Health Risk Of Polycyclic Aromatic Hydrocarbons Research Articles

Characteristics, sources, and health risks of PAHs and their derivatives in indoor dust in Zhengzhou

The occurrence, source, and health risk of polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and oxy-PAHs (OPAHs) in indoor dust collected from three types of microenvironments (offices, classrooms, and dormitories) at a university campus in Zhengzhou were analysed. The results showed that the average concentration of the total PAHs was 2403.21 ± 981.99 ng g−1, with PHE (20.06% of Σ18PAHs) and BkF (15.46%) being the dominant species. The average concentrations of total NPAHs and OPAHs were 11.09 ± 5.12 and 385.80 ± 255.27 ng g−1, with 2+3N-FLT (39.15%) and 9-FLO (39.76%) as the most abundant species of NPAHs and OPAHs, respectively. The average concentrations of total PAHs, NPAHs, and OPAHs in different microenvironments displayed obvious spatial specificity with the highest values in dormitories. The main source of PAHs, as identified by diagnostic ratios, was petroleum combustion, coal/biomass combustion and vehicle exhaust emissions. The average incremental lifetime cancer risk (ILCR) for undergraduates exposed to dust in classrooms and dormitories exceeded 10−6, indicating a potential cancer risk. The most important exposure pathway was dermal contact, while the inhalation route was negligible.

Characteristics, Sources Apportionment, and Health Risks of PM2.5-bound PAHs and Their Derivatives Before and After Heating in Zibo City

Atmospheric polycyclic aromatic hydrocarbons (PAHs) and their derivatives are a global problem that influences the environment and threatens human health. To investigate the characteristics, sources, and health risk assessment of PM2.5-bound PAHs and their derivatives, PM2.5 were collected at an urban site in Zibo from November 5 to December 26, 2020, and the concentrations of 16 conventional PAHs, nine NPAHs, and five OPAHs in PM2.5 were analyzed using gas chromatography-mass spectrometry. Source apportionment of PAHs and their derivatives was conducted using diagnostic ratios and a PMF model, and the health risks of PAHs and their derivatives to adult men and women were evaluated using the source-dependent incremental lifetime cancer risk (ILCR) model. The results showed that the average concentrations of ∑16pPAHs, ∑9NPAHs, and ∑5OPAHs in PM2.5 of Zibo City during the sampling period were (41.61 ± 13.40), (6.38 ± 5.70), and (53.20 ± 53.47) ng·m-3, respectively. The concentrations of the three PAHs increased significantly after heating, which were 1.31, 2.04, and 5.24 times larger than those before heating. During the sampling period, Chr, BaP, and BaA were the dominant components of pPAHs; 9N-Ant and 2N-Flt + 3N-Flt were the dominant components of NPAHs; and ATQ and BZO were the dominant components of OPAHs. Source apportionment results showed that motor vehicles were the main source of PAHs and their derivatives in PM2.5 before heating, whereas after heating, the main sources were the mixed source of coal and biomass combustion and secondary formation. The total BaP equivalent (TEQ) was 14.5 ng·m-3 during the sampling period, and the TEQ increased significantly after heating, which was approximately 1.2 times of that before heating. Assisted by the individual PAH source apportionment results, the ILCR of PM2.5-boundPAHs and NPAHs in Zibo City had a certain potential carcinogenic risk for adult males (1.06 × 10-5) and females (9.32 × 10-6). Among them, the health risks of PAHs from gasoline vehicles, diesel vehicles, and coal/biomass combustion were significantly higher than those from other emission sources.

