Ring Polycyclic Aromatic Hydrocarbons Research Articles

PAHs in the surface water and sediments of the middle and lower reaches of the Han River, China: Occurrence, source, and probabilistic risk assessment

Polycyclic aromatic hydrocarbons (PAHs) pose versatile risks to the environment and human health. However, studies on their occurrences, spatial distributions, seasonal variations, possible sources and potential risks of the Han River are still not clear. In this study, 16 PAHs were investigated in the surface water and sediments from 15 sampling sites of the Middle and Lower Reaches of the Han River during the dry, normal, and flood seasons. It was found that the sum concentration of PAHs (ΣPAHs) determined by GC-MS ranged from 18.3 to 146.8 ng/L (mean 77.4 ng/L) in surface water, while it was 137.1–1478.4 ng/g (mean 679.6 ng/g) in sediments. The two to three rings PAHs in surfer water and four-five-ring in sediments PAHs comprised the majority of the detected compounds. The level of PAHs in dry season was higher than that in the flood and normal seasons, and the distributions of PAHs varied substantially along the river without clear trend in surface water and sediments. The sources of PAHs in surface water and sediments were mainly from biomass and coal combustion, followed by petroleum combustion. The human health risk of PAHs were evaluated using the risk entropy method of Kalf in surface water, and the mean effects range-median quotient method in sediments, respectively. Overall, the potential health risks caused by PAHs are still acceptable with special concerns about certain specific issues.

Sources of coal remains from the Jartai Pass Site in Nilka County, Xinjiang, China

The Jartai Pass site is a Late Bronze Age (3600–3000cal. a B.P.) settlement site in Nilka County, Xinjiang, China, containing the world’s earliest coal-burning remains including coal and ash. To investigate possible sources of coal used at the Jartai Pass site, extractable polycyclic aromatic hydrocarbons (PAHs) of the coal remains and coals around the site were analyzed. The concentrations of total PAHs (∑PAHs), 16 US Environmental Protection Agency prioritized PAHs (∑16PAHs), and alkylated PAHs (∑aPAHs) in 14 coal remains samples ranged from 1680–8579, 1090–4193, and 180–4066 ng/g, respectively. Four samples had higher PAH concentrations than the other 10 samples and were dominated by parent 4–6-ring PAHs and alkylated 2–3-ring PAHs. The other 10 samples were dominated by parent 2–3-ring PAHs, indicating different sources for the coal remains at the site. Total PAH concentrations in six coal samples around the site ranged from 2858–21582 ng/g. Three raw coal samples from mines were dominated by parent 2–3-ring PAHs, and the other three outcrop coals were dominated by parent 4–6-ring PAHs and alkylated 2–3-ring PAHs, revealing a significant difference in the PAH composition between raw coal and weathered outcrop coal. Based on the regional coalfield geology and development history of coal utilization in China, we suggest that the coals used at Jartai Pass site were from outcrop coal seams. The four high-PAH coal remains might have been from the coal line on the bank of the Kashgar River. Considering the amount used at the site over a long period, we speculate that the remaining coal may have been from the subsurface layer of the outcrop coal seam, indicating variation in mining depth. This study provides a basis for understanding coal remains unearthed at an archeological site in northwestern China and early coal utilization by humans.

Biochar application strategies for polycyclic aromatic hydrocarbons removal from soils

Polycyclic aromatic hydrocarbons (PAHs) are known as a hazardous group of pollutants in the soil which causes many challenges to the environment. In this study, the potential of biochar (BC), as a carbonaceous material, is evaluated for the immobilization of PAHs in soils. For this purpose, various bonding mechanisms of BC and PAHs, and the strength of bonds are firstly described. Also, the effect of impressive criteria including BC physicochemical properties (such as surface area, porosity, particle size, polarity, aromaticity, functional group, etc., which are mostly the function of pyrolysis temperature), number of rings in PAHs, incubation time, and soil properties, on the extent and rate of PAHs immobilization by BC are explained. Then, the utilization of BC in collaboration with biological tools which simplifies further dissipation of PAHs in the soil is described considering detailed interactions among BC, microbes, and plants in the soil matrix. The co-effect of BC and biological remediation has been authenticated by previous studies. Moreover, recent technologies and challenges related to the application of BC in soil remediation are explained. The implementation of a combined BC-biological remediation method would provide excellent prospects for PAHs-contaminated soils.

