US EPA Polycyclic Aromatic Hydrocarbons Research Articles

Polycyclic aromatic hydrocarbons in sewage-irrigated vegetables from industrial cities in Haryana, India.

The majority of Indians consume a lot of vegetables because of their health advantages. High concentrations of polycyclic aromatic hydrocarbons (PAHs) in vegetables may be seriously harmful to consumers' health. The method for identifying and measuring 16 USEPA polycyclic aromatic hydrocarbons (PAHs) in samples of sewage-irrigated vegetables from three industrial cities in Haryana, India, is described in this research. Ultrasonication, liquid-liquid extraction using n-hexane as a solvent, clean-up using a Florisil column, and reversed-phase high-performance liquid chromatography with a UV detector were all included in the process. The PAHs were successfully linearized (R2 > 0.99) at various doses. Results for PAH recovery ranged from 90 to about 100%. The limit of quantification was 0.002-0.580, and the limit of detection was 0.0006-0.174 µgkg-1. Data indicated that the highest mean concentrations of ∑16 PAHs were detected in Spinach (123.36 µgkg-1), in carrot (105.09 µgkg-1), and in cucumber (63.40 µgkg-1) among leafy, underground, and fruity vegetables, respectively.

Pollution level, source, and health risk assessment of PAHs in food products and environmental media in Nantong, China: A pilot case

The following study is an analysis of the pollution characteristics, dietary intake levels, and health effects of 16 polycyclic aromatic hydrocarbons (PAHs) in vegetables, fruits, and meat products in Nantong City, China. The PAHs content, pollution level, carcinogenic risk, and correlation of soil and local atmospheric environment in the crop irrigation area were determined. A total of agricultural products (n = 42), soil samples (n = 18), and air samples (n = 42) were freshly collected from selected irrigation areas in Nantong to detect the content of 16 US EPA PAHs. The total contents of PAHs in vegetables, fruits, and meat products were 16.4 − 136.5 ng/g, 86.0 − 225.1 ng/g, and 0.1 − 23.4 ng/g, respectively. Phe (32.00 −37.24%) and Pyr (27.25 −28.79%) were two PAHs with the highest pollution. The total contents of 16 PAHs in both soil and air were 31.5 − 288.2 ng/g and 1.08 − 28.85 ng/m3, respectively. The single PAHs with the highest pollution were BaP (36.48%) and Flu (21.45%). The characteristic ratio analysis method was used to trace the source of PAHs. Accordingly, PAHs in the three types of food sources primarily originated from the burning of coal, oil or biomass, and was consistent with the air or soil pollution sources. The total exposure to PAHs in vegetables, fruits, and meat products was 18.81 − 66.82 ng/d, 5.69 − 8.62 ng/d, and 0.82 − 2.45 ng/d, respectively. The lifetime incremental carcinogenic risk was 4.20 × 10−7 − 6.41 × 10−6, 1.0 × 10−7 − 7.8 × 10−7, and 1.9 × 10−8 − 2.0 × 10−7, which corresponds to a relatively low−risk level. In comparison, the total exposure of soil and air were 4.15 × 10−7 − 1.54 × 10−6 mg·kg−1·d−1 and 2.71 × 10−6 − 1.40 × 10−5 mg·kg−1·d−1, respectively, and the non−carcinogenic and carcinogenic risk of soil were 3.07 × 10−5 − 1.21 × 10−4 and 1.09 × 10−8 − 3.98 × 10−8, respectively. The carcinogenic risk of air was 8.42 × 10−6 − 4.35 × 10−5, indicating that the risk of cancer is within the acceptable range; however, it cannot be ignored.

