Polycyclic Aromatic Hydrocarbons Concentrations Research Articles

Polycyclic aromatic hydrocarbons (PAHs) evidence for frequent combustion events on land during the Permian–Triassic transition in Northwest China

The Siberian Traps large igneous province and intensive continental arc volcanism are regarded as the primary drivers of the severe environmental changes that triggered the end-Permian mass extinction. However, detailed correlations between volcanism and the collapse of terrestrial ecosystems remain ambiguous. This study used polycyclic aromatic hydrocarbons (PAHs) records and mercury spikes from the terrestrial Dalongkou section as refined proxies for volcanic combustion events. The mercury anomalies, PAH concentrations, and PAH ratios provide insight into the terrestrial ecosystem collapse during the Permian–Triassic (P–T) transition. Based on the multiple PAH ratios, the source and composition of PAHs exhibit obvious pyrolytic-derived origins during the late Permian. Combined with the biostratigraphic records and our PAH proxies in the Dalongkou section, terrestrial ecosystems experienced stepwise crisis and change owing to volcanic effects and frequent high-temperature combustion events during the P–T transition. During the main terrestrial P–T crisis interval, the increased PAH concentrations indicate that the combustion events were gradually enhanced under worse climatic conditions. Based on the PAH records, enhanced soil erosion accompanied by frequent wildfires was found to occur under extremely high-temperature climatic conditions caused by intensive volcanic activity during the P–T transition.

Potential of Pinus eldarica Medw. tree bark for biomonitoring polycyclic aromatic hydrocarbons in ambient air

Urban trees' biomonitoring of pollutants such as polycyclic aromatic hydrocarbons (PAHs) yields pertinent and useful data for air pollution management. The aim of this study was to biomonitor PAHs in pine (Pinus eldarica Medw.) trees in the city of Isfahan and identify their sources. In total, 34 samples of outer bark of the trees were collected and their contents of 16 EPA PAHs were analyzed. With a median value of 136.3 ng/g, the total PAH contents in tree barks varied from 53.4 to 705.2 ng/g. The average values of the diagnostic ratios for Ant/(Ant + Phe), Flu/(Flu + Py), BaA/(BaA + Chr) and IP/(IP + BP) were 0.19, 0.49, 0.45 and 0.49, respectively, revealing the PAHs majority source of pyrogenic. Meanwhile, principal component analysis showed two major types of PAHs sources including pyrogenic (fossil fuel combustion and industrial activities) and petrogenic (uncombusted) sources. The average ratio An/(An + Phe) and Flu/(Flu + Py) in bark samples was close to their relevant ratios in ambient air which demonstrated the potential use of this approach for biomonitoring of PAHs.

Characteristics of Polycyclic Aromatic Hydrocarbons in Size-Resolved Particles in the Roadside Environment of Beijing: Seasonality, Source, and Toxicological Effects

The polycyclic aromatic hydrocarbons (PAHs) in size-resolved particles emitted from diverse sources are required for quantification to reduce the emissions in order to protect public health. Twenty-four PAHs in size-segregated particles in the roadside environment of Beijing were observed from 1 October 2021 to 30 September 2022. The size distributions of PAHs were bimodal, with peak concentrations ranging from size fractions of 0.43 to 0.65 μm and 4.7 to 5.8 μm in all four seasons, respectively. The highest concentration of PAHs in fine particles (PM2.1) was 35.3 ng m−3 in winter, followed by 16.0 ng m−3 in autumn, 15.3 ng m−3 in spring, and 6.5 ng m−3 in summer. Conversely, the concentration of PAHs in coarse particles (PM2.1–9) ranged from 6.8 ng m−3 (summer) to 20.5 ng m−3 (winter) from low to high. The size fractions of 0.43–2.1 μm PAHs increased most from clear to polluted days, which could be ascribed to the heterogeneous reactions. Source apportionment using positive matrix factorization showed that four sources, namely biomass combustion, coal combustion, diesel vehicles, and gasoline vehicles accounted for PAHs with the estimation of 17.4%, 22.1%, 26.4%, and 23.2% to PAHs in PM2.1; and 19.6%, 24.3%, 23.6%, and 20.1% in PM2.1–9, respectively. Furthermore, we used the human alveolar epithelial cell (BEAS-2B) to assess the toxicological effects of size-resolved atmospheric PAHs. The results showed that the cell survival rate caused by fine particles was lower than that of coarse particles with the same concentrations of PAHs, which is mainly related to the higher content of highly toxic PAHs in fine particles.

