Environmental monitoring and health risk assessment of polycyclic aromatic hydrocarbons (PAHs) through honeybees (Apis mellifera), honey and pollen

Polycyclic aromatic hydrocarbons in atmospheric PM2.5 and PM10 in the semi-arid city of Xi'an, Northwest China: Seasonal variations, sources, health risks, and relationships with meteorological factors

Molecular distribution, sources and potential health risks of fine particulate-bound polycyclic aromatic hydrocarbons during high pollution episodes in a subtropical urban city

The people living in Onne are highly vulnerable to PAH exposure due to constant exposure to black soot through oral, dermal, and inhalation routes. This work aims to determine the PAHs profile of selected soils in Onne, to determine the health risks associated with PAHs exposure through the soil, and to determine the impact of reduced industrial and other activities on the PAHs profile and associated public health risks. This study evaluated 16 priority polycyclic aromatic hydrocarbon (PAHs) pollutants in soil samples from the four (4) major clans in Onne using a gas chromatography flame ionization detector (GC-FID) during and after the COVID-19 lockdown. The results showed a differential presence of PAHs during and after the lockdown. Of the 16 priority PAHs, 10 and 8 PAHs were respectively detected during and after the COVID-19 lockdown. High molecular weight PAHs such as benzo(k)fluoranthene and benzo(a)anthracene were major contributors during the lockdown, while low molecular weight PAHs such as naphthalene, acenaphthylene, and fluorene were present at higher levels after the lockdown. An assessment of health risk by incremental lifetime cancer risks revealed that the entire population of Onne might be at risk of cancer development across periods, though a higher risk was presented during the lockdown. In addition, children under the age of 18 may be at greater risk. To the best of our knowledge, there is no previous report on the impact of the COVID-19 lockdown on soil PAH profile and health risks, with particular attention to the Onne industrial host community. Earlier work considered the ecological risks of heavy metals on dumpsites in Onne. Taken together, the PAH-contaminated soil in Onne poses an immediate health concern. Therefore, reduced anthropological activities, as evident during the COVID-19 lockdown, may play a role in exposure and cancer risk reduction. While there may not be another lockdown due to the challenging impacts associated with a physical lockdown, firmly controlled economic activity can be a solution if embraced by stakeholders. The COVID-19-lockdown was encumbered with restricted movements and security checks, which limited the number of samples collected. However, the Local Government Council (Department of the Environment) granted permission for the researchers to work with a minimal threat to their lives.

PM2.5 and PM2.5–10 samples were simultaneously collected in Urumqi from January to December 2011, and 14 priority polycyclic aromatic hydrocarbons (PAHs) were determined. The mean concentrations of total PAHs in PM2.5 and PM2.5–10 were 20.90~844.22 ng m−3 and 19.65~176.5 ng m−3 respectively, with the highest in winter and the lowest in summer. Above 80% of PAHs were enriched in PM2.5, which showed remarkable seasonal variations compared to coarse particles. High molecular weight (HMW) PAHs were predominant in PM2.5 (46.61~85.13%), whereas the proportions of lower molecular weight (LMW) and HMW PAHs in PM2.5–10 showed a decreasing and an increasing trend, respectively, from spring to winter. The estimated concentrations of benzo[a]pyrene equivalent carcinogenic potency (BaPeq) in PM2.5 (10.49~84.52 ng m−3) were higher than that of in PM2.5–10 (1.15~13.33 ng m−3) except in summer. The estimated value of inhalation cancer risk in PM2.5 and PM2.5–10 were 1.63 × 10−4~7.35 × 10−3 and 9.94 × 10−5~1.16 × 10−3, respectively, far exceeding the health-based guideline level of 10−4. Diagnostic ratios and positive matrix factorization results demonstrated that PAHs in PM2.5 and PM2.5–10 were from similar sources, such as coal combustion, biomass burning, coking, and petroleum combustion, respectively. Coal combustion was the most important source for PAHs both in PM2.5 and PM2.5–10, accounting for 54.20% and 50.29%, respectively.

