Total Polycyclic Aromatic Hydrocarbons Research Articles

Distribution and sources of polycyclic aromatic hydrocarbons in cascade reservoir sediments: influence of anthropogenic activities and reservoir hydrology.

The construction of dams has caused disruptions to river connectivity, leading to alterations in the deposition of hydrophobic organic contaminants in reservoir sediments. Further investigation is warranted to explore the impact of cascade reservoirs with differing hydrological characteristics on polycyclic aromatic hydrocarbons (PAHs) distribution in sediment. This study examines the presence of 30PAHs in the sediments collected from six cascade reservoirs situated in the Wujiang River basin during January and July 2017. The results showed that Σ30PAHs ranged from 455-3000ng/g dw (mean 1030ng/g dw). Anthropogenic activities and reservoir hydrology determined the distribution trend of PAHs in sediments, with an overall increase from upstream to midstream and then a decrease downstream. The PAH levels were highly linked to the secondary industry (P < 0.05). This was further supported by the relationship between the PAH emissions from coal combustion and traffic sources analyzed by the positive matrix factorization model and economic parameters in the wet season (P < 0.01). At the same time, reservoir age (RA) showed a positive correlation with PAH concentrations (P < 0.05), while hydraulic retention time (HRT) exhibited a negative correlation with PAH levels (P = 0.03). The relationship between total organic carbon (TOC) and PAHs in stream sediments worldwide was nonlinear (P < 0.01), with PAH concentrations initially rising and then falling as TOC levels increased. Concerns regarding carcinogenic risk were raised due to contributions from coal and vehicular sources, with the risk increasing with RA.

Occurrence and exposure to polycyclic aromatic hydrocarbons (PAHs) in traditional dry-cured or smoked meat products from Brazil

Polycyclic aromatic hydrocarbons (PAHs) are classified as environmental and food contaminants, with several adverse health effects, especially genotoxic and carcinogenic actions. In processed meats, they are the major contaminants, especially those subjected to smoking processes. Considering that the population is exposed to PAHs through several routes, and that the ingestion of contaminated food is considered the main one, evaluating the concentrations of these contaminants in food becomes essential, as well as the exposure and risk to the population at different ages through ingestion of the evaluated products. In the current study, the levels of nine PAHs (PAH9) were measured in 205 processed meat products commercially available and with high consumption in Brazil. The methodology involved saponification, extraction with n-hexane, purification with solid-phase extraction (SPE) silica cartridges, and quantification by liquid chromatography with fluorescence detection. In general, 83% of all samples were contaminated with at least one of the studied PAHs, and the measured PAH9 levels ranged between < LOQ-108.24 µg/kg. The highest mean of total PAHs was found in smoked sausage (108.24 μg/kg), while the lowest content was found in ham (1.83 μg/kg). Benzo[a]pyrene (BaP) and PAH4 (benz[a]anthracene, chrysene, benzo[b]fluoranthene, and BaP) exceeded the maximum permissible limits of the European Union (EU) in three (1.5%) and 18 samples (8.7%), respectively. The results of margin of exposure results (MOE ≥ 10,000) and incremental lifetime cancer risk (ILCR) values (10 − 6 < ILCR < 10 − 4) in all ten types of meat indicated there were low significant potential health problems related to meat products consumption for the Brazilian population.Graphical

Tourism activities significantly contributed toatmospheric pollutants in a remote town of Tianshan revealed by the continuous observation of two years

The large reduction in tourism activities in 2020 provided a unique opportunity to investigate their contribution on atmospheric pollutants in Bayanbulak, a remote town in Tianshan, China. In this scenic and sensitive region, we measured total suspended particulates (TSP) along with concentrations of polycyclic aromatic hydrocarbons (PAHs), organic carbon (OC), elemental carbon (EC) and water-soluble inorganic ions (WSIIs) during the lockdown in 2020 and compared these to levels in the pre-pandemic period of 2019. The study revealed significant reductions in PAHs, OC, EC, and some WSIIs concentrations during the tourist season (May–October) of 2020 compared with 2019, whereas variations between non-tourist seasons were less pronounced. Furthermore, by comparing pollutant characteristics in tourist seasons of these two years, we found that 5- and 6-ring groups were main PAH constituents in 2019, while 5- and 3-ring groups contributed more to total PAHs in 2020. OC/EC ratio increased from 2019 to 2020, indicating an increase of biomass burning contribution after the lockdown. Using positive matrix factorization, we determined that emissions from tourism-related transportation and combustion of natural gas and coal (mainly for cooking) contributed 21.9% and 46.6%, respectively, to certain atmospheric pollutants in 2019, whereas they decreased significantly to 3% and 19.4% in 2020 with dust and biomass contributions increased substantially. The levels of PAHs, OC, and EC from tourism-related sources were as high as 9.31 ng m−3, 1.28 μg m−3 and 0.11 μg m−3 and decreased by 54.37%, 25.16%, and 9.54%, respectively, compared to 2019. Hence, the impact of tourism must be considered during the assessment of local air pollutant emissions, particularly in remote areas.

