Total Amount Of Polycyclic Aromatic Hydrocarbons Research Articles

Preliminary study for Polycyclic aromatic Hydrocarbons mobilization from contaminated marine sediment using synthetic and natural surfactants

The persistent presence of Polycyclic Aromatic Hydrocarbons (PAHs) in soils and sediments due to their chemical properties requires new methods to mobilize and make them more available for remediation purposes. In this work, the evaluation of the abilities of eight different non-ionic sugar-based and totally biodegradable surfactants, such as synthetic alkyl polyglycosides (APGs), biological sophorolipids (SLs) and biological rhamnolipids (RLs), was conducted in order to provide a preliminary guideline for the selection of the surfactant and the technical approach for PAHs extraction from the sediment. The reference sample was a marine sediment collected from Bagnoli (Naples, Italy) that was characterized to evaluate the level of PAHs contamination, which resulted equal to 3.51 g Kg−1 of total PAHs in the sediment. By using surfactants solutions with a surfactant concentration five times greater than critical micelle concentration (Cs = 5x CMC), a preliminary washing test in batch configuration was conducted, then followed by multiple consecutive washes (MCW) of the sediment to assess the solubilization of PAHs from the sediment by the action of selected surfactants. The results show an evident advantage given by the employment of each studied surfactant in mobilizing PAHs, compared to distilled water as benchmark. In detail, the synthetic alkyl polyglycosides APG2 led to a 3.4 % of total PAHs mobilization in the preliminary washing test with a maximum peak of 9.8 % for a single compound. The MCW test demonstrates that more consecutive washes can increase the amount of total PAHs removed, with a similar contribution from each wash, and that biosurfactants can be more attractive after several washes thanks to the increased capacity of PAHs mobilization. Interestingly, the high efficiency of surfactant to mobilize PAHs makes the soil washing a more attractive technology for removing PAHs from the marine sediments.

Sediment records and multi-media transfer and fate of polycyclic aromatic hydrocarbons in Dianchi Lake over the past 100 years

This study analyzed the fate and transfer of PAHs through multiple media in Dianchi Lake and the sediment records of polycyclic aromatic hydrocarbons (PAHs) in sediments. The model simulation results showed the simulated concentrations to be in good agreement with the measured values. The concentration and total amount of PAHs were the highest in the sediment, which is an important sink for PAHs in lake systems. The main transport direction of the PAHs in the three phases was from the atmosphere to the water to the sediment. Advection and emission inputs were the primary input pathways for PAHs in the atmosphere, and advection output was the main removal path. The main input sources pathways for PAHs in sediments was the sedimentation of particulate matter in water, with diffusion and degradation being the primary methods of removal. Advection and atmospheric dry and wet deposition were the main sources of PAHs in water, with particulate deposition being the primary removal process. The range of PAHs was 336–3520 ng/g in sediments in Dianchi Lake, with an average of 1569 ng/g, peaking in 2012. Among the predicted future PAH concentrations in the sediments under the five shared socioeconomic pathways (SSPs), the lowest PAH concentration was found under SSP3 from 2025 to 2035, whereas the lowest PAH concentration was found under SSP4 from 2035 to 2050. In the sustainable path of SSP1, although the concentration of PAH pollutants showed an increasing trend in the short term, the increase in PAHs concentration in sediments slowed in the long run.

Polycyclic aromatic hydrocarbons and petroleum products in soil samples of urban areas in Eastern Siberia

Introduction. In industrial cities, the problem of environmental pollution by supertoxicants, which include the class of polycyclic aromatic hydrocarbons (PAHs), is especially acute. Since among PAHs there are substances that have a carcinogenic effect, their quantitative identification in environmental objects is an urgent task.
 Materials and methods. The content of PAHs and petroleum products (PP) in the soil of an industrial city, taken in various functional zones, was studied. Determination of sixteen PAHs was carried out by gas chromatography-mass spectrometry (GC-MS) with optimized sample preparation. It is proposed to determine PAHs by GC-MS using dispersive liquid-liquid microextraction (DLLME). Petroleum products (PP) were determined by the fluorimetric method.
 Results. Total PAHs content (ΣPAH) varied from 7.50 to 319.11 µg/kg. ΣPAH-carcinogens in the residential and sanitary protection zones was on average 25.1–31.2 times higher than in the background site. PP content levels in urban soils ranged from 3.0 to 62.4 mg/kg.
 Limitations. The study is limited to the study of the upper layers of soil up to 5 cm. The possibility of PAH migration into groundwater has not been studied.
 Conclusion. The structure of PAHs was dominated by 4-6-nuclear structures: dibenz(a,h)anthracene, benzo(g,h,i)perylene, fluoranthene, benzo(b)fluoranthene, etc., making up > 87% of the total amount of PAHs. The proportion of these polyarenes in the total ΣPAH in the residential area increases by 1.3 times compared to the background, which indicates the possibility of their technogenic origin. The PAH and PP indicators are characterized by a scatter of data and, as a result, 
 a large influence of the local factor on the formation of soil cover pollution.

