Low Levels Of Polycyclic Aromatic Hydrocarbons Research Articles

Integrated evaluation of workplace exposures and biomarkers of bladder cancer among textile dyeing workers

BackgroundThe textile industry is the second risk factor for bladder cancer, after smoking. Previous studies focused on the impact of exposure to high concentrations of bladder carcinogenic chemicals in the textile dyeing industry on the elevation of bladder cancer biomarkers. This study aimed to evaluate bladder carcinogenic air pollutants in a textile dyeing factory and investigate its role and the role of serum 25-hydroxyvitamin D (25-OH vit. D) on cancer bladder biomarkers in exposed workers.MethodsA cross-sectional study was conducted. Particulate and vapor forms of polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) were monitored in the printing, dyeing, and preparing sections of a textile factory. Bladder tumor antigen (BTA), nuclear matrix protein 22 (NMP-22), and 25-OH vit. D were estimated in all the exposed workers (147 exposed workers) and in workers not occupationally exposed to chemicals (130 unexposed workers).ResultsAromatic bladder carcinogenic compounds were either in low concentrations or not detected in the air samples of working areas. BTA and NMP-22 of exposed workers were not significantly different from the unexposed. However, 25-OH vit. D was significantly lower in the exposed than unexposed workers. There was a significant inverse correlation between 25-OH vit. D and duration of exposure in exposed workers.ConclusionThe mean levels of PAHs and VOCs were within the safe standard levels in the working areas. The non-significant difference in BTA and NMP-22 between the exposed and unexposed groups suggests the presence of occupational exposures to safe levels of bladder carcinogenic aromatics, while the significantly lower 25-OH vit. D levels among the exposed than the unexposed groups could suggest the potential association of 25-OH vit. D with occupational exposures to low levels of PAHs and VOCs, and this association was found to be inversely correlated with the duration of exposures. Accordingly, more specific predictor tests must be applied for early diagnosis of bladder cancer among the exposed workers.

Ornithogenic sedimentary profiles of n-alkanes and PAHs constrain breeding penguin population dynamics at Cape Bird, Ross Island, Antarctica, over the past 1,500 years

Ornithogenic sediment may contain important paleoecological information concerning past bird population dynamics. In this paper, we analyse the distribution of n-alkanes and polycyclic aromatic hydrocarbons (PAHs) in two sedimentary profiles collected from abandoned penguin colonies at Cape Bird, Ross Island, Antarctica. The geochronology of the sediment profiles was determined using 210Pb and AMS 14C dating techniques, and spans the past 1500 years. We observe low levels of n-alkanes (0.93–2.67 μg g−1) and PAHs (20.5–46.8 ng g−1) concentrations dominated by short-chain n-alkanes, low-molecular-weight and alkyl PAHs. Principal Component Analysis (PCA) shows that the PC 1 scores for n-alkanes and PAHs are significantly correlated with the input intensity of penguin guano and penguin bioelements. Using these proxies in combination with Generalized Additive Model (GAM), we reveal that breeding penguin population growth reaches a historical peak during the Medieval Climate Anomaly (MCA) prior to 1550 CE. This growth in population size corresponds to the extent of sea ice cover and the activity of the local atmospheric-ocean circulation. Warming induced by El Niño and the positive phase of the Southern Annular Mode, along with the expansion of ice-free zones and increased oceanic nutrient and food availability, are considered primary factors contributing to the growth of breeding penguin populations. Additionally, variations in sea ice extent and Amundsen Sea Low significantly influence penguin population dynamics. Our study suggests that n-alkanes and PAHs may be valuable organic proxies for reconstructing historical changes in breeding penguin populations, with the local sea ice extent and atmospheric-oceanic circulation exerting a major influence on Antarctic penguin population dynamics.

Biomonitoring of polycyclic aromatic hydrocarbons in firefighters at fire training facilities and in employees at respiratory protection and hose workshops.

