PAH Concentrations Research Articles

Source characteristics of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in surface soils of Shenyang, China: A comparison of two receptor models combined with Monte Carlo simulation

The surface soil concentrations of 16 PAHs and 15 PCBs were simultaneously determined by gas chromatography-tandem mass spectrometry in 21 locations of urban areas of Shenyang. The average concentrations of PAHs and PCBs were 26.40 ± 34.68 mg/kg and 48.03 ± 27.47 μg/kg, respectively. Factor analysis with nonnegative constraints (FA-NNC) and absolute principal component score with multiple linear regression (APCS-MLR) model were used to explore and evaluate the sources of PAHs and PCBs in the study area. The results of FA-NNC showed that PAHs in soils were mainly from traffic emissions (49.64%), coal combustion (46.88%) and petrogenic source (3.49%). The PCBs in soils were mainly from commercial and high temperature combustion mixed sources (20.3%), combustion and industry emission mixed sources (21.1%), electrical equipment sources (22.2%) and traffic emission sources (36.4%). The results of APCS-MLR were consistent with those of FA-NNC. The uncertainty of FA-NNC and APCS-MLR model was analyzed by Monte Carlo simulation method. The results revealed the reliability of the two receptor models on source apportionment. The estimated carcinogenic risks indicated that the risks of PAHs in soils exceed the acceptable range (10−6-10−4), while the risks of PCBs were below the acceptable risk level of 10−6.

Polycyclic aromatic hydrocarbon concentrations in soil of three communities in Rivers State

The study was conducted in three communities in Rivers State. These communities include Okochiri community in Okrika, Mgbuodohia in Obio-Akpor and Chokocho in Etche. Soil at two different depths were sampled on a composite basis using EGASPIN 2018 procedures, extracted and analyzed for sixteen priority PAHs using US EPA 8270 (2014) procedures. Studies show the total concentration of PAHs in soil sample taken from Okochiri community in Okrika at depths of 0 - 15 cm and 15 - 30 cm was found to be 145.32 mg/kg and 101.6 mg/kg during the dry season respectively but in the wet season the total concentration was found to be 607.08 mg/kg and 242.46 mg/kg at the two depths. In Mgbuodohia, the dry season result for the two depths, showed a total concentration of 14.68 mg/kg and 27.33 mg/kg and, 16.12 mg/kg and 14.94 mg/kg in the wet season. In Chokocho, the result showed a total concentration of 4.33 mg/kg and 252 mg/kg in the dry season and 23.87 mg/kg and 10.23 mg/kg in the wet season. Result showed a higher concentration of PAHs in the tops soil (0- 15 cm) compared to the subsoil at the depth (15 - 30 cm). The total PAHs concentration was consistently higher in the wet season than in the dry season. The concentration of PAHs was found to be majorly higher in the topsoil than the subsoil both in the dry and wet season. Diagnostic ratios reveal major source to be petrogenic. The concern for the environment and humans should prompt important stakeholders to take measures that will lead to mitigate the impact of these toxic chemical.

Microbial Community Response to Various Types of Exogenous Organic Matter Applied to Soil.

Recycling of solid biowaste and manure would reduce the dependence of agriculture on synthetic products. Most of the available studies on the effects of exogenous organic matter (EOM) application to soil were focused on nutrients and crop yield, with much less attention to microbiological processes in soil, especially using modern molecular methods. The aim of this study was to evaluate the effects of various types of manure, sewage sludge and bottom sediment on the biochemical activity and biodiversity of soil and plant yield in a pot experiment. The soil was treated with a range of EOM types: six types of manure (cattle, pig, goat, poultry, rabbit and horse manure; two bottom sediments (from urban and rural systems); and two types of municipal sewage sludge. All EOMs stimulated dehydrogenases activity at a rate of 20 t ha-1. Alkaline phosphatase was mostly stimulated by poultry manure and one of the sludges. In general, the two-fold greater rate of EOMs did not further accelerate the soil enzymes. The functional diversity of the soil microbiome was stimulated the most by cattle and goat manure. EOMs produce a shift in distribution of the most abundant bacterial phyla and additionally introduce exogenous bacterial genera to soil. Poultry and horse manure introduced the greatest number of new genera that were able to survive the strong competition in soil. EOMs differentiated plant growth in our study, which was correlated to the rate of nitrate release to soil. The detailed impacts of particular amendments were EOM-specific, but in general, no harm for microbial parameters was observed for manure and sludge application, regardless of their type. There was also no proof that the PAH and pesticide contents measured in manure or sludge had any effect on microbial activity and diversity.

