High Polycyclic Aromatic Hydrocarbons Content Research Articles

The effect of shrubs admixture in pine forest stands on soil bacterial and fungal communities and accumulation of polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent toxic pollutants. The species composition of the stand is important in shaping the quality of soil organic matter and, consequently, the PAH content. The main purpose of the research was to determine the role of shrubs in shaping PAH accumulation in forest soils. The study covered the soils of the pine stands of the Rybnik Forest District, which experiences some of the highest deposition of industrial emissions in Europe. Pine stands with admixture of shrubs (alder buckthorn Frangula alnus and European hazelnut Coryllus avellana) growing in the same soil conditions were selected for the study. Samples for analyses were collected from the organic horizon (O) (from a depth of 0–7 cm) and humus mineral horizon (A) (from a depth of 7–15 cm). The organic C and total N concentrations, pH, alkaline cation content, soil enzyme activity and PAH content were determined. Additionally, the taxonomic composition of soil bacterial and fungal communities was determined. The highest activity of enzymes was noted in soils under influence of shrubs. The enzymatic activity was positively correlated with the content of total N, organic C, pH H2O and KCl and negatively with the C/N ratio. The highest PAH content was recorded in the soils of pine stands without the admixture of shrubs. Our research indicates the importance of shrubs in shaping the properties of surface horizons of forest soil and, consequently on the accumulation of PAHs. Shrubs stimulate biochemical activity of soils which results in lower PAHs accumulation by providing more easily decomposable organic matter.

Content, Distribution, Source Analysis, and Risk Assessment of PAHs in Arable Soils of Taiyuan

PAHs (polycyclic aromatic hydrocarbons) accumulated in arable soils have significant impacts on farmland quality and human health, which has attracted wide attention from scientists and the public. A total of 22 arable soil samples were collected from Taiyuan, an old industrial city, including three districts (industrial zones, hilly areas, and sewage irrigation area), and the contents of 21 PAHs were detected using the GC-MS method. The sources of PAHs in soils were analyzed using the diagnostic ratios (DRs) method and positive matrix factorization (PMF) model, and the soil health risks were analyzed using the incremental lifetime cancer risk (ILCR) model. The results indicated that the average concentrations of Σ21PAHs and Σ16PAHs in arable soils of Taiyuan were 934.6 ng·g-1 and 787.7 ng·g-1, respectively, which were lower than the soil pollution risk screening value of agricultural land stipulated in GB 15168-2018. 3-5 rings PAHs were the dominant components, accounting for~90% of the Σ21PAHs. Approximately 60% of sites in industrial zones, 13% in hilly areas, and 33% in the sewage irrigation area had high PAHs contents larger than 1000 ng·g-1. The spatial distribution of PAHs showed that more severe PAHs pollution in the soil occurred in industrial areas than that in the other two districts. The DRs suggested that the combustion of coals, bio-masses, and traffic emissions were the dominant sources for PAHs pollution in arable soils in Taiyuan. The simulation results of the PMF model indicated that the sources and contribution rates of PAHs in cultivated soils were coal and biomass burning sources (59%), traffic sources (22%), and coking sources (19%). The risk assessment confirmed that the arable soils in Taiyuan had high potential carcinogenic risks; thus, more attention should be paid to the PAHs pollutions in arable soils.

Polycyclic aromatic hydrocarbons in two sedimentary environments of the Tertiary Krepoljin coal basin

