typical industrial city, and determined the contents of 13 heavy metals (HMs) (0.00 mg kg^-1-6380 mg kg^-1), 16 polycyclic aromatic hydrocarbons (PAHs) (0.00 mg kg^-1-27.7 mg kg^-1), 7 polychlorinated biphenyls (PCBs) (0.30 μg kg^-1-168 μg kg^-1), and 8 organochlorine pesticides (OCPs) (0.00 mg kg^-1-4.52 mg kg^-1). The soil ecological risks of compound pollutants were assessed. The results showed that PAHs were the greatest risk pollutants, followed by PCBs and HMs, and OCPs were the smallest risk pollutants. Most of the ecological risks of compound pollutants were classified as "moderate severity" level according to the (contamination severity index) CSI evaluation criteria. With the help of modern industrial economic theory, through the analysis of the annual accumulation of pollutants, it is possible to predict the future pollutant content in Changchun, and the soil risks could be forewarned. The results showed that if active measures were not taken to reduce the accumulation of PAHs in Changchun soil, the CSI-PAHs would be classified as "ultra-high severity" level in 2035.

Biochar applications combined with paddy-upland rotation cropping systems benefit the safe use of PAH-contaminated soils: From risk assessment to microbial ecology

This study aimed to establish a method allowing the safe use of polycyclic aromatic hydrocarbon (PAH)-contaminated soils through the combination of biochar applications and different cropping systems. The impact of biochar applications under different cropping systems on the human health risks of PAHs and soil microbiology was elucidated. The residual PAHs were the lowest in rhizosphere soils amended with 2% corn straw-derived biochar pyrolyzed at 300 °C (CB300) under the paddy-upland rotation cropping (PURC) system. Human health risks resulting from the ingestion of PAH-contaminated carrot roots / rice grains under the PURC system were significantly lower than those under continuous upland cropping systems. The greatest diversity, richness and network complexity of soil microbial communities occurred under the PURC system combined with the 2% CB300 treatment. Soil microbial functions associated with soil health and PAH biodegradation were enhanced under this strategy, while the pathogen group was inhibited. Primarily owing to its high sorption capacity, bamboo-derived biochar pyrolyzed at 700 °C realized in the reduction of PAHs, but weakly influenced shifts in soil microbial communities. Overall, the combination of PURC systems and low-temperature-pyrolyzed nutrient-rich biochar could efficiently reduce the human health risks of PAHs and improve soil microbial ecology in agricultural fields.

Comprehensive assessment of heavy metals pollution of farmland soil and crops in Jilin Province

As a major agricultural province in China, it is necessary to study the content of heavy metals in farmland soil and crop in Jilin Province and to evaluate the risks to ecology and human health. This study presented the work completed on 79 soil samples, 10 rice samples, 66 maize samples and 15 soybean samples collected from Jilin Province farmland and evaluated six heavy metals (Zn, Cu, Pb, Cd, Hg and As) concentrations. The results showed that the concentrations of the six heavy metals in farmland soil and crop samples from Jilin Province basically met the soil standards and food health standards of China. The agricultural soil pollution spatial distribution was the most serious in the south of Jilin Province and the lightest in the west. The non-carcinogenic risks faced by children eating crops were higher than those of adults, but the carcinogenic risks were lower than those of adults. Both of the two health risks to adults and children from eating crops were very limited. The results would help determine the heavy metals pollution in farmland soil in Jilin Province efficiently and accurately and helped decision makers to achieve a balance between production and environmental regulation.