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic to humans and are formed by incomplete combustion. PAHs are always present during firefighting operations, and fire department members can be exposed to them in the workplace. In this study, we analyzed 1-hydroxypyrene (1-OHP) in 36 urine samples from nine firefighters, collected before and after fire training sessions, and 32 urine samples from eight employees at respiratory protection and hose workshops. To assess breakthrough PAH exposure through personal protective equipment and potential dermal uptake, some of the workshop employees wore cotton garments under their regular workwear. Cotton samples were then examined for the presence of 17 semi-volatile and low-volatility PAHs. After firefighting exercises, we observed approximately a fivefold increase in mean 1-OHP concentrations in samples from firefighters, from 0.24 μg/L to 1.17 μg/L (maximum: 5.31 μg/L). In contrast, 1-OHP levels in workshop employees were found to be low, with the majority of urine samples yielding concentrations below the limit of quantification (LOQ: 0.05 μg/L, maximum: 0.11 μg/L). Similarly, low PAH levels were found on the workshop employees' cotton undergarments, with maximum concentrations of 250 and 205 ng/g for pyrene and benzo[a]pyrene, respectively. In conclusion, significant increases in 1-OHP in urine were observed in firefighters after training sessions, whereas work-related exposure remained low among workshop employees.

Assessment of environmental risk related to the polycyclic aromatic hydrocarbons (PAH) in the sediments along the eastern Adriatic coast

Polycyclic aromatic hydrocarbons (PAH) were investigated in the sediments at 24 locations in the coastal area of Adriatic Sea. Total PAH concentrations ranged from 14,98 to 26145,62 µg kg-1, with the highest levels determined in the sediments of Šibenik Bay and the lowest in the sediment near Island of Pag. Unsubstituted PAH were prevailing PAH group in the sediments from the Šibenik Bay and in the Coastal area, while methyl-substituted PAH were dominant group in the sediments of the Kaštela Bay. In order to estimate the possible toxicological significance of PAH concentrations, Sediment Quality Assessment was done according to three different sets of sediment quality guidelines. A high environmental risk was calculated for each station in Šibenik Bay; for the station in vicinity of the Industrial port of Split and for the two stations in Coastal zone. Low environmental risk was determined in less urbanised areas such as Island of Pag. Sediment extracts were further analysed for acute toxicity by measurements of decrease in bioluminescence upon exposure to sediment extracts. Obtained results show disagreement between sediment toxicity predicted upon PAH levels in sediment and experimentally obtained sediment toxicity. Sediment extracts in which low PAH levels were measured showed high acute toxicity indicating that concentrations of PAH alone are a poor indicator of sediment toxicity. Correlation analysis between concentrations of specific PAH compounds and toxicity revealed the strongest association between acute sediment toxicity and sulphur-containing PAH suggesting the S-PAH should be considered in sediment toxicity assessment.

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.
 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. 
 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.
 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. 
 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.

Roads with underlying tar asphalt - spreading, bioavailability and toxicity of their polycyclic aromatic hydrocarbons

Some of the older Swedish roads contain road tar underneath a surface layer of bituminous asphalt. This road tar, also known as tar asphalt, contains large amounts of polycyclic aromatic hydrocarbons (PAHs). There is concern about PAHs spreading from the bottom layers of these older roads to the surrounding environment, and that because of this spreading road tar asphalt should not be recycled but rather placed in landfills. However, a risk assessment of PAH spreading below roads has not yet been conducted. The first aim of this study was to assess this potential spreading of PAHs from underlying tar asphalt to the sand beneath, the soil next to the roads, as well as nearby groundwater. The second aim was to measure the bioavailability and estimate the toxicity of PAHs in all relevant media using polyoxymethylene (POM) passive samplers. Four road sections and nearby groundwater in northern Sweden were investigated, including a control road without tar asphalt. PAHs were detected in all analysed solid media at varying concentrations: in asphalt from 2.3 to 4800 mg kg−1, in underlying sand from <1.5 to 460 mg kg−1 and in slope soil from <1.5 to 36 mg kg−1. However, the spread of PAHs from the asphalt to roadside soil and groundwater was very limited. Groundwater at most of the road sections contained very low or non-detectable levels of PAHs (<0.08–0.53 μg L−1, excluding one site where fuel contamination is hypothesized). The PAHs generally showed low bioavailability. Only asphalt with PAH content >1200 mg kg−1 exhibited bioavailable concentrations that exceeded threshold concentrations for serious risk. The most PAH contaminated sand and soil samples exhibited low toxicity when considering bioavailability, only in some cases exceeding chronic toxicity threshold concentrations. These results were compared with the Swedish EPA's guideline values for PAH in contaminated soil, which is shown to overpredict toxicity for these sites. Further research on the leaching and transportation processes of PAHs from subsurface tar asphalt is recommended for developing risk analysis approaches.