Polycyclic aromatic hydrocarbons including dibenzopyrenes in indoor air samples from schools and residences in Germany

Polycyclic aromatic hydrocarbons (PAH) are several hundred organic substances that are formed in the course of incomplete combustion of organic material. Of particular importance are the carcinogenic effects of PAH. Various dibenzopyrenes as well as benzo[c]fluorene (BcFl) seems to have a particular toxicological potency, which have hardly been investigated in indoor air so far.Therefore, the indoor air samples of 27 classrooms and 35 central living spaces of residences in Germany were collected to analyze 56 particle-bound PAH as well as naphthalene (Nap).The PM10 values in schools and residences ranged between 9.1 and 210 μg/m³ (mean: 93.4 μg/m³) and from 3.6 to 52.0 μg/m³ (mean: 12.0 μg/m³), respectively. For the sum of the 16 priority US EPA PAH (except acenaphthylene and naphthalene) means (95th percentiles) in classrooms and residences were 1.20 ng/m³ (2.77 ng/m³) and 0.84 ng/m³ (2.64 ng/m³), respectively. Higher values were observed for naphthalene with mean concentrations of 596 ng/m³ (2,800 ng/m³) in classrooms and 243 ng/m³ (530 ng/m³) in residences.For classrooms and residences mean concentrations of 8.3 pg/m³ and 7.4 pg/m³ for dibenzo[a,l]pyrene (DBalPyr), 16.4 pg/m³ and 11.9 pg/m³ for dibenzo[a,e]pyrene (DBaePyr), 9.2 and 5.7 pg/m³ for dibenzo[a,h]pyrene (DBahPyr), and 6.4 and 4.2 pg/m³ for BcFl were observed, respectively, while DBaiPyr was found in only one sample above LOD.The BaPeq (benzo[a]pyrene equivalents) for the sum of 20 PAH is on average 482 pgTEQ/m³ (schools) and 393 pgTEQ/m³ (residences), which corresponds to an incremental lifetime cancer risk to 42 × 10−6 and 34 × 10−6.Although dibenzopyrenes and BcFl are found only in very low concentrations in indoor air, they have a significant impact on the risk if the assumptions about the toxicological potency of this group turn out to be valid.

Synergistic cancer risk assessment from PM1 bound metals and PAHs in the Indo-Gangetic Region

The atmospheric particulate matter (PM) contains a significant amount of human carcinogens such as metals and Polycyclic Aromatic Hydrocarbons (PAHs). Previous studies have clearly shown that these carcinogens pose serious health issues due to the inhalation of particulate matter. Since the synergistic roles of these carcinogens are rarely considered, these studies frequently underestimate the health risk to humans. The current research aims to bridge this information gap by estimating the synergistic carcinogenic risk assessment owing to PM1 bound metals and PAHs across the densely populated Indo-Gangetic Plain (IGP). The carcinogenic risk assessment was conducted in accordance with the USEPA guidelines on these various PM1 bound components. The Incremental Lifetime Cancer Risk (ILCR) due to heavy metals, such as Lead (Pb) and Chromium (Cr), was found beyond the acceptable limit (> 10−4). The risk due to PM1 bound USEPA PAHs was also significantly higher (> 10−5). This study further estimated the potential toxicity from broad domain of environmental PAHs present in ambient air by considering relevant estimation factors from existing literature. The projected risk from these diverse environmental PAHs was of the order 10−4. Further, source identification of PAHs based on diagnostic isomer ratios revealed that diesel exhaust, biomass burning, and coal combustion are the dominant PAHs sources. Moreover, the exposure to these pollutants is higher in winter and post-monsoon periods. Overall, the synergistic carcinogenic risk found from metals and PAHs was of the order 10−3. In a nutshell, inhalation of PM1 bound heavy metals and PAHs at IGP can result in the development of 1000 cancer cases per million population, which is the highest value compared to other parts of the world. The present study demands immediate policy interventions not only for the reduction of particulate pollution, but also for the reduction of carcinogenic species from the ambient air in order to improve human health.

Preliminary investigation of polycyclic aromatic hydrocarbons (PAHs) concentration, compositional pattern, and ecological risk in crude oil-impacted soil from Niger delta, Nigeria