Sources and health risks of polycyclic aromatic hydrocarbons during haze days in eastern China: A 1-year case study in Nanjing City

This study investigates the distribution of sixteen priority polycyclic aromatic hydrocarbons (PAHs), various sources of PAHs, and their probable cancer-causing risks in the soil samples collected from urban cities in Bihar, India. During the winter season, the ∑16 PAH concentration was dominant and ranged from 979.36 to 5149.37 ngg-1 with a mean value of 2684.79 ngg-1, while for the summer season, it ranged from 690.06 to 4539.55 ngg-1 with a mean value of 2194.31 ngg-1. The (4-ring) PAH compounds were the major contributors, accounting for 40% and 37% in the winter and summer seasons, respectively followed by (5- and 6-ring) PAHs at 30% and 32%, and (2- and 3-ring) PAHs at 29% and 30% in the respective seasons. Carcinogenic PAHs constituted ~ 50% of the ∑16 PAHs, with mean values of 1353.97 ngg-1 and 1098.09 ngg-1 for the winter and summer seasons, respectively. Positive matrix factorization (PMF) confirmed the dominance of fossil fuel burning and biomass burning as a primary source in the urban soil of Bihar. Total mean benzo(a)pyrene equivalent (BaPeq) values for the ∑16 PAHs were 312.04 ngg-1 for the winter season and 262.83 ngg-1 for the summer season. These values were higher in current study sites as compared with other studies. However, the concentration range fell within the limit set by the Canadian soil quality standard (700.00 ngg-1) and exceeded the limit of the Dutch target value (32.96 ngg-1). The Incremental Lifetime Cancer Risk (ILCRs) from dermal and ingestion pathways were approximately 104 to 105 times lower than the inhalation pathway, suggesting greater risk. The study revealed higher mean cancer risk values for children (1.16 × 10-5) and adults (1.03 × 10-5) in the winter season, falling within the unacceptable range (10-6 and 10-4) of carcinogenic risk that might lead to human health risk in the study sites.

The concentrations and compositional patterns of the United States Environmental Protection Agency (US EPA) 16 priority polycyclic aromatic hydrocarbons (PAHs) were determined in surface soils of an urban environment in the Niger Delta of Nigeria with a view to providing information on the sources, extent of contamination and human health risks of PAHs in these soils. The analyses were performed by means of gas chromatography-mass spectrometry (GC-MS) after extraction of the soils with hexane/dichloromethane and clean-up of the extracts. The concentration of Σ16 PAHs in the urban soils ranged from 188 to 684 µg kg−1, while the ΣPAH7c (carcinogenic PAHs) ranged from 28.5 and 571 µg kg−1. The estimated carcinogenic and mutagenic potency factors for these sites ranged from 2.34 to 197 and 9.66 to 195 µg kg−1 respectively. The composition of PAHs in these soils follows the order: 5-rings>4-rings>3-rings>6-rings>2-rings, and higher molecular weight PAHs accounted for a significant proportion of the Σ16 PAH concentration in this study. The results indicated that there is a high potential risk of cancer development as a result of exposure of PAHs via ingestion, dermal contact and inhalation. The diagnostic ratios indicate that the PAHs in these soils originated mainly from pyrogenic processes, such as combustion of petroleum, fossil fuels and biomass such as woods, charcoal straw and grasses. The results of this study provided information on the concentrations and compositional patterns of PAHs, which is useful in understanding the effects, sources, fate and transport of PAHs in soils, as well as environmental quality management and environmental forensic studies.