Age frequency, growth, mortality, and PAH levels of roughtongue bass (Pronotogrammus martinicensis) following the Deepwater Horizon oil spill

Age, growth, mortality, and polycyclic aromatic hydrocarbons (PAHs) in roughtongue bass (Pronotogrammus martinicensis) were examined in the northern Gulf of Mexico following the 2010 Deepwater Horizon oil spill. Fish (N = 1090) were collected from September 2014 to July 2015 from the Alabama Alps (54 km from the spill site) and Roughtongue Reef (111 km from the spill site). Sites were dominated by the 2010 year-class. Growth rates were significantly lower for fish from Alabama Alps compared to Roughtongue Reef (p < 0.001) and likely linked to proximity of the Mississippi River discharge. Mean total PAH ± SD was 50 ± 52.6 and ranged from 0 to 220 ppb. These PAH levels were below a 300-ppb minimum effect level and not significantly different between sites. The dominant 2010 year-class, low PAH levels, and similar growth rates to pre-spill measures indicated that the Deepwater Horizon oil spill had little effect on roughtongue bass.

Determination of polycyclic aromatic hydrocarbons (PAHs) in smoking cessation aids by using high-performance liquid chromatography

A method has been developed and validated for the determination of polycyclic aromatic hydrocarbons (PAHs) in the electronic liquid/gas (e-liquid/e-gas) of electronic cigarettes (e-cigarettes) and ignitable/non-ignitable smokeless cigarettes by high-performance liquid chromatography–fluorescence detection. The proposed method was further applied to detect the presence of PAHs in 16 commercially available smoking cessation aids. The analytical method for benz [a]anthracene, chrysene, benzo [b]fluoranthene, benzo [k]fluoranthene, benzo [a]pyrene, dibenz [a,h]anthracene, and benzo [g,h,i]perylene (BghiP) was validated in terms of linearity, limit of detection, limit of quantification, recovery (%), accuracy (%), and precision (%). Results showed low levels of PAHs in all samples, except for the non-ignitable cigarettes. In particular, BghiP was detected in e-liquid even though a mixture of food-grade propylene glycol and vegetable glycerin was used, and at least one PAH was present in the e-gas of all e-cigarettes, except for one. From these results, it is necessary to prepare an accurate quantitative analysis method and investigate unexpected hazardous materials generated from smoking cessation aids to prevent health problems and provide the scientific basis for safety management.

Occurrence and distribution of PAHs and microbial communities in nearshore sediments of the Knysna Estuary, South Africa.

This study investigated the polycyclic aromatic hydrocarbons (PAHs) occurrence, and their impact on the microbial community and PAH-degrading genera and genes in the Knysna Estuary of South Africa. The results reveal that the estuary exhibits low PAH levels (114.1-356.0ngg-1). Ignavibacteriae and Deferribacteres, as well as Proteobacteria and Bacteroidetes, are keystone phyla. Among measured environmental factors, total organic carbon (TOC), nutrients such as nitrite and nitrate, metals as Al, Cr, Cu, Ni, Pb and Zn, and environmental properties (pH and salinity) are primary contributors to structuring the bacterial community assemblage. The abundance of alpha subunit genes of the PAH-ring hydroxylating dioxygenases (PAH-RHDα) of Gram-negative bacteria lies in the range of (2.0-4.2)×105 copies g-1, while that of Gram-positive bacteria ranges from 3.0×105 to 1.3×107 copies g-1. The PAH-degrading bacteria account for up to 0.1% of the bacterial community and respond mainly to nitrate, TOC and salinity, while PAHs at low concentration are not significant influencing factors. PAH degraders such as Xanthomonadales, Pseudomonas, and Mycobacterium, which play a central role in PAH-metabolization coupled with other biogeochemical processes (e.g. iron cycling), may contribute to maintaining a healthy estuarine ecosystem. These results are important for developing appropriate utilization and protection strategies for pristine estuaries worldwide.