Crude oil contamination could serve as an important source of polycyclic aromatic hydrocarbons (PAHs) in the environment. Determining the concentration and distribution of PAHs and their ecological risk could provide clues for appropriate remediation. The present study investigated the concentrations, composition pattern, and ecological risk of PAHs in crude oil-contaminated soil collected from the Niger Delta, Nigeria. The concentrations of Σ29PAHs and 16 priority US-EPA PAHs (Σ16PAHs) in the soil ranged from 24230.68 to 40845.32 ng/g (average: 29953.47 ng/g) and 7361.66–14141.49 ng/g (average: 9819.96 ng/g), respectively. The concentrations of Σ16PAHs US-EPA in all the studied locations far exceeded the safety value of 1000 ng/g set by the soil quality guidelines of Switzerland and above which is regarded as being highly contaminated for Agricultural soils of Poland. The percentage composition of 2-, 3-,4-, 5-, and 6-ring in the soils were 33.69%, 56.31%, 9.47%, 0.52%, and 0.02% of the total PAHs, respectively, indicating the predominance of low molecular weight PAHs typical of petrogenic origin. Ecological risk assessment indicated a high risk to the soil biota and ecosystem in the studied soil samples as presented by individual PAH and total PAHs. 2-, 3- and 4-ring PAHs in the soil contributed significantly to the ecological risk burden in the soils. This research work provides useful information on the ecological risk associated with crude oil contamination and consequently would assist the government in formulating precise, targeted, and effective remediation measures for soil contaminated with crude oil.

Spatial distribution of polycyclic aromatic hydrocarbons in dust and soils from informal trade sites in southern Nigeria: Implications for risk and source analysis

Polycyclic aromatic hydrocarbons (PAHs) are a group of semi-volatile and persistent organic compounds considered priority pollutants because of their pervasive nature and high toxicity to the ecosystem and humans. Therefore, this study aimed to evaluate the PAH concentrations in dust and soils around informal trade sites (ITS) in Nigeria to determine the level of risk, sources, and significance of these activities to the PAH load of the environment. The 16 US EPA PAHs in dust and soils from ITS were determined by gas chromatography-mass spectrometry (GC-MS). The PAH concentrations in dust from these informal trade sites varied from 120 to 8790, 56 to 4780, and 102–1090 μg kg−1 for automobile mechanic workshops (AMW), car dismantling (CDS), and material recovery sites (MRS), respectively, whereas those of soils ranged from 3000 to 95,500, 554 to 14,700, and 966–25,200 μg kg−1 for AMW, CDS, and MRS respectively. The PAH profiles indicated that 3- to 5-ring PAHs were prominent in dust and soils around the ITS. The concentrations of the US EPA 16 PAHs in dust and soils from these ITS showed no correlation with organic matter, while the concentrations of PAH homologues in soils of these ITS showed no correlation with those of dust. Incremental lifetime cancer risk (ILCR) values in the magnitude of 10−4 to 101 were obtained for adult and childhood exposure to PAHs in dust and soils from these ITS. Exposure to PAHs in dust from these ITS gives rise to less risk than for soils. The results indicated that automobile mechanic workshops contribute more PAHs to the environment than car dismantling and material recovery activities. The source analysis showed that the PAH contamination of these sites arises from burning of biomass, plastic materials, and oils, and emissions from vehicles.

The effect of pyrolysis temperature and feedstock on biochar agronomic properties

As biochar gains popularity within agricultural applications, proper selection of feedstocks and pyrolysis conditions are crucial to maximising its added value. In this study, biochars were characterised for elemental composition, potentially toxic elements, the sum of 16 US EPA polycyclic aromatic hydrocarbons and biochar agronomic properties (pH, acid-buffering capacity, biochar stability, electrical conductivity, cation exchange capacity and water holding capacity) to provide more insight concerning biochar properties and pyrolysis parameters that influence the biochar agronomic properties. Eighteen feedstocks for biochar production were screened based on four selection criteria: moisture content, ash content, fixed carbon content and the presence of potentially toxic elements. Eight feedstocks (spent peat, woody green waste, tree bark, applewood, flax shives, spent coffee grounds, insect frass and chicken manure) were selected and processed into 24 biochars (at three pyrolysis temperatures: 450, 600 and 750 °C) using slow pyrolysis in a pilot-scale rotary kiln reactor. The results showed that feedstock and pyrolysis temperature are crucial factors for biochar composition, toxicity and agronomic properties. The sum of 16 US EPA polycyclic aromatic hydrocarbons showed a significant increase for biochars produced at 750 °C compared to those produced in the 450–600 °C range.Furthermore, some potentially toxic elements (Zn, Cu, Cr) revealed a decrease in concentration above 600 °C. It is recommended not to exceed a pyrolysis temperature of 600 °C in the reactor configuration used. Lastly, feedstock-independent models were constructed for pH, electrical conductivity and acid-buffering capacity through the biochar properties measured. These models may provide a gateway to reverse engineer biochars based on suitable feedstock and pyrolysis temperature selection.