Hydrocarbon markers for assessing the influence of human activities in the tropical semi-arid region (Acaraú River, state of Ceará, Brazil)

Coastal ecosystems are facing increasing anthropogenic stressors, including rapid urbanization rates and extensive fossil fuel usage. Nevertheless, the distribution of hydrocarbons in the Brazilian semi-arid region remains relatively uncharacterized. In this study, we analyzed ten surface sediment samples (0–2 cm) along the banks of the Acaraú River to assess the chronic contributions of aliphatic and aromatic hydrocarbons. The Acaraú River is a crucial riverine-estuarine area in the semi-arid region of Northeast Brazil. Ultrasound-assisted extraction and gas chromatograph coupled to a mass spectrometer were used to identify target compounds: 45 PAHs, 27 n-alkanes (C10–C38), and two isoprenoids. At most stations, the predominant grain size was sand, and the organic carbon content was less than 1%. The total n-alkanes concentration ranged from 14.1 to 170.0 μg g−1, while individual pristane and phytane concentrations ranged from not detected (nd) to 0.4 μg g−1 and nd to 0.7 μg g−1, respectively. These concentrations resemble those found in unpolluted sediments and are lower compared to samples from urbanized coastal areas. The total USEPA PAHs concentration varied from 157.8 to 1364 ng g−1, leading to the characterization of sediment samples as moderately polluted. Based on diagnostic ratios calculated from both alkane and PAH concentrations, the sediment samples were predominantly deriving from pyrolytic sources, with some contribution from petrogenic sources. The most abundant group was 5-ring PAHs (mean: 47.3 ± 36.7%), followed by 3-ring PAHs (mean: 17.9 ± 13.7%). This predominance indicates a pyrolytic origin of hydrocarbons in the Acaraú River. The concentrations reported here were representative of the level of background hydrocarbons in the region. Regarding the sediment quality assessment, BaP TPE calculated for the Acaraú River ranged from 13.2 to 1258.4 ng g−1 (mean: 409.3 ± 409.4 ng g−1). When considering site-specific sediment quality values for the coast of the state of Ceará, half of the stations are classified as strongly contaminated, and toxic effects are expected to occur (SQGq >0.25) for the ∑16 PAHs measured in the samples, especially due to dibenz [a,h]anthracene concentrations.

Linking PAHs concentration, risk to PAHs source shift in soil and water in epikarst spring systems, Southwest China

A systematic assessment of the variations in the ecological risk of PAHs and the key emission sources controlling the variations is of great importance to human health and aquatic organisms. PAH concentrations, composition, source, and ecological risk in soils and water in two different periods (2010–2011 and 2019) of three typical epikarst springs in Southwest China were investigated. Results showed that PAH concentrations in soil and water have an overall downward trend (a reduction of 57 % and 93 %, respectively) in the past 10 years, which is consistent with the downward trend in the relative contribution rate of raw coal production (a 66 % reduction). In terms of composition, the proportion of low-ring PAHs decreased, medium-ring and high-ring PAHs increased in the soil profile. The proportion of low-ring PAHs did not change obviously, the proportion of medium-ring PAHs increased, and the proportion of high-ring PAHs decreased in epikarst springs. The source of PAHs changed remarkably over time, the relative contribution of coal combustion to PAHs decreased from 38 % to 20 %, and the vehicle contribution of PAHs increased from 31 % to 44 % in soils. The relative contribution rate of unburned oil and coke oven and biomass combustion change is less. Furthermore, the ecological risk of PAHs in the soils was reduced from moderate risk 2 to moderate risk 1, the risk in epikarst spring was reduced from high risk to moderate risk 2 after 10 years. This study demonstrates that substituting petroleum and coal with green energies can reduce PAH concentrations and risk.