Assessment of PAH exposure and health risks among South Korean firefighters based on urinary PAH metabolites

Polycyclic aromatic hydrocarbons (PAHs) comprise a group of compounds resulting from the incomplete combustion of organic matter. Firefighters engaged in fire suppression are highly exposed to PAHs. This study centered on evaluating the exposure levels and health risks of PAHs in South Korean firefighters involved in firefighting activities. The concentrations of 10 PAH metabolites in the urine of firefighters were measured immediately after, and two weeks post their engagement in extinguishing a large tire factory fire. The levels of OH-PAHs in urine samples immediately after fire suppression were elevated by a factor of 1.01–1.84 compared to urine samples from non-exposed period. The median concentration of total PAH metabolites (OH-PAHs) was higher in urine samples immediately after fire suppression (5910 ng/g creatinine) than in urine samples from non-exposed periods (5020 ng/g creatinine). However, the ∑OH-PAH levels in firefighters’ urine were related to personal habits such as smoking. The concentrations of all individual OH-PAHs in the urine samples of nonsmokers exhibited a substantial increase, ranging from 1.37 to 2.3 times, clearly demonstrating that firefighting activities were a substantial source of PAH exposure. The calculated values associated with the health risks stemming from exposure to PAHs, including carcinogenic risk, total estimated daily intake (TEDI), and hazard quotients/index (HQs/HI), all fell within acceptable limits, indicating negligible risk. However, the HQ/HI values and TEDI for individual and total PAH exposures, except those for naphthalene, were 1.36–2.00 times higher in firefighters' samples taken after firefighting operations compared to those during regular duty. This underscores the need for more comprehensive investigations to comprehend the singular impact of firefighting activities due to the diverse sources of PAH emissions in the environment.

Parent and halogenated polycyclic aromatic hydrocarbons exposure in aluminum smelter workers: Serum levels, accumulation trends, and association with health indicators

Polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (HPAHs) can be unintentionally formed and released during industrial thermal processes. However, information on internal exposure and health risks of PAHs and HPAHs for thermal industry workers is very limited. In this study, serum samples from 220 aluminum smelter workers in East China were analyzed, and the relationship between the levels of these pollutants and various health indicators was also assessed. The workers had markedly higher serum concentrations of PAHs and HPAHs than the controls. The serum concentrations of ∑13PAHs and ∑9HPAHs increased with increasing age and occupational exposure duration in male workers. A positive correlation was observed between the ∑13PAH and ∑9HPAH serum concentrations, and the concentration of ∑13PAHs was approximately 50 times higher than that of ∑9HPAHs. For benzo[a]pyrene equivalent (BaPeq)-based risk assessment, the contribution of PAHs and HPAHs to the risk was 80 % and 20 % in the workers. PAHs and HPAHs showed a positive association with pulmonary hypofunction, hypertension and abnormal electrocardiogram. This study indicates occupational exposure to these toxic pollutants remains a significant issue and provides evidence that elevated serum levels of ∑13PAHs and ∑9HPAHs may be associated with an increased risk of lung and cardiovascular diseases.

Distribution, Sources, and Health Risk of Polycyclic Aromatic Hydrocarbons in Farmland Soil of Helan, China