Characterization, source apportionment, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in urban soils from 23 cities in China.

Concentrations, composition profiles, sources, and health risks of 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in urban soils from 23 cities across China based on metadata collected from previous studies between 2005 and 2021 were investigated. ΣPAH concentrations in urban soils from 23 cities across China ranged from 0.1231 to 17.2000mg/kg (mean = 2.7171 ± 3.8276mg/kg). Overall PAH contamination in urban soils across China was moderate compared to that in global cities. Based on energy consumption and climate conditions, the spatial distributions of mean ΣPAH concentrations in Northeast China were highest, followed by those in North China, West China, East China, and South China. Individual PAH composition profiles decreased in the order: 4-ring PAHs (41.36%) > 5-ring PAHs (21.77%) > 3-ring PAHs (18.53%) > 6-ring PAHs (14.00%) > 2-ring PAHs (2.27%). Diagnostic ratios and positive matrix factorization (PMF) revealed that PAHs in urban soils were mainly derived from fossil fuel combustion (from coal, natural gas, and biomass), especially in North, Northeast, and East China, with smaller contributions from petrogenic sources. Health risk assessment results suggest that although there are potential cancer risks from PAHs, risks were acceptable. Toxic equivalent concentration (TEQ) and the corresponding oral cancer slope factor (CFS0) contributed most to the uncertainty of total risks. This study will help develop strategies to reduce PAH risk management in urban soils in China.

Estimating the deposition of polycyclic aromatic hydrocarbons in human airways: The role of particle size

Most previous studies used atmospheric concentrations of polycyclic aromatic hydrocarbons (PAHs) to estimate the risk of exposure via inhalation, but neglected the disparities in the effects of particle size. In this study, an extensive literature search retrieved data from 35 cities on atmospheric PAHs and particle size distributions, and a multiple-path particle dosimetry model was used to simulate the PAH deposition in human airways. The results revealed that the median concentration of total PAHs was 38 (range, 0.6–2074.2) ng/m3, while the median concentration of benzo(a)pyrene equivalent (B[a]Peq) was 11 ng/m3. Together with exposure to congener-specific PAHs, the median deposited concentrations of total PAHs or B[a]Peq were the highest in particulate matter (PM) with diameters of 1–2.5 μm, followed by > 1 μm and coarse PM, which can be explained by the general increase in proportions of high molecular weight PAHs with decreasing PM size. While the deposited PAHs were dominated by 3–5 rings PAHs, the deposited B[a]Peq was concentrated in 5-ring. Moreover, although differences in the contributions of the ring number between deposited and ambient PAHs were negligible, the contributions of fine PM were 11.9% and 9.5% greater for deposited PAHs and B[a]Peq, respectively. These results indicate that the risk of exposure to PAHs attached to fine PM is underestimated previously.

Insights into the house dust-bound polycyclic aromatic hydrocarbons and their potential human health risk in Greater Cairo, Egypt