In the present study, statistical correlation analysis and multivariate statistical techniques (PCA/FA) were employed to investigate polycyclic aromatic hydrocarbons (PAHs) in sediments, such as illite-montmorillonite (IM) and calcite (Ct), from two sedimentary environments of the Tertiary Krepoljin brown coal basin in Serbia. The coal and sediment layers were formed in fresh-water bogs during the Lower Miocene period. The total amount of extractable PAHs was determined by gas chromatography with a triple quad mass detector (GC-MS-MS), and it ranged from 449 to 10585 μg l−1 in all sediments. Eight of the total 16 PAHs, which ranged from 175.17 to 658.42 μg l−1, include benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, dibenzo[a,h]anthracene, benzo[g,h,i]perylene, and indeno[1,2,3-cd]pyrene, which are regarded as potentially carcinogenic, indicating a higher possibility of adverse ecological effects. Medium molecular-weight (MMW) PAHs were found to be predominant in all sediments. PAH concentrations are affected by several factors, such as carbon content, H/C mole ratio, and (less significant) O/C mole ratio. The non-existence of a correlation between the N/C ratio and other parameters indicates unspecific changes which accompany the original organic matter. The lower-sulfur Ct sediment samples were found to have a higher PAH content than higher sulfur IM samples, leading to the conclusion that the PAH content of sediments may be related to the depositional environment.

The effect of pre‐pyrolysis chemical treatment of waste tyre rubber crumbs: comparison between pre‐treated and conventional waste tyre‐derived oil

AbstractBACKGROUNDPyrolysis process is one of the most effective recycling methods due to its ability to recover products like gas, oil and char with oil being the major/important product. The shortcomings of waste tyre‐derived oil from the conventional pyrolysis process are that the oil contains high amounts of sulfur and polycyclic aromatic hydrocarbons (PAHs) and has a pungent smell, which makes it difficult to utilize further. The aim of this study is to investigate the effect of chemical pre‐treated waste tyre rubber crumb‐derived oil versus conventional waste tyre oil. The instrumentation utilized in this study was to solely investigate the shortcomings of waste tyre pyrolysis (high sulfur and PAH content and also high temperature required for waste tyre pyrolysis).RESULTSThe results showed a reduction in amounts of both sulfur and PAHs in treated waste tyre‐derived oil by about 83% and 77% respectively. Also, there was a reduction in initial pyrolysis temperature for the treated waste tyre crumb as compared to untreated waste tyre crumb: a temperature range of 96–115 °C for treated waste tyre crumbs as compared to 300–400 °C for untreated waste tyre crumbs.CONCLUSIONSThe success of this study means the production of quality oil at a low temperature with lower amounts of PAHs and sulfur and less odour, plus the possibilities of it being used as a petroleum fuel or for extraction of important compounds like benzene, toluene, xylene, limonene and C12–C20 acids. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Levels, sources, and risk assessment of PAHs residues in soil and plants in urban parks of Northwest China

Polycyclic aromatic hydrocarbons (PAHs) will be ingested by people through different ways to threaten their health during play, so the environmental quality of the park directly affects the health of tourists and residents. Using eight typical parks in Urumqi in Northwest China as the study area, we used GC–MS to detect the PAHs content in the park surface soil and 10 common plants in the park in different seasons. The results showed that the content of PAHs in park soil in the summer was 5–6 times that in the winter, and the monomer PAHs in some park soil sampling points were higher than the soil pollution risk screening value. And the contamination level at these sampling sites was also higher compared to other sampling sites. In summer, the plants with high PAHs content in leaves are short herbs, while in winter, they are tall arbors. The PAHs of the park soil are mainly composed of high-cyclic aromatic hydrocarbons, and are mainly of traffic origin. The proportion of low-ring aromatic hydrocarbons in the winter was significantly higher than that in the summer. The source of PAHs in plants in summer is similar to that in soil, but the source of PAHs in plants in winter is more complex. The toxicity equivalent concentration method values of soil PAHs in South Park, Zhiwu Park, Shihua Park and Toutunhe Park were higher than that in other parks. The lifetime carcinogenic risk (ILCRs) values of some sampling points in these four parks in the summer were relatively high. The average ILCRs of adults and children in all parks reached a low-risk level in summer. The carcinogenic risk in children is much higher than that of adults.

A modified receptor model for source apportionment of sediment polycyclic aromatic hydrocarbons.