With the development of industry and agriculture, polycyclic aromatic hydrocarbons (PAHs) in the agricultural sector have gradually increased to different degrees, leading to an escalation in environmental pollution. In turn, this escalation has presented a significant possibility of endangering agricultural practices on farmland and has had a serious impact on regional sustainable development. Therefore, a total of 117 samples of soil were gathered to research the pollution level, distribution, sources, and health risk of PAHs in Helan farmland soils. A reference was used for the identification and quantification of PAH content using high-performance liquid chromatography (HPLC) with an ultraviolet detector, and their spatial distribution was analyzed utilizing the Arc Geographic Information System (ArcGIS). The source of PAHs was analyzed by absolute principal component scores/multiple linear regression (APCS-MLR). The lifetime cancer risk increment model and Monte Carlo sensitivity analysis were used to assess the potential health hazards to humans associated with PAHs in soil. Within the current study area, PAHs were higher in the northwest. The results showed that the total content of PAHs in Helan farmland soil ranged from 17.82 to 1544.73 ng·g−1 with a mean of 408.18 ng·g−1, which indicated the middle degree of pollution in farmland soil. The verification results of the APCS-MLR model showed that the correlation coefficient between the measured values and the predicted values ranged from 0.661 to 0.984, which suggested that the APCS-MLR model demonstrated favorable suitability for conducting source analysis of PAHs in the soil within the study region. Based on the contribution of PAHs from each source, the main sources of PAHs in Helan farmland soil were the combustion source (biomass, diesel, and natural gas combustion) and the transportation source (gasoline for vehicles and traffic exhaust emissions). The health risks’ estimation showed that PAHs in farmland soil did not have potential health risks for adults but represented a carcinogenic risk for children via the main exposure pathway of ingestion with the mean intake of 1.28 × 10−5. Meanwhile, the carcinogenic risks (CRs) of dermal contact for the mean value of adults (9.32 × 10−7) was found to be higher than that for children (3.18 × 10−8). From the Monte Carlo simulation, the soil particle uptake rate was the most sensitive to the health risks of children and adults with risk probabilities of 26% and 52%, and the risk probabilities from body weight were −11% and −1%, whose negative value indicated that the increase in body weight could reduce the health risks to human. These findings could provide reference for the study of soil organic pollution in Helan farmland soil and contribute significantly to the preservation of the ecological environment, maintaining human health and safety, and promoting the sustainable development of regional farmland.

A comprehensive assessment framework for the risk and source of polycyclic aromatic hydrocarbons (PAHs) using two weight of evidence (WOE) approaches in bays of Shandong Province, China

Polycyclic aromatic hydrocarbons (PAHs) are one of the most widely distributed typical persistent organic pollutants (POPs) in the global environment, and the high PAHs pollution level worldwide calls for the establishment of environmental risk assessment and source analysis techniques for effective control. Here, we selected four bays of Shandong Province, one of the areas in China with the severest emissions of PAHs, as the research area, and chose clam Ruditapes philippinarum as the sentinel species, to systematically assess the ecological risk, bioeffects, and health risks of PAHs, identify their sources, and establish a comprehensive assessment framework for marine POPs using weight of evidence (WOE) approach. Taken together, ecological, bioeffect, and health risk assessments for marine POPs were integrated using Sediqualsoft model of WOE in seawater and sediment, and the overall risk level of PAHs in Shandong coastal area was ‘Moderate’. Meanwhile, the primary source of PAH was analyzed based on socio-economic parameters using a WOE framework, which was mainly derived from traffic and coal in seawater and sediment, respectively. Collectively, a comprehensive framework for assessing risk and source of marine POPs was built for the first time, and it may be applicable to other environments and pollutants.

Characteristic Variation of Particulate Matter-Bound Polycyclic Aromatic Hydrocarbons (PAHs) during Asian Dust Events, Based on Observations at a Japanese Background Site, Wajima, from 2010 to 2021

Asian dust (AD) events and total suspended particles (TSPs) were observed at the Kanazawa University Wajima Air Monitoring Station (KUWAMS), a Japanese background site, during the East Asian winter monsoon periods (from November to May of the following year) from 2010 to 2021. Nine kinds of polycyclic aromatic hydrocarbons (PAHs) were determined in each TSP sample. In this study, a total of 54 AD events were observed. According to the different pathways of long-range transportation, AD events were divided into AD-high events (transported at higher altitudes, approximately 4000 m) and AD-low events (transported at lower altitudes, approximately 2500 m). The TSP concentrations increased sharply in the AD events and were higher in the AD-high events (39.8 ± 19.5 μg/m3) than in the AD-low events (23.5 ± 10.5 μg/m3). AD did not have a significant effect on the ΣPAHs characteristic variation, as ΣPAHs (ΣPAHs = fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, benzo[ghi]perylene, and indeno [1,2,3-cd]pyrene) concentrations in non-AD periods, AD-high events, and AD-low events were 543 ± 374, 404 ± 221, and 436 ± 265 pg/m3, respectively. The PAH compositions were also consistent. As a result, the TSP concentration was affected by the input air mass transported at higher altitudes from the desert region while the PAH concentration was impacted by the air mass at lower altitudes, which carried the PAHs emitted from fossil fuels and biomass combustion in northeastern China. Moreover, the health risks of PAHs were calculated with the inhalation lifetime cancer risk, which ranged from 10−6 to 10−5 ng/m3, indicating a potential carcinogenic risk at the KUWAMS during the East Asian winter monsoon periods.