Data dealing with polycyclic aromatic hydrocarbons (PAHs) levels in settled dust of Greater Cairo houses (GCH), Egypt, and their implication on human health risk are scarce. The goal of this study was to gain insights into the characterisations of PAHs in settled dust in GCH and their associated carcinogenic and mutagenic risks. ƩPAH concentrations were 3125 and 268 ng/g in settled dust in GCH and rural houses (RH), respectively. Heavier congeners (4–6 aromatic ring PAHs) represented 86.5% (GCH) and 92% (RH) of ƩPAHs. Houses on main streets are exposed to higher levels of PAHs than those on the side streets. The main sources of PAHs in GCH and RH were vehicular emissions (pyrogenic sources) and PAHs in GCH come from local emissions and in RH from the surrounding urban cities. Results showed that the carcinogenicity of PAHs associated with dust exceeds their mutagenicity. Based on Incremental Lifetime Cancer Risk (ILCR) estimations, the order of cancer risk (CR) was as follows: urban houses (UH) > suburban houses (SUH) > RH. CR and ILCRs calculations suggest that children and adults exposed to settled dust-bound PAHs in GCH and RH have an increase in CR, as CR and ILCRs values exceeded accepted levels.

Washing of Coastal Sediment from Mboppi River (Douala, Cameroon) Polluted by Polycyclic Aromatic Hydrocarbons (PAHs) using Sodium Dodecyl Sulfate (SDS)

Because of their hydrophobic nature, polycyclic aromatic hydrocarbons (PAHs) have low solubility in an aqueous medium and strong adsorption on soils and sediments, resulting in their persistence in the environment. This work was undertaken with the goal of having enough data to set up a stirred reactor, which will be used in the treatment of soils and sediments polluted by hydrocarbons while preserving the environment. To this end, sediment samples from the Mboppi were taken successively during the rainy season and the dry season. Gas chromatography coupled with a flame ionization detector (CPG/FID) was used to carry out a preliminary analysis of the samples. Then, chemical washing treatment tests using sodium dodecyl sulfate (SDS) were carried out on the most polluted sediment sample using a complete factorial plan with three factors (temperature, speed, and duration of agitation) to determine the parameters that influence depollution yields. It appears that the temperature (80 °C), the speed (1000 rpm), and the stirring time (40 min) give a better desorption yield (85.79%). The results show that SDS can effectively and significantly reduce the content of PAHs in sediments. The reduction of HMW-PAHs was observed, with the highest percentage (82.69%) obtained for 6 ring PAH under the same conditions. The environmental health risk assessment was reduced from 74.34 to 24.41, thus showing how far the washing with SDS is satisfactory.

Polycyclic aromatic hydrocarbons (PAHs) in riparian soils of the middle reach of Huaihe River: A typical coal mining area in China

ABSTRACT In the present research work, the concentration, distribution, composition, sources, potential toxicity, and ecological risk of PAHs in riparian soils of the middle reach of Huaihe River (along a 430-kilometer stream gradient) were studied. The total concentrations of PAHs varied from 210 to 39000 ng g−1, with a mean concentration of 3400 ± 8400 ng g−1 and a median value of 760 ng g−1. The middle section (Huainan-Bengbu section) with frequent coal mining and utilization activities was found to be the most contaminated region. High molecular weight (5- and 6- ring PAHs) and medium molecular weight (4- ring PAHs) PAHs were predominant. Based on the diagnostic ratios method and positive matrix factorization (PMF) model, PAHs in riparian soils were mainly originated from pyrogenic sources including vehicle emissions, and biomass and coal combustion. The calculation of total TEQBaP concentrations and risk quotient (RQ) indicated a low to moderate risk level of PAHs in most regions of the study area, but some specific sites showing high toxicity and ecological risk should be caused alarm and attention.

Elevated urbanization-driven plant accumulation and human intake risks of polycyclic aromatic hydrocarbons in crops of peri-urban farmlands.