Increased concentration of PAH derivatives in biochar-amended soil observed in a long-term experiment

During biochar preparation or application some toxic substances may be formed. The established limitations of the content of polycyclic aromatic hydrocarbons (PAHs) aim to monitor the fate of PAHs in the life cycle of biochar. The latest studies have revealed that besides PAHs, some of their derivatives with confirmed toxicity are formed. There has been no policy regards PAH derivatives in biochar yet. The aim of the presented studies was the estimation the changes in the content of PAHs and their derivatives during the agricultural application of biochar. A pot experiment with grass revealed that in a short time, both the content of PAHs and their derivatives was reduced. Similarly, when biochar was added to soil in a long-term experiment, the content of determined derivatives was below the limit of detection, whereas interestingly, the content of pristine PAHs increased with time. Co-addition of biochar and sewage sludge increased the content of PAHs and their derivatives indicating potential environmental hazard due to their presence. However, the key point is the estimation of the bioavailability of PAHs and their derivatives as only the bioavailable fraction is revealing the environmental hazard.

Levels and risk assessment of polycyclic aromatic hydrocarbons, acrylamide and 5-hydroxymethylfurfural in yerba mate and its infusions

The occurrence and the risk of exposure to acrylamide (AA), 5-hydroxymethylfurfural (HMF) and polycyclic aromatic hydrocarbons (PAHs) in yerba mate leaves and infusions have been evaluated. The AA and HMF content have been examined for the first time, as most articles have focused only on PAHs occurrence or pro-healthy benefits of yerba mate. The results showed that acrylamide was detected in all samples, in the range 20–243 μg/kg, with the significantly lower amounts in the samples from Paraguay, and the highest from Argentina. HMF was found in 26 samples of 30, up to 466 mg/kg. The infusion transfers of acrylamide and HMF were higher than 21%, reaching even 77%. The total PAH amount in the leaves varied from 289 to 10643 μg/kg, and ƩPAH4 13-1871 μg/kg. The Brazilian samples contained significantly lower total PAH content than the Argentinian and Paraguayan samples. The transfer ratio from leaves to infusions was below 12 and 2.1% for total PAHs and PAH4. The results of multivariate method of analysis (Principal Component Analysis and Hierarchical Cluster Analysis) showed that yerba mate from Brazil and from Paraguay had their own specific features probably resulting from the method of thermal processing of the leaves. Finally, the calculated MOE values for all contaminants indicated a low level of concern for human health, which suggests that moderate consumption of yerba infusions should not pose a threat to human health.

Variability in Water Capacity of Small-Leaved Linden Associated with Both the Presence of Honeydew and Various Sources of Pollution.

The process of water retention on the surface of the assimilation apparatus of plants is inextricably linked with the water capacity of tree crowns and depends mainly on the condition of the leaf itself. The main objective of the present study was to investigate how the honeydew coverage and the location of trees related to the content of polycyclic aromatic hydrocarbons affected the differences in the capability of small-leaved linden leaves to capture water. Honeydew coverage was determined with the use of AutoCAD, whereas the content of polycyclic aromatic hydrocarbons was determined using gas chromatography. The value of S (water capacity) was much lower before the appearance of honeydew on the leaf than at the peak moment of honeydew collection. This is due to the hydrophobic properties of the substance. It was also found that the content of polycyclic aromatic hydrocarbons (PAH) in leaves varied depending on the distance of trees from pollution sources, and it was found that the amount of PAHs increased with the growth of honeydew on leaves and in locations exposed to pollution. The highest S and the total amount of PAHs occurred with the combination of the largest amount of pyrogenic impurities with the highest amount of honeydew. Combing pollutants from the air by plants is a very important function, but it may also change the physical properties of leaves, such as wettability.