Characteristics, Source and Risk Assessment of Soil Polycyclic Aromatic Hydrocarbons around Oil Wells in the Yellow River Delta, China

The Yellow River Delta (YRD) is the most complete wetland ecosystem in the warm temperate zone of China and is rich in oil resources. However, with petroleum extraction and the development of the economy, pollution of the YRD has been paid increasing attention, in particular, pollution via polycyclic aromatic hydrocarbons (PAHs), as they have caused great harm to human health and the ecosystem balance. Based on the investigations of a research group in 2009, this study re-collected samples according to the same sampling points and analyzed the concentration, composition, source, ecological risk and health risk of PAHs in 2021. The concentration of ΣPAH16 in the surface soil of YRD in 2009 ranged from 2.6 to 8275.46 ng/g, with an average of 1744.41 ng/g. The concentration of ΣPAH16 in 2021 ranged from 56.25 to 582.56 ng/g, with an average of 149.63 ng/g. Therefore, the pollution situation in the YRD in 2021 was significantly improved compared with 2009. The composition of PAHs in soil in 2009 and 2021 was similar, which was dominated by low-ring PAHs. The evaluation results of the toxicity equivalent factor method showed that there was no potential ecological risk in the soil in 2009 and 2021. The evaluation results of the lifetime cancer risk increment model showed that the incremental lifetime cancer risk models (ILCRs) of soil PAHs in 2009 and 2021 were lower than the safety threshold of 10−6; therefore, there was no carcinogenic risk. The existing management measures for oil wells need to be further promoted to protect the regional ecological environment in the YRD.

Factor analysis of recent variations of atmospheric polycyclic aromatic hydrocarbons (PAHs) and 1-nitropyrene (1-NP) in Shenyang, China from 2014 to 2020

Shenyang is the provincial capital of Liaoning province in China, and the high population and heavy machinery manufacturing cause severe air pollution. Nine polycyclic aromatic hydrocarbons (PAHs) and 1-nitropyrene (1-NP) were characterized in aerosol samples collected in Shenyang in summer and winter from 2014 to 2020. The mean annual concentration of PAHs and 1-NP decreased from 102 to 18.7 ng/m3 and 105 to 61.3 pg/m3, respectively, from 2014 to 2020. The change from coal to electric and natural gas heating, transition from small coal-heating stoves to large stoves and vehicle and fuel upgrades resulted in decreases in atmospheric PAH and 1-NP concentrations. The noteworthy finding in this study was that the proportion of 4-ring PAHs increased in summer but decreased in winter from 2014 to 2020 in Shenyang. Possible factors were considered that a higher cetane rating of fuel with a new standard reduced emissions in summer, higher combustion temperatures of large coal-heating stoves and use of air pollution control devices in winter. In contrast, although the health risks of PAHs and 1-NP in Shenyang significantly decreased from 2014 to 2020, the values are still higher than the national standards in the winter of 2020. Additional environmental regulations in Shenyang are urgently needed to further decrease PAH concentrations below national air quality standards.

Occurrence, distribution and risk assessment of polycyclic aromatic hydrocarbons in soils around main water source areas of Beijing, China.