Origin of biomarkers (PAH, n-alkane, hopane, estrane) in different colors of plastic resin pellets and surface sediments from coastal area of the Makuran-Oman Sea

The unique attributes of the study area, situated near the Strait of Hormuz—an extensively utilized oil shipping corridor for Iran and neighboring Arabian nations—encompass oil extraction and exploitation, the establishment of an oil export hub, the advancement of petrochemical industries, as well as tourism and transportation activities. This research represents the first examination of the sources of plastic resin pellet release, addressing both local and non-local contributions. To conduct this study, samples of plastic resin pellet and coastal and intertidal surface sediments were collected from seven stations on the shores of the Oman Sea in Hormozgan province (Sirik, Garook, Ziarat, Karpan, Koohestak, Gohardo, and Kargan) with four replications to determine the origin and spatial distribution pattern of hydrocarbons and the diffusion source of plastic resin pellets (offshore or regional). Plastic resin pellets were separated based on color (white, yellow, brown, and black). Soxhlet was used to extract hydrocarbons, two stages of column chromatography were used to separate compounds, and gas chromatography–mass spectrometry (GC–MS) was used to identify and determine their concentration. The total n-alkanes concentration ranged from 2940 to 18,711 (μg/g) in coastal surface sediments, from 19,721–1678 (μg/g) in intertidal surface sediments, and from 11,481.50 to 55,601.41 (μg/g) in plastic resin pellets. A similar trend was found for the total PAH concentration which ranged from 135.57 to 3890.62 (ng/g) in coastal sediments, from 1820.28 to 6579.55 (ng/g) in intertidal sediments, and from 3714.19 to 66/1920451 (ng/g) in plastic resin pellets. According to the sediment pollution criteria, a high pollution level was assessed in most of the stations. In most of the surface sediments and plastic resin pellets, the presence of unresolved complex mixture (UCM), the carbon preference index (CPI) lower than 1, and the diagnostic ratios of PAH, hopane, and sterane compounds indicated petrogenic origin for hydrocarbons. The results of principal component analysis based on 16 diagnostic ratios of PAH, n-alkane, hopane, and sterane compounds showed that brown and black plastic resin pellets were placed in a different group than the coastal and intertidal sediments and white and yellow plastic resin pellets. Most likely, the diffusion source of brown and black plastic resin pellets is different and through open water.

Content of Selected Harmful Metals (Zn, Pb, Cd) and Polycyclic Aromatic Hydrocarbons (PAHs) in Honeys from Apiaries Located in Urbanized Areas.

The chemical composition of honey, and therefore its quality and properties, is influenced by many factors, including its botanical origin and the harvesting conditions-the location of the apiary, access to melliferous plants, the proximity of industrial infrastructure and communication routes, etc. This quality may be reduced by undesirable, toxic compounds that penetrate honey from a contaminated environment, such as heavy metals and residues from other environmental pollutants. Therefore, the aim of our research was to assess the quality of honeys from urbanized areas-in particular, to assess contamination with heavy metals and persistent organic pollutants (PAHs). In total, 35 samples from six different apiaries located in urbanized areas were examined. The content of heavy metals (Cd, Pb, Zn) was determined by atomic absorption spectrophotometry (AAS), and the content of total PAHs as the sum of the concentrations of the compounds benzo(a)anthracene, chrysene, benzo(b)fluoranthene and benzo(a)pyrene was determined by high-performance liquid chromatography with fluorescence detection (HPLC-FLD). The average zinc content ranged from about 2 to 4.5 mg/kg, the average lead content ranged from 3.5 µg/kg to 388 µg/kg and the average cadmium content ranged from 0.5 to 14 µg/kg. It was found that all honeys contained certain amounts of harmful metals, and only lead exceeded the permissible limits. None of the samples tested contained sum content of PAHs exceeding 10 µg/kg of honey. Contrary to our expectations, the results obtained indicate that honeys from urbanized areas do not contain these harmful substances. In general, the presence of harmful metals does not, however, reduce honey's quality or its health value.

