Polycyclic Aromatic Hydrocarbons Congeners Research Articles

Multimedia distribution, dynamics, and seasonal variation of PAHs in Songhua wetland: Implications for ice-influenced conditions

The knowledge of polycyclic aromatic hydrocarbons (PAHs) in wetlands remains limited. There is a research need for the dynamics between interfaces of multimedia when ice is present in this fragile ecosystem. In this study, sediment, open-water, sub-ice water, and ice samples were collected from the Songhua wetland to study the behaviors of PAHs with and without influences from ice. The concentration of all individual PAHs in sub-ice water (370–1100 ng/L) were higher than the open-water collected from non-ice-covered seasons (50–250 ng/L). Enrichment of PAHs in the ice of wetland was found, particularly for high-molecular-weight PAHs (HMW). This could be attributed to the relatively lower polarity of hydrocarbons compounds, making them more likely to remain in the ice layer during freezing. Source assessments reveal common sources for sub-ice water and ice, which differ from those in the open water in non-ice-covered seasons. This difference is primarily attributed to heating activities in the Harbin during winter. The average percentage contributions were 79% for sub-ice water and 36% for ice related to vehicle exhausts and coal combustion. Additionally, wood burning contributed 25% to sub-ice water and 62% to ice. Sediment in the wetland was found to serve as a final deposit particularly for heavier PAHs, especially those with 6 rings. Sediment also has the potential to act as a source for the secondary emission of low-molecular-weight PAHs (LMW) congeners into the water. PAHs in wetland displayed low ecological risk, while HMW PAHs with relative higher ecological risk is recommended to be further monitored.

Variations of the atmospheric polycyclic aromatic hydrocarbon concentrations, sources, and health risk and the direct medical costs of lung cancer around the Bohai Sea against a background of pollution prevention and control in China

Abstract. The Bohai Sea (BS) region, an area of China that is severely polluted with atmospheric polycyclic aromatic hydrocarbons (PAHs), has received wide attention in recent decades. To characterize the variations of the concentrations and sources of PAHs from June 2014 to May 2019, 15 PAH congeners (Σ15PAHs) were measured in atmospheric samples (N = 228) collected at 12 sites around the BS, and the health risk and direct medical costs associated with lung cancer caused by exposure to PAHs were also estimated. The annual daily average concentration of Σ15PAHs was 56.78 ± 4.75 ng m−3, which was dominated by low molecular weight PAHs (LMW-PAHs) containing three rings (58.7 ± 7.8 %). During the 5-year sampling period, the atmospheric Σ15PAHs concentration reduced by 17.5 % for the whole BS region, with an especially large drop of 51.7 % observed in the tightly controlled area of Tianjin (TJ), which was mainly due to a decrease in the concentration of high molecular weight PAHs (HMW-PAHs) containing five or six rings. Generally, the concentration of Σ15PAHs was highest in winter and lowest in summer, which can mainly be attributed to the change in LMW-PAH concentration. Based on the positive matrix factorization (PMF) model, PAHs in the BS region were mainly ascribed to coal combustion and biomass burning. The PAH contributions of coal combustion and motor vehicles showed different trends for the BS region (PAHs from coal combustion rose by 7.2 % and PAHs from motor vehicles fell by 22.4 %) and for TJ (PAHs from coal combustion fell by 12.6 % and PAHs from motor vehicles rose by 6.9 %). The incidence of lung cancer (ILCR) caused by exposure to atmospheric PAHs decreased by 74.1 % and 91.6 % from 2014 to 2018 in the BS region and in TJ, respectively. This was mainly due to the decrease in the concentration of highly toxic HMW-PAHs and was reflected in USD 10.7 million of savings in direct medical costs of lung cancer caused by exposure to PAHs, which represent a decrease of 46.1 % compared to the corresponding costs before air pollution prevention and control was implemented around the BS. There was an even higher reduction in medical costs of 54.5 % in TJ. Hence, this study proves that implementing pollution prevention and control not only effectively reduced the concentration of pollutants and the risks caused by them, but it also significantly reduced the medical costs of diseases caused by the corresponding exposure.