Polycyclic aromatic hydrocarbons (PAHs) in urban environments have been globally concerned due to their significant health impacts on residents. However, little is known about potential risks of PAHs from centralized water source areas. In the present study, 326 soils samples from the main water source areas of Beijing were collected and the occurrence, source appointment, and risks of PAHs were systematically investigated based on the monitoring results from high-performance liquid chromatography (HPLC). The total PAHs (∑16 PAHs) concentrations ranged from 5.70 to 1512ng/g with median value of 44.2ng/g, in which 4-ring and 5-ring groups were the major components. PAHs concentrations in the cultivated land were significantly higher than other areas, which could reflect significant impact of soil organic matter and total nitrogen contents on the spatial variations of PAHs. Further source identifications through positive matrix factorization model (PMF) revealed that biomass (22.5%), coal (21.4%), gasoline (17.6%) and diesel (16.4%) combustion were dominant sources of soil PAHs in the study area. Moreover, the risk assessment indicated that total ecological and health risk of PAHs were negligible, but individual PAH, including pyrene and benzo(b)fluoranthene, should be concerned due to their potential risks in several monitored stations located in the secondary protection area of four reservoirs. Our study provided new insights into environmental risks of soils in main water source areas from PAHs and could be helpful for organic micropollutant controlling and drinking water safety in rapidly urbanizing cities.

Types and Source Apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) in Soil-Groundwater of a Closed Coking Plant in Shanxi Province, China

To clarify the impact of coking industry activities on the soil-groundwater Polycyclic aromatic hydrocarbon (PAH) occurrence, a typical coking site in Shanxi Province was taken as the study area, and soil and groundwater samples were collected to analyze the pollution level, composition, and distribution of PAHs in soil-groundwater. The sources of PAHs in the study area were identified based on the positive matrix decomposition model (PMF); the health risks of PAHs were calculated based on the carcinogenic and non-carcinogenic health risk model from the Technical Guidelines for Risk Assessment of Soil Pollution for Construction Land (HJ 25.3-2019) and toxicity equivalent quantity (TEQ). The results showed that ∑PAHs of soil ranged from 0 to 6077.7 mg/kg, with an average value of 198.02 mg/kg; ∑PAHs of groundwater ranged from 0 to 18.30 mg/L, with an average value of 9.39 mg/L. In horizontal distribution, ∑PAH content and types in the tar processing area were much higher than those in the surrounding area, and PAHs might migrate to the southwest through infiltration; in vertical distribution, ∑PAH content reached a peak at 5 m underground. According to the PMF model results, four primary sources of ∑PAHs were identified, which were the coking production source (55.0%), coal and petroleum combustion source (22.6%), atmospheric deposition source (13.1%) and residents living source (9.3%). The total average ∑PAH carcinogenic and non-carcinogenic health risks of soil in the study area were 7.05 × 10−6 and 0.695; the average TEQBaP−∑PAHs was 1.650 mg·TEQ/g; as for groundwater, they were 3.08 × 10−6 and 32.04; the average TEQBaP−∑PAHs was 9.390 μg·TEQ/L, indicating that PAHs both in soil and groundwater had potential health risks. This study provides a basis for the same coking site type for pollution control, secondary utilization, and data support for future site restoration.

Health Impacts of Air Pollution in Tianjin

Ambient air pollution is a dominant determinant of health. The health effects and economic losses due to air pollution are very important for decision-making. Since the implementation of the "Air Pollution Prevention and Control Action Plan" and "blue sky defense war" policies, the air quality of Tianjin has changed significantly. Here, the health effects and economic losses attributable to ambient air pollution in Tianjin from 2013 to 2020 wereestimated. For the particulate matter which has complex components, we assessed the inhalation health risks of heavy metals and polycyclic aromatic hydrocarbons (PAHs) in PM2.5. The variation in the concentration of the main components of PM2.5 was also analyzed. The results showed that improved air quality had positive health benefits. The health benefits from SO2 were the highest among the six air pollutants, and 3786 deaths were avoided in 2020 compared to in 2013 due to lower SO2 concentration. The economic losses caused by air pollutants ranged from several billion to ten billion yuan. Among the six air pollutants, particulate matter and ozone had higher health losses in recent years. The health risks of heavy metals and PAHs in PM2.5 showed a decreasing trend. However, Cr(Ⅵ), As, Cd, and Ni in PM2.5in the winter of 2020 still had respiratorysystem carcinogenic risk, whereas there was no health risk of PAHs in PM2.5in 2019-2020. The concentrations of main components of PM2.5 have decreased significantly. In the future, the reduction of health loss caused by air pollution depends on synergy governance of particulate matter and ozone and further research on health effects.