Determination of PAH Contamination in Breast Milk Samples from Hungarian Volunteering Mothers, Using HPLC-FLD.

(1) The evidence is mounting that polycyclic aromatic hydrocarbons (PAHs) are a class of hazardous organic compounds with established carcinogenic and toxic properties. Humans may be exposed to PAHs through several different routes, including diet, inhalation, and dermal contact. There is also a possibility that they could transfer into breast milk following maternal exposure, which could potentially endanger breastfeeding infants. (2) The objective of this study was to ascertain the concentration of polycyclic aromatic hydrocarbons (PAHs) in breast milk samples from 50 Hungarian mothers, employing high-performance liquid chromatography with fluorescence detection (HPLC-FLD). An Incremental Life Risk Calculation (IRCL) model estimated the carcinogenic risk to infants. (3) Total PAH concentrations ranged from 0 to 78 ng/mL, with fluorene (5.3 ng/mL), phenanthrene (3.2 ng/mL), and pyrene (2.5 ng/mL) being the most abundant. PAHs were detected in 48 of the 50 samples, with phenanthrene present in 92% of samples. Dibenzo (a,h)anthracene was not detected. (4) According to the model measurements, most of the samples were within acceptable risk levels; however, 2 samples out of 50 posed a higher risk. Statistical analysis of questionnaires completed by the mothers indicated that factors such as diet, residence, and education may influence PAH levels in breast milk.

A National-Scale Study of Polycyclic Aromatic Hydrocarbons in Surface Water: Levels, Sources, and Carcinogenic Risk

Elucidating pollution characteristics of polycyclic aromatic hydrocarbons (PAHs) in water and assessing the associated carcinogenic risks is crucial for improving public health. PAHs in the surface water of seven main river basins across China, compiled from 95 studies from 2004 to 2022, were used to investigate geographic variations of occurrence, source, and carcinogenic risk. Total PAH concentrations exhibited substantial geographic distributions ranging from 300 to 7552 ng·L−1. Low molecular weight PAHs predominated, showing three-ring PAHs abundant in the north, while two-ring PAHs dominated in the south due to distinctions regarding energy consumption. The northern basins exhibited higher concentrations of PAHs than the southern owing to the synergistic impacts of low temperature, increased energy consumption, and higher industrial activities. Coal combustion and industrial emissions were the primary contributors in the northern basins, accounting for 23–44% and 20–38%, respectively, which were associated with pollutants released from heavy industries and space heating during cold periods. In contrast, vehicle exhaust emissions and petroleum leakage from river transport constituted the principal sources in the relatively economically developed southern basins, accounting for 24–35% and 31–57%, respectively. A lifetime carcinogenic risk model revealed that the highest health risks existed in adults, followed by adolescents and children. Toxic concentrations of BaP and the daily intake of water directly enhanced the PAHs’ carcinogenic risks, while body weight featured negative correlations with the risks.

Variability of PAH Patterns in Upper Forest Soil (Sub)horizons—A Case Study From South‐Central Poland

ABSTRACTPolycyclic aromatic hydrocarbons (PAHs) are a class of contaminants characterized by their persistent and toxic nature. This study examines the variability in PAH distribution patterns in the upper layers of forest soils, focusing on the influence of different characteristics of individual soil (sub)horizons. A total of 130 samples were collected from five forest areas in south‐central Poland and analyzed for the 16 priority PAHs. Samples were taken from the organic fermentative‐humic (Ofh), humic (A), and humic‐eluvial (AE) (sub)horizons. The highest mean concentrations of total PAHs were found in the subhorizon‐Ofh (Ofh—1547 μg kg−1, A—1103 μg kg−1, AE—109 μg kg−1). The PAH content was significantly correlated with SOM content and pH, but this correlation was only significant in the horizon‐A. The percentage contributions of 3‐, 4‐, 5‐, and 6‐ring compounds to the total PAHs varied among the investigated soil (sub)horizons. The subhorizon‐Ofh had the highest percentage contribution of 6‐ring PAHs, 4‐ and 5‐ring PAHs were most prevalent in the horizon‐A, while 3‐ring compounds in the horizon‐AE. The variability in PAH patterns was also reflected in individual PAH ratios (BaA/BaA+Chr, IcdP/IcdP+BghiP), confirming the different behavior of 4‐, 5‐, and 6‐ring compounds in these (sub)horizons. This suggests that the retention of PAHs in the investigated (sub)horizons is influenced by several factors, including pH, degree of SOM decomposition, and mineral fraction, each to a different extent. Our findings reveal significant knowledge gaps regarding the behavior and accumulation of PAHs in soil (sub)horizons, underscoring the need for further research.