As an ubiquitous carcinogen, polycyclic aromatic hydrocarbons (PAHs) are closely related to anthropogenic activities. The process of urbanization leads to the spatial interlacing of farmlands and urbanized zones. However, field evidence on the influence of urbanization on the accumulation of PAHs in crops of peri-urban farmlands is lacking. This study comparatively investigated the urbanization-driven levels, compositions, and sources of PAHs in 120 paired plant and soil samples collected from the Yangtze River Delta in China and their species-specific human intake risks. The concentrations of PAHs in crops and soils in the peri-urban areas were 2407.92ngg-1 and 546.64ngg-1, respectively, which are significantly higher than those in the rural areas. The PAHs in the root were highly relevant to those in the soils (R2 = 0.63, p < 0.01), and the root bioconcentration factors were higher than 1.0, implying the contributions of root uptake to plant accumulations. However, the translocation factors in the peri-urban areas (1.57 ± 0.33) were higher than those in the rural areas (1.19 ± 0.14), indicating the enhanced influence through gaseous absorption. For the congeners, the 2- to 3-ring PAHs showed a higher plant accumulation potential than the 4- to 6-ring PAHs. Principal component analysis show that the PAHs in the peri-urban plants predominantly resulted from urbanization parameters, such as coal combustion, vehicle emissions, and biomass burning. The mean values of estimated dietary intake of PAHs from the consumption of peri-urban and rural crops were 9116ngday-1 and 6601.83ngday-1, respectively. The intake risks of different crops followed the order rice > cabbage > carrot > pea. Given the significant input of PAHs from urban to farmland, the influence of many anthropogenic pollutants arising from rapid urbanization should be considered when assessing the agricultural food safety.

Priority Organic Pollutants and Endocrine-Disrupting Compounds in Arctic Marine Sediments (Svalbard Islands, Norway).

The present study investigated the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs) and phenolic endocrine-disrupting compounds (PEDCs), including bisphenol A (BPA), 4-nonylphenol (4-NP), and its monoethoxylate (NP1EO) and diethoxylate precursors in marine sediments in an Arctic fjord (Svalbard, Norway). The contribution of different local sources of contamination was also evaluated, together with a risk assessment for the marine environment. Samples were collected during two consecutive summer seasons (2018 and 2019), and target contaminants were analyzed with gas chromatography-mass spectrometry (MS) and high-performance liquid chromatography-MS/MS. The results showed no statistical differences between total PAH concentrations measured in 2018 (mean value 53.7 ± 54.3 ng/g) and 2019 (mean value 58.1 ± 63.6 ng/g). Low-ring (three or four rings) PAHs were the most abundant congeners, and single PAH ratios indicated a predominance of petrogenic sources (i.e., coal and liquid fossil fuel combustion). Nonylphenols and BPA showed a significant decrease in 2019 compared to 2018; 4-NP and NP1EO prevailed in both years, particularly in sediments close to the Ny-Ålesund research village. Overall, the results indicate that local anthropic activities are the major source of contamination in the Kongsfjorden ecosystem, but also melting waters from glaciers in the summer season can play an important role as a secondary source of pollutants previously trapped in ice. Comparison between our data and empirical and mechanistic indices derived from sediment quality guidelines suggests that the occurrence of PAHs and PEDCs in sediments does not currently pose a risk for this Arctic ecosystem, but further investigation is needed on the spread of hazardous contaminants and their effects on these fragile environments. Environ Toxicol Chem 2023;42:953-965. SETAC.

Evaluation of the adsorption efficiency of carcinogenic PAHs on microplastic (polyester) fibers—preliminary results

Paper presents the results of investigations on sorption capacity of selected carcinogenic polycyclic aromatic hydrocarbons (PAHs) on microplastics fibers. Accumulation of organic micropollutants such as PAHs is indicated as one of the important problems in the case of microplastics present in surface water, including sea water. Concentrations of the micropollutants can reach even several mg/kg of microplastics. An unrecognized problem are sorption capacities of microfibers towards PAHs. Recent research works indicate that microfibers are commonly present in sewage sludge. Content of the fibers in this waste material can reach over 23000 particles per 1 kg of sludge dry matter. The fibers mainly come from cloth washing. It is obvious that the adsorption capacity of the fibers can affect the concentration of PAHs in sewage sludge. The aim of the study was to evaluate sorption capacities of polyester fibers towards PAHs. Adsorption of PAHs were provided under static conditions. After 24 h of adsorption 1255 μg/g of carcinogenic PAHs was adsorbed onto the polyster fibers. Amount of 6-ring PAHs was equal to 154 μg/g, whereas 5- i 4- ring ones, 562 and 539 μg/g, respectively. The results have confirmed that hydrophobic PAHs can be adsorbed onto polystyrene fibers and as a result cumulate in sewage sludge.