Total and bioavailable polycyclic aromatic hydrocarbons in unused and operated heat-not-burn tobacco products and conventional cigarettes

Tobacco product waste poses a global environmental issue, affecting urban and coastal areas alike. The present studies report, for the first time, the total and bioavailable polycyclic aromatic hydrocarbons (PAHs) concentrations in unused and operated heat-not-burn (HnBs) tobacco products. To enable direct comparisons, identical sets of studies were conducted using conventional cigarettes (CCs). Five low-molecular PAHs were determined in HnBs at total concentrations that were of the same order before and after operation (Σ5PAH = 47.37 ± 3.44 ng unit−1 and Σ5PAH = 69.36 ± 5.78 ng unit−1 in unused and used HnBs, respectively). The incomplete combustion of organics during smoking of CCs, yielded substantially higher amounts of PAHs with their sum (Σ10PAHs = 1449 ± 113 ng unit−1) being >20 times larger than those in HnBs. The tobacco and filter were the most contaminated parts in HnBs. In unused CCs, tobacco had the highest PAHs load and after smoking, the spent filter was the most contaminated part, containing ∼80% of the total amount of PAHs. Naphthalene was the most abundant PAH detected in all tobacco products. Despite the high total PAH concentrations found in smoked CCs, the sums of the bioavailable PAH concentrations were of the same order in all tested tobacco products (Σ5PAH = 61.38 ± 1.79 ng unit−1 in unused HnBs, Σ5PAH = 70.87 ± 7.67 ng unit−1 in used HnBs, Σ4PAH = 66.92 ± 5.95 ng unit−1 in unused CCs, and Σ6PAH = 47.94 ± 1.26 ng unit−1 in smoked CCs). This finding was related to smoking affecting PAHs’ leachability from CCs and delaying their desorption from the solid matrix. Adjusting the pH, salt and humic acids content at environmentally relevant values did not affect PAHs leaching at 24 h of soaking. Finally, the leaching behavior of PAHs in natural waters (river water, rainwater, and seawater) was found similar to that in ultrapure water, experimentally verifying the ability of tobacco product waste to leach PAHs into the aquatic environment.

Contamination and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons in Seasoning Flour Products in Hunan, China.

Polycyclic aromatic hydrocarbons (PAHs) are persistent organic pollutants with carcinogenic, teratogenic, and mutagenic effects. Dietary intake is one of the significant exposure pathways of PAHs. In this study, gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) was used to detect 16 priority PAHs listed by the United States Environmental Protection Agency (USEPA) in seasoning flour products distributed in Hunan Province. The consumption of seasoning flour products by the Hunan population was investigated by questionnaire. The results showed that the detection rate of PAHs in seasoning flour products in Hunan Province was 92.41%. Among them, benzo[a]anthracene (BaA), phenanthrene (PHE), fluoranthene (FLA), and chrysene (CHR) were dominant. The total PAHs and benzo[a]pyrene (BaP) contents of soggy seasoning flour product samples were higher than those of crisp samples and chewy samples. The total amount of PAHs in rod-shaped and flaky samples were higher than that in filamentous and granular samples. The margin of exposure (MOE) values of various seasoning flour products and all age groups (children, adolescents, and adults) was much more significant than 10,000. Moreover, the incremental lifetime of cancer risk (ILCR) values of all age groups were below 1 × 10-5. The above results indicate that PAHs in seasoning flour products have a relatively low health risk for the Hunan population. Still, it is recommended that susceptible populations (children, adolescents, etc.) should control their intake of flour products.

Effectiveness of dermal cleaning interventions for reducing firefighters’ exposures to PAHs and genotoxins