The effects of the rock stratigraphy on TPH/PAH absorption and transmission in some sections of the Gokana and Khana Local Government Areas

Concentration of TPH/PAH in soils in parts of Gokana and Khana local government areas of Rivers state were examined using samples from 30 shallow wells drilled with hand auger. The core intervals penetrated, ranged between 0 on the surface to 100cm at total depth and was composited into two sections corresponding to upper 0 – 0.5m and lower 0.51 – 0.1m sections respectively. The samples were described to determine their sedimentological characteristics and effect on absorption and transmission of fluids. The total hydrocarbon content in samples of the study area were determined following the EPA 1664 Hexane Method (Method No: EPA 418.1/413.2 & EPA 1664). Individual concentrations of identified PAH congeners were noted and combined to generate the PAH concentrations in each of the two composited sections of the 30 sampled locations. The sedimentology of the logged sections consists mostly of peaty clay, clayey sands and organic clay in the upper section and clayey silt and clayey sand in the lower section. TPH in the study area ranged between 20612mg/kg at Location 15 to 37.09mg/kg at Location 11 for the upper (0 – 0.5m) sections and 14731mg/kg at Location 12 to 14.67mg/kg at Location 17 for the lower (0.51 – 1m) section. PAH ranged from 9.55mg/kg at Location 12 to <0.01mg/kg at several other Locations for the upper (0 – 0.5m) sections and 5.71mg/kg at Location 11 to <0.01mg/kg at several other Locations for the lower (0.51 – 1m) section. Correlation of sedimentology descriptions with the geochemical analysis indicates high concentrations of total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) within the upper (0 – 0.5m) sections than in the lower (0.51 – 0.1m) sections in consonant with the stratigraphy of the logged section.

Distribution and sources of polycyclic aromatic hydrocarbons in surface sediments of the East China marginal seas: Significance of the terrestrial input and shelf mud deposition

To investigate the distribution, sources, influencing factors, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in East China Marginal Seas (ECMSs) sediments, we measured the concentrations of 16 PAHs in 104 surface sediment samples collected from the ECMSs in 2014 and 2016. Total PAH concentration (∑PAHs) ranged from 4.49 to 163.66 ng/g dry weight (dry w), with 65.98 ± 33.00 (mean ± SD) ng/g dry w. The highest PAH concentrations and total organic carbon were observed in areas with fine-grained sediments in the Bohai Sea (BS), Yellow Sea (YS), and coastal East China Sea (ECS), indicating the prominent influence of regional hydrodynamics and sediment properties. The dominant PAH congener in BS and YS was BbF, whereas coastal ECS was Phe. The heterogeneity of PAH sources implies that terrestrial PAH input and shelf mud deposition have crucial roles in the source–sink processes of PAHs in a strongly human-influenced marginal sea.

Polycyclic aromatic hydrocarbons in the sediments of highly polluted coastal area in the Red Sea: levels, spatial distribution, and risk assessment.

The southern part of the Jeddah coast faces a range of pollution challenges that can impact the water quality and ecosystem in the area. Pollution sources are represented mainly by treated wastewater (TWW), harbor activities, and atmospheric deposition from vehicle exhaustemissions. Polycyclic aromatic hydrocarbons (PAHs) are among the persistent organic pollutants that interfere with all environmental matrices and could cause humane mutagenic and carcinogenic effects. In the present study, 16 priority parent and 21 methylated PAHs (∑37PAHs) were assessed in the sediments of three hot spot coastal sites (Islamic Jeddah port, Al-Arbaeen, and Al-Shabab lagoons) to evaluate the factors affecting their spatial distribution, examine their probable sources and potential adverse effects. The total detected concentrations of ∑37PAHs ranged from 785.9 to 8359.8ng/g dw (average: 2296.3 ± 2017.3ng/g dw). The highest levels of ∑37PAHs were detected near TWW stations. The highest individual PAH congeners observed were phenanthrene, anthracene, and pyrene. PAH molecular diagnostic ratios pointed out different pyrogenic sources. In some specific stations, there was an overlap of petrogenic origin. The sediment samples contained high concentrations of methylated PAHs, with concentrations ranging from 558.42 to 6321.21ng/g dw and an average concentration of 1679.1 ± 1430.7ng/g dw. The sediment quality guidelines indicated that adverse biological effects are likely to occur at least at the two TWW disposal stations and the sediments in these stations are at risk. The values of the mutagenic equivalence quotient (MEQ) and toxic equivalence quotient (TEQ) of carcinogenic PAHs were recorded at 39.88 and 33.17ng/g, respectively.

Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) in Seafood from Orashi River in Omoku, Rivers State of Nigeria and Human Health Risk Assessment

This study investigated the level of polycyclic aromatic hydrocarbons (PAHs) in seafood, namely, C. sapidus (Crab), P. mollusca (Mollusc), Cambarus sp. (Crayfish), Caridea (Shrimp) from Orashi River in Omoku, Rivers State of Nigeria. The PAHs in the samples were determined by gas chromatography–mass spectrometry. There was no variation in the relative level of PAHs congeners. The mean concentrations of individual PAHs decreased in the order: D(a,h)ant > Pyr > Fluth > B(g,h,i)p > B(a)A > B(b)f > Ind (1,2, 3)pyr > B(a)pyr > Chr > B(k)flu > Ant > Flu > Phen > Aceth > Ace > Nap. Anthracene contributed the highest PAHs values, with 51.685% in Caridea. The EDI values of B(a)P, Ʃ2PAH, Ʃ4PAH, Ʃ8PAH across all the seafood were within the maximum permissible limit recommended by EFSA; this suggests that the accumulation of the PAHs in the body system are within the permitted levels. Similarly, the HI of the PAHs congeners obtained from this study were less than 1 which is the safe limit recommended by USEPA. The total Excess Cancer Risk of the PAHs congeners obtained from this study exceeded the permissible maximum limit recommended by USEPA. This study suggests that the water may be contaminated with PAHs which have the tendency to cause non-carcinogenic and carcinogenic risk because of frequent and high consumption of seafoods.

Aged polycyclic aromatic hydrocarbons as stratigraphic marker in the Anthropocene: Evidence from Tibetan Lake sediments

Polycyclic aromatic hydrocarbons (PAHs) were supposed to serve as combustion marker reflecting the past energy use, but it was unclear whether their sediment records in the Anthropocene were “weathered” due to aging-induced formation of bound residues. In this study, the total concentration of PAHs (the sum of rapid desorption, slow desorption, and bound residue fractions) were determined in four dated sediment cores from eastern to central Tibet using multi-step sequential extraction method. The total 16 PAH concentrations were 11.8, 13.5, 18.9, and 29.4 ng/g dw (in average) in the Co Ngoin, Pung Co, Ahung Co, and Putok lakes, respectively. The stratigraphic records and estimated source contributions of PAHs in different areas of Tibet exhibited a coherent change in the mid-20th century in response to the Holocene-Anthropocene transition. The sediment PAHs also displayed a comparable pattern when the bound residue fraction was not accounted for, suggesting their effective retainability under natural aging conditions. This may be elucidated by the enduring forward and back conversions between slow desorption and bound residue fractions, which manifested similar time-dependent variations across PAH congeners. The distinct conversion tendencies of different congeners were predicted by the binding affinity of congeners to surface/inner regions of organic matter using molecular docking simulations. Our findings demonstrate the persistence of sediment PAH records under natural aging and validate the use of PAH documentary evidence for investigating the Anthropocene.

Assessment of health risks of PAHs from rural cooking emissions: Neighborhood diffusion and the impact of village settlement characteristics