Integrated Insights into Source Apportionment and Source-Specific Health Risks of Potential Pollutants in Urban Park Soils on the Karst Plateau, SW China.

The online version contains supplementary material available at 10.1007/s12403-023-00534-3.

Parent and Halogenated Polycyclic Aromatic Hydrocarbons in the Serum of Coal-Fired Power Plant Workers: Levels, Sex Differences, Accumulation Trends, and Risks.

Workers in coal-fired power plants are at a high risk of exposure to polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (HPAHs), yet no studies have investigated such exposure of HPAHs. In this study, 12 PAHs and 8 chlorinated PAHs, but no brominated PAHs, were detected in >80% of serum samples from workers of a coal-fired power plant in eastern China. Serum HPAH concentrations were higher in plant workers (16-273 ng/g lipid) than in people without occupational exposure (12-51 ng/g lipid), and serum PAH and HPAH concentrations both in male and female workers were positively correlated with the occupational exposure duration, with an estimated doubling time of 11-17 years. Correlations were found between concentrations of ∑8HPAHs and ∑12PAHs but not between 7-chlorobenz[a]anthracene (7-ClBaA) and 1-chloropyrene (1-ClPyr) and their respective parent PAHs. In males, total concentrations of PAHs and HPAHs were positively correlated with pulmonary hypofunction and hypertension but not with abnormal electrocardiogram. The benzo[a]pyrene equivalents ratio of ∑8HPAHs/∑12PAHs was 0.3 ± 0.1. Among the HPAHs in the serum, 9-chlorophenanthrene, 7-ClBaA, and 1-ClPyr showed high health risks. This study is the first report on HPAH exposure in coal-fired power plant workers and provides new evidence on the health risks of PAHs and HPAHs in humans.

Dietary exposure and risk assessment of European Union priority (EU 15+1) polycyclic aromatic hydrocarbons from milks and milk powders in China

Dairy products, characterized by rich nutrition and unique flavor, occupy an increasing share of the human diet with the development of higher living standards. However, trace hazardous contaminants in dairy products, such as polycyclic aromatic hydrocarbons (PAH), are arousing public concern. In this study, we investigated 82 milks and milk powders from Shanghai markets for the occurrence of 20 PAH, including 16 European Union priority (EU 15+1) PAH and 4 derivatives. Furthermore, we carried out a risk assessment of dietary exposure of PAHs from dairy products based on detection results and data on body weight and dietary intake obtained from questionnaires. Two assessment methods were used in this study: the incremental lifetime cancer risk (ILCR) and margin of exposure (MOE) methods. The ILCR of all age groups was 10-6 to 10-4, indicating a potential but acceptable carcinogenic risk. The MOE of the 4 groups (divided by age and sex) was >104, indicating no significant carcinogenic risk of PAH exposure from dairy products. In both methods, children had the highest risk because of their greater consumption of dairy products, followed by seniors, young adults, and middle-aged adults. Results of this study provide reference data on the exposure level and health risk of PAHs from dairy product intake.