Polycyclic aromatic hydrocarbons: Measuring the air quality of three communities in Port Harcourt, Rivers State

There are a good number of major oil-producing companies as well as numerous activities that involve the combustion of organic matter. These activities release enormous quantities of pollutants into the atmosphere and there seems to be a paucity of data that captures the concentration of pollutants in the air as well as their health implications. This study was aimed at determining the levels/concentrations of polycyclic aromatic hydrocarbons in the surrounding air of three communities in Port Harcourt, Rivers State. Rivers State houses two oil refineries, a fertilizer company, and numerous companies. Sampling was conducted using the EGASPIN 2018 sampling procedure. Air samples were collected unto sterilized filter paper from the three communities using a Bosean meter. Sample extraction and analysis were conducted using GC-FID (EPA 8270). The study was conducted over the dry and wet seasons in 2019. Dry season result showed the presence of majorly four low molecular weight polycyclic aromatic hydrocarbons - naphthalene, fluorene, phenanthrene, and anthracene; in Okrika, concentrations of were 2.766±1.429 mg/kg, 0.976±0.491 mg/kg, 0.014±0.007 mg/kg and 0.040±0.023 mg/kg respectively; in Mgbuodohia the concentrations were 0.822±0.668 mg/kg, 1.199±0.626 mg/kg, 0.008±0.004 mg/kg and 0.012±0.009 mg/kg respectively; in Chokocho the concentrations were 0.144±0.097 mg/kg, 1.074±0.738 mg/kg, 0.001±0.000 mg/kg, and 0.142±0.067 mg/kg respectively. Wet season results showed the concentration of naphthalene, fluorene, phenanthrene, and anthracene; in Okrika, the concentration was 0.271±0.034 mg/kg, 0.108±0.019 mg/kg, 0.055±0.009 mg/kg and 0.001±0.000 mg/kg respectively; in Mgbuodohia the concentrations were 0.014±0.002 mg/kg, 0.005±0.004 mg/kg, 0.009±0.002 mg/kg and 0.001±0.000 mg/kg respectively; in Chokocho the concentrations were 0.001±0.000 mg/kg, 0.001±0.000 mg/kg, 0.002±0.001 mg/kg and 0.001±0.000 mg/kg. Against the backdrop of past studies linking the concentration of PAHs to the presence of refineries and other anthropogenic human activities, the Chokocho study location was chosen as a control site. The result agrees with the premise that air around regions where there is relatively less human activity like the combustion of organic matter, tend to have lower concentration of polycyclic aromatic hydrocarbon content. The total concentrations of PAHs in the air during the dry season are 3.809 mg/kg, 2.045 mg/kg, and 1.375 mg/kg in Okrika, Mgbuodohia, and Chokocho respectively, showing Okrika to be the most polluted followed by Mgbuodohia and lastly Chokocho. Source apportionment points to petrogenic, pyrolytic, and other possible sources. The detection of just four out of the sixteen priority PAHs points to the fact that there seems to be more effect on other matrices like soil and water.

Voyaging of halogenated polycyclic aromatic hydrocarbons, an emerging group of pollutants, on micro-mesoplastics in the marine environment

The limited existing research on the accumulation of hazardous chlorinated and brominated polycyclic aromatic hydrocarbons (ClPAHs and BrPAHs) in micro-mesoplastics (mMPs) motivated this investigation. We collected mMPs from the coastal environments of Sri Lanka and Japan. Out of 75 target compounds analyzed, 61 were detected, with total parent PAH concentrations reaching 16,300 and 1770 ng/g plastic in Sri Lanka and Japan, respectively. The total parent PAH concentrations in mMPs from the southern Sri Lankan coastline were relatively higher than those from the eastern coastline. Phenanthrene and naphthalene were the dominant parent PAH congeners in most mMP samples. Chlorinated pyrenes and brominated naphthalene were predominant among halogenated PAHs. The estimated toxic equivalency quotient (TEQ) ranged from 0.67 to 1057 ng-TEQ/g plastic, with the highest levels observed in polystyrene (PS) particles from the southern Sri Lankan coast. Benzo[a]pyrene and dibenzo[a,h]anthracene exhibited elevated TEQ for parent PAHs, whereas dichloropyrene, and dibromopyrene represented the highest TEQs for ClPAHs and BrPAHs, respectively. The data evidenced that several HPAH congeners can increase the PAH-like toxicity (∼86%) in mMPs. This study provides insights into the accumulation of parent and halogenated PAHs in mMPs, highlighting their potential combined implications in marine and terrestrial ecosystems.