Quantification of Brominated Polycyclic Aromatic Hydrocarbons in Environmental Samples by Liquid Chromatography Tandem Mass Spectrometry with Atmospheric Pressure Photoionization and Post-column Infusion of Dopant

A sensitive method for the quantification of brominated polycyclic aromatic hydrocarbons (BrPAHs) in environmental samples is yet to be developed. Here, we optimized the analytical conditions for liquid chromatography tandem mass spectrometry with atmospheric pressure photoionization and post-column infusion of dopant (LC-DA-APPI-MS/MS). We then compared the sensitivity of our developed method with that of conventional gas chromatography high-resolution MS (GC-HRMS) by comparing the limits of quantification (LOQs) for a range of BrPAHs. Finally, to evaluate our developed method, 12 BrPAHs in sediments and fish collected from Tokyo Bay, Japan, were analyzed; 9 common PAHs were also targeted. The LOQs of the developed analytical method were 14 - 160 times lower than those of GC-HRMS for the targeted BrPAHs. The developed analytical method is a sensitive approach for determining the concentrations of BrPAHs in sediment and fish samples.

Accumulation and transformation of benzo[a]pyrene in Haplic Chernozem under artificial contamination

Polycyclic aromatic hydrocarbons (PAHs) have been a major concern because of their carcinogenicity, mutagenicity, teratogenicity and wide distribution in the environment. Over 90% of PAHs in the environment exist on soil surface/sediment. Benzo[a]pyrene (BaP) is one of the predominant PAHs in soil. Thus, it is critically important to understand the patterns of BaP accumulation and transformation peculiarities in soil for the risk assessment. The studies were conducted in model experiment with Haplic Chernozem spiked with various doses of BaP (20, 200, 400 and 800 µg kg^-1) equivalent to 1, 10, 20 and 40 levels of maximum permissible concentrations. The unique properties of Haplic Chernozem were studied allow to accumulate and transform BaP as well as barley plants ability to absorb of some BaP concentration. Extraction of BaP from the soil was carried out by the saponification method. The qualitative and quantitative determination of BaP and other polycyclic aromatic hydrocarbons (PAHs) was performed by high-performance liquid chromatography with fluorescence detection (Agilent 1260 Germany, 2014). BaP accumulation in soil depended on the applied BaP concentrations in Haplic Chernozem. Studying the features of PAHs transformation in the soil of a model experiment 1 year after the compound application showed the BaP content in the soil decreased up to 11-40%. Two years after the BaP application the content in the soil decreased up to 15-44% from the initial BaP content in the soil. The percentage of BaP concentration reduction in Haplic Chernozem increased with an increase in the dose of the applied xenobiotic. An increase in the dose of the applied pollutant to the soil of the model experiment contributed to an increase in all PAHs, which indicated a rapid BaP transformation in Haplic Chernozem. The PAHs content in the soils of model experiment in the first year of the research formed the following descending series: pyrene > chrysene > fluoranthene > phenanthrene. In the second year of research the phenanthrene content became higher than the fluoranthene content. The content of these compounds exceeded 20% of the total PAHs content in the soil samples in the first and second years of the model experiment. The features of PAHs accumulation and transformation in soils under artificial pollution showed the degradation of large-nuclear PAHs, starting from 5-ring polyarenes, and their structural reorganization into the less-nuclear polyarenes, such as 4-, 3-, and 2-ring PAHs. During the 2 years of the model experiment the BaP concentration in the soil decreased up to 15-44% from the initial BaP content in the soil.

Risk assessment of polycyclic aromatic hydrocarbons and their chlorinated derivatives produced during cooking and released in exhaust gas

Cooking exhaust gas includes polycyclic aromatic hydrocarbons (PAHs) that are unintentionally generated during cooking, which exposes the cook and others in the vicinity to these toxic compounds. However, information on the occurrence of PAHs, particularly their chlorinated derivatives (ClPAHs), in cooking exhaust gas is limited. Here, we determined the concentrations of 12 PAHs and 20 ClPAHs in cooking exhaust gas emitted during gas-grilling of a Pacific saury using a typical Japanese fish grill in an indoor kitchen. The total concentrations of PAHs and ClPAHs in the cooking exhaust gas were 3400 and 19 ng m^-3, respectively. All 12 PAHs were detected in the cooking exhaust gas, with phenanthrene (2100 ng m^-3), fluorene (630 ng m^-3), and anthracene (200 ng m^-3) detected at the highest concentrations. Four of the 20 ClPAHs were detected, with 9-monochlorinated phenanthrene detected at the highest concentration (12 ng m^-3). The exposure rates for the cook to the PAHs and ClPAHs in the cooking exhaust gas, estimated using the National Institute of Advanced Industrial Science and Technology - Indoor Consumer Exposure Assessment Tool (AIST-ICET), were in the range of 7.2-72 ng-BaP_eq kg^-1 day^-1 (toxic equivalent concentrations relative to the toxicity of benzo[a]pyrene), which was comparable with that for dietary ingestion of cooked foods (54 ng-BaP_eq kg^-1 day^-1). A risk assessment of exposure to PAHs and ClPAHs in cooking exhaust gas in the indoor environment revealed that this gas may pose a health risk to the cook (incremental lifetime cancer risk: 2.1 × 10^-6 to 2.1 × 10^-5), indicating that further investigations are warranted.