Firefighters are exposed to carcinogenic and mutagenic combustion emissions, including polycyclic aromatic hydrocarbons (PAHs). Fire service and firefighter cancer advocacy groups recommend skin cleaning using wipes or washing with detergent and water after exposure to smoke, although these strategies have not been proven to reduce exposures to harmful combustion products such as PAHs. This study assessed dermal decontamination methods to reduce PAH exposures by firefighters participating in live fire training scenarios. Study participants (n = 88) were randomly assigned to an intervention group (i.e., two types of commercial skin wipes, detergent and water, or a control group who did not use any skin decontamination). PAHs were measured in personal air (during the fire) and dermal wipe samples (before and after fire suppression and after dermal decontamination). PAH metabolites and mutagenicity were measured in urine samples before and after fire suppression. Airborne PAH concentrations during the fire ranged between 200 and 3,970 μg/m3 (mean = 759 μg/m3, SD = 685 μg/m3). Firefighters had higher total PAHs and high-molecular-weight PAHs on their skin after the fire compared to before (1.3- and 2.2-fold, respectively, p < 0.01). Urinary PAH metabolites increased significantly following exposure to the training fires by 1.7 to 2.2-fold (depending on the metabolite, p < 0.001). Urinary mutagenicity did not differ significantly between pre- and post-fire for any of the decontamination methods. Detergent and water was the only intervention that removed a significant amount of total PAHs from the skin (0.72 ng/cm2 preintervention vs. 0.38 ng/cm2 postintervention, p < 0.01). However, fold changes in urinary PAH metabolites (i.e., pre- vs. post-exposure levels) did not differ among any of the dermal decontamination methods or the control group. These data suggest that despite on-site attempts to remove PAHs from firefighters’ skin, the examined interventions did not reduce the internal dose of PAHs. Future work should investigate preventing initial exposure using other interventions, such as improved personal protective equipment.

Oxidative stress generated by polycyclic aromatic hydrocarbons from ambient particulate matter enhance vascular smooth muscle cell migration through MMP upregulation and actin reorganization

BackgroundEpidemiological studies have suggested that elevated concentrations of particulate matter (PM) are strongly associated with the incidence of atherosclerosis, however, the underlying cellular and molecular mechanisms of atherosclerosis by PM exposure and the components that are mainly responsible for this adverse effect remain to be established. In this investigation, we evaluated the effects of ambient PM on vascular smooth muscle cell (VSMC) behavior. Furthermore, the effects of polycyclic aromatic hydrocarbons (PAHs), major components of PM, on VSMC migration and the underlying mechanisms were examined.ResultsVSMC migration was significantly increased by treatment with organic matters extracted from ambient PM. The total amount of PAHs contained in WPM was higher than that in SPM, leading to higher ROS generation and VSMC migration. The increased migration was successfully inhibited by treatment with the anti-oxidant, N-acetyl-cysteine (NAC). The levels of matrix metalloproteinase (MMP) 2 and 9 were significantly increased in ambient PM-treated VSMCs, with MMP9 levels being significantly higher in WPM-treated VSMCs than in those treated with SPM. As expected, migration was significantly increased in all tested PAHs (anthracene, ANT; benz(a)anthracene, BaA) and their oxygenated derivatives (9,10-Anthraquinone, AQ; 7,12-benz(a)anthraquinone, BAQ, respectively). The phosphorylated levels of focal adhesion kinase (FAK) and formation of the focal adhesion complex were significantly increased in ambient PM or PAH-treated VSMCs, and these effects were blocked by administration of NAC or α-NF, an inhibitor of AhR, the receptor that allows PAH uptake. Subsequently, the levels of phosphorylated Src and NRF, the downstream targets of FAK, were altered with a pattern similar to that of p-FAK.ConclusionsPAHs, including oxy-PAHs, in ambient PM may have dual effects that lead to an increase in VSMC migration. One is the generation of oxidative stress followed by MMP upregulation, and the other is actin reorganization that results from the activation of the focal adhesion complex.

Polycyclic aromatic hydrocarbons (PAHs) in Greater Cairo water supply systems.

Polycyclic aromatic hydrocarbons (PAHs) pose a constant threat to the environment and public health. There are numerous activities in the Greater Cairo area that emit and release significant amounts of PAHs. Concentrations of these PAHs are released into the air and mixed with surface water, limiting its use. In this study, 17 PAH compounds are mapped at eight sites along the Nile River and its tributaries in Greater Cairo. In addition, their removal efficiency is evaluated with the conventional treatment in eight water treatment plants. PAHs were analyzed using GC-MS from January to December 2018. Naphthalene, anthracene, fluorene, pyrene, and phenanthrene were detected. The total amount of PAHs in raw water was highest in Shamal Helwan (1,325 ± 631 ng/l) and lowest in Mostorod (468 ± 329 ng/l), and the removal ranged from 25 to 31%. Further research is needed to integrate other techniques to reduce PAHs using the conventional treatment, and more efforts should be made to reduce the presence and release of PAHs in raw water.