Multiple-Integrated Biomarker Indexes to Assess the Responses of the Flatfish Achirus lineatus during Exposure to Light Crude Oil Water Accommodated Fraction.

In the present study, we evaluated the biological response of Achirus lineatus to water accommodated fraction (WAF) of light crude oil (American Petroleum Institute gravity 35°) during a sub-chronic bioassay (14 and 28 days) at two different concentrations: 5% v/v (1.20µg∙L- 1 expressed as total polycyclic aromatic hydrocarbons [∑25 PAH]) and 10% v/v (6.61µg∙L- 1 [∑25 PAH]). The responses were evaluated through the biomarker response index (BRI), the integrated biomarker response (IBRv2) and the bioconcentration factor (BCF). The results showed an increase in biological response in relation to WAF concentration and exposure time, which resulted in a slight and moderate disturbance in the basal condition and bioconcentration level of metals (Pb > Ni > V > Cd) in fish tissue. Results in the present study denote that flatfish such as A. lineatus may be negatively influenced by spilled light crude oil.

The trophodynamics of polycyclic aromatic hydrocarbons in marine food webs: The importance of trophic level span from insights into Liaodong Bay (China).

The occurrence and trophic transfer of polycyclic aromatic hydrocarbons (PAHs) in aquatic ecosystems is vital to assess ecological risks. PAHs concentrations were analyzed in seawater, sediment, plankton, and marine species (15 fish species, 8 invertebrate species, 3 marine mammals), collected from Liaodong Bay (China). Bioaccumulation and biomagnification were calculated to demonstrate the biotransfer pattern of PAHs from the environmental matrix to high-level predators through the food web. Total PAHs concentrations ranged from 81.2 to 197.6 ng/L in seawater, 51.4 to 304.8 ng/g (dw) in sediment, and 65.3 to 28,885 ng/g (lw) in all biota samples. Three- and four-ring PAHs constituted major components (> 81% in each case) of PAH congener profiles. Lower biota-sediment accumulation factors (BSAFs) and bioaccumulation factors (BAFs) values indicated limited bioaccumulation of PAHs within marine organisms. Also, 77% of biomagnification factors (BMFTL) values of PAHs in spotted seal and finless porpoise were >1, whereas opposite transfer patterns of PAHs were observed in food webs with trophic values of 1.5-3.5 and 3.0-4.0; that is, trophic dilution (trophic magnification factor (TMF) <1) and trophic magnification (TMF >1), respectively. This study provides novel insights into the importance of TL span for trophodynamics of PAHs within food webs.

Eco-friendly electrospun nanofibers for air filtration enhanced by TiO2 nanoparticles reactive phases for superior capturing the emitted polycyclic aromatic hydrocarbons (PAHs)

The electrospinning nanofibrous filters have attracted much attention owing to their distinctive physicochemical properties. This work focused on designing a novel, straightforward prototype model and fabricating eco-friendly electrospun nanofiber filters as promising air filtration. The synthesized electrospun nanofiber is composed of cellulose acetate (CA) and thermoplastic polyurethane (TPU), which was enhanced by TiO2 nanoparticles to improve the capturing of low, medium, and high molecular weight PAHs. The fabricated CA:TPU/TiO2 and their derivatives were analyzed using FT-IR, XRD, TEM, SEM, TGA, and mechanical characteristics. Different concentrations of TiO2 (2 %, 4 %, 6 %, 8 %) were evaluated. The determinations of PAHs were achieved using gas chromatography-mass spectrometry (GC–MS) with a TG-5MS column. The newly designed prototype has two air pathways with identical specifications; therefore, it could simultaneously evaluate the efficiency of two filters. In Motobas dumpsite (agricultural sources), the results indicated that the highest efficiency of electrospun nanofiber filters was CA:TPU/TiO2 6 %, captured 3041 µg/m3 of total PAHs, and also in the incinerator stack (industrial sources) was CA:TPU/TiO2 6 % captured 9401 µg/m3 of total PAHs. The concentrations of low molecular weight PAHs were greater than the high molecular weight in all sites, and the electrospun CA:TPU/TiO2 was the most effective catalyst for air purification.