Solid fuel cooking in rural areas has led to substantial emissions of air pollutants, notably polycyclic aromatic hydrocarbons (PAHs), especially in developing countries such as China. The potential health risks associated with outdoor exposure of residents to PAHs from fugitive cooking exhaust within rural settlements also merit consideration. Consequently, this study employs computational fluid dynamics (CFD) techniques to evaluate the neighborhood diffusion of benzo[a]pyrene (B[a]P), a carcinogenic PAH congener, in a cluster shape rural settlement. Subsequently, the health risks associated with outdoor exposure to neighborhood-diffused PAHs were quantified using the incremental lifetime cancer risk (ILCR) for the susceptible population. The simulations encompass four settlement characteristics, including the angle between approaching wind and streets (θ), street width (SW), slit distance (SD), and building arrangement, to analyze their influence on the neighborhood diffusion of PAHs. The results demonstrate that the highest ILCR resulting from outdoor PAHs exposure within the main activity areas of neighboring buildings exceeds the United States Environmental Protection Agency (USEPA)'s limit of 1×10−6 across all simulated cases. Additionally, settlement characteristics significantly affect the neighborhood diffusion of cooking-generated B[a]P. Smaller θ and staggered arrangement lead to a reduction in the affected area by B[a]P, but result in higher concentrations and ILCR near the source building. Meanwhile, wider street width proves to be an effective strategy for reducing concentrations and ILCR for both neighboring buildings and entire settlement. These findings offer valuable insights for policymakers and urban planners to develop environmentally sustainable rural communities that minimize health risks associated with cooking activities.

Atmospheric Transport of Polycyclic Aromatic Hydrocarbons into Three Alpine Valleys: Influence of Local-Scale Wind Patterns and Chemical Partitioning.

Current understanding of atmospheric transport of polycyclic aromatic hydrocarbons (PAHs) is limited in alpine areas due to complex meteorology and topography. To better understand atmospheric transport in these areas, we measured 16 PAHs in lichens, biomonitors of atmospheric PAHs, along three transects extending from a highway into otherwise remote alpine valleys. While the valleys neighbored one another and were morphologically similar, they differed in their orientation relative to regional winds. In the valley characterized by regional winds oriented up-valley, PAH concentrations in lichens remained consistent across the transect. In the other two valleys, where regional winds were oriented down or across the valley, 3-6 ring PAHs declined rapidly with increasing distance from the highway, and PAH concentrations in the lichens declined more rapidly for higher molecular weight PAHs than lower molecular weight PAHs. We hypothesize that this trend was driven by differences in gas-particle partitioning and vegetative scavenging between PAH congeners. These results illustrate the importance of both physical transport and chemical partitioning in alpine areas where small differences in topography can lead to significant differences in chemical transport.

Migration of polycyclic aromatic hydrocarbons in the rhizosphere micro-interface of soil-ryegrass (Lolium perenne L.) system

The unclear multi-media and multi-interface processes of polycyclic aromatic hydrocarbons (PAHs) in environments have drawn great concern. Here, 16 controlled PAHs were selected to reveal the differences in the bioavailability and migration of congeners in soil-ryegrass exposure system. The presence of ryegrass in the exposure groups (with newly introduced PAHs) resulted in a decrease in PAHs dissipation (31.3 %) from soil compared to the unplanted groups (43.2 %). The presence of ryegrass inhibited the soil-air exchange process, which has not been widely reported. PAH congeners with less benzene rings (molecular weight < B[a]A) had consistent bioavailability before and after long-term aging, the competition between adsorption/absorption to plants and soil was not strong (RCFs < 3.5), and their migration in the rhizosphere rapidly reached equilibrium. PAH congeners with more benzene rings (molecular weight ≥ B[a]A) adsorbed to soil particles and significantly decreased their bioavailability after long-term aging. Their concentrations in the rhizosphere were stable and lower than bulk soil, revealing their slow equilibrium process in soil. In addition, PAHs with larger molecular weight and KOW showed less migration at the rhizosphere micro-interface. The migration behavior of congeners with close KOW depended on their molecular structure. Congeners with non-symmetric K-region or L-region showed greater migration ability in the rhizosphere. These findings revealed the fate of PAHs, especially different PAH congeners, in the rhizosphere interfaces for the first time, and explored the molecular mechanisms that affect their rhizosphere behaviors, improving the understanding and knowledge of PAHs in the microenvironment, providing new data on evaluating and controlling the environmental risks of PAHs.