Composition of PAHs in Biochar and Implications for Biochar Production.

The content of polycyclic aromatic hydrocarbons (PAHs) in biochar has been studied extensively; however, the links between biomass feedstock, production process parameters, and the speciation of PAHs in biochar are understudied. Such an understanding is crucial, as the health effects of individual PAHs vary greatly. Naphthalene (NAP) is the least toxic of the 16 US EPA PAHs but comprises the highest proportion of PAHs in biochar. Therefore, we investigate which parameters favor high levels of non-NAP PAHs (∑16 US EPA PAHs without NAP) in a set of 73 biochars. On average, the content of non-NAP PAHs was 9 ± 29 mg kg–1 (median 0.9 mg kg–1). Importantly, during the production of the biochars with the highest non-NAP PAH contents, the conditions in the post-pyrolysis area, where pyrolysis vapors and biochar are separated, favored condensation and deposition of PAHs on biochar. Under these conditions, NAP condensed to a lower degree because of its high vapor pressure. In biochars not contaminated through this process, the average non-NAP content was only 2 ± 3 mg kg–1 (median 0.5 mg kg–1). Uneven heat distribution and vapor trapping during pyrolysis and cool zones in the post-pyrolysis area need to be avoided. This demonstrates that the most important factor yielding high contents of toxic PAHs in biochar was neither a specific pyrolysis parameter nor the feedstock but the pyrolysis unit design, which can be modified to produce clean and safe biochar.

Efficiency of Penicillium canescens in Dissipating PAH in Industrial Aged Contaminated Soil Microcosms and Its Impact on Soil Organic Matter and Ecotoxicity

The filamentous fungus Penicillium canescens, isolated from oil-polluted soil, was evaluated for its ability to dissipate high-molecular-weight polycyclic aromatic hydrocarbons (PAH). The study was conducted in a microcosm containing 180 g of historical PAH-contaminated soil under non-sterile conditions with two incubation temperatures (14 °C and 18 °C) on a 12-h cycle. The experiment was conducted over 8 months, with four experimental conditions created by varying the volumes of the bulking agent and vegetable oil (olive oil) and the time of addition of these compounds. The PAH dissipation performance of the fungal augmentation treatment was compared with that achieved with a biostimulated soil (bulking agent and vegetable oil) and with the untreated soil as control. The greatest PAH dissipation was obtained with P. canescens bioaugmentation (35.71% ± 1.73), with 13 of the 16 US EPA PAH significantly dissipated, at rates above 18%, and particularly high-molecular-weight PAH, composed of more than three fused aromatic rings. Nematode toxicity tests indicated a significant decrease in the toxicity of soil bioaugmented by this fungus. Fulvic and humic contents were significantly increased by this treatment. All these results suggest that bioaugmentation with P. canescens can be used to restore soils with long-term PAH contamination.

Reduction of carcinogenic PAHs from petrodiesel engine exhaust by blending of green diesel (A new development in renewable fuels) with different biodiesel fuels

The aim of this research was to reduce 16 carcinogenic USEPA polycyclic aromatic hydrocarbons (PAHs) generated from petrodiesel engine exhaust by blending green diesel with a variety of biodiesel fuels. In the study, biodiesel samples were synthesized in laboratory from different raw materials using low cost methods. The exhaust engine used for this study was a diesel engine, model no. DIFM 028 of DidacInternational Janakpuri, New Delhi. These PAHs had a recovery range between 25%–75%. Jatropha oil green diesel was obtained from SSS-NIBE Kapurthala, Punjab, India. Jatropha oil green diesel and biodiesel samples were blended with diesel in different ratio (20:80, 30:70 and 40:60) to investigate the exhaust behavior of petrodiesel engine. It was found that B(a)A and B(a)P were the common PAHs in high concentration in almost all of the samples. According to FTIR results, vegetable oil is esterified to produce biodiesel. The results and analysis were supported by cluster analysis, factor analysis, and Hierarchical Clustering. Based on our results, we found that blending Jatropha oil green diesel with diesel significantly reduces the concentration of almost all PAHs. Blending green diesel with several different biodiesel to operate on a Petrodiesel engine has proven to be one of the most effective ways to reduce the amount of air pollution emitted by automobiles. A study like this could prove helpful in reducing carcinogenic pollutants from our environment.