Occurrences of Deposited Polycyclic Aromatic Hydrocarbons in Wax of Plant Leaves Using Laser Scanning Microscopy and Gas Chromatography–Mass Spectrometry

The knowledge of the deposition fate of ambient polycyclic aromatic hydrocarbons (PAHs) on plant leaves is limited. To fill in this knowledge gap, this study strives to observe the intermolecular complex between the polycyclic aromatic hydrocarbons and epicuticular wax of plant leaves using laser scanning microscopy. Epicuticular wax refers to a type of organic mixture that covers the outermost layer of leaves. The leaves of 20 tree species were collected in Beijing in July 2023. The concentrations of 31 PAHs were quantified by gas chromatography–mass spectrometry. Furthermore, the intermolecular complexes of polycyclic aromatic hydrocarbons and epicuticular wax were found with a fluorescence spectrofluorometer and laser scanning microscopy. The levels of total PAHs across 20 tree species ranged from 12.4 ng g−1 to 68.4 ng g−1. Differences in the amounts of total PAHs across tree leaves were observed, which may be ascribed to the differences in leaf surface across tree types. The higher concentration of low-molecular-weight PAHs was found in leaves compared to high-molecular-weight PAHs. The fluorescence spectrofluorometer identified the formation of a new intermolecular complex with fluorescence emission at an excitation wavelength of 340 nm between PAHs and epicuticular wax relative to PAHs. We used laser scanning microscopy with a 405 nm laser for excitation to observe the new intermolecular complex of PAHs and epicuticular wax on the stomata and epicuticular wax of leaves. This study found the intermolecular complex of PAHs on the surface of leaves in situ, which provides important information about the deposition fate of ambient PAHs.

Polycyclic aromatic hydrocarbons (PAHs) in black crusts on stone monuments in Milan: detection, quantification, distributions, and source assessment

In the field of conservation of cultural heritage, one must always consider the environmental conditions in which the works of art are located and the level of atmospheric pollution to which they are exposed, especially in the case of monuments stored outdoors. The present study is focused on the detection and the quantification of polycyclic aromatic hydrocarbons (PAHs) in black crust samples from the Monumental Cemetery of Milan (Italy), and the assessment of their sources through the analysis of the distributions of the different compounds in the samples, together with the use of diagnostic ratios. Six black crust samples taken from funerary monuments were analyzed. Fourteen polycyclic aromatic hydrocarbons were identified (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, chrysene, benzo[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-cd]pyrene) by high-performance liquid chromatography with a diode-array detector (HPLC–DAD), with a total concentration from 0.72 to 3.81 μg/g (mean of 1.87 μg/g). The known carcinogenic benzo[a]pyrene accounted for 5–10% of the total polycyclic aromatic hydrocarbons in the samples analyzed, with concentrations up to 0.20 μg/g. Moreover, the study of the distribution and diagnostic ratios allowed us to confirm that anthropogenic sources such as traffic and the proximity of the train station are the major causes of the degradation of the monuments contained in this Cemetery.

An evaluation of in utero polycyclic aromatic hydrocarbon exposure on the neonatal meconium microbiome

IntroductionIn utero exposure to environmental polycyclic aromatic hydrocarbon (PAH) is associated with neurodevelopmental impairments[1–8], prematurity[9–12] and low birthweight[9,13–15]. The gut microbiome serves as an intermediary between self and external environment; therefore, exploring the impact of PAH on microbiota may elucidate their role in disease. Here, we evaluated the effect of in utero PAH exposure on meconium microbiome. MethodsWe evaluated 49 mother-child dyads within Fair Start Birth Cohort with full term delivery and adequate meconium sampling. Prenatal PAH was measured using personal active samplers worn for 48 h during third trimester. Post-processing, 35 samples with adequate biomass were evaluated for association between tertile of PAH exposure (high (H) vs low/medium (L/M)) and microbiome diversity. ResultsNo significant differences were observed in alpha diversity metrics, Chao1 and Shannon index, between exposure groups for total PAH. However, alpha diversity metrics were negatively associated with log benzo[a]anthracene (BaA) and log chrysene (Chry) with high exposure, but positively associated with log benzo[a]pyrene (BaP) with low/medium exposure. After adjustment for birthweight and sex, alpha diversity metrics were negatively associated with log BaA, BaP, Chry, Indeno (Zhang et al., 2021; Perera et al., 2018)pyrene (IcdP) and total PAH with high exposure. Conversely, with low/medium exposure, alpha diversity metrics positively correlated with log BaP and benzo[b]fluoranthane (BbF). No significant difference in beta diversity was observed across groups using UniFrac, weighted UniFrac, or Bray-Curtis methods. Differential expression analysis showed differentially abundant taxa between exposure groups. ConclusionBacterial taxa were detectable in 35/49 (71%) meconium samples. Altered alpha diversity metrics and differentially abundant taxa between groups suggest in utero PAH exposure may impede early colonization. Sample size is limited, but these findings provide supporting evidence for wider scale research. Research on long-term impact of prenatal PAH exposure on childhood health outcomes is ongoing. Differential effects of specific PAHs need further evaluation.