New Ray on Remediation of High Rings Polycyclic Aromatic Hydrocarbons: Remediation of Raw Petroleum Sludge Using Solidification and Stabilization Method

New Ray on Remediation of High Rings Polycyclic Aromatic Hydrocarbons: Remediation of Raw Petroleum Sludge Using Solidification and Stabilization Method

Effects of physical and chemical aging on polycyclic aromatic hydrocarbon (PAH) content and potential toxicity in rice straw biochars.

Polycyclic aromatic hydrocarbons in biochars threaten their environmental application. The aging process may affect the concentration of PAHs, potential toxicity, and the properties of biochar. In this study, the aged biochars were obtained by simulated physical aging method (freeze-thaw treatment) and chemical aging method (H2O2 chemical oxidation). The PAH contents in biochars were measured, and their potential toxicity was assessed. Meanwhile, the influence of aging process on the physicochemical properties of biochar was also investigated. This study shows that the change of PAH content of aged biochars depended on pyrolysis temperature, ambient temperature, and oxidant concentration. Furthermore, physical and chemical aging process influenced the distribution of different ring PAHs in biochars. High-ring-number PAHs (four, five, six-ring PAHs) appeared in some aged biochar. Aging at ±20 °C and 0.01 M H2O2 increased the toxic equivalent quantity of all biochars which may be attributed to the change of the physicochemical properties influencing the different PAH ring distribution in biochars. The contribution of PAHs with different rings to TEQ varied in pristine and aged biochars. Physical and chemical aging process significantly affected the properties of biochars, such as element content, ash content, surface area, pore volume, pH, functional groups, and surface morphology. Correlation analysis confirmed that surface area and pore volume are dominant factors determining the PAH content in the biochars. Therefore, the aging process indeed affected the PAH concentration and toxicity of PAHs in biochar. Assessing PAH behavior in biochar over long timescales should not be overlooked.

Accumulation of polycyclic aromatic hydrocarbons in the road green infrastructures of sponge city in Northwestern China: Distribution, risk assessments and microbial community impacts

The construction of “sponge city” made the belts on both roadsides be built in the form of bioretention tanks, resulting in runoff pollutants were accumulated in the bioretention tanks. To identify the pollution level and source of polycyclic aromatic hydrocarbons (PAHs) in the bioretention tanks, the soil samples were collected on the eight typical roads of the sponge city. The total contents of ∑PAHs in the bioretention tanks were 10,524–20,462 μg/kg (mean 15,029 μg/kg), and the pollution level of PAHs in the non-flood season was significantly higher than that in the flood season. The PAHs in bioretention tanks were dominated by 4-ring PAHs, with a proportion of 39.36%. The characteristic ratio method was proposed to identify the chemical source of PAHs, and the results indicated that PAHs in the bioretention tanks were mainly supplied by the combustion source and petroleum source. The ecological risk quotient (RQ) values showed that the accumulation of PAHs in the bioretention tank had certain potential ecological risks, and the RQ values of pyrene (PYR) were the highest. Incremental lifetime cancer risks (ILCR) indicated that PAHs in soil posed negligible cancer risks by inhalation way, but much stronger risks by dermal and ingestion ways. The roads with the highest and lowest PAHs content were selected for microbial ecology analysis, and the microbial abundances showed significant decreasing trends from the flood season to the non-flood season. The PAHs accumulated in the bioretention tanks had significant impacts on the microbial community, which made the microorganisms tend to PAHs-degrading bacteria.