Structural Selectivity of PAH Removal Processes in Soil, and the Effect of Metal Co-Contaminants

Polycyclic aromatic hydrocarbons (PAHs) form a convenient structural series of molecules with which to examine the selectivity exerted on their removal by soil microbiota. It is known that there is an inverse relationship between PAH molecular size and degradation rates in soil. In this paper, we look at how the magnitude of the slope for this relationship, m, can be used as an indicator of the effect of metal co-contaminants on degradation rates across a range of PAH molecular weights. The analysis utilises data collected from our previous microcosm study (Deary, M.E.; Ekumankama, C.C.; Cummings, S.P. Development of a novel kinetic model for the analysis of PAH biodegradation in the presence of lead and cadmium co-contaminants. Journal of Hazard Materials 2016, 307, 240–252) in which we followed the degradation of the 16 US EPA PAHs over 40 weeks in soil microcosms taken from a high organic matter content woodland soil. The soil was amended with a PAH mixture (total concentration of 2166 mg kg−1) and with a range of metal co-contaminant concentrations (lead, up to 782 mg kg−1; cadmium up to 620 mg kg−1; and mercury up to 1150 mg kg−1). It was found that the magnitude of m increases in relation to the applied concentration of metal co-contaminant, indicating a more adverse effect on microbial communities that participate in the removal of higher molecular weight PAHs. We conclude that m is a useful parameter by which we might measure the differential effects of environmental contaminants on the PAH removal. Such information will be useful in planning and implementing remediation strategies.

Community-based assessment of marine resources contamination after a large-scale oil spill.

As of August 2019, several oil slicks reached the Brazilian coast, compromising local ecosystems and the economy of coastal communities. In this context, this study aimed to assess seafood quality at the Canavieiras Extractive Reserve (RESEX), located in the state of Bahia, Northeastern Brazil, by determining polycyclic aromatic hydrocarbons (PAHs) concentrations in local biota following the oil spill. It was designed and carried out in a participatory manner, involving RESEX fishers, shellfish and crab gatherers and managers, as well as university researchers. A total of 72 biota samples were analyzed, and the sum of the 16 priority USEPA PAHs ranged from less than the limit of detection to 30.81 ng g-1 (w.w.). When also considering alkylated compounds, concentrations ranged from 3.53 to 360.75 ng g-1 (w.w.). No sample contained PAHs concentrations suggestive of human consumption risks. No difference in PAHs concentrations between the six studied areas and regarding different biota feeding habits were observed. Higher PAHs concentrations were generally noted in molluscs, as these organisms do not have enzyme systems capable of metabolizing these compounds. This initiative demonstrated the feasibility of participatory construction resulting in a study concerning valued species to local communities, ensuring a contribution to local fishing and marketing activities.

Comprehensive insights into the occurrence, source, distribution and risk assessment of polycyclic aromatic hydrocarbons in a large drinking reservoir system