Inventory, source and health risk assessment of nitrated and parent PAHs in agricultural soils over a rural river in Southeast China

Nitrated polycyclic aromatic hydrocarbons (NPAHs) have become a concerning topic because of their widespread occurrence and carcinogenicity. However, studies on NPAHs in soils, especially in agricultural soils, are still limited. In this study, a systematic monitoring campaign of 15 NPAHs and 16 polycyclic aromatic hydrocarbons (PAHs) was performed in agricultural soils from the Taige Canal basin in 2018, which is a typical agricultural activity area of the Yangtze River Delta. The total concentration of NPAHs and PAHs ranged from 14.4 to 85.5 ng g−1 and 118–1108 ng g−1, respectively. Among the target analytes, 1,8-dinitropyrene and fluoranthene were the most predominant congeners accounting for 35.0% of ∑15NPAHs and 17.2% of ∑16PAHs, respectively. Four-ring NPAHs and PAHs were predominant, followed by three-ring NPAHs and PAHs. NPAHs and PAHs had a similar spatial distribution pattern with high concentrations in the northeastern Taige Canal basin. The soil mass inventory of ∑16PAHs and ∑15NPAHs was evaluated to be 31.7 and 2.55 metric tons, respectively. Total organic carbon had a significant impact on the distribution of PAHs in soils. The correlation between PAH congeners in agricultural soils was higher than that between NPAH congeners. Based on diagnostic ratios and principal component analysis-multiple linear regression model, vehicle exhaust emission, coal combustion, and biomass combustion were the predominant sources of these NPAHs and PAHs. According to the lifetime incremental carcinogenic risk model, the health risk posed by NPAHs and PAHs in agricultural soils of the Taige Canal basin was virtually negligible. The total health risk in soils of the Taige Canal basin to adults was slightly higher than that to children.

Field Calibration of Semipermeable Membrane Devices (SPMDs) for Persistent Organic Pollutant Monitoring in a Reservoir

Persistent Organic Pollutants (POPs) in water can reach levels below ppt (ng L−1), representing a challenge for risk assessment using long-term exposure. Therefore, sampling devices to monitor trace levels of organic compounds are suitable due to their sensitivity and low detection limits. In this work, the field calibration and monitoring for POPs, such as Polycyclic Aromatic Hydrocarbons (PAHs) and pesticides, in a drinking water reservoir were carried out using semipermeable membrane devices (SPMDs). The SPMDs were spiked with deuterated PCBs used as PRCs, and their dissipation was measured at 5, 10, 15 and 24 days. The SPMDs were dialyzed in hexane twice and the initial amount (N) and final amount (No) of PRCs in extracts were estimated by GC/MS to calculate the sampling rate (Rs) for target compounds. The PCBs were dissipated more than 30% at 24 days, and Rs were calculated between 27.8 and 72.7 L day−1 for PAHs and 35.8 and 71.3 L day−1 for pesticides. Finally, PAH congeners such as Naphthalene, Acenaphthylene, Acenaphthene, Fluorene, Phenanthrene, Anthracene, Fluoranthene and Pyrene were detected at water concentration (Cw) ranges between 0.5 and 2.7 ng L−1, whilst chlorpyrifos was the only pesticide detected at 19.0 ng L−1 in the reservoir. This calibration showed that PRCs do not dissipate entirely in 24 days and that dissipation modelling may be applied for Cw estimation of POPs in reservoirs.

Trophic transfer of polycyclic aromatic hydrocarbons in marine mammals based on isotopic determination

The tissue distribution (liver, kidney, heart, lung, and muscle), source, and trophic transfer of 15 polycyclic aromatic hydrocarbons (PAHs) were studied on 14 stranded East Asian finless porpoises (Neophocaena asiaeorientalis sunameri), 14 spotted seals (Phoca largha), and 9 stranded minke whales (Balaenoptera acutorostrata) from Yellow Sea and Liaodong Bay. The PAHs levels ranged from below the limit of detection to 459.22 ng g−1 dry weight in the tissues of the three marine mammals, and light molecular weight PAHs were the primary pollutants. Although the PAHs levels were relatively higher in internal organs of the three marine mammals, generally no tissue-specific distribution of the PAHs congeners was found, either for gender-specific distribution of PAHs in the East Asian finless porpoises. However, species specific PAHs concentration distribution were obtained. The PAHs were mainly originated from petroleum and biomass combustion in the East Asian finless porpoises, while those for the spotted seals and minke whales were complex. Trophic level associated biomagnification was found for phenanthrene, fluoranthene, and pyrene in the minke whale. Benzo(b)fluoranthene exhibited a significant biodilution with increasing trophic levels in the spotted seals, but the total concentration of the PAHs showed a significant biomagnification with increasing trophic levels. Trophic level-associated biomagnification of acenaphthene, phenanthrene, anthracene, and ∑PAHs were found in the East Asian finless porpoise, while pyrene exhibited obvious biodilution with increasing trophic levels. Our current study filled knowledge gaps on tissue distribution and trophic transfer of the PAHs in the investigated three marine mammals.