PAH bioaccumulation in two polluted sites along the eastern coast of the Red Sea, Saudi Arabia

Significant amounts of polycyclic aromatic hydrocarbons (PAHs) accumulate in specific habitats and organisms, such as mangroves and benthic organisms, due to the PAHs’ direct attachment to sediments in the environment or the feeding activity of the organisms, especially in contaminated coastal areas. The present study investigates the effect of sewage effluents on the bioaccumulation of PAHs in two polluted sites along the coastal area of Jeddah city. PAH levels in the mangrove sediments, roots, and leaves ranged between 230.09 and 17.94, 32.79 and 409.86, and 111.14 and 795.2 ng/g, respectively, following the general trend of sediments < roots < leaves. Though all mangrove roots showed bioaccumulation factors (BAFroots) higher than 1, the leaves bioaccumulation factors (BAFleaves) exceeded 26, clearly indicating PAHs accumulated not only via a translocation pathway but also from the surrounding atmosphere. These results suggest that mangroves could serve as an in situ eco-friendly resource for the dissipation of PAHs in marine sediments and the atmosphere. Although higher levels of PAHs were detected in Al-Arbaeen Lagoon sediments (ranging between 89.18 and 1056.46 ng/g), lower levels of PAHs were observed in the gastropod Littorina Littorea (range 113.21–265.96 ng/g) in this area, with biota-sediment accumulation factors (BSAF) ranging from 0.23 to 2.10. Only one Al-Arbaeen site presented sediments with a petrogenic origin, with a BSAF value higher than 1 in the gastropod. Based on sediment quality guidelines, adverse biological effects should rarely occur at the studied sites under the present PAH levels.

PAH SORPTION TO NANOPLASTICS AND THE TROJAN HORSE EFFECT AS DRIVERS OF MITOCHONDRIAL TOXICITY AND PAH LOCALIZATION IN ZEBRAFISH.

Plastics are world-wide pollutants that pose a potential threat to wildlife and human health. Small plastic particles, such as microplastics and nanoplastics, are easily ingested, and can act as a Trojan Horse by carrying microorganisms and pollutants. This study investigated the potential role of the Trojan Horse effect in the toxicity of nanoplastics to the vertebrate model organism, zebrafish (Danio rerio). First, we investigated if this effect could affect the toxicity of nanoplastics. Second, we analyzed if it could contribute to the biodistribution of the associated contaminants. And third, we focused on its effect on the mitochondrial toxicity of nanoplastics. We incubated 44 nm polystyrene nanoparticles with a real-world mixture of polycyclic aromatic hydrocarbons (PAHs) for 7 days and removed the free PAHs by ultrafiltration. We dosed embryos with 1 ppm of nanoplastics (NanoPS) or PAH-sorbed nanoplastics (PAH-NanoPS). Neither type of plastic particle caused changes in embryonic and larval development. Fluorescence microscopy and increased EROD activity suggested the uptake of PAHs in larvae exposed to PAH-NanoPS. This coincided with higher concentrations in the yolk sac and the brain. However, PAH-only exposure leads to their accumulation in the yolk sac but not in the brain, suggesting that that the spatial distribution of bioaccumulated PAHs can differ depending on their source of exposure. Both nanoplastic particles affected mitochondrial energy metabolism but caused different adverse effects. While NanoPS decreased NADH production, PAH-NanoPS decreased mitochondrial coupling efficiency and spare respiratory capacity. In summary, the addition of PAHs to the surface of nanoplastics did not translate into increased developmental toxicity. Low levels of PAHs were accumulated in the organisms, and the transfer of PAHs seems to happen in tissues and possibly organelles where nanoplastics accumulate. Disruption of the energy metabolism in the mitochondria may be a key factor in the toxicity of nanoplastics, and the Trojan Horse effect may amplify this effect.

Cluster analysis of urinary tobacco biomarkers among U.S. adults: Population Assessment of Tobacco and Health (PATH) biomarker study (2013–2014)

Tobacco use delivers nicotine, tobacco-specific nitrosamines (TSNAs), volatile organic compounds (VOCs), and polycyclic aromatic hydrocarbons (PAHs), which are metabolized and excreted in urine offering useful biomarkers of exposure. Previous studies compared individual toxicants across tobacco users. Based on a group of biomarkers, cluster analysis was used to define tobacco toxicant exposure profiles. Clusters with distinct exposure profiles, were determined and described, based on levels of urinary biomarkers of exposure to nicotine, TSNAs, VOCs, and PAHs among a national sample of current, established, adult tobacco users, and examine the association of use behavior and cluster membership. The PATH Biomarker Wave 1 data were analyzed. Current established tobacco users with complete urinary biomarker data were included (N = 6724). User groups included cigarette smokers, users of electronic cigarette (ECIG), smokeless tobacco (SLT), and dual and poly tobacco users. Cluster analysis, pairwise comparisons, and multinomial logistic regression were conducted. Cigarette smokers were primarily in clusters with high biomarker concentrations across all groups, but actual concentrations were associated with smoking quantity. A cluster with high TSNAs but low levels of PAHs and VOCs was heavily populated by SLT users. Exclusive ECIG users, depending on use frequency, were predominantly in clusters with low biomarker concentrations, except for one cluster that had relatively high TSNAs. Clusters heavily populated by dual and poly tobacco users were the same as those heavily populated by cigarette smokers. Ten exposure profiles (clusters) were determined and linked to tobacco use behavior. Findings could inform future research and policy initiatives.