The resource, environment, and ecological value of drinking reservoirs have received widespread concerns due to the pollution of persistent organic pollutants such as polycyclic aromatic hydrocarbons (PAHs). Therefore, we comprehensively studied the occurrence, source, distribution, and risk assessment of representative PAHs in Fengshuba Reservoir (FSBR) (large drinking reservoir, China). The total concentrations of 16 USEPA PAHs in the water phase, porewater phase, sediment phase, and soil phase were in ranges of 109.72-393.19 ng/L, 5.75-35.15 μg/L, 364.4-743.71 μg/kg, and 367.81-639.89 μg/kg, respectively. The naphthalene (Nap) was the dominant PAHs in the water phase, while it was Nap and phenanthrene (Phe) in porewater, sediment, and soil phase. The main sources of PAHs in FSBR were biomass combustion. Redundancy analysis indicated that the NTU, NO2-, NH4+, Chl-α, and IC were the dominant factors influencing the PAH distribution in water phase, and the PAHs in sediment phase was affected by T and NO3-. Pseudo-partitioning coefficients indicated that the PAHs in the porewater phase were more likely to migrate to the sediment phase. Risk assessment indicated that the PAHs both in the water and sediment phases were generally in a low-risk state, while the PAHs in the soil phase were in a moderate-risk state, and the Nap was in a high-risk state, and exposure to the PAHs in FSBR through drinking and skin exposure had little impact on consumers' health. In summary, Nap could be used as a key indicator to evaluate the existence and potential risk of PAHs in FSBR.

Polycyclic aromatic hydrocarbons (PAHs) in soils of an industrial area in semi-arid Uzbekistan: spatial distribution, relationship with trace metals and risk assessment

The concentrations, composition patterns, transport and fate of PAHs in semi-arid and arid soils such as in Central Asia are not well known. Such knowledge is required to manage the risk posed by these toxic chemicals to humans and ecosystems in these regions. To fill this knowledge gap, we determined the concentrations of 21 parent PAHs, 4,5-methylenephenanthrene, 6 alkylated PAHs, and biphenyl in soils from 11 sampling locations (0–10, 10–20 cm soil depths) along a 20-km transect downwind from the Almalyk metal mining and metallurgical industrial complex (Almalyk MMC), Uzbekistan. The concentrations of Σ29 PAHs and Σ16 US-EPA PAHs were 41–2670 ng g−1 and 29–1940 ng g−1, respectively. The highest concentration of Σ29 PAHs occurred in the immediate vicinity of the copper smelting factory of the Almalyk MMC. The concentrations in topsoil decreased substantially to a value of ≤ 200 ng g−1 (considered as background concentration) at ≥ 2 km away from the factory. Low molecular weight PAHs dominated the PAH mixtures at less contaminated sites and high molecular weight PAHs at the most contaminated site. The concentration of Σ16 US-EPA PAHs did not exceed the precautionary values set by the soil quality guidelines of, e.g., Switzerland and Germany. Similarly, the benzo[a]pyrene equivalent concentration in soils near the Almalyk MMC did not exceed the value set by the Canadian guidelines for the protection of humans from carcinogenic PAHs in soils. Consequently, the cancer risk due to exposure to PAHs in these soils can be considered as low.

Environment impact and probabilistic health risks of PAHs in dusts surrounding an iron and steel enterprise

Dust can be regarded as environmental medium that indicates the level and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) coming from different pollution sources. In this study, samples including road dust, roof dust, and bare soil near an iron and steel enterprise (ISE) in Laiwu city of North China were collected. To assess the environment impact, atmosphere particulates and one flue dust from a coking plant were simultaneously sampled. Sixteen USEPA PAHs were detected quantitatively by Gas Chromatography Mass Spectrometry (GC–MS). A laser particle size analyzer was used to obtain the grain size of the dust particle samples. The results showed that PAH concentrations displayed great variability in the dust samples. The ∑16PAHs concentration was found to be between 0.460 and 46.970 μg/g (avg ± sd 10.892 ± 1.185 μg/g) in road dust, between 0.670 and 17.140 μg/g (avg ± sd 6.751 ± 0.692 μg/g) in roof dust, and 13.990 ± 1.203 μg/g in bare soil. In the environment atmosphere sites, the ∑16 PAHs value in PM2.5 constituted a very large proportion of PM10, indicating that PAHs in finer particle sizes should be given greater emphasis. The ∑16PAHs concentration was relatively high in the area close to the ISE because of the great impact of the ISE industrial activities. PAH concentration curves were similar, and the most abundant individual PAHs in the atmosphere sites were BbF, BkF, and Flu, and BbF, BkF, and Chry in dusts. Toxicity analysis revealed that PAHs with four rings, including carcinogenic PAHs, were the dominant pollutants in the studied area. The toxic equivalency value (TEQBaP), the carcinogenic health risk assessment value recommended by the US EPA, was calculated for seven carcinogenic PAHs, revealing that they account for more than 93.0% of the total TEQBap of the 16 PAHs and indicating the major toxic equivalent concentration contributor. Incremental lifetime cancer risk (ILCR) estimation results showed that PAHs tended to bring about great health risks through skin contact, followed by ingestion and inhalation. By comparison, road dust exhibited greater carcinogenic risks than roof dust, and bare soil may undergo heavier pollution. Therefore, the results of this study would be helpful in the effort to understand the PAHs pollution from the steel industry, which will provide some guidance for the probabilistic assessment of local health risks.