Restoration of soils contaminated with PAHs by the mixture of zeolite composites mixed with exogenous organic matter and mineral salts

The major cause of soil degradation (contamination, erosion, compaction) is closely linked to agriculture, i.e., unsustainable agriculture practices, which are reflected in the depletion of the soil organic carbon pool, loss in soil biodiversity, and reduction of C sink capacity in soils. Therefore, the agricultural practice of applying carbon-rich materials into the soil is an attractive solution for climate change mitigation and soil ecosystem sustainability. The paper aimed to evaluate the effectiveness of the addition of organic-mineral mixtures to the mineral salts (NPK), including the exogenous organic matter (lignite) mixed with zeolite-carbon (NaX-C) or zeolite-vermiculite (NaX-Ver) composites in the restoration of soils contaminated with PAHs. The addition of zeolite composites to fertilizer resulted in a significant reduction in soil PAH levels and a corresponding reduction in plant tissue content, without compromising yields, compared to the control and separate application of NPK. A Significant correlation between PAHs and pHH2O, pHKCl, EC and dehydrogenase activity (DhA) was found in soils. The addition of zeolite composites with lignite significantly reduced the content of PAHs in straws, especially following the application of NaX-C. However, in the case of grains, the highest percentage reduction in comparison to NPK was observed for the highest dose of NaX-Ver.

Health Implications of Bioaccumulation of PAHs in Fluted Pumpkin (Telfairia occidentalis) and Waterleaf (Talinum fruticosum) along the Imo River Watershed, Imo State, Nigeria

The health implication of PAHs has been of great concern due to its contamination of the food chain. This study was carried out to identify the health challenges associated with the bioaccumulation of PAHs in Fluted Pumpkin (Telfairia occidentalis) and Waterleaf (Talinum fruticosum) along Imo River Watershed, Imo State, Nigeria. A total of 8 soil samples (0-30cm) were randomly collected from different activity areas on the watershed and analyzed for the presence of the 16 US-EPA priority PAHs in both soil and vegetable samples. The analysis of PAHs in the soil and vegetable samples were carried out in accordance with EPA 8270: (GC-MSD) and the results revealed that amongst the 16 US-EPA priority PAHs, eight of them were detected in the soil and vegetable samples. The total concentration of PAHs detected in the soil and vegetable samples were Naphthalene(0.146mg/kg), Acenaphthylene(0.010mg/kg), Acenaphthene(0.210mg/kg),Phenanthrene(0.021mg/kg),Anthracene(0.041mg/kg),Flouranthene(0.130mg/kg),Pyrene(0.020mg/kg),Benzo(b)fluoranthene(8.641mg/kg) and Naphthalene(0.090mg/kg),Acenaphthene(0.011mg/kg),Fluorene(0.010mg/kg),Phenanthrene(0.230mg/kg),Anthracene(0.190mg/kg),Flouranthene(0.010mg/kg),Benzo(b)fluoranthene(2.711mg/kg),I(1,2,3-cd)PY(0.540mg/kg) respectively. The decreasing order for individual PAHs concentration in the soil and vegetable samples within the study area were Benzo(b)Flouranthene>Acenaphthene>Naphthalene>Fluoranthene>Anthracene> Phenanthrene> Pyrene> Acenaphthelyne and Benzo(b) Flouranthene>I(1,2,3-cd)PY> Phenanthrene> Anthracene> Naphthalene>Acenaphthene> Fluorene>Fluoranthene respectively. For both soil and vegetables, total PAHs concentrations recorded in Obowo zone were observed to be higher than Okigwe zone. The result also revealed high values of PAHs in the edible vegetable samples collected around abattoirs and abandoned waste dump. It is therefore evident from this study that abattoirs and waste dumps have the potential to emit huge amount of PAHs to soil resource, which is taken up by edible vegetables leading to several health challenges when the vegetables are consumed. Different exposure to PAHs results in immune function suppression, cataracts, kidney and liver damage, skin inflammation, asthma, nausea, vomiting, eye irritation, diarrhea, confusion, lung and other cancers and probably death in chronic cases. There is need for public education on the consumption of vegetables grown in and around abattoirs and areas dominated by waste dumps.