Objective Measurement of Carcinogens Among Dominican Republic Firefighters Using Silicone-Based Wristbands

PURPOSE Firefighters around the world are exposed to physical hazards and toxic chemical agents during fire incident response. Occupational epidemiologic studies of the firefighter workforce have documented an excess cancer risk for brain, digestive, genitourinary, and lymphohematopoietic organs compared with the general population. Despite the elevated cancer risk, little is known about what specific types of carcinogenic chemicals first responders encounter during a typical work shift, particularly in low-resources settings, like the Dominican Republic. This pilot study characterizes objective measurements of carcinogenic exposure using passive sampling silicone-based wristbands among Dominican firefighters. METHODS Firefighters from a metropolitan fire service in the Dominican Republic were asked to wear a silicone-based wristband during one typical 24-hour shift. A pre- and postshift survey was administered to the firefighter to assess their self-reported sociodemographic, employment, and work shift characteristics. Wristbands were collected after their 24-hour shift and processed for the type and quantity of polycyclic aromatic hydrocarbons (PAHs), a family of known carcinogenic compounds, to which firefighters were exposed. RESULTS Among 15 firefighters who wore a wristband during their 24-hour shift, 73.3% responded to a fire with an average of 3.7 calls during the shift. Fire incident responses included structural fires (54.5%), outside and other fires (36.4%), and vehicle fires (9.1%). Total PAH exposure was significantly higher among Dominican firefighters who responded to a fire compared with firefighters with no fire during their shift (261 parts per billion [ppb] v 117 ppb, respectively; P = .003). Among the 19 PAHs quantified, low-molecular-weight phenanthrene was present in the highest concentration (32 ppb) among firefighters not responding to fires. CONCLUSION Passive objective sampling of PAHs using silicone-based wristbands among Dominican firefighters showed direct exposure to carcinogenic compounds during a typical 24-hour firefighter shift. Firefighters not attending a fire had lower levels of PAHs, suggesting carcinogenic contaminants are present at the fire station.

The effects of extracting procedures on occurrence of polycyclic aromatic hydrocarbons in edible oils.

Polycyclic aromatic hydrocarbons (PAHs) are one of the most hazardous naturally occurring chemical contaminants of food. Edible oils are easily contaminated by PAHs generated during high-temperature processing steps such as oil extraction and refining. In this study, the effects of different extraction methods on the levels of PAHs in sesame oils and red pepper seed oils were assessed. GC-MS was used to determine the levels of PAHs in edible oils. Sesame oils extracted from seeds by plate-pressing extraction method had lower levels of PAHs than those extracted by screw-expeller extraction method from sesame flour. Furthermore, the levels of PAHs increased by 62.2% when the extraction time was longer. Notably, the PAHs already present in oils could be effectively reduced by refining procedures such as sinking, centrifugation, filtration, and neutralization with alkali.

Urinary metabolites of polycyclic aromatic hydrocarbons in pregnant women and their association with a biomarker of oxidative stress.