Polycyclic aromatic hydrocarbon exposure burden: Individual and mixture analyses of associations with chronic obstructive pulmonary disease risk

Accumulating data demonstrate that polycyclic aromatic hydrocarbons (PAH) exposure is linked to compromised respiratory diseases. This study aimed to analyze urinary PAH metabolites and their associations with chronic obstructive pulmonary disease (COPD) in a sample size of 3015 subjects from a total population of 50,588 from the National Health and Nutrition Examination Survey (NHANES) in 2007–2016. Results showed that the most predominant metabolite was 1-Hydroxynaphthalene (1-NAP, 84%) with a geometric mean concentration of 50,265 ng/L, followed by its homologue 2-NAP (10%), both of which arose from sources including road emission, smoking and cooking. Multiple logistic regression showed that seven of the ten major PAH metabolites were correlated with increased COPD risk: including 1-NAP (OR: 1.83, 95%CI: 1.25, 2.69), 2-Hydroxyfluorene (2-FLU, OR: 2.29, 95%CI: 1.42, 3.68) and 1-Hydroxyphenanthrene (1-PHE, OR: 2.79, 95%CI: 1.85, 4.21), when compared to the lowest tertile after adjusted for covariates. Total exposure burden per PAH congener sub-group demonstrated persistent positive correlation with COPD for ∑PHE (OR: 1.80, 95%CI: 1.34, 2.43) and ∑FLU (OR: 2.74, 95%CI: 1.77, 4.23) after adjusted for covariates. To address the contribution of PAH exposure as mixture towards COPD, weighted quantile sum (WQS) regression analyses revealed that 1-NAP, 9-Hydroxyfluorene (9-FLU), 3-Hydroxyfluorene (3-FLU) and 1-PHE were among the top contributors in the associations with COPD. Our results demonstrate the contemporary yet ongoing exposure burden of PAH exposure for over a decade, particularly towards NAPs and FLUs that contribute significantly to COPD risk, calling for more timely environmental regulation.

Effect of Smoking and Grilling on Polycyclic Aromatic Hydrocarbons in Ghanaian Tilapia.

The study assessed 18 Polycyclic Aromatic Hydrocarbons (PAHs) in O. niloticus (Nile tilapia) sampled from an aquaculture cage (farm) and a wild catch. The PAHs in fish samples were analysed using Gas Chromatography-Mass Spectrometry. Four PAHs (in order of levels: Indeno [1,2,3-cd] pyrene > Anthracene > Perylene > Pyrene; 100-0.8 µg/kg) and only one PAH (Pyrene: 4 µg/kg) were detected in raw samples from the cage and wild catch respectively. Chargrilling significantly increased Pyrene levels after cooking (wild: 4-11 µg/kg; cage: 5-23 µg/kg, p < .05), and likewise Anthracene levels in cage samples (13-153 µg/kg) but decreased Indeno [1,2,3-cd] pyrene levels from 100 ± 20 to 1.2 ± 0.2 µg/kg in cage samples. Smoking significantly increased 13 to 15 PAH congeners' levels (from < 1.0 up to 340 µg/kg) and total PAHs (wild: 4 to 840 µg/kg; cage: 110 to 560 µg/kg), and decreased Indeno [1,2,3-cd] pyrene (100 to 1.3 µg/kg) in cage samples but showed no effect on Benzo [g, h, i] perylene and Dibenzo [a, h] anthracene levels in all samples. For smoked samples, Benzo [a] pyrene and PAH4 (Benzo [a] anthracene, Chrysene, Benzo [b] fluoranthene, and Benzo [a] pyrene) exceeded the respective maximum permissible limits of 2 µg/kg and 12 µg/kg, and significantly influenced the levels of carcinogenic PAHs (CPAH, 135-170 µg/kg). Nevertheless, the Excess Cancer Risk (ECR) estimates, from a conservative approach, were far below the threshold (10-4), implying that consuming smoked or grilled tilapia from the study site is safe.