Targeting the right parameters in PAH remediation studies

Contaminated land burdens the economy of many countries and must be dealt with. Researchers have published thousands of documents studying and developing soil and sediment remediation treatments. Amongst the targeted pollutants are the polycyclic aromatic hydrocarbons (PAHs), described as a class of persistent organic compounds, potentially harmful to ecosystems and living organisms. The present paper reviews and discusses three scientific trends that are leading current PAH-contaminated soil/sediment remediation studies and management. First, the choice of compounds that are being studied and targeted in the scientific literature is discussed, and we suggest that the classical 16 US-EPA PAH compounds might no longer be sufficient to meet current environmental challenges. Second, we discuss the choice of experimental material in remediation studies. Using bibliometric measures, we show the lack of PAH remediation trials based on co-contaminated or aged-contaminated material. Finally, the systematic use of the recently validated bioavailability measurement protocol (ISO/TS 16751) in remediation trials is discussed, and we suggest it should be implemented as a tool to improve remediation processes and management strategies.

SEASONAL VARIATION OF VOLATILE POLY AROMATIC HYDROCARBONS (PAHS) RELEASED FROM DIFFERENT SOURCES IN SOUTH CAIRO

Understanding the seasonal variations of polycyclic aromatic hydrocarbons (PAHs) concentrations in ambient air in urban/rural or industrial regions is important to the effective control of air pollution in these regions. Based on an approximately a year round dataset (from January to November 2014), a total of 48 atmospheric samples were collected by high volume active air sampler over one year seasonal monitoring in order to assess the variation of PAHs concentrations in different areas through different seasons in south Al Tabbin area. The gaseous and particulate phases of PAHs were extracted and analyzed using GC/MS together. The total air concentrations of 16 USEPA PAHs in the study area ranged from 76.48 ± 19.44 µg/m3 to 26995.86 ± 2835.91 µg/m3, with an average concentration of 7085.08 ± 773.98 µg/m3. Seasonal trends of PAH concentrations were observed with high concentration in winter and low in summer where the average concentration of PAHs in winter were ~1.6 times higher than that in summer. This mainly attributed to meteorological conditions.

Color Characteristics and Content of Polycyclic Aromatic Hydrocarbons of Traditional Dry Fermented Sausages Throughout Processing in Controlled Conditions

Petrovská klobása is traditional dry fermented sausage with intense red color, what differentiate it from other products of the same type. Very important factor in traditional sausage production is smoking, providing unique surface color of Petrovská klobása. On the other hand, smoking produces certain types of potentially carcinogenic chemicals, such as polycyclic aromatic hydrocarbons (PAH). Having in mind that assignment of the science is to help in transition of production from small household conditions to industrial ones, primarily with shortening fermentation and ripening time, and keeping the standard quality of the product the main aims of this work were to investigate the effects of autochthonous starter culture (Staphylococcus xylosus) addition on color formation of Petrovská klobása; and to determine the content of PAH in Petrovská klobása smoked in industrial conditions. Instrumental color characteristics (CIE L*a*b* system), contents of 13 US-EPA PAH (from Environmental Protection Agency list), pH values and moisture contents were determined during the processes of smoking, drying and ripening (throughout 60 days of production). Sensory evaluation of color was performed additionally, at the end of drying period (day 60 of production). Dry fermented sausages produced with addition of autochthonous starter culture had significantly (P < 0.05) higher value of redness-a* (27.94) and better sensory score (P < 0.05) for color (4.3) comparing to control group of sausages (25.23; 3.9, respectively) at the end of drying period. Results of this study demonstrated that addition of S. xylosus had positive effect on color of the Petrovská klobása. Contents of benzo[a]pyrene and PAH4 were below the limits of detection in all analyzed samples of Petrovská klobása smoked in industrial conditions (2 days per 5 hour). These results indicated the safety of sausages produced in this manner, from the PAH point of view. Highlights Effect of autochthonous starter culture on color of dry fermented sausages was analyzed Staphylococcus xylosus had positive effect to color of the Petrovská klobása BaP and PAH4 values were below the limit of detection in samples of Petrovská klobása Sausages smoked in industrial conditions (2 day per 5 hour) were safety from the PAH point of view