Gaseous and particulate 21 PAHs were monitored at a residential site in Ulsan, South Korea, over three seasons (December 2013–August 2014). The mean concentrations of Σ21 PAHs were highest in winter (16.2 ± 8.2 ng/m3), followed by spring (8.37 ± 4.53 ng/m3) and summer (6.23 ± 2.53 ng/m3). The mean gaseous concentration of Σ21 PAHs (7.39 ± 4.39 ng/m3) was 2.7 times higher than that of particulate PAHs (2.70 ± 3.38 ng/m3). To identify the sources of PAHs (both types of sources and their areas), diagnostic ratios, principal component analysis, and concentration-weighted trajectory (CWT) were used. The results showed that pyrogenic sources (e.g., coal combustion) were the primary emission sources of PAHs in winter and spring. In summer, the influence of both coal and heavy oil combustion was dominant, suggesting that PAHs could be transported from industrial areas of Ulsan (e.g., petrochemical and nonferrous industrial complexes) by seasonal winds. Regarding emission source areas, the CWT analysis revealed that in winter and spring, PAHs in Ulsan could be attributed to emissions from regional areas, e.g., China and North Korea. The PAH concentrations were also used to assess the health risks associated with the inhalation of these compounds for adults aged 18–70. The results showed that the cancer risks from Σ19 PAHs and Σ13 PAHs did not exceed the guideline set by the US EPA (10−6), indicating no cancer risks for this target group. However, it is worth noting that certain PAHs, which are not listed as priority PAHs by the US EPA, make significant contributions to the benzo[a]pyrene equivalent and the associated cancer risks. Therefore, it is necessary to investigate not only the priority PAHs but also other PAH species to fully evaluate their effect on human health.

Polycyclic aromatic hydrocarbons (PAHs) are widespread in the urban environment, particularly in urban soil, which are affected by intensive human activities. The purpose of this study was to determine the levels of PAHs in urban areas of Nanjing, China, apportion their sources, and evaluate their health risk. One hundred eighty topsoil samples (0–10 cm) were collected from 180 grids of 1 km × 1 km in the main urban area of Nanjing, China, which was divided into four different land use classes. All the soil samples were analyzed for 16 US Environmental Protection Agency (US EPA) priority PAHs by HPLC. Source of PAHs was explained by isomer ratios and principal component analysis, and health risk of PAHs was assessed by benzo[a]pyrene (BaP) toxic equivalency factors. The average concentration of PAHs ranged from 41.19 to 7016.65 μg kg−1, with an average of 979.59 μg kg−1. PAHs in soil characterized by different land uses, in decreasing order, were as follows: university (UN) > traffic area (TA) > forest park (FP) > residential area (RA). PAHs in FP soils were mainly attributed to biomass combustion, while TA soils exhibited clear traffic emission characteristics. PAHs for UN and RA came from mixed sources. A principle component analysis (PCA) and ordinary kriging map indicated coal combustion and vehicle emissions as the major contributors to PAHs in Nanjing urban soils, respectively. A health risk assessment based on the BaP toxic equivalency approach indicated a potential risk level of PAHs. The mean value of PAH concentrations in UN was the highest. However, the maximum was detected in TA. The PAHs in soil samples originated mainly from coal combustion and petroleum combustion sources. There was a potential health risk level of PAHs in Nanjing urban areas.

Source-oriented risk assessment of inhalation exposure to ambient polycyclic aromatic hydrocarbons and contributions of non-priority isomers in urban Nanjing, a megacity located in Yangtze River Delta, China

Biomass energy sources are still popular in the rural areas of developing countries for cooking and space heating. Since the incomplete combustion of agricultural residues in home-made ranges might lead to both outdoor and indoor air pollution and cause potential health threat to the rural population, we monitored the ambient levels of 16 US EPA priority polycyclic aromatic hydrocarbons (PAHs) at a typical rural site. Ambient particulate PAH samples (PM2.5 and PM10) were taken during both cooking and non-cooking periods. Source emission monitoring was also conducted for both improved and traditional cooking stoves used in the area. Ambient PAHs had a significant increase during the cooking periods and varied from 72.1 to 554.4 ng/m3. The highest total PAH levels were found during the supper cooking time, in which five-and six-ring species accounted for a large proportion. The observed PAH levels during cooking periods at this rural site were even higher than those in urban areas. A good correlation was found between the benzo[a]pyrene level and the total PAH concentration (r=0.98), making benzo[a]pyrene a potential molecular marker for PAH pollution in the rural areas, where biomass burning is typical. The profiles of the particulate PAHs in both ambient air and source emissions showed a high proportion of high molecular-mass PAHs. In addition, emission factors of 16 PAHs from an improved household stove were found to be significantly lower than those from traditional stoves used in China and in other Asian countries.