Polycyclic aromatic hydrocarbons (PAHs) have become a serious threat to human health and ecological security due to their persistence and high toxicity. Lake sediments are in a relatively closed environment, so PAHs and other pollutants can be preserved for a long time. Accurate analysis of the sources of PAHs in sediments is an important prerequisite for PAH pollution control. However, the existing PAHs source resolution receptor model (the absolute principal component analysis - multilinear regression (APCA-MLR) and positive matrix factorization (PMF)) has many defects, such as great uncertainty in the process of matrix rotation. In this study, we collected sediment samples from Taihu Lake and tested their PAH content, and the existing receptor model was improved. High PAH contents were distributed in Meiliang Bay, Zhushan Bay, Gonghu Bay and areas close to the shore. "High-High" areas were distributed in Meiliang Bay, Gonghu Bay and areas close to the shore. "Low-Low" areas appeared in the central and southern parts of Taihu Lake. The results show that the improved positive matrix factorization partition computing (PMF-PC) model is significantly better than the APCA-MLR and PMF models in terms of both numerical simulation accuracy and the spatial distribution consistency of PAHs. The correlations (R2) between the measured and simulated values of low-molecular-weight PAHs (L-PAHs), high-molecular-weight PAHs (H-PAHs) and PAHs were 0.992, 0.989 and 0.993, respectively. The contributions of biomass sources, coal combustion sources and petroleum sources to PAHs in Taihu Lake sediments reached 16.7%, 31.7% and 51.6%, respectively. Fossil fuel sources were mainly concentrated in areas near the shore, and the contribution was lower in areas far from the shore. Although the algorithm still needs to be improved, the PMF-PC model may become a useful tool for the source apportionment of PAHs in sediments.

The Effect of Partial Substitution of Beef Tallow on Selected Physicochemical Properties, Fatty Acid Profile and PAH Content of Grilled Beef Burgers.

The objective of this study was to analyze the impact of partial replacement of beef tallow with sunflower, canola, linseed, olive oil and milk fat on physical properties, oxidation stability, fatty acid profile and PAHs (polycyclic aromatic hydrocarbons) content of beef burgers. Studies have shown a strong relationship between the fatty acid profile and the PAH content (especially of the heavy PAHs). The partial replacement of beef tallow with oils and milk fat (MF) contributed to a change in the fatty acid profile and a reduction in the hardness of the burgers. The highest PAH content was found in samples with canola oil (CO), which had the highest levels of monounsaturated fatty acids (MUFA), and in the control group (CON) without fat substitution, which had the highest levels of saturated fatty acids (SFA) and trans conformations. Substitution of animal fat with vegetable oils contributed to a change in the color of the burgers’ surface, as there was a statistically significant increase in the L* color component and a decrease in the a* component. The burgers with canola oil (CO) and linseed oil (LO) were the most susceptible to oxidation, whereas the burgers with reduced fat content (CON_LOW FAT) were the most stable in terms of oxidation, where the malondialdehyde (MDA) content was 32.8% lower compared with the control group (CON). The studies confirm that partial replacement of beef tallow with vegetable oils and milk fat and reduction in fat content in burgers to be grilled can be an effective way to change their fatty acid profile and reduce the cyclization reaction of organic compounds leading to the formation of PAH. Correlation coefficient analysis showed that there is a relationship between fatty acid profile and the presence of selected PAHs in grilled beef burgers. The results of this study indicate that replacing beef tallow with vegetable oils is a promising approach in designing meat products with controlled PAH content.

A Tale of Three Dust Populations: Variable R V and Extreme Polarization along Sight Lines toward ζ Ophiuchi