Modelling PAHs Transfer from Polluted Soil to Herbaceous Species in Phytoremediation Attempts

To address the soil–plant transfer modelling of 13 US-EPA Polycyclic Aromatic Hydrocarbons (PAHs), a mechanistic model—MM_19—has been developed based on the fugacity concept. For that, the Mackay_97 model has been improved in terms of reconsidering the losses related to the transport and transformation mechanisms taking place in the compartments—roots and aboveground shoots—of the three short-life species (Eleusine indica, Cynodon dactylon and Alternanthera sessilis). Model input parameters consist of both experimental and literature data, including the initial soil and air PAHs content, flowrates, PAHs physico-chemical properties, retention times and transport half-lives of PAHs inside plant species. Using in situ weather data and Penman’s law, xylem flows were estimated as the evapotranspiration for each plant. Model calibration was performed using a Generalized Reduced Gradient (GRG) nonlinear optimization solver method. Sensitivity analysis showed that the phloem flow was the most sensitive among all tested parameters. According to the Nash–Sutcliffe efficiency (NSE), the MM_19 model is more efficient than the Mackay_97 model for all three plant species. Finally, the impact of PAHs physico-chemical parameters on their sol-plant transfer was discussed in terms of slight, intermediate and high molecules weight. The NSE values showed that the MM_19 model is more efficient than the Mackay_97 model. Indeed, comparisons between experimental and simulated results in the MM_19 model showed similarities for each compartment of the plant species. Thus, the MM_19 model can be used to predict the soil–plant transfer of organic pollutants.

The occurrence and levels of polycyclic aromatic hydrocarbons (PAHs) in African environments-a systematic review.

In the African continent, several studies have been conducted to determine PAH pollution levels with their associated health risks in the environment. However, these studies are very much disconnected. The objective of this study is to conduct a systematic review that serves as a comprehensive report on the PAH-related studies conducted in the African continent. Data sources are from Google Scholar and PubMed. English language studies that reported on PAH levels in smoked fish and meat, soils and dust, aquatic environments, indoor and outdoor air, and ready-to-eat food items were selected. Specific PAHs included the following: 33 PAHs comprising ofthe 16 USEPA PAHs, non-alkylated PAHs, non-alkylated PAHs, oxygenated PAHs (OPAHs), and azaarenes (AZAs). Study appraisal and synthesis methods: The Newcastle-Ottawa Scale (NOS) was adapted to assess the quality of the selected studies basing on their sampling methods, analytical techniques, and results. A total of 121 studies were reviewed, with the majority (56) being from Nigeria. PAH levels in smoked fish and meat, soils and dust, aquatic environments, indoor and outdoor air, and ready-to-eat food items recorded total concentrations of PAHs ranging from 5 to 3585 μg/kg, BDL to 6,950,000 μg/kg, 0 to 10,469,000 μg/kg, 0 to 7.82 ± 0.85 μg/m3, and 2.5 to 7889 ± 730 μg/kg respectively. Carcinogenic risk assessment for children and adults ranged from very low to very high levels when compared to the ILCR range (10-6 to 10-4) defined by the USEPA. Out of 54 African countries, only 19 were represented. The majority of selected studies failed to apply any standard protocols for sample collection and analysis. The low to very high PAH levels reported in studies calls for effective actions on environmental health. Similar systematic reviews are expected to be performed in other continents for a global assessment of PAH pollution.