Seasonal distribution and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Giresun coast of southeastern Black Sea

Seasonal sediment samples were collected along the Giresun coastline of southeastern Black Sea and analyzed to detect the levels of 16 polycyclic aromatic hydrocarbons (PAHs). The PAH levels, ranging from 28.47 to 444.36 ng g−1 with the mean of 102.57 ng g−1 remained lower than those detected in most of the other sediment studies conducted worldwide. The percentage of three-ring PAHs (38.9%) was rather high, followed by that of 5-ring PAHs (21.8%). Detection rates revealed that PAHs in surface sediments along the Giresun coastline are mainly associated with coal combustion and local emissions. The evaluation with sediment quality guidelines (SQGs) showed that the level of PAHs was comparable to that at which the risk of adverse biological effects cannot be ruled out (≥TEL and <PEL) in some stations. The risk posed by PAHs in Giresun coastal sediments appears to be low to moderate ecological risk according to the risk quotient.

Occurrences, Sources, and Human Health Risk Assessments of Polycyclic Aromatic Hydrocarbons in Marine Organisms From Temperate Coastal Area

The pollution characteristics of 16 polycyclic aromatic hydrocarbons (PAHs) in marine organism species (6 species of fishes and 2 species of crustaceans) from the coastal area of the East China Sea were determined. The concentrations of 16 PAHs in the studied organisms ranged from 29.73 to 87.02 ng/g dw and 2- and 3-ring PAHs were the most abundant compounds in the aquatic organisms. The habitat, diet and predator-prey relationship have posed potential effects on the PAH accumulation in marine organisms. The source identification of PAHs was performed by using the molecular diagnostic ratios and principal component analysis (PCA). The results showed that the main sources of PAHs in the marine organisms were coal combustion, followed by mixture of gasoline combustion, oil combustion, crude oil spill and vehicle emissions. The incremental lifetime cancer risk of human via ingestion process of marine organisms in this sea area was also estimated and the assessment showed that it posed an acceptable but non-negligible risk to human health.

Understanding exposure risks of women and children to PAHs in biomass using households of Brahmaputra valley

Introduction: Biomass burning is a principal contributor of Polycyclic Aromatic Hydrocarbons (PAHs) in the air. A vast majority of rural households in South Asia are still using crude biomass fuel in kitchens causing poor air quality. This pushes the children and women population to severe exposure risk. In this work, 14 PAHs out of 16 priority PAHs of the United States Environmental Protection Agency (USEPA)-bound to Biomass Fuel Smoke Particles (BFSPs) produced during burning various crude biomass fuels in rural kitchens had been characterized.&#x0D; Materials and methods: Representative rural households were taken for this study. Two sets of samples were collected during dry and wet periods using filter paper by a passive collection method and analyzed by High Performance Liquid Chromatography (HPLC).&#x0D; Results: PAHs with even number of rings (2-ring and 4-ring PAHs) dominated the Biomass Fuel Smoke Particles (BFSPs). PAH contents in BFSPs of the wet period were higher than the dry period samples. Different PAH ratios differed from reported studies on ambient atmosphere particulates and test environment. Higher Incremental Lifetime Cancer Risk (ILCR) values were found during the wet period compared to the dry period in most BFSPs. The risk via ingestion and dermal contact was about 104 to 105 magnitudes higher than the inhalation risk.&#x0D; Conclusion: The study reported seasonal variation of PAHs from biomass fuels and associated health risks to the exposed population. The higher levels of PAHs and the associated health risks may pose significant risks to the exposed women and children.