An Investigation on the Removal of High Concentrations of PAHs Using Two-Liquid Phase System

Two-liquid phase systems consisting of two insoluble liquids can be effective in removing high concentrations of hydrocarbons from aqueous environments. In this study, the removal efficiencies of Naphthalene (Nap), Acenaphthene (Acn), Fluorene (Flu), Fluoranthene (Flr), Anthracene (Ant), and Pyrene (Pyr) at high concentrations in the two-liquid phase system were investigated. Two-liquid phase systems were constituted using Bis (2-Ethylhexyl) sebacate (BES) and aqueous fermentation media. Nutrient Broth (NB) and Bushnell Haas Yeast (BHY) medium were used as aqueous fermentation media. Acn, Flu, Flr, Ant, Pyr, and Nap were degraded at a rate of 93.1%, 80.8%, 57.6%, 68.5%, 63.8%, and 100%, respectively with BES/NB system. In the BES/BHY system, Acn, Flu, Flr, Ant, Pyr, and Nap, were degraded at a rate of 29.6%, 44.3%, 22.8%, 68.1%, and 19.7%, 45.4%, respectively. When both systems are compared, it has been shown that the BES/NB system can be effective under specified conditions.

Oil-Contaminated Soil Remediation with Biodegradation by Autochthonous Microorganisms and Phytoremediation by Maize (Zea mays).

Biological methods are currently the most commonly used methods for removing hazardous substances from land. This research work focuses on the remediation of oil-contaminated land. The biodegradation of aliphatic hydrocarbons and PAHs as a result of inoculation with biopreparations B1 and B2 was investigated. Biopreparation B1 was developed on the basis of autochthonous bacteria, consisting of strains Dietzia sp. IN118, Gordonia sp. IN101, Mycolicibacterium frederiksbergense IN53, Rhodococcus erythropolis IN119, Rhodococcus globerulus IN113 and Raoultella sp. IN109, whereas biopreparation B2 was enriched with fungi, such as Aspergillus sydowii, Aspergillus versicolor, Candida sp., Cladosporium halotolerans, Penicillium chrysogenum. As a result of biodegradation tests conducted under ex situ conditions for soil inoculated with biopreparation B1, the concentrations of TPH and PAH were reduced by 31.85% and 27.41%, respectively. Soil inoculation with biopreparation B2 turned out to be more effective, as a result of which the concentration of TPH was reduced by 41.67% and PAH by 34.73%. Another issue was the phytoremediation of the pre-treated G6-3B2 soil with the use of Zea mays. The tests were carried out in three systems (system 1-soil G6-3B2 + Zea mays; system 2-soil G6-3B2 + biopreparation B2 + Zea mays; system 3-soil G6-3B2 + biopreparation B2 with γ-PGA + Zea mays) for 6 months. The highest degree of TPH and PAH reduction was obtained in system 3, amounting to 65.35% and 60.80%, respectively. The lowest phytoremediation efficiency was recorded in the non-inoculated system 1, where the concentration of TPH was reduced by 22.80% and PAH by 18.48%. Toxicological tests carried out using PhytotoxkitTM, OstracodtoxkitTM and Microtox® Solid Phase tests confirmed the effectiveness of remediation procedures and showed a correlation between the concentration of petroleum hydrocarbons in the soil and its toxicity. The results obtained during the research indicate the great potential of bioremediation practices with the use of microbial biopreparations and Zea mays in the treatment of soils contaminated with petroleum hydrocarbons.

Transcriptomic analysis reveals responses to a polluted sediment in the Mediterranean copepod Acartia clausi

Marine sediments are regarded as sinks for several classes of contaminants. Characterization and effects of sediments on marine biota now require a multidisciplinary approach, which includes chemical and ecotoxicological analyses and molecular biomarkers. Here, a gene expression study was performed to measure the response of adult females of the Mediterranean copepod Acartia clausi to elutriates of polluted sediments (containing high concentrations of polycyclic aromatic hydrocarbons, PAHs, and heavy metals) from an industrial area in the Southern Tyrrhenian Sea (Bagnoli-Coroglio).Functional annotation of the A. clausi transcriptome generated as reference here, showed a good quality of the assembly and great homology with other copepod and crustacean sequences in public databases. This is one of the few available transcriptomic resources for this widespread copepod species of great ecological relevance in temperate coastal areas. Differential expression analysis between females exposed to the elutriate and those in control seawater identified 1000 differentially expressed genes, of which 743 up- and 257 down-regulated. Within the up-regulated genes, the most represented functions were related to proteolysis (lysosomal protease, peptidase, cathepsin), response to stress and detoxification (heat-shock protein, superoxide dismutase, glutathione-S-transferase, cytochrome P450), and cytoskeleton structure (α- and β-tubulin). Down-regulated genes were mostly involved with ribosome structure (ribosomal proteins) and DNA binding (histone proteins, transcription factors). Overall, these results suggest that processes such as transcription, translation, protein degradation, metabolism of biomolecules, reproduction, and xenobiotic detoxification were altered in the copepod in response to polluted elutriates. In conclusion, our results contribute to gaining information on the transcriptomic responses of copepods to polluted sediments. They will also prompt the selection of genes of interest to be used as biomarkers of exposure to PAHs and heavy metals in molecular toxicology studies on copepods, and in general, in comparative functional genomic studies on marine zooplankton.