A Thorough Study for PAHs in Dump Materials from Open-pit Lignite Mining, Maritsa Iztok Basin, Bulgaria

Polycyclic aromatic hydrocarbons (PAHs) in six samples from Bulgarian Lignite Dumps Maritsa Iztok are tracked and amounts are determined. For isolation of soluble organic matter (SOM) ca: 40 g of powdered dump samples were Soxhlet extracted by chloroform. After asphaltenes precipitation, maltenes were separated via column chromatography. The first two fractions were further analyzed. Gas chromatography-mass spectrometry (GC-MS) was applied to appreciate organic matter sources and to identify and quantify PAHs in the samples. The set of PAHs determined pointed out that 3 and 4 ring unsubstituted PAHs as dominant in the dump extracts. Total organic carbon (TOC) values of the samples varied in the range 1.18-5.63 wt.%. Phenanthrene + Methylphenanthrene amounts were in the range 0.44-2.98 mg/kg TOC, while for Fluoranthene + Pyrene were in the range 0.06-0.52 mg/kg TOC. Total amounts of PAHs varied in the range 7-41 microg/kg sample. Values were compared with the legislation norms for PAHs in soils. All magnitudes were under the regulation norms for harmful substances in soil published by the Bulgarian National Legislation (2008). In conclusion, the study is in an equivocal proof for the negligible amounts of PAHs in dump materials from Maritsa Iztok lignite mining. However, their amounts in dumps should be measured and monitored bearing in mind the huge territories covered by these waste materials of mining industry.

Effects of fuel-bound methyl groups and fuel flow rate in the diffusion flames of aromatic fuels on the formation of volatile PAHs

Aromatic hydrocarbons constitute a significant fraction of fossil-derived transportation fuels. They are also used as additives to suppress autoignition and to increase fuel energy density. However, they produce harmful polycyclic aromatic hydrocarbons (PAHs) and soot during combustion. In this work, the effects of methyl group(s) and the flow rate of aromatic fuels (benzene, toluene, and m-xylene) on the concentration of volatile PAHs bound to soot formed in diffusion flames are studied. Soxhlet extraction using dichloromethane as the solvent is used to extract PAHs from soot particles collected from the flames of aromatic fuels. The extracts are analyzed using a gas chromatograph coupled to a mass spectrometer. Among the sixteen priority PAHs, fifteen of them are detected on soot particles along with benzo(e)pyrene and other organic compounds such as oxygenated compounds and mono-aromatic hydrocarbons. The PAHs containing two to three aromatic rings were found to be in higher concentrations than those with four or more rings. The total amount of PAHs collected at different fuel flow rates from the three aromatic fuels increased marginally in the following order: benzene < toluene < m-xylene. With increasing fuel flow rate, while the soot emission increased drastically, the concentration of volatile PAHs increased nearly linearly at a very slow rate. The toxicity of soot particles from different flames with increasing fuel flow rate is also reported.

Contamination of Scots pine forests with polycyclic aromatic hydrocarbons on the territory of industrial city of Siberia, Russia.

Anthropogenic contamination with polycyclic aromatic hydrocarbons (PAH) coming from a powerful aluminum smelter has been estimated by the accumulation of these substances (17 substances: phenanthrene, fluoranthene, pyrene, chrysene, acenaphthylene, acenaphthene, anthracene, fluorene, benz[а]anthracene, benz[b]fluoranthene, benz[k]fluoranthene, benz[а]pyrene, benz[е]pyrene, perylene, indeno[1,2,3-c,d]pyrene, benz[g,h,i]perylene, dibenz[a,h]anthracene) in needles of Scots pine (Pinus sylvestris L.) in the residential areas of Bratsk, East Siberia, Russia. It has been found that the total PAH amount reaches the maximum values (982ng/g) in the needles of trees growing in a residential zone, remote from the smelter up to 10km (Central Urban District), where more than half of the city's population lives. On the territory remote up to 25km (Padunsky District), PAH needle levels decline, but are still 14.5-17.5 times higher than the background ones and at a distance of 45km (Pravoberezhny District), they still exceed background levels (30ng/g) by 4.7-8.1 times. Qualitative analysis of PAH showed the prevalence (up to 90% of the total amount) of 3-4 ring PAHs in pine needles on the entire studied territory. PAH concentrations increase when approaching the smelter with the highest values in the Central City District. Within the urban area, the content of PAHs with 5-6 rings (benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene (B[a]P), benz[a]anthracene, dibenz[a,h]anthracene, indeno[1,2,3-c,d]pyrene, benzo[g,h,i]perylene) is also significantly increased. In the Central District, needle concentration of B[a]P, which is a class 1 carcinogen, exceeds the background one by 22 times, the Padunsky District-by 7 times, and the Pravoberezhny District-by 3 times. In the territories of the Central Districts, needle level of perylene, which is a marker of territory pollution by aluminum smelter emissions, is 18 times, the Padunsky District-by 10 times, Pravoberezhny District-by 2.5-3 times higher than in the background, where the perylene level is below the detection limit (< 0.2ng/g).