Nationwide health risk assessment of juvenile exposure to polycyclic aromatic hydrocarbons (PAHs) in the water body of Chinese lakes

The high emissions of polycyclic aromatic hydrocarbons (PAHs) pose a serious threat to the lake ecosystem and human health, and the human health risk assessment of PAH exposure is expected as an urgent project in China. This paper focused on 44 Chinese lakes in 6 lake zones to investigate the occurrence, composition and source of 19 PAHs in water body and estimate the human health risk under PAH exposure. The "List of PAH Priority Lakes" in China was generated based on the combination of incremental lifetime cancer risk (ILCR) model and Monte Carlo simulation. Our results showed that the Σ₁₇ PAHs ranged from 3.75 ng·L^-1 to 368.68 ng·L^-1 with a median of 55.88 ng·L^-1. Low-ring PAHs were the predominant compounds. PAH profiles varied significantly at lake zone level. Diagnostic ratios showed that PAHs might derive from petroleum and coal or biomass combustion. Benzo[a]pyrene-equivalent toxic concentrations (BaPeq) of the Σ₁₇ PAHs ranged from 0.07 ng·L^-1 to 2.26 ng·L^-1 (0.62 ± 0.52 ng·L^-1, mean ± standard deviation) with a median of 0.47 ng·L^-1. Benzo[a]anthracene (BaA), benzo[a]pyrene (BaP) and benzo[e]pyrene (BeP) were the main toxic isomers. Juvenile exposure to PAHs via oral ingestion (drinking) and dermal contact (showering) had negligible and potential health risks, respectively. Juveniles were the sensitive population for PAH exposure. 15 lakes were screened into the "List of PAH Priority Lakes" in three priority levels: first priority (Level A), moderate priority (Level B) and general priority (Level C). Lake Taihu, Lake Chaohu and Lake Hongze were the extreme priority lakes. Optimizing the economic structures and reducing the combustion emissions in these areas should be implemented to reduce the population under potential health risk of PAHs.

Facile synthesis of polydivinylbenzene coated magnetic polydopamine coupled with pressurized liquid extraction for the extraction and cleanup of polycyclic aromatic hydrocarbons in soils

Due to the trace levels of polycyclic aromatic hydrocarbons (PAHs) in soil and the complexity of soil matrices, effective sample pretreatment methods are of great significance to obtain accurate analytical results. In this paper, polydopamine (PDA) encapsulated Fe₃O₄ particles were used as seeds for in situ polymerization of divinylbenzene (DVB) to derive magnetic hybrid material Fe₃O₄@PDA@PDVB. Coupled with pressurized liquid extraction, Fe₃O₄@PDA@PDVB was investigated as a selective adsorbent for the extraction and cleanup of PAHs in soil. The prepared magnetic material was characterized and demonstrated to possess strong hydrophobicity and superparamagnetism. Under optimal conditions, Fe₃O₄@PDA@PDVB can effectively extract 15 PAHs from a 30% methanol solution within 2 min, and it is more selective for PAHs than for n-alkane in soil extracts. The matrix effect significantly decreased after extraction by the prepared material, which showed superiority to a silica gel column method (EPA 3630C Method). The developed method was linear (5-1000 ng g^-1) with coefficient of determination (R²) ranging from 0.9986-0.9998, and the limits of detection were 0.13-0.54 ng g^-1. Additionally, repetitive experiments indicated that the prepared material was reproducible and reusable with relative standard deviations below 8.4% and 8.6%, respectively. Finally, the new method was successfully employed to determine the concentrations of PAHs in genuine soil and standard reference material, and the results were comparable to those of widely utilized EPA methodology.