In this study, PM2.5 samples were collected synchronously at Gaoxin and Linxiao in Luoyang City during autumn and winter (4 October 2018 to 30 January 2019). Sixteen priority polycyclic aromatic hydrocarbons (PAHs) associated with fine particulate matter were analyzed by gas chromatography mass spectrometry (GC-MS). The concentrations and composition characteristics of the PAHs on clean and polluted days were studied. Diagnostic ratio analysis and principal component analysis (PCA) were used to identify the emission sources of PM2.5-bound PAHs and the equivalent carcinogenic concentration of benzo[a]pyrene (BaP) and incremental lifetime cancer risks (ILCRs) model were applied to evaluate health risks. During the sampling period, the concentrations of PAHs at Gaoxin and Linxiao ranged 24.33-90.26 ng·m-3 and 23.81-76.99 ng·m-3, respectively. With the increase in PM2.5 pollution, PAH concentrations increase significantly (the mean PAH concentration on polluted days was approximately 1.3 times higher than during clean days). PAH profiles at different polluting levels were similar; 4-ring PAHs (43%-48%) > 5-6 ring PAHs (32%-35%) > 2-3-ring PAHs (20%-22%). Diagnostic ratios and PCA demonstrated that PAHs in the study area were mainly derived from combustion sources including coal combustion, biomass burning, and motor vehicle emissions. The coal combustion was the main pollution source in the study area (clean days=49.28%-56.38%, polluted days=49.44%-60.60%). The results of the equivalent carcinogenic concentration of benzo[a]pyrene (BaP) and ILCR model revealed that the human health risk on polluted days was higher. Moreover, the cancer risks from adult exposure to PAHs were higher than those child exposure, which has an acceptable level of risk (<10-6).

This study was done to determine the concentration of PAHs in urban soil of Delhi (India). Surface top soil (up to 10 cm depth) samples were collected from four different sampling sites including industrial, roadside, residential, and agricultural areas of Delhi and 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) were evaluated. Total PAH concentrations at industrial, roadside, residential, and agricultural sites were 11.46 ± 8.39, 6.96 ± 4.82, 2.12 ± 1.12, and 1.55 ± 1.07 mg/kg (dry weight), respectively, with 3–7 times greater concentrations in industrial and roadside soils than that in residential and agricultural soils. The PAH pattern was dominated by 4- and 5-ring PAHs (contributing >50% to the total PAHs) at industrial and roadside sites with greater concentration of fluoranthene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]anthracene, benzo[ghi]perylene, and pyrene, whereas, residential and agricultural sites showed a predominance of low molecular weight 2- and 3-ring PAHs (fluoranthene, acenaphthene, naphthalene, chrysene, and anthracene). Isomeric pair ratios suggested biomass combustion and fossil fuel emissions as the main sources of PAHs. The toxic equivalency factors (TEFs) showed that carcinogenic potency (benzo[a]pyrene-equivalent concentration (B[a]Peq) of PAH load in industrial and roadside soils was ∼10 and ∼6 times greater than the agricultural soil.

Source identification and health risk assessment of atmospheric PM2.5-bound polycyclic aromatic hydrocarbons in Jamshedpur, India

The distribution patterns and health risk assessment of nitrated polycyclic aromatic hydrocarbons (NPAHs), hydroxy polycyclic aromatic hydrocarbons (OH-PAHs), and regular 16 priority polycyclic aromatic hydrocarbons (PAHs) in sediment from the Songhua River in northeastern China were investigated in this research. During dry seasons, concentrations of 16 USEPA priority PAHs, OH-PAHs, and NPAHs were extremely high, with average values of 1220 ± 288, 317 ± 641, 2.54 ± 3.98, and 12.2 ± 22.1ng/g (dry weight, dw). The dry period level was confirmed to be 4 times greater than the wet period concentration. Modeling with positive matrix factorization (PMF) and estimation of diagnostic isomeric ratios were applied for identifying sources, according to the positive matrix factorization model: vehicle emissions (38.1%), biomass burning (25%), petroleum source (23.4%), and diesel engines source (13.5%) in wet season as well as wood combustion (44.1%), vehicle source (40.2%), coke oven (10.8%), and biomass burning (4.9%) in the dry season. The greatest seasonal variability was attributed to high molecular weight compounds (HMW PAHs). BaP was confirmed to be 81% carcinogenic in this study, which offers convincing proof of the escalating health issues.