Declining Pulmonary Function in Populations with Long-term Exposure to Polycyclic Aromatic Hydrocarbons-Enriched PM2.5.

This study assesses the effects of long-term exposure to ambient air pollutants on inflammatory response and lung function. We selected 390 male coke oven workers with exposure to polycyclic aromatic hydrocarbons (PAHs) and fine particulate matter (PM2.5) and 115 control workers. The average duration in the exposed group was 9.10 years. The total amount of PAHs was more enriched in PM2.5 which collected from the coke oven workshops compared with the control areas. Correspondingly, the internal PAHs exposure indicated by urinary 1-hydroxypyrene (1-OHP) in the exposure group increased 25.7-fold compared to that of the control group. Moreover, the increasing level of urinary 1-OHP was associated withthe decrease of forced expiratory volume in 1 s to forced vital capacity ratio (FEV1/FVC). In non-current smokers of exposure group, inverse correlation of 1-OHP with FEV1/FVC was also found. Particularly, an exposure duration-dependent decline in FEV1/FVC and mean forced expiratory flow between 25% and 75% of forced vital capacity (FEF25-75%) indicated that small airways were functionally obstructed. Furthermore, the increasing serum high-sensitivity C-reactive protein (hs-CRP) was correlated with the decline in pulmonary function in all subjects. These findings provide a clue that long-term exposure to PAHs-enriched PM2.5 impairs pulmonary function in occupational population.

Pollution, source apportionment and health risk of potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) in urban street dust of Mashhad, the second largest city of Iran

Street dust samples from industrial, residential and heavy density traffic areas in Mashhad metropolis were collected to study the mineralogy, distribution, accumulation, health risk assessment and probable sources of potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs). Also, the oral bioaccessibility of PTEs using a simple bioaccessibility extraction test (SBET) was investigated. X-ray diffraction analysis of dust samples showed that the mineralogy of dust is dominated by quartz (also α-quartz), calcite (also Mg-calcite), and dolomite. Calculation of geoaccumulation index indicated that the dust is much enriched in Hg, Pb, Zn, Cu, Sb and Cd. Combined multivariate statistical and geochemical methods successfully differentiated the anthropogenic PTEs from natural ones. Zn, Hg, Pb and Cu showed high bioaccessibility. Moreover, carcinogenic and non-carcinogenic effects of PTEs due to exposure to urban street dust were assessed for both children and adults. It is found that the total amount of PAHs (∑16 PAHs) varied from 764 to 8986.7 μg/kg, with the most serious species being 4-ring PAHs. Molecular indices and ring classes indicated that the sources of PAHs were both petrogenic and pyrogenic. The incremental lifetime cancer risks of exposure to dust PAHs for children and adults living in the study area were 7 × 10−4 and 6.2 × 10−4 respectively, indicating a high potential carcinogenic risk.

Comprehensive assessment of the content of polycyclic aromatic hydrocarbons and dependence of their accumulation in meat products

Dependences of the quantity of polycyclic aromatic hydrocarbons (PAH) on the conditions for the formation of components of smoke compositions, the type of wood, the formulation, the technology of production, and the type of packaging material have been studied. An increase in temperature from 450 to 700 °C lead to a 2-3-fold increase in the amount of PAH in meat products. It has been established that the use of a polyamide coating reduced the total carcinogenicity of sausages by 2.0-3.7 fold compared with protein and natural shells, which in terms of PAH accumulation were the most dangerous. Fibrous shell was able to provide a reduction in PAH level in the product up to 40% compared to natural one. The permeability of the fat fraction of the product for PAH was up to 10 fold higher than that of proteins and carbohydrates. The data obtained made it possible to determine the safety criteria for smoked meat products, taking into account the potential carcinogenic hazard of each PAH. The optimal indicators of the presence of PAH in the product are 8 PAH (benz[a]pyrene, chrysene, benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[g,h,i]perylene, dibenz[a,h]anthracene, indeno[1,2,3-c,d] pyrene). The PAH exposure on the human body has been determined under the constant consumption of smoked meat products. The prospective use of barrier protection technologies, substances possessing antiradical activity, and protective films to reduce residual PAH content has been proved. The results of the studies showed a 5-fold decrease in the total amount of PAH when using films impregnated with fat-containing micro anemulsion of vegetable or animal fat. The effect increased when meat was marinateв in a 9% solution of acetic acid or 3% solution of ascorbic acid.