Abstract Dust permeates the interstellar medium, reddening and polarizing background starlight, but dust properties vary with local environment. In order to characterize dust in a highly irradiated diffuse cloud, we measure the reddening and optical polarization toward 27 stars surrounding the midlatitude b = +24° O9.2IV star ζ Ophiuchi, using new optical spectroscopy and polarimetry. We incrementally deredden and depolarize with distance, allowing us to distinguish dust components along these sight lines. The data indicate three distinct dust populations: a foreground component characteristic of average Milky Way dust (R V ≈ 3.1, d ≲ 180 pc), a highly polarizing mid-distance component in the vicinity of ζ Oph (R V ≈ 2.4, 200 pc < d < 300 pc), and a nonpolarizing distant component (R V ≈ 3.6, 600 pc < d < 2000 pc). Prominent 8 μm infrared striations spanning the field of view likely have high polycyclic aromatic hydrocarbon content and are illuminated by ζ Oph. Foreground-subtracted polarizations roughly align with these striations, which, we argue, lie immediately behind ζ Oph and constitute the highly polarizing mid-distance dust. This component polarizes very efficiently (P V > 9.1E(B − V)), implying a high degree of grain alignment and suggesting that the bulk of the polarization occurs in a small fraction of the volume. The large R V in the distant component reveals that dust above the Galactic plane (z > 250 pc) may contain a greater fraction of large grains than the Milky Way average.

Influence of Plant Extract Addition to Marinades on Polycyclic Aromatic Hydrocarbon Formation in Grilled Pork Meat.

Marinating is one of the most common methods of pre-processing meat. Appropriate selection of marinade ingredients can influence the physicochemical properties of the meat and can reduce the level of polycyclic aromatic hydrocarbons (PAHs) in the final product. The effects of the inclusion of natural plant extracts such as bay leaf (BL), black pepper (BP), turmeric (TU), jalapeno pepper (JP) and tamarind paste (TA) in marinades on the physicochemical properties of grilled pork neck were studied. The addition of spice extracts to marinades increased the proportion of colour components L* and b*. The use of TU, TA, JP, MX and C marinades lowered the hardness and pH of the meat. The highest phenolic compound levels were observed in the case of the mixture of all extracts (MX) and JP marinades, and the highest total antioxidant capacity was exhibited by the BL and MX marinades. The highest PAH content was recorded in the CON marinade (Σ12PAH 98.48 ± 0.81 µg/kg) and the lowest in the JP marinade (4.76 ± 0.08 µg/kg), which had the strongest, statistically significant reducing effect (95% reduction) on PAH levels. Analysis of correlation coefficients showed a relationship between the total antioxidant capacity of the marinades and the PAH content in grilled pork.

Polycyclic Aromatic Hydrocarbons in the Bottom Sediments of the River – Sea Mixing Zone on the Example of the River Chernaya and the Sevastopol Bay (the Black Sea)

Purpose. The study is aimed at determining concentrations of the polycyclic aromatic hydrocarbons (PAHs) and at revealing their pattern distribution in the bottom sediments of the "river – sea" contact zone on the example of the Sevastopol Bay and the river Chernaya. Methods and Results. Granulometric composition of the bottom sediments was determined by the decantation and dispersion method. Identification and quantitative determination of PAHs were carried out by the high performance liquid chromatography method. The total PAHs content in the bottom sediments of the area under study varied from 12 to 670 ng/g of dry weight. The pollutant content was minimum in the river site beyond the geochemical barrier. In the area where the river Chernaya flows into the Sevastopol Bay, the PAHs content was 121 ng/g. The highest PAHs content was revealed in the Sevastopol Bay bottom sediments, more precisely, in 1.5 km southwest of the river Chernaya flowing into the bay. 14 PAHs were identified in the estuary zone of the river, 4 of them (naphthalene, 2-methylnaphthalene, fluorene, anthracene) were in the trace amounts. The maximum concentration (99%) of silty material was observed in the Sevastopol Bay water area. The silt fractions were distributed as follows: 20% – aleuritic-pelite fraction, 79% – pelitic-aleurite fraction. Directly in the area of the river inflow into the bay, accumulation of the sand fraction (7%) and the maximum portion of pelitic silts were noted. Conclusions. The recorded values of PAHs corresponded to the natural non-toxic levels. PAHs identified in the bottom sediments of the river estuary zone are of the mixed, predominantly petrogenic origin. The obtained data show that in the conditions of the "river – sea" contact zone, the PAHs accumulation in general and their individual fractions were governed mainly by presence of silt in the bottom sediments.