Simultaneous determination of polycyclic aromatic hydrocarbons and polychlorinated biphenyls in Pu-erh tea by dispersive solid-phase extraction coupled with GC-MS/MS

A novel method for the simultaneous determination of 13 PAHs and 18 PCBs residues in Pu-erh tea samples was established by combining GC-MS/MS with dispersive-solid phase extraction (d-SPE). Sample pretreatment procedure was achieved by NaCl addition and using acetone/ethyl acetate/n-hexane (50:30:20, v/v/v) extraction followed by d-SPE clean-up with strong cationic exchanger (SCX), primary secondary amine (PSA), polyvinylpolypyrrolidone (PVPP) and graphitized carbon black (GCB). The proposed method had good linearity in the range of 0.5–200 μg/L with correlation coefficients (R2 > 0.998). The detection limit ranges (LODs) were from 0.2 to 1.5 µg/kg. The spiked experiments in raw Pu-erh tea and ripened Pu-erh tea at 2.5–50 µg/kg concentrations showed satisfactory recoveries (70.2–114.7%) for all analytes with RSDs of < 10%. The validated methodology was successfully applied to 86 Pu-erh tea samples. No PCBs residue was more than LODs, and the detection frequency and concentration of PAHs in different types of Pu-erh tea varies greatly were found.

Ecotoxicity of sediments in Ho Chi Minh city’s canals

For an ecotoxicological screening of recently deposited sediments, samples were collected from Ho Chi Minh City’s canals in August 2015. The sediments were characterized by physico-chemical analysis of metals, PAHs, PCBs, and other organic micropollutants, and standard sediment toxicity testing. The results showed that the sediments from the canals from both the urban and suburban areas contained a mixture of contaminants with concentrations of several metals, PAHs, PCBs and OCs being above thresholds for effects to benthic organisms. The results of the chemical analyses were corroborated by toxicity detected in standard laboratory tests with crustaceans (ostracods) and insect (midge) larvae. Conspicuous concentrations at the μg/g level were found for the fragrances galaxolide and OTNE, and nonylphenol, triclosan and the UV filters octocrylene, 2-EHDP and EHMC were measured at all sampling sites at concentrations of several tens and even hundreds ng/g. Highest concentrations were measured for the pyrethroid insecticide permethrin in sediments from the urban area and for the pyrethroid insecticide bifenthrin in sediments from suburban areas (3692.9 ng/g dw and 477.6 ng/g dw, respectively). Insecticides were identified as the most probable contributors to the observed toxicity.

Adjusting effects of pyrolytic volatiles interaction in char to upgrade oil by swelling waste nylon-tire

Waste nylon-tire (WNT) is a typical solid municipal waste, pyrolysis efficiently disposes WNT to produce oil containing high-value chemicals. Upgrading the quality of oil is the key to improve WNT pyrolysis economy. Herein, swelling was applied to pretreat WNT, and swelled waste nylon-tire (SWNT) was pyrolyzed at different temperatures (400 °C–600 °C). Lower than 500 °C, swelling pretreatment realized the number of compounds in oil by GC–MS decreased 59.57% at 400 °C (60.78% at 450 °C, 67.97% at 500 °C) compared to Waste nylon-tire pyrolytic oil (TPO). Over 500 °C, this phenomenon weakened, decreased 47.67% at 550 °C (11.48% at 600 °C). At 400 °C and 450 °C, long chain methyl esters yield was over 30 A.% instead of short chain alkanes in TPO. D-limonene yield was over 20 A.% in oil of swelled waste nylon-tire (STPO). From 500 °C to 600 °C, swelling pretreatment affected the relative content of BTX and PAHs. At 500 °C and 550 °C, the relative content of BTX in STPO was more than twice of TPO, and BTX reached 28.75 A.% at 600 °C. PAHs in STPO appeared at 500 °C higher than TPO (450 °C), and PAHs was 0.73 A.% at 500 °C. Swelling pretreatment could produce more larger pores in particle during pyrolysis, which sharply inhibited the interaction of volatiles inside tire, so the number of compounds in oil sharply decreased at lower temperatures. Over 550 °C, temperature became the dominant role for generating oil, and components tended to be similar for STPO and TPO. CS2 with high-volatility released quickly from WNT during pyrolysis, it could be recycled to reduce final cost and environment impacts.