Exposure to polycyclic aromatic hydrocarbons (PAHs) during pregnancy may pose adverse health risk to both the mothers and babies. In the present study, 188 pregnant women of different trimesters were recruited in Guangzhou, south China, and nine hydroxyl PAHs (OH-PAHs) and a biomarker of DNA oxidative damage, 8-hydroxy-2'-deoxyguanosine (8-OHdG), were determined in their urine samples. All OH-PAHs except for 4-hydroxyphenanthrene and 6-hydroxychrysene were found in > 90% samples, with total concentration in the range of 0.52 to 42.9μg/g creatinine. In general, concentration levels of OH-PAHs in pregnant women were lower than those in general population in the same research area but with higher levels in working women than in housewives. The mean daily intakes of PAHs from dietary estimated by urinary OH-PAHs were 0.021, 0.004, 0.047, and 0.030μg/kg_bw/day for naphthalene, fluorene, phenanthrene, and pyrene, respectively, which were much lower than the reference doses (20, 30, and 40μg/kg_bw/day for naphthalene, pyrene, and fluorene, respectively) derived from chronic oral exposure data by the United States Environmental Protection Agency. The low exposure levels of PAHs may be attributed to the traditional dietary taboo of Chinese pregnant women, which is to minimize the consumption of "toxic" food. The concentrations of 8-OHdG (4.67-49.4μg/g creatinine) were significantly positively correlated with concentrations of several OH-PAHs, such as metabolites of naphthalene, fluorene, and phenanthrene (r = 0.3-0.6). In addition, the concentrations of 8-OHdG were higher in working women than in housewives when exposed to the same levels of PAHs, partly indicating the possible relation between work-related pressure for working women and the oxidative stress.

Polycyclic aromatic hydrocarbons (PAHs) associated with PM2.5 within boundary layer: Cloud/fog and regional transport

A study of PM2.5-associated PAHs analysis at Mount Lushan (1165m) was conducted to investigate the distributions of PAHs in PM2.5 and influences of cloud/fog. The main purpose was to quantify the main emission sources of PAHs and estimate regional transport effects within the boundary layer. Mount Lushan is located between the boundary layer and troposphere, which is an ideal site for atmosphere transport investigation. The concentrations of PAHs in PM2.5 were analyzed with GC–MS. The results showed that the volume concentration was 6.98ng/m3 with a range from 1.47 to 25.17ng/m3 and PAHs mass were 160.24μg/g (from 63.86 to 427.97μg/g) during the sampling time at Mount Lushan. The dominant compounds are BbF, Pyr and BP. In terms of aromatic-ring PAHs distributions, 4–6-ring PAHs are predominant, indicating that the high-ring PAHs tend to contribute more than low-ring PAHs in particulates. Due to frequent cloud/fog days at Mount Lushan, PAHs concentrations in the PM2.5 were determined before and after cloud/fog weather. The results demonstrated that the cloud/fog and rain conditions cause lower PAHs levels. Regression analysis was used for studying the relationship of PAHs distributions with meteorological conditions like temperature, humidity and wind. The results showed that the temperature and wind speed were inversely related with PAHs concentration but humidity had no significant relationship. Furthermore, backward trajectories and PCA combined with DR (diagnostic ratio analysis) were employed to identify the influences of regional transport and main emission sources. The results revealed that PAHs in PM2.5 were mainly affected by regional transport with the main emissions by mobile vehicle and steel industry, which contributed about 56.0% to the total PAHs in the area of Mount Lushan. In addition, backward trajectories revealed that the dominant air masses were from the northwest accounting for about one third of total PAHs.

Effect of natural antioxidants on inhibition of parent and oxygenated polycyclic aromatic hydrocarbons in Chinese fried bread youtiao

The effects of three natural antioxidants (rosemary extract, tea polyphenol, and antioxidant of bamboo) on the levels of 16 polycyclic aromatic hydrocarbons (PAHs) and five oxygenated PAHs (OPAHs) in typical Chinese fried food youtiao were investigated, with synthesized antioxidant tert-butylhydroquinone (TBHQ) added to the frying oil for comparison. Soybean and palm oils were chosen as frying oils. The antioxidants were added to the frying oil in concentrations of 60, 120, and 180 mg/kg, and PAH and OPAH analysis was performed using GC-MS. Furthermore, the acid value, peroxide value, and polar components were detected to evaluate the antioxidant effect. Compared to samples without added antioxidants, the addition of TBHQ, rosemary extract, tea polyphenol, and antioxidants of bamboo reduced the total PAH and total OPAH concentrations by up to 30.30%, 23.47%, 11.38%, and 28.85%, respectively, for youtiao fried in soybean oil, and by up to 38.94%, 27.56%, 9.45%, and 39.26%, respectively, for youtiao fried in palm oil. The best inhibition was achieved by antioxidant of bamboo, which also showed good performance in slowing youtiao quality degradation. These results could inform good frying practice to improve the quality of fried food with low PAH and OPAH levels, and aid understanding of the new potential benefits of natural antioxidant extracts.