Politsiklicheskiye aromaticheskiye uglevodorody v donnykh otlozheniyakh zony smesheniya reka – more na primere reki Chernoy i Sevastopol'skoy bukhty (Chernoye more)

Purpose. The study is aimed at determining concentrations of the polycyclic aromatic hydrocarbons (PAHs) and at revealing their pattern distribution in the bottom sediments of the "river – sea" contact zone on the example of the Sevastopol Bay and the river Chernaya. Methods and Results. Granulometric composition of the bottom sediments was determined by the decantation and dispersion method. Identification and quantitative determination of PAHs were carried out by the high performance liquid chromatography method. The total PAHs content in the bottom sediments of the area under study varied from 12 to 670 ng/g of dry weight. The pollutant content was minimum in the river site beyond the geochemical barrier. In the area where the river Chernaya flows into the Sevastopol Bay, the PAHs content was 121 ng/g. The highest PAHs content was revealed in the Sevastopol Bay bottom sediments, more precisely, in 1.5 km southwest of the river Chernaya flowing into the bay. 14 PAHs were identified in the estuary zone of the river, 4 of them (naphthalene, 2-methylnaphthalene, fluorene, anthracene) were in the trace amounts. The maximum concentration (99%) of silty material was observed in the Sevastopol Bay water area. The silt fractions were distributed as follows: 20% – aleuritic-pelite fraction, 79% – pelitic-aleurite fraction. Directly in the area of the river inflow into the bay, accumulation of the sand fraction (7%) and the maximum portion of pelitic silts were noted. Conclusions. The recorded values of PAHs corresponded to the natural non-toxic levels. PAHs identified in the bottom sediments of the river estuary zone are of the mixed, predominantly petrogenic origin. The obtained data show that in the conditions of the "river – sea" contact zone, the PAHs accumulation in general and their individual fractions were governed mainly by presence of silt in the bottom sediments

Microbial Ecotoxicity of Biochars in Agricultural Soil and Interactions with Linear Alkylbenzene Sulfonates

Large-scale application of biochar on agricultural land offers the prospect of soil improvement and carbon sequestration for climate-change mitigation. However, negative side-effects on the soil microbial ecosystem are poorly understood, notably in relation to the functions of native microbiomes under realistic routes of biochar exposure. Due to divergent properties, different biochars might interact with soil in complex ways. This might result in decreased or increased ecotoxicity from biochar contaminants, such as heavy metals and polycyclic aromatic hydrocarbons (PAHs). Using five biochars produced from straw and wood under contrasting pyrolysis conditions, we traced their ecotoxicological dose-effect using a bioassay for potential ammonia oxidation (PAO), through microorganisms that are sensitive stress indicators. Assays were made after soil/biochar interaction for up to 3 weeks, where straw biochar with the lowest PAH content (<0.5 mg kg−1) showed the most pronounced dose-effects to PAO, corresponding to a 10% effect concentration (EC10) of 4.6% (dry weight biochar/dry weight soil). In comparison, straw biochar with the highest PAH content was least ecotoxic (EC10, 15.2% after 3 weeks) and wood biochars pyrolysed at high temperature (700–725 °C) showed no ecotoxicity to PAO. Interactions between biochars and anionic surfactants, i.e., linear alkylbenzene sulfonates, which are common soil pollutants, resulted in varying effects on PAO, but the effects were small and of limited ecological importance for soil-amended biochars. In conclusion, the results showed that short-term microbial side-effects of biochar in the soil ecosystem were minor at relevant field application rates (such as <30 Mg ha−1 mixed into a plough layer of 20 cm), and that inherent PAHs in biochar were not a likely source of short-term ecotoxicity. However, there were notable differences in the effects eventually observed at very high biochar rates, stressing that individual biochars need specific ecotoxicological assessment before their safe application at large scale in agricultural soils.