Assessment of soil pollution with polycyclic aromatic hydrocarbons in Ulan-Ude

: For the first time, polycyclic aromatic hydrocarbons (PAH) contamination of the soil cover of Ulan-Ude, the capital of the Republic of Buryatia, was studied. The content of 16 individual polyarenes was analyzed in the upper horizon of background chestnut and urban soils, sampled during soil and geochemical survey in July–August 2022. The average concentration of total PAHs in the soil cover of Ulan-Ude was 735 ng/g, which was 8 times as much as the concentration in the background soils (87 ng/g). The PAH amount in the soil of various functional zones decrease in the following order: railway transport &gt; motor traffic &gt; industrial &gt; one-story residential &gt; multi-story residential &gt; recreational. At the same time, the amount of PAHs in the railway transport zone was 2.6–5.2 times higher than in other functional zones, which indicates that railway transport is the most powerful source of PAHs in the city. Contamination of soils with polyarenes in all functional zones is determined primarily by medium- (46%) and high-molecular-weight (41%) compounds. Among PAHs with low molecular weight, phenanthrene prevailed (9% of the total PAHs), but medium-molecular-weight fluoranthene (18%) and pyrene (13%) showed higher share; high-molecular-weight compounds dominated by benzo(ghi)perylene (12%), benzo(b)fluoranthene (10%), indeno(1,2,3-cd)pyrene (8%) and benzo(a)pyrene (6%). The total amount of 16 PAHs in the soil cover of the city varied within the range of 17–9 540 ng/g. The highest levels of pollution (3 226–9 540 ng/g) were recorded at 9 sampling points (4% of the city), which form the most contrasting local PAH anomalies. In more than half of the territory of Ulan-Ude, the total amount of PAHs did not exceed 500 ng/g. The indicator ratios of individual PAHs made it possible to determine the dominant types of sources, which include railway transport and coal combustion. The contribution to the environmental hazard of soil contamination with PAHs in Ulan-Ude was mainly made by benzo(a)pyrene (64%) and, to a lesser extent, by benzo(b)fluoranthene (9.6%), indeno(1,2,3-cd)pyrene (7.2%), dibenzo(ah)anthracene (6.5%) and benzo(a)anthracene (6.1%).

A field investigation of 3 masks proposed as respiratory protection for wildland firefighters: a randomized controlled trial in British Columbia, Canada.