Occurrence, sources, and spatial variation of POPs in a mountainous tropical drinking water supply basin by passive sampling

Persistent organic pollutants (POPs) are widely distributed along the world and their levels in surface waters may pose a risk to human health due to consumption of contaminated water or fish long-term exposure to contaminated water. The occurrence of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in the Piedras river (Colombia) is a problem of serious concern since freshwater is conducted to a drinking water supply system that provides more than 3 million users. In this research, we deployed silicone rubber membranes as passive samplers in two sampling campaigns at seven sampling stations selected along the river, to assess sources and spatial variation of POPs. The measurements confirmed freely dissolved concentration of the EPA prioritized PAHs (excluding naphthalene), PCBs, heptachlor isomers, dieldrin, endosulfan isomers, among other POPs at trace levels in the water source. The Risk Quotient (RQ) method was applied to prioritize POPs with the highest potential toxicity over aquatic ecosystems. The OCP Heptachlor overcome RQ, while Dieldrin and Endosulfan, and some PAHs congeners such as Perylene, Pyrene, Benzo[a]pyrene, and Fluoranthene displayed medium-risk RQ. Significant differences between sampling stations assessed by One-way ANOVA suggested that the main PAHs and PCBs sources to the river were the punctual discharge from the WWTP and a leachate discharge form a landfill located in the study area. Additionally, nonpoint sources of OCPs were identified. Our results showed that the origin of PAHs and PCBs are associated with urban activities, while the contribution of OCPs is related to the presence of legacy pesticides from past usage in agricultural activities in the basin.

Human Health Risk Assessment of Polycyclic Aromatic Hydrocarbons in Water Samples around Eket Metropolis, Akwa Ibom State, Nigeria

Aims: Polycyclic aromatic hydrocarbons (PAHs) are very toxic and persistent environmental contaminants. The paper is aimed at investigating the cancer risk exposure of PAHs in borehole water collected around five automobile repair workshops within Eket metropolis.&#x0D; Place and Duration of Study: Samples were collected between June - August (2018) in wet season and November (2018) – January (2019) in dry season from boreholes around the vicinity of five automobile repair workshops within Eket metropolis. &#x0D; Methodology: The water samples were prepared in the laboratory following standard procedures and analysed for 16 United States Environmental Protection Agency (US EPA) priority PAHs using Gas Chromatography–Mass Spectrometer (GC–MS). A total of fifteen PAH congeners were detected in the samples.&#x0D; Results: Total PAHs concentrations in borehole water from all sampling sites were in the range of 1.71–16.07 mg/L and 1.07–12.97 mg/L for both dry and wet seasons respectively. The low PAHs levels recorded in water for the wet season was linked to dilution effect. Low molecular weight PAHs were more dominant in all samples. The estimated cancer risks of exposure to PAHs by ingestion in the water samples ranged from 7.10 × 10-7 to 1.12 × 10-4 and 6.76 × 10-6 to 3.69 × 10-1 for adults and children respectively in both seasons. The estimated cancer risks due to dermal exposure to PAHs in the water samples ranged from to 7.18 × 10-3 to 1.07 × 10-1 and 5.67 × 10-3 to 1.08 × 10-1 for adults and children respectively in both seasons. &#x0D; Conclusion: Carcinogenic risks due to dermal exposure calculated for both adults and children were higher than the US EPA acceptable cancer risk and much higher for children, which suggest that children could be prone to cancer and need to be monitored.