Effects of manufacturing procedures and preparation conditions on European Union priority polycyclic aromatic hydrocarbons in Oolong tea samples

The study evaluated the changes in polycyclic aromatic hydrocarbons (PAHs) of Oolong tea samples at each heat treatment stage of the manufacturing process, different post-treatment methods and different brewing conditions. The content of PAHs in the tea leaves was significantly increased during stir fixation (280 °C for 8 min) stage of the manufacturing process. In the subsequent heat treatment process, the PAHs content did not change much until the Oolong tea product (primary) was further roasted. The level of PAHs increased with the roasting time. Charcoal roasting resulted in higher PAHs content in the product compared with electric roasting. Higher brewing temperature caused higher level of PAHs released into the tea infusion. The level of released PAHs decreased with the increase of the number of tea brewing (the total released PAHs was about 4%). The risk assessment results for PAHs in the tea infusions showed a low level of health concern.

Polycyclic aromatic hydrocarbons (PAHs) persistence, bioavailability and toxicity in sewage sludge- or sewage sludge-derived biochar-amended soil

Soils can be contaminated with polycyclic aromatic hydrocarbons (PAHs) when either sewage sludge (SSL) or biochar (BC) are used. There are no comparative studies regarding the effects of soil amendment with SSL or BC on the persistence, bioavailability and toxicity of PAHs. This research compared the persistence of PAHs (based on the extractable content, Ctot) and their bioavailability (freely dissolved, Cfree) as well as the toxicity (solid phase: Phytotoxkit F with Lepidium sativum and the Collembolan test with Folsomia candida; leachates: Phytotestkit F with L. sativum and Microtox® with Aliivibrio fischeri) of soil amended with SSL or with SSL-derived BCs. BCs were produced from three different sewage sludges at a temperature of 500 °C. SSLs or BCs were added to the soil at a rate of 1% (30 t/ha). Adding SSL to the soil increased more the PAH content in it than after BC application, which was associated with a higher content of PAHs in SSL. Losses of Σ16 Ctot and Cfree PAHs were higher than those observed for biochar only in the case of one SSL. In the other cases, PAH losses were either higher for biochar or did not differ significantly between SSL and BC. On the other hand, the analysis of the individual groups of PAHs showed significant differences between SSL and BC, both for Ctot and Cfree. Nonetheless, these differences were largely driven by the type of sewage sludge and biochar. Only in the case of root growth inhibition the toxicity higher was for the SSL-amended soils than for the BC-amended ones. In the other cases, varying results were observed which were determined by the type of sewage sludge/biochar, similarly to PAH losses.

Occurrence of polycyclic aromatic hydrocarbons in groundwater from rural areas in eastern China: Spatial distribution, source apportionment and health cancer risk assessment

Polycyclic aromatic hydrocarbons (PAHs) pollution in well water has become more widespread, especially in rural areas. The development of small workshops has brought economic growth; however, a sharp increase in the level of pollution due to combustion of fossil fuels has also been observed. A lack of effective measures to control environmental pollution and strict legislation in these regions can contribute to higher PAHs emissions. In the study, the distribution and level of 16 PAHs in well water in rural eastern China were reported. The total concentrations of 16 priority PAHs varied from 4 to 169 ng/L, and an arithmetic mean of 38 ± 25 ng/L. Moreover, the highest PAHs content was found in well water from Shandong Province, and the average concentration was 60 ± 48 ng/L. The distribution of total 16 PAHs illustrated a decreasing trend from north to south. However, the distribution of PAHs with 2-rings and 4-rings was found to be higher in Jiangsu and Hebei province, respectively. The PAHs source identification results showed that the dominant source was coal and biomass combustion, which was consistent with the local conditions. The values of health cancer risks (CRs) were calculated, and that indicated that hazard quotients of nine non-carcinogenic contaminants were lower than one and might not have negative health risks. However, for carcinogenic PAHs, CRs values of the dermal pathway were higher than 10−6, and those for benzo [a]pyrene (BaP) and dibenzo [a, h] anthracene (DbA) were even higher (>10−4), indicating significant high risks to children and adults.