Wildland firefighters are exposed through the lungs and skin to particulate matter, fumes, and vapors containing polycyclic aromatic hydrocarbons (PAH). Wearing respiratory protection should reduce pulmonary exposure, but there is uncertainty about the most effective and acceptable type of mask. Firefighters from 6 unit crews working with the British Columbia Wildfire Service were approached and those consenting were randomly allocated within each crew to a "no mask" control group or to use 1 of 3 types of masks: X, half-face respirator with P100/multi gas cartridge; Y, cloth with alpaca filter; Z mesh fabric with a carbon filter. Crews were followed for 3 consecutive firefighting days. The mask allocated was constant for each firefighter throughout. All participants completed a brief questionnaire at the start and end of each day, giving information on mask use, respiratory symptoms, and assessment of mask qualities. Spot urine samples were collected pre and post shift to assess 1-hydroxypyrene (1-HP) concentration as an indicator of total PAH absorption. Skin wipe samples from the hands and throat were collected pre and post shift and analyzed for PAH concentration. On each day monitored, 4 participants carried sampling pumps to measure total particulates and PAHs on particles and in vapor phase. The primary outcome was the concentration of urinary 1-HP at the end of the fire day. Secondary outcomes were changes in respiratory and eye symptoms during the course of the shift, reported mask use, and perception of mask qualities. The analysis used a 3-level random intercept regression model that clustered observations within individuals and crews. We aimed to detect any relation of allocated mask type to the 4 outcomes, having allowed for estimated exposure. Information was collected from 89 firefighters, including 14 women: 49% (37/75) of male firefighters were bearded. Nineteen fire days were monitored for a total of 263 firefighter × days, 64 to 68 for each intervention group. The end of shift 1-HP was higher than the start of the shift. Urinary 1-HP was more strongly related to PAHs on the skin than in the breathing zone. Men with beards had higher end-of-shift urinary log 1-HP/creat (ng/g) than other firefighters. None of the groups allocated a mask had lower 1-HP than the no-mask group, either in the study group overall or when stratified by beard-wearing. Among those without either beards or a failed fit-test, Mask Z reduced at the end of shift 1-HP where airborne PAH concentration was high. End-of-shift symptoms were related to particle mass in the breathing zone but was not mitigated by any of the masks. Hours electing not to wear a mask increased from the first to third shift for all mask types. Mask Z was rated as more comfortable than other types. Mask X was rated highest on fit and perceived protection. Mask Y gained the lowest ratings on fit, comfort and feelings of protection. Allocated masks did not provide protection overall, but the results highlighted the need for a wider understanding of the circumstances in which wearing efficient protection is well-advised.

Ecological and Geochemical Assessment of the State of Soils in the City of Baikalsk According to the Content of Polycyclic Aromatic Hydrocarbons

The pollution of the topsoils of the city of Baikalsk (Irkutsk region) under the influence of industrial emissions and wastes of the Baikal Pulp and Paper Mill (BPPM) was studied. The content of 16 individual PAH structures in samples of urban and background soils taken during the soil geochemical survey in the summer of 2019 was analyzed. Relatively low levels of PAH content were found in the lignin sludge from the BPPM and СHP ash. The concentration of total PAHs in CHP ash reaches 46 mg/ kg with a predominance of low molecular weight compounds (the proportion of naphthalene and its homologues is 24% and 34% of the total PAHs, respectively), among high molecular weight PAHs, 5-nuclear benzo(b)fluoranthene dominates (16%). In lignin sludge, the amount of PAHs is 7.16 mg/kg with the predominance of benzo(b)fluoranthene (83%). In the soils of Baikalsk, the average total content of PAHs (38.4 mg/kg) is 5 times higher than the background content. In urban soils, 4–5-nuclear fluoranthene (61.1%) and benzo(b)fluoranthene (29.4%) prevail. This makes it possible to attribute soil pollution to the fluoranthene type. The soils of the motor transport (total PAH 105 mg/kg) and industrial (59.5 mg/ kg) zones are the most polluted, where the most contrasting PAH anomalies were formed. In descending order of the amount of PAHs, the land use zones of the city form a series: motor transport industrial residential one-storey railway transport residential multi-storey recreational zone. Several local anomalies in the amount of PAHs are distinguished, forming two large pollution halos in the western and eastern parts of the city. The leading factors in the accumulation of high molecular weight PAHs in soils are acid-alkaline conditions and soil organic matter, while the accumulation of low molecular weight polyarenes is mainly controlled by pH. The environmental hazard of pollution of Baikalsk soils with polyarenes is due to benzo(b)fluoranthene, its contribution is 83.5%.

Experimental study on emissions and particulate characteristics of diesel engine fueled with plastic waste oil, acetone-butanol-ethanol and diesel blends