Source identification and health risk assessment of PAHs in surface soils from the vicinity of Arad-Kouh processing and disposal complex, Tehran, Iran

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) as ubiquitous pollutants can pose potential environmental and also human health risks. Therefore, this study was conducted for detecting, identifying the sources and evaluating the health risks of PAHs in topsoils in vicinity of Arad-Kouh processing and disposal complex, Tehran, Iran in 2020. In so doing, a total of 30 surface soil samples were collected from 10 sampling sites adjacent to Arad-kouh complex. After extraction of analytes, the gas chromatography/mass spectrometry (GC–MS) method was used to determine the rates of PAH compounds in surface soil samples. Based on the results obtained, the total concentrations (µg kg−1) of 16 PAHs ranged from 863 to 1384 with a mean of 1123. PAHs with 4–6 rings in their molecules with 65.3% of ∑16PAH mass dominated the PAH profiles. Molecular diagnostic ratios (MDRs) indicated that most of PAH compounds could originate from pyrogenic sources. The total incremental lifetime cancer risks (ILCRs) of PAH compounds with an average value of 4.20E-05 (ranging from 3.02E-05 to 5.23E-05), indicating a low potential carcinogenic risk of PAH compounds in the study area, especially through dermal contact. Although, the ILCRs values showed negligible adverse health effects from direct ingestion and inhalation of PAH compounds in the study area, regular and periodic monitoring of content and sources identification of PAHs in different environments and efforts to mitigate of their pollution for human health maintenance are recommended.

Health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in the soil around thermal power plants in southwest China

This study aimed to evaluate the PAH contamination levels and to assess the health risk of PAH in soils of two typical thermal power plants. The PAH content was detected using gas chromatography-mass spectrometry (GC-MS). The carcinogenic risk and the hazard quotient were assessed for health risk using the “Chinese Technical Guidelines for Risk Assessment of Contaminated Sites HJ 25.3-2014.” The results showed that the average concentration of Σ16PAHs in the soils around thermal power plants A and B are 7436 μg/kg and 8975 μg/kg, respectively indicating heavily pollution. The comprehensive carcinogenic risk of PAHs in thermal power plants A and B ranged from 0.26 × 10−6 to 4.16 × 10−6. Forty percent of the sampling sites exceeded the acceptable risk level (10−6), which is a potential carcinogenic risk to the workers. Among the seven kinds of carcinogens, Bap (39.91%) and DBA (36.10%) had the highest carcinogenic risk. Oral ingestion (57.22%) and skin contact (42.49%) were the major exposure pathways that could be blocked by wearing masks, gloves, and protective clothing. The control values for oral ingestion (0.32717 mg/kg) of DBA and Bap with the highest contribution rate of the carcinogenic risk and the lowest control value were selected as reference safety thresholds for PAHs in thermal power plants.

Negative role of biochars in the dissipation and vegetable uptake of polycyclic aromatic hydrocarbons (PAHs) in an agricultural soil: Cautions for application of biochars to remediate PAHs-contaminated soil

Biochars were studied for their impacts on the dissipation and vegetable uptake of polycyclic aromatic hydrocarbons (PAHs) in an agricultural soil. The health risks of PAHs taken up by vegetables were assessed by growing Chinese cabbage in both unamended soil and biochar-amended soils. In the unamended soil, the total 16 PAHs (Σ16PAHs) content decreased by 77.38% after planting the vegetable. The dissipation percentages of low-molecular-weight PAHs (LMW-PAHs), medium-molecular-weight PAHs (MMW-PAHs), and high-molecular-weight PAHs (HMW-PAHs) were 82.37%, 72.65%, and 68.63%, respectively. A significant negative correlation was determined between the dissipation percentages of PAHs in soil and the logKow of PAHs (p < 0.01), indicating that the affinity of PAHs for soil particles was one of an important limiting factors on the dissipation of PAHs. The uptake of PAHs by plant was significantly reduced with the increase in the molecular weight of the PAHs (76.55% for LWM-PAHs, 17.13% for MMW-PAHs, and 6.05% for HMW-PAHs). Addition of biochars to the soil decreased the dissipation of Σ16PAHs (73.59–77.01%), mostly due to a decrease in the dissipation of LMW-PAHs and MMW-PAHs. This finding was due to the immobilization of LMW-PAHs and MMW-PAHs within the biochar micropores. A marked reduction of Proteobacteria in biochar-amended soils also resulted in the decreased biodegradation of PAHs. Four of six biochars significantly increased the concentrations of Σ16PAHs in plant by 30.10–74.22%. Generally, biochars significantly increased the uptake of LMW-PAHs by plant but had little influence on the plant uptake of MMW-PAHs and HMW-PAHs. Three of six biochars notably increased the incremental lifetime cancer risk values based on the exposure of PAHs by vegetable consumption.