Effects of woody biochar on dry thermophilic anaerobic digestion of organic fraction of municipal solid waste

This study presents the results of semi-pilot scale anaerobic digestion tests conducted under dry thermophilic conditions with the addition of biochar (6% on fresh mass basis of inoculum), derived from an industrial gasification plant, for determining biogas and biomethane production from organic fraction of municipal solid waste. By using two types of inocula (from a full-scale dry anaerobic digestion plant and from lab-scale biomethanation tests), the obtained experimental results did not show significant increase in methane yield related to the presence of biochar (330.40 NL CH4 kgVS−1 using plant inoculum; 335.41 NL CH4 kgVS−1 using plant inoculum with biochar, 311.78 NL CH4 kgVS−1 using lab-inoculum and 366.43 NL CH4 kgVS−1 using lab-inoculum with biochar), but led to significant changes in the microbial community composition. These results are likely related with the specific biochar physical-chemical features and low adsorption potential.Resulting digestate quality was also investigated: biochar-enriched digestates were characterized by increased biological stability (809 ± 264 mg O2 kgVS−1 h−1 vs. 554 ± 76 mg O2 kgVS−1 h−1 for biochar-free and biochar-enriched digestates, respectively), lower heavy metals concentrations (with the exception of Cd), but higher polycyclic aromatic hydrocarbons content, with a reported maximum concentration of 8.9 mgPAH kgTS−1 for biochar-enriched digestate derived from AD test with lab-inoculum, which could trigger non-compliance with regulation limits for agricultural reuse of digestates. However, phytotoxicity assessments showed a decreased toxicity of biochar-containing digestates when compared to biochar-free digestates.

Polycyclic aromatic hydrocarbons (PAHs) in dry tea leaves and tea infusions in Vietnam: contamination levels and dietary risk assessment.

The total mean ∑[Formula: see text] in samples were from 75.3 to 387.0ng/g dry weight (d.w) and showed high value in black dry tea, followed by herbal, oolong, and green tea. The mean ∑[Formula: see text] (a combination of benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) values were 54.3ng/g, 16.4ng/g, 14.2ng/g, and 6.6ng/g for black, herbal, green, and oolong teas, respectively. Concentration for benzo[a]pyrene (BaP) was from 0.4 to 35.8ng/g, and the BaP equivalent concentration values ranged from 0.3 to 48.1ng/g. There was only 1 black tea sample that BaP concentration exceeded the maximum level according to European Union (EU) standards. Tea samples marketed in Vietnam showed insignificant difference with the samples from other origins by same analytical method. Black teas showed high PAHs contents in dry tea samples but the released percentage of sum of PAHs from tea-to-tea infusion was lower than that in other tea type samples. The released percentages of PAH4 from tea-to-tea infusion were 40.7, 15.4, and 1.9 for green, herbal, and black tea. High temperature in black tea manufacturing processes might reduce essential oil content in tea that might effect on the PAHs partially release into the infusion. Indeed, based on EU regulations, we may conclude that tea consumers are safe in risk of exposure to PAHs obtained from teas.

Exploring the effect of composting technologies on the recovery of hydrocarbon contaminated soil post chemical oxidative treatment

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous organic pollutants that contaminate large areas. They are mainly released to environment by anthropogenic activities principally due to the petrochemical industry. The low biodegradation rate characteristic of PAHs in aged contaminated soils could be overcome trough the chemical oxidation. In this study, composting with the soil and stimulation with mature compost were the strategies applied in soil microcosms after chemical oxidation with ammonium persulfate in a PAHs chronically contaminated soil.A 29% of PAHs elimination and an increase of their bioavailability were found after chemical oxidation with ammonium persulfate. Due to the oxidative treatment the total bacterial and the gram-positive population PAH dioxygenase genes were significantly reduced and no gram-negative PAHs degraders were detected.The following application of organic amendments produced a higher increase in total bacteria and recovery of the degrading population of GP PAH after one year of treatment, in comparison with the pre-oxidized soil bioremediation, only promoted by irrigation and aeration. Also a significant increase in the content of bioavailable PAHs was observed. However, from both composting strategies only the stimulation with mature compost led to a net PAHs removal. Taking into account the residual dissolved total carbon and humification degree (E4/E6 ratio), it was attributed to the preferential consumption of more easily degradable compounds than hydrocarbons the low removal efficiency observed after one year of treatment.Due to the high bioavailable content of PAH and the residual sulfate, long-term treatments will require careful monitoring to reduce environmental risks.