Simultaneous determination of polycyclic aromatic hydrocarbons and their chlorinated derivatives in grilled foods

Polycyclic aromatic hydrocarbons (PAHs) are unintentionally generated in foods that are cooked, and dietary ingestion of these PAHs is regarded as the dominant route of exposure to PAHs. Some chlorinated PAHs (ClPAHs) are more toxic than their corresponding parent PAHs and can also be generated in food during cooking. Knowledge of the concentrations of ClPAHs in cooked foods has been limited by the lack of an adequate analytical method for measuring ClPAH concentrations in cooked foods. In this study, we developed an analytical method for simultaneous determination of PAHs and ClPAHs in lipid-rich foods. The combination of a potassium hydroxide silica gel column and an activated carbon cartridge enabled us to simultaneously measure PAH and ClPAH concentrations in raw and grilled fish and meats. Twelve kinds of PAHs (e.g., fluorene [Fle], phenanthrene [Phe], fluoranthene [Flu], and pyrene [Pyr]) were detected in grilled foods. The concentrations ranged from below the limit of quantitation (<LOQ) to 310 ng g^-1. We also detected 9-monochlorinated Phe (9-ClPhe), 3-monochlorinated Flu (3-ClFlu), 8-monochlorinated Flu (8-ClFlu), and 1-monochlorinated Pyr (1-ClPyr); those concentrations ranged from <LOQ to 0.16 ng g^-1. The total concentrations of PAHs were significantly lower in gas-grilled meats than in charcoal-grilled meats. In contrast, the concentrations of ClPAHs were significantly higher in gas-grilled meats than in the charcoal-grilled meats. This pattern could be attributed to the difference of reaction temperatures needed to generate them. Toxic equivalent (TEQ) concentrations, which were calculated based on toxicities relative to benzo[a]pyrene (BaP), were much higher in the grilled foods (0.12-12 ng-BaP_eq g^-1) for PAHs than for ClPAHs (<LOQ to 0.026 ng-BaP_eq g^-1).

Polycyclic aromatic hydrocarbon (PAHs) geographical distribution in China and their source, risk assessment analysis

In China, the huge amounts of energy consumption caused severe carcinogenic polycyclic aromatic hydrocarbon (PAHs) concentration in the soil and ambient air. This paper summarized that the references published in 2008-2018 and suggested that biomass, coal and vehicular emissions were categorized as major sources of PAHs in China. In 2016, the emitted PAHs in China due to the incomplete combustion of fuel was about 32720 tonnes, and the contribution of the emission sources was the sequence: biomass combustion > residential coal combustion > vehicle > coke production > refine oil > power plant > natural gas combustion. The total amount of PAHs emission in China at 2016 was significantly decreased due to the decrease of the proportion of crop resides burning (indoor and open burning). The geographical distribution of PAHs concentration demonstrated that PAHs concentration in the urban soil is 0.092-4.733 μg/g. At 2008-2012, the serious PAHs concentration in the urban soil occurred in the eastern China, which was shifted to western China after 2012. The concentration of particulate and gaseous PAHs in China is 1-151 ng/m3 and 1.08-217 ng/m3, respectively. The concentration of particle-bound PAHs in the southwest and eastern region are lower than that in north and central region of China. The incremental lifetime cancer risk (ILCR) analysis demonstrates that ILCR in the soil and ambient air in China is below the acceptable cancer risk level of 10-6 recommended by US Environmental Protection Agency (EPA), which mean that there is a low potential PAHs carcinogenic risk for the soil and ambient air in China.