Plastic waste poses a significant environmental challenge due to its non-biodegradable nature and accumulation in landfills. Converting plastic waste into usable fuel could offer a promising solution for mitigating these issues while addressing the emission-related challenges of diesel engines. This study investigates the impact of plastic waste oil (WPO) obtained through pretreatment and catalytic pyrolysis, blended with acetone-butanol-ethanol (ABE) and diesel fuel, on diesel engine. The aim was to evaluate how these blends affect gaseous emissions, organic compounds, and particle-bound carbon, focusing on their potential to reduce harmful pollutants compared to pure diesel fuel. The results indicated that the ABE5W15D blend significantly reduced smoke and CO emissions by 35.7 % and 17.43 %, respectively, with a slight decrease in HC emissions. However, the ABE20W blend showed elevated NOx levels due to higher ignition delay and increased cylinder pressure. Compared to pure diesel (D100), ABE10W10D and ABE5W15D blends reduced total polycyclic aromatic hydrocarbons (PAHs) emissions by 26.8 % and 37.4 %, respectively. Naphthalene was the dominant PAH, remarkably increasing with W20D use, while longer-chain alkanes associated with lubricant oil had higher W20D emissions. The ABE5W15D blend notably reduced organic carbon (OC) emissions by approximately 38.26 % compared to D100. ABE20D exhibited lower elemental carbon (EC) emissions than D100, although it had higher EC than OC. The W20D blend resulted in larger particle diameters, whereas ABE10W10D showed lower particle counts in the 7–15 nm range. In conclusion, blending plastic waste oil with ABE and diesel fuel can effectively mitigate certain pollutants, depending on the blend composition.

Analysis and Formation of Polycyclic Aromatic Hydrocarbons in Canned Minced Chicken and Pork during Processing.

Polycyclic aromatic hydrocarbons (PAHs) represent important toxic compounds formed in meat products during processing. This study aims to analyze 22 PAHs by QuEChERS coupled with GC-MS/MS in canned minced chicken and pork during processing. After marinating raw minced chicken and pork separately with a standard flavoring formula used for canning meat in Taiwan, they were subjected to different processing conditions including stir-frying, degassing and sterilizing at 115 °C/60 min (low-temperature-long-time, LTLT) and 125 °C/25 min (high-temperature-short-time, HTST). The quantitation of PAHs in these meat products revealed the formation of only three PAHs including acenaphthylene (AcPy), acenaphthene (AcP) and pyrene (Pyr) in canned minced chicken and pork during processing with no significant difference in total PAHs between the meat types. Analysis of PAH precursors showed the presence of benzaldehyde at the highest level, followed by 2-cyclohexene-1-one and trans,trans-2,4-decadienal in canned minced chicken and pork, suggesting PAH formation through the reaction of benzaldehyde with linoleic acid degradation products and of 2-cyclohexene-1-one with C4 compounds through the Diels-Alder reaction, as well as the reaction of trans,trans-2,4-decadienal with 2-butene. Monounsaturated and polyunsaturated fatty acids were present in the largest proportion in LTLT-sterilized chicken/pork, followed by HTST-sterilized chicken/pork and raw chicken/pork, and their levels did not show a high impact on PAH formation, probably due to an insufficient heating temperature and length of time. A two-factorial analysis suggested that PAH formation was not significantly affected by the sterilization condition or meat type. Principal component analysis corroborated the observed results implying the formation of PAHs in canned minced chicken/pork under different processing conditions with an insignificant difference (p > 0.05) between them, with the individual PAH content following the order of Pyr > AcPy > AcP.

Assessment of Hydrocarbon Contamination Using 2D Resistivity Imagining Method and Geochemical Analysis in Ibadan, Southwestern Nigeria

The study examined the use of 2D resistivity imaging survey and geochemical analysis to map and assess the level of soil contamination due to hydrocarbon spillage in Araromi Auto Spare Parts Market Ibadan, Southwestern Nigeria. The objectives are to provide 2D inverted resistivity sections beneath the study area, delineate anomalously low resistivity zones indicative of long-term hydrocarbon contamination in the sections, and determine concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in the suspected soils. Five traverses were run using Wenner array with electrode spacing varied from 5 m to 15 m and station increment of 5 m. The resistivity data were processed by using 2D inversion procedure to generate the 2D inverted resistivity sections. Geochemical analysis was conducted on five soil samples collected at 1 m depth in the low resistivity zones delineated on the 2D inversion sections, to determine the concentration of Polycyclic Aromatic Hydrocarbons (PAHs) to assess the level of contamination. The 2D inverted sections delineated low resistivity anomalies, ranging from 1.25 Ωm to 5.54 Ωm, characteristic of mature biodegraded hydrocarbon contamination. The results of geochemical analysis revealed total PAH concentration of 1390 µg/kg to 16140 µg/kg suggesting that the study area is heavily contaminated by the used motor oil. The combined use of 2D resistivity imaging and geochemical analysis has shown that soils beneath the study area has been heavily contaminated by the used motor oil, and may constitute potential health risk to the soil and groundwater systems in its vicinity. The results are expected to serve as useful guide in planning remediation programme.