FEATURES OF LIPID COMPOSITION OF SPHAGNUM AND TRUE MOSSES FROM VARIOUS NATURAL CLI-MATIC ZONES

A composition of 16 lipid samples of sphagnum and true mosses (Bryales) growing at an average annual temperature ranging from -9.1 °C to 1.5 °C is investigated by gas chromatography-mass spectrometry. The individual composition and content of n-alkanes, fatty n-acids and their esters, n-alkane-2-ones, aldehydes, farnesylfuranes, polycyclic aromatic hydrocarbons (PAHs), tocopherols, squalene, steroids, sesqui-, di- and triterpenoids of these mosses are determined. True mosses differ from sphagnum mosses in their lower content of n-alkanes, n-alkan-2-ones, n-aldehydes, tocopherols and cyclic terpenoids, and a higher content of PAHs. Campesterol prevails among steroids of true mosses, while stigmasterol and sitosterol dominate in sphagnum mosses. Sitosterol prevails in sphagnum mosses growing in areas with a negative average annual temperature. An increase in the temperature of the habitat results in a decrease in the relative content of n-alkanes with odd number of carbon atoms in the molecule in true mosses, and a slight decrease in their average chain length in sphagnum mosses. It is shown that terpenoids are the most dependent on natural habitat conditions of mosses. This is indicated by the content of squalene, sesqui- and diterpenoids, the ratio of hydrocarbons to oxygen-containing structures of cyclic triterpenoids, and that of compounds from series of perhydropicene and cyclopentapeperhydrochryzene. The increased humidity of habitat of a moss eliminates the effect of temperature. The stability of composition of n-alkanes and n-alkan-2-ones of sphagnum mosses developing under various conditions makes it possible to consider these compounds as potential chemotaxonomic markers of sphagnum mosses in peat deposits.

Small Molecular Weight Aldose (d-Glucose) and Basic Amino Acids (l-Lysine, l-Arginine) Increase the Occurrence of PAHs in Grilled Pork Sausages.

(1) Background: Amino acids and carbohydrates are widely used as additives in the food industry. These compounds have been proven to be an influencing factor in the production of chemical carcinogenic compounds polycyclic aromatic hydrocarbons (PAHs). However, the effect of the properties of the amino acids and carbohydrates on the production of PAHs is still little known. (2) Methods: We added different (i) R groups (the R group represents an aldehyde group in a glucose molecule or a ketone group in a fructose molecule); (ii) molecular weight carbohydrates; (iii) polarities, and (iv) acid-base amino acids to pork sausages. The effects of the molecular properties of carbohydrates and amino acids on the formation of PAHs in grilled pork sausages were investigated. (3) Results: The results showed that a grilled sausage with aldehyde-based d-glucose was capable of producing more PAHs than a sausage with keto-based d-fructose. A higher PAH content was determined in the grilled pork sausage when the smaller molecular weight, d-glucose, was added compared with the sausage where the larger molecular weight, 4-(α-d-glucosido)-d-glucose and cellulose were added. The addition of basic amino acids (l-lysine, l-arginine) was capable of producing more PAHs compared with the addition of acidic amino acids (l-glutamic acid, l-aspartate). When amino acid containing a benzene ring was added, a smaller volume of PAHs was produced compared with the addition of other amino acids. (4) Conclusions: Our study suggests that systematic consideration of molecule properties is necessary when using food additives (amino acids and carbohydrates) for food processing.