The Impact of Highly Weathered Oil from the Most Extensive Oil Spill in Tropical Oceans (Brazil) on the Microbiome of the Coral Mussismilia harttii.

In 2019, the largest oil spill ever recorded in tropical oceans in terms of extent occurred in Brazil. The oil from the spill was collected directly from the environment and used in an exposure experiment with the endangered reef-building coral Mussismilia harttii. The treatments of the experiment were control (without oil), 1% oil, 2.5% oil, and direct contact of coral with oil. The most abundant hydrocarbon in the seawater of the experiment was phenatrene, which is toxic to corals. However, overall, the concentration of PAHs was not very high. The analysis of the maximum photosynthetic capacity of Symbiodiniaceae dinoflagellates showed a small impact of oil on corals, mainly on the contact treatment. However, coral microbiomes were affected in all oil treatments, with the contact treatment showing the most pronounced impact. A greater number and abundance of stress-indicating and potentially pathogenic bacteria were found in all oil treatments. Finally, this highly weathered oil that had lain in the ocean for a long time was carrying potentially coral-pathogenic bacteria within the Vibrionaceae family and was able to transmit some of these bacteria to corals. Bacteria within Vibrionaceae are the main causes of disease in different species of corals and other marine organisms.

In vitro toxicity and lung cancer risk: Atmospheric particulate matter from a city in southeastern Brazil impacted by biomass burning

The effects of PM10 on human health were investigated using samples collected in São Carlos city (São Paulo state), by the determination of the concentrations of PAHs and derivatives, together with evaluations of cytotoxicity and the formation of ROS in in vitro tests. In 2016, the mean concentrations of PM10, ΣPAHs, Σoxy-PAHs, Σnitro-PAHs, Σsaccharides, and Σions were 21.12 ± 9.90 μg m−3, 1.47 ± 1.70 ng m−3, 0.37 ± 0.31 ng m−3, 0.84 ng m−3, 119.91 ± 62.14 ng m−3, and 5.66 ± 4.52 μg m−3, respectively. The PM10 concentrations did not exceed the limit thresholds set by national legislation, however, the annual lung cancer risk calculated was 2.59 ± 1.22 cases per 100,000 people, in the dry season, which accounts for the annual risk (April to September). Moreover, the carcinogenic activities of the PAHs mixture were more than 1000-fold higher in the dry season (dry season: BaPeq = 0.30 ng m−3; wet season BaPeq = 0.02 ng m−3). The concentrations of most analytes were also higher during the dry season, as had already been demonstrated in the same city. This was due to reductions in precipitation, relative humidity and air temperature, and increased biomass burning, which was the main source of PM10 in the city in 2016 (contribution rate of more than 50%). Toxicological results also showed the negative impacts of PM10, exposure to PM10 extracts for 72 h reduced the viability of A549 and MRC5 cells, and the formation of ROS was observed. The cellular responses obtained using combined and individual extracts of PM10 differed and were sometimes associated with specific compounds. These demonstrate the importance of monitoring PM toxicity using different approaches and the main anthropogenic sources’ contribution. Therefore, to improve air quality and human health, existing legislation needs to be modified to incorporate these tests.