Emissions of polycyclic aromatic hydrocarbons during biomass combustion in a drop tube furnace

The objective of this work is to investigate experimentally the formation of polycyclic aromatic hydrocarbons (PAH) during the combustion of biomass in a drop tube furnace (DTF). A number of biomass fuels, including furniture residues, grape pomace, kiwi residues, olive residues, wheat straw, rice husk and platanus residues were used in this work, with the tests performed at three temperatures (900, 1000 and 1100°C). The solid fuels feed rate was 23g/h and the total air flow rate was 4L/min, ensuring a residence time in the DTF of around 2s. In order to collect the PAH in the effluent gas, a narrow tube containing XAD-2 resin was connected to the flue gas duct of the DTF. A quartz fiber filter was placed just before it to collect the particulate matter, including soot, present in the flue gas. The analysis and quantification of the PAH combined Soxhlet extraction and gas chromatograph-mass spectrometer. Flue gas concentrations of O2, CO2, CO, hydrocarbons and NOx were measured to gather information regarding the combustion conditions. The results showed two distinct features for the variation of the total PAH emissions: one decreasing with temperature and other with a maximum at 1000°C. Grape pomace, kiwi residues and platanus residues presented the lowest PAHs emission (20.8–54.2mgPAH/kg fuel). A direct relation between the total amount of PAHs and the toxic equivalency value was found.

Seasonal variations of metal pollution and distribution, sources, and ecological risk of polycyclic aromatic hydrocarbons (PAHs) in sediment of the Al Hawizah wetland, Iran

ABSTRACTThe pollution of surface sediments of Al Hawizah wetland by metals and polycyclic aromatic hydrocarbons (PAHs) has been fully investigated. For determination of PAHs and metals concentration in sediments, eight sampling stations were selected in the study area. The results showed that the concentration of Mn is the highest, while the content of Cr is the lowest in both the seasons. The concentration of Cr and V is lower than mean crust content, while Cu concentration is more than mean crust content. The results obtained from Muller's geochemical index are indicative of range from uncontaminated to moderately contaminated. Based on potential ecological risk (RI), the Al Hawizah wetland had low ecological risk. The total PAHs concentrations ranged from 1071 to 15540 ng/g dry weight, with a mean of 9417.50 ng/g in the summer, while total amounts of PAHs in the winter ranged from 1542 to 17283 with a mean 10321.25 ng/g dry weight. The area of study was affected by pyrogenic and petrogenic sources (51.74 and 48.26%, respectively), in the winter. The concentrations of polycyclic aromatic hydrocarbons (PAHs) compounds were lower than effects range median (ERM) standard while were higher than effects range low (ERL) standard, except station 1, in both seasons.

Evergreen or deciduous trees for capturing PAHs from ambient air? A case study

Tree canopies play a key role in the cycling of polycyclic aromatic hydrocarbons (PAHs) in terrestrial ecosystems, as leaves can capture PAHs from the air. In this study, accumulation of PAHs was compared in an evergreen species, P. pinaster, and in a deciduous species, Q. robur, in relation to some physio-morphological characteristics. For this purpose, pine needles and oak leaves collected from different sites across Galicia (NW Spain) were analysed to determine PAH contents, specific leaf area, stomatal density and conductance.Leaves and needles contained similar total amounts of PAHs. The major contribution of particle-bound PAHs in oak (the concentrations of 4- and 5-ring PAHs were two times higher, and those of 6-ring PAHs five times higher in oak than in pine) may be related to the higher specific leaf area (13 and 4 cm2 g−1 dry mass in respectively oak and pine). However, the major contribution of vapor-phase PAHs in pines may be affected by the stomatal conductance (two times higher in pine than in oak). Moreover, an increase in the diameter at breast height of trees led to an increase in accumulation of PAHs, with pine capturing higher amounts of low and medium molecular weight PAHs. The study findings underline the potential role of trees in improving air quality, taking into account the canopy biomass and life cycle.