Spatial distributions, source apportionment and ecological risk of SVOCs in water and sediment from Xijiang River, Pearl River Delta.

Xijiang River is an important drinking water source in Guangxi Province, China. Along the Xijiang River and surrounding tributary, the pollution profile of three important groups of semi-volatile organic compounds, including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and phthalate esters (PAEs), was analyzed. Relatively low levels of PAHs (64-3.7×102ngL-1) and OCPs (16-70ngL-1), but high levels of PAEs (7.9×102-6.8×103ngL-1) occurred in the water. Comparatively, low levels of OCPs (39-1.8×102ngg-1) and PAEs (21-81ngg-1), but high levels of PAHs (41-1.1×103ngg-1) were found in sediment. Principal component analyses for source identification indicated petroleum-derived residues or coal and biomass combustion, and vehicular emission was the main sources for PAHs. The OCPs sources of each category were almost independent, whereas the new input of HCHs and p,p'-DDTs probably existed in some areas. PAEs were mainly originated from personal care products of urban sewage, plastic and other industrial sources. Ecological risk through the risk quotient analysis indicated a small or significant potential adverse effect on fish, daphnia and green algae. Nevertheless, the integrated risk of all pollutants should be taken into account in future study.

Polycyclic aromatic hydrocarbons exposure decreased sperm mitochondrial DNA copy number: A cross-sectional study (MARHCS) in Chongqing, China

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that have adverse effects on the male reproductive function. Many studies have confirmed that PAHs preferentially accumulate in mitochondria DNA relative to nuclear DNA and disrupt mitochondrial functions. However, it is rare whether exposure to PAHs is associated with mitochondrial damage and dysfunction in sperm. To evaluate the effects of PAHs on sperm mitochondria, we measured mitochondrial membrane potential (MMP), mitochondrial DNA copy number (mtDNAcn) and mtDNA integrity in 666 individuals from the Male Reproductive Health in Chongqing College Students (MARHCS) study. PAHs exposure was estimated by measuring eight urinary PAH metabolites (1-OHNap, 2-OHNap, 1-OHPhe, 2-OHPhe, 3-OHPhe, 4-OHPhe, 2-OHFlu and 1-OHPyr). The subjects were divided into low, median and high exposure groups using the tertile levels of urinary PAH metabolites. In univariate analyses, the results showed that increased levels of 2-OHPhe, 3-OHPhe, ∑Phe metabolites and 2-OHFlu were found to be associated with decreased sperm mtDNAcn. After adjusting for potential confounders, significantly negative associations of these metabolites remained (p = 0.039, 0.012, 0.01, 0.035, respectively). Each 1 μg/g creatinine increase in 2-OHPhe, 3-OHPhe, ∑Phe metabolites and 2-OHFlu was associated with a decrease in sperm mtDNAcn of 9.427%, 11.488%, 9.635% and 11.692%, respectively. There were no significant associations between urinary PAH metabolites and sperm MMP or mtDNA integrity. The results indicated that the low exposure levels of PAHs can cause abnormities in sperm mitochondria.

Spatial-temporal distributions, sources of polycyclic aromatic hydrocarbons (PAHs) in surface water and suspended particular matter from the upper reach of Huaihe River, China

The spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in surface water from the upper reach of Huaihe River were investigated. The water and suspended particulate matter (SPM) samples from 16 sites were collected during three sampling cruises. The concentrations of ΣPAHs ranged from 79.94 to 421.07ng/L with the average values of 140.37ng/L in water and from 10.87 to 201.42ng/L with the average values of 61.23ng/L in SPM. In comparison to survey during March 2007, alleviated PAHs pollution was ascribed to the adjustment of energy structure. LMW PAHs (2- and 3-ring) were abundant in water and SPM samples with high detection frequencies. Seasonal variations of PAHs indicated that high concentrations of PAHs were recorded in the dry period (67.47–560.16ng/L) and low levels of PAHs were detected in the flood period (27.87–458.47ng/L) in water, while the high concentration of PAHs in SPM ranged from 4.14 to 342.32ng/L in the dry period and low concentration from 2.42 to 129.23ng/L in the level period. In situ water-SPM phase distribution revealed that PAHs tended to be transported with water phase in the studied area. Ratios of specific PAHs were calculated to evaluate the possible sources of PAHs contamination, which reflected PAHs in water and SPM derived from the mixed of pyrogenic and petroleum origins in different seasons.