Pollution Characteristics and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Farmland Soil and Crops in the Suburbs of Urumqi

In order to understand the occurrence of PAHs in soil and crops, the enrichment capacity of different crops for PAHs, and the distribution characteristics of PAHs in different parts of crops, the crops and soil planted in the farmland around Urumqi were studied as examples. Samples were collected in the farmland gathering area in the suburb of Urumqi in July 2021. A total of 100 crop samples were collected, including 21 crop species and 45 surface soil samples. The results showed that 16 types of PAHs were detected in the soil and crops. The total concentration of PAHs in farmland soil ranged from 19.06 to 1870.86 μg·kg-1, and the average concentration was 127.40 μg·kg-1. Seven carcinogenic PAHs accounted for 42.85%-79.20% of the 16 types of PAHs, among which BaP was the main pollutant in the soil. Through the characteristic ratio method, it was found that the main sources of PAHs in the soil were biomass and coal combustion. Total PAHs in crops ranged from 1.86 μg·kg-1 to 974.05 μg·kg-1, with an average of 303.30 μg·kg-1. Different crops had different enrichment capacities for PAHs. Among the 21 crops sampled, the accumulative content of PAHs in pumpkin was the highest (431.75 μg·kg-1). In leaf vegetable crops, the content of PAHs in leaves was higher than that in roots and fruits. In fruit and vegetable crops, the PAH content in fruit was higher than that in the root or leaf. There was a significant correlation between high cyclic PAHs in soil and PAHs in plant leaves. The health risk assessment of PAHs in crops showed that dietary intake had potential carcinogenic risk and even had high carcinogenic risk in adult male and female groups, which requires further attention.

PROXIMATE ANALYSIS AND DETERMINATION OF POLYCYCLIC AROMATIC HYDROCARBONS IN PROCESSED ANIMAL SKIN SOLD IN MAJOR MARKETS IN SOUTH WEST NIGERIA.

This study aimed at determining the nutritional and level of chemical contaminants (heavy metals and Polyaromatic Hydrocarbons PAHs) incommonly consumed animal skin sold in major markets in South-West, Nigeria. Proximate analysis (crude protein, moisture content, carbohydrate, ash content, oil content, nitrogen value and crude fibre) and heavy metals and PAHs concentrations were determined to evaluate the nutritional composition and safety of regular consumption of these products and to validate the notion that animal skin as a source of protein, can replace meat in meals. Samples of animal skin were purchased from three major markets in Lagos and Ogun State. Proximate composition was determine using standard analytical methods, while levels of heavy metal (Fe, Pb, Cd, Cr and As) and PAHs were using Atomic Absorption Spectroscopy and GC-MS respectively.The results of proximate composition were as follows (%); for the brown samples; the moisture content (≤81.40±1.80, ash content (≤0.94±0.01, oil content (≤1.60±0.01, crude protein (≤3.75±0.85, crude fibre (≤1.25±0.01) and carbohydrate (≤14.51±1.20). The concentrations of heavy metals detected in the samples were as follows (mg/kg); Fe ≤0.068±0.001, Cd ≤0.006±0.001, Pb≤0.004 ±0.001 and Cr≤0.004±0.001, all were below the maximum permissible limit set by WHO and USEPA while, Arsenic was below the detection limit of the instrument. Seventeen PAHs were detected in the samples and all were above the maximum permissible limits with high health risk. It is therefore advised that cow skin be discouraged and more awareness created so that people will know the dangers to health posed by this harmful practice.&#x0D;

Integrated Ecological Risk Assessment of the Agricultural Area under a High Anthropopressure Based on Chemical, Ecotoxicological and Ecological Indicators

Agricultural land is often located close to highly urbanised/industrialised areas and is subject to continuous anthropogenic pressure associated with the emission of many pollutants, ultimately deposited in the soil. Most studies on ecological risk assessment have only analysed the total contaminants’ concentration, which does not reflect their bioavailability or toxicity and often leads to an overestimation of risk. Therefore, in our study, we used an interdisciplinary approach, whereby the final conclusions about the risk in a given area are based on the integration of detailed data from chemical, ecotoxicological and ecological analysis. The research was carried out on agricultural land exposed to high levels of anthropopression for more than 100 years. Chemical measurements comprised both the total and bioavailable PAH content. A battery of bio-assays describing effects on soil retention and habitat function was used for ecotoxicity testing, and ecological indicators included enzymatic activity, respiration, microbial biomass, carbon mineralisation and nitrification. The integrated IntRisk index ranged from 0.19 to 0.94, and this was mainly due to high values of the chemical risk index, while the ecotoxicological and ecological results indicated no or low risk. The majority of the area (almost 90%) had acceptable risk levels, no/low risk (IntRisk &lt; 0.5) at 57% of the sites and medium risk at 28% of the area. Very high unacceptable risk (IntRisk 0.77–0.94) was only at three sampling sites. The integration of data from a set of 15 indicators allowed us to derive quantitative risk indexes and delineate the limited area which needs additional action.