Concentrations, sources, and risk assessment of polycyclic aromatic hydrocarbons (PAHs) in black, green and fruit flavored tea in Turkey

This study was performed to identify the levels and possible sources of EPA priority PAHs in different types of commercially sold and consumed tea samples in Turkey. Health risk related to PAHs exposure due to tea consumption was also estimated. The average total PAH concentrations were measured as 317.0, 352.3, and 452.3 μg/kg for 25 black, three green, and 12 flavored Turkish tea samples. The results showed that 3- and 4-ring PAHs were the predominant groups for all tea samples. Factor analysis was utilized to identify the source characteristics of PAHs in tea samples. The results indicated that emissions from direct contact during transport and storage of tea leaves have significant impacts in addition to those from thermal processing during production. The estimated lifetime cancer risks ranged from 4.4 × 10−5 to 2.0 × 10−4 for all tea samples, indicating low-to-moderate risks for consumers of these tea products. All the estimated cancer risk values for PAHs in this study were higher than permissible risk levels, while three flavored tea samples were higher than the acceptable risk levels specified by US EPA.

Determination of particulate polycyclic aromatic hydrocarbons in ambient air by gas chromatography-mass spectrometry after molecularly imprinted polymer extraction

A solid phase extraction procedure (SPE) is described for the quantitative analysis of polycyclic aromatic hydrocarbons (PAHs) in atmospheric particulate matter (PM), as ubiquitous environmental pollutants routinely measured in air quality monitoring. A SPE cartridge was used based on a molecular imprinted polymer (MIP-SPE) properly tailored for selective retention of PAHs with 4 and more benzene fused rings. The performance of the clean-up procedure was evaluated with the specific concern of selective purification towards saturated hydrocarbons, which are the PM components mostly interfering GC analysis of target PAHs. Under optimized operative conditions, the MIP-SPE provided analyte recovery close to 95% for heavier PAHs, from benzo(α)pyrene to benzo(ghi)perylene, and close to 90% for four benzene rings PAHs, with good reproducibility (RSDs: 2.5%-5.9%). Otherwise, C17-C32n-alkanes were nearly completely removed. The proposed method was critically compared with Solid Phase Micro Extraction (SPME) using a polyacrylate fiber. Both methods were successfully applied to the analysis of ambient PM2.5 samples collected at an urban polluted site. Between the two procedures, the MIP-SPE provided the highest recovery (R% ≥ 93%) for PAHs with 5 and more benzene rings, but lower for lighter PAHs. In contrast, SPME showed a mean acceptable R% value (∼ 80%) for all the investigated PAHs, except for the heaviest PAHs in the most polluted samples (R%: 110%-138%), suggesting an incomplete purification from the interfering n-hydrocarbons.

Distribution, risk assessment, and source apportionment of polycyclic aromatic hydrocarbons (PAHs) using positive matrix factorization (PMF) in urban soils of East India.

This study investigated 16 United States environmental protection agency priority PAHs profiles and their sources in 40 urban soils collected from two industrialised cities, Jamshedpur and Bokaro, in east India and assessed their health risk to humans. The results showed the predominance of high molecular weight (HMW) PAHs (4-5 rings). The total PAHs concentration in surface soils ranged from 2223 to 11,266ng/g and 729 to 5359ng/g (dw), respectively, for Jamshedpur and Bokaro. Higher concentrations of PAHs were recorded at the selected industrial areas and heavy traffic zones of both cities. In JSR city 4-ring PAHs contributed 43% of total PAHs trailed by 5-ring PAHs 27.2%. Similarly, in BKR city 4-ring PAHs contributed 34% of the total PAHs, followed by 3-ring PAHs 28.9% and 5-ring PAHs 22.9%. Total organic carbon in surface soils exhibited moderate correlation with the low molecular weight (ΣLMW) PAHs (R2 = 0.69) and a comparatively strong correlation with the ΣHMW PAHs (R2 = 0.89), suggesting strong adsorption of HMW PAHs to urban soils. The Diagnostic and PMF modelling analysis indicated that the major sources of PAHs contamination in soils were petroleum combustion, vehicular emissions, biomass, and coal combustion. The health risk assessment shows that the cumulative probability of carcinogenic risks was under the acceptable limits of 10-4 to 10-6. At some sampling areas in both cities, the maximum value of total exposure cancer risk slightly exceeded the acceptable limits indicating some carcinogenic risk for adults.