The combination of warming and copper decreased the uptake of polycyclic aromatic hydrocarbons by spinach and their associated cancer risk

Both climate warming and co-contamination of polycyclic aromatic hydrocarbons (PAHs) and heavy metals are environmental issues of great concern. However, the interactive effects of warming and heavy metals on PAH accumulation in edible plants and the PAH-associated health risk remain unclear. In this study, enclosed soil/water-air-plant microcosm experiments were conducted to explore the effects of copper (Cu), warming (+6 °C), and their combination on the uptake of four deuterated PAH (PAH-d10) by spinach (Spinacia oleracea L.) in aged soil. PAH-associated health risks for soil, plant, and air exposure pathways were also assessed. The results showed that both individual Cu or warming decreased the PAH-d10 concentrations in root and shoot (non-normalized by lipid content) as well as the total PAH-associated cancer risk. Although antagonism existed between warming and Cu, compared to the presence of Cu, warming further reduced the spinach uptake of PAHs-d10 and total PAH-associated cancer risk, and the reductions were stronger at higher Cu levels. The inhibitory effect of the binary combination on PAH-d10 root uptake was attributed to decreased root lipid content and phytoavailable concentrations of PAHs-d10 in soil as a consequence of biodegradation, aging effect and cation-π interaction. The antagonism between warming and Cu on spinach uptake could be explained by their opposite effects on PAH-d10 biodegradation and the inhibition of the cation-π interaction caused by warming. Additionally, the shoot uptake of PAHs-d10 was mainly controlled by their soil to air to shoot partitioning. The findings suggest that the interactive effects of climate warming and co-existing pollutants should be taken into account for the assessment of plant uptake and health risk of PAHs.

Distribution, sources and health risk of PAHs in urban air-conditioning dust from Hefei, East China.

In recent decades, indoor air quality (IAQ) has become one of the most important human health issues. The potential properties and potential health hazards of polycyclic aromatic hydrocarbons (PAHs) are associated with their long-term residues, bioaccumulation and semivolatility, and they can also be transferred through a variety of media, such as the atmosphere, water and soil. Dust particles from indoor and outdoor emission sources adhere to A-C filters and can represent air quality to a certain extent. However, few studies have focused on PAHs in A-C filter dust in Hefei, China. In this study, 16 PAHs were selected, dust samples were collected from A-C filters from three different functional districts, and GC-MS analysis of the samples was performed. The concentration of the ∑16PAHs ranged from 7.34 to 326.84μgg-1, 5.07-15.34μgg-1, 4.09-47.26μgg-1 and 0.97-13.38μgg-1 in dust samples from the Administrative District (AD), Industrial District (ID), Commercial District (CD) and Outdoors (OD), respectively. The total PAH concentration in A-C dust was much higher than that in dust deposited outdoors in the urban area. The percentage of 5-6 ring PAHs accounted for more than 70% of the ∑16PAHs, which shows that the PAHs in A-C dust mainly come from pyrolysis rather than a diagenetic source. Principal component analysis (PCA) and diagnostic ratios were used in a source analysis, and the results indicated that the main PAHs emission sources in the different functional districts were coal, wood and biomass combustion. The incremental lifetime cancer risk (ILCR) values indicated a medium to high potential carcinogenic risk for adults and children exposed to dust with PAHs. Particularly, skin contact and ingestion of carcinogenic PAHs from dust are the major exposure pathways and present an exposure risk that is four to five orders of magnitude higher than the risk of inhalation.