Comparison of polycyclic aromatic hydrocarbon accumulation in crab tissues with the ambient marine particles from shallow hydrothermal vents, northeast Taiwan

This study investigated and compared polycyclic aromatic hydrocarbons (PAHs) in crab (Xenograpsus testudinatus), suspended particulate matter, and surface sediment sampled from Kuei-shan-tao (KST) shallow water vents just offshore northeast Taiwan. The total concentrations of PAHs (t-PAHs) in suspended particles near the vents (533–685 ng g−1 dw) were two orders of magnitude higher than the overlying sediment (3.42–6.06 ng g−1 dw). The t-PAHs in sediment were significantly lower than those found in suspended particulate matter and all crab tissues tested, including hepatopancreas (192–1154 ng g−1 dw), gill (221–748 ng g−1 dw), muscle (30–174 ng g−1 dw), and exoskeleton (22–96 ng g−1 dw). Principal component analysis (PCA) indicated tissue-specific bioaccumulation of PAHs in crabs. The compositions of PAHs in gill, muscle, and exoskeleton were mainly low molecular weight, while the composition in the hepatopancreas included both high and low molecular weight PAHs. Highly variable but characteristic PAH congeners and concentrations in crab tissues and ambient aquatic particles reflect bioaccumulation.

Source apportionment and health risk of exposure to ambient polycyclic aromatic hydrocarbons (PAHs) bound to particulate matter in Sabzevar, Iran

Ambient polycyclic aromatic hydrocarbons (PAHs) emissions are a major environmental problem in urban areas. We aimed to assess the concentration of PAHs-bound to particulate matter (PM), source apportionment and carcinogenic risk due to inhalation exposure to PAHs. We selected 30 sampling locations in Sabzevar, Iran (2021). PM bounds-PAHs samples were collected using a PM passive sampler. Monte Carlo simulation technique with sensitivity analysis was used to assess the carcinogenic risk of inhalation exposure to PAHs. The Positive Matrix Factorization (PMF) model was used for source apportionment of ambient PAHs. The median (iterquartile range (IQR)) of total PAHs was 1056.2 (848.5) ppb. The median (IQR) ratio of total LMW/HMW PAHs was 1.9 (1.4), indicating petrogenic sources of PAHs. The 95th percentile of lifetime cancer risk (LTCR) for children, adolescents, and adults in both genders was higher than the threshold level recommended by USEPA (i.e., 1 × 10−6). The PMF model indicated five possible PAH sources, including combustion of biomass, natural gas, combustion petroleum-based fuels, traffic sources of mixed gasoline and diesel combustion, and industrial activities. The spatial autocorrelation models indicated a clustered distribution pattern for all PAHs congeners except Anthracene. Our results suggested that point sources of ambient PAHs should be paid more attention to in urban areas. Moreover, inhalation exposure to ambient PAHs had a potential carcinogenic risk for the inhabitant of Sabzevar.

Effects of polycyclic aromatic hydrocarbons on gestational hormone production in a placental cell line: Application of passive dosing to in vitro tests

Air pollution includes polycyclic aromatic hydrocarbons (PAHs), which have been correlated to endocrine disruptor pathways during early pregnancy. PAHs have been found in the placenta and cord blood, which may affect the hormones involved in placental development. We studied the effects of some airborne PAHs on beta human chorionic gonadotropin (β-hCG) and progesterone production by using a syncytial BeWo cell line as a placental model. PAH congeners were spiked in silicon rubber membrane (SRMs) and were then introduced into the cell medium by the passive dosing method to reach a freely dissolved concentration for BeWo cell exposure. Ultrahigh-performance liquid chromatography coupled with a diode array detector was used to analyze the PAHs, and electrochemiluminescence was used to test the hormone levels. Our results showed that passive dosing can deliver low levels of PAH congeners in the cell medium, which allowed us to calculate the individual release constants at equilibrium and to estimate their effects. Benzo[a]pyrene was released quickly from the SRMs to the cell medium, which can be attributed to its lipophilic properties. The PAHs were shown to decrease the β-hCG level in the short term and progesterone level in the long term, so they may serve as a pathway for endocrine disorder in trophoblastic cells. This approximation may explain observations of impaired endometrium receptivity and placental dysfunction, which enhance adverse pregnancy outcomes such as embryonic mortality and intrauterine growth restriction.