Organic Micropollutants in the Agricultural Chain of Production of Strawberries by Irrigation with Treated Wastewater and Assessment of Human Health Implications

Treated water reuse is vital for sustainable water management and reducing the strain on freshwater resources, particularly in agriculture, which has a great impact on freshwater withdrawal. Despite the benefits, the reuse of treated wastewater carries risks due to residual chemical and microbiological contaminants, such as the organic micropollutants polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), which are not fully removed by current treatment processes and can affect plant growth and human health when used for irrigation. This study focuses on monitoring the PAHs and PCBs in wastewater used for irrigating strawberries, assessing their transfer to crops and potential health risks. The effluents of four wastewater treatment plants were monitored for two years (2017 and 2018) and used to irrigate strawberries grown in plot installations. Effective and robust analytical methodologies (60–99% recoveries, optimal reproducibility) were developed for wastewater and strawberry analysis. The analysis of the treated wastewaters showed the presence of residual PAH and PCB concentrations at hundreds of ng/L. The strawberry crops were further analyzed to measure the PAHs and PCBs. Since two PAHs were present in strawberries, a risk assessment was performed (EPA methodology), finding that the residual contamination of treated waters does not pose a significant health risk, for both adults and children, through the consumption of fruits.

Assessment of Quality of Smoked Fish Using Briquettes Crafted from Rice Husks and Fruit Peels

ABSTRACT The quest for alternative smoking fuels, beyond traditional wood, is essential to enhance the quality of smoked fish. This research focuses on evaluating the smoked fish quality achieved with briquettes derived from various sources: rice husks (53%) (BriqRi); pineapple peel (53%) (BriqAn); a combination of rice husks (18%) and pineapple peel (19%) (BriqRiAn); pineapple (19%) and orange peel (18%) (BriqAnO); and a composite blend of all three fuels (18% each) (BriqRiAnO). A total of 60 units each of horse mackerel (Trachurus trachurus) and mackerel (Scomber scombrus) underwent smoking using five different types of briquettes. The evaluation encompassed both physicochemical and sensory parameters of the smoked fish, along with an analysis of polycyclic aromatic hydrocarbons (PAH) contents. Significantly, higher weight losses post-smoking (p < 0.05) were observed in fish smoked with BriqAnO and BriqAn briquettes. The sensory evaluation conducted by a panel indicated that BriqRiAnO briquettes produced fish with the highest scores (p˂ 0.05). Furthermore, fish smoked with BriqRi rice husk briquettes exhibited the lowest levels of PAHs, whereas fish smoked with BriqAn pineapple peel briquettes showed the highest levels for most PAHs. Notably, no Benzo[a]pyrene (BaP) hydrocarbon was detected in fish smoked using any of the briquettes. These findings suggest that briquettes derived from agricultural residues hold promise for enhancing fish smoking techniques in Benin.

Characterization of polycyclic aromatic hydrocarbon from open burning of disposable COVID-19 facemask: Spatial distribution and risk assessment

The use of facemasks as a preventive measure against infection of the COVID-19 virus has some associated environmental impacts, especially in Subs-Saharan African countries where the used facemasks are being disposed of using open burning. Hence this study characterized Polycyclic Aromatic Hydrocarbons (PAHs) emissions from different COVID-19 facemask materials and determined the associated risk of open burning of facemask. Facemasks of different materials were sourced from open dump sites. Each material was combusted in an open reactor and the emissions were collected using A filter-sorbent sampling system. Analysis of PAHs in the sample was carried out using GCMS. The associated health risk was assessed using Incremental Life Cancer Risk (ILCR) and Hazard Quotient (HQ). The result showed the concentration of PAHs emission ranged ∑ PAHs 73.33 –368.16 µg/m3 while carcinogenic PAHs ranged ∑ CarPAHs 26.79–179.74 µg/m3. The result also showed the surgical and N95 facemask emits the highest concentration of PAHs. The modeled annual ground-level PAHs Isopleth reveals the presence of a high concentration of PAHs around the vicinity of the burning site after a year. Proper disposal of these facemask using controlled medical incinerator is highly recommended.

Spatial-temporal Distribution and Source Analysis of Polycyclic Aromatic Hydrocarbons in the Sediments of Poyang Lake

The concentrations, spatial-temporal distribution, and influencing factors of 16 polycyclic aromatic hydrocarbons (PAHs) in the sediments of Poyang Lake were studied, and a quantitative source analysis of PAHs in different areas of the lake was conducted. PAHs were widespread within the sediments. The concentrations of ∑16PAHs in the surface sediments of all sites ranged from 203 to 2 318 μg·kg-1. The concentrations of PAHs in the surface sediments of the lake body were higher than those in the surface sediments of the inlet rivers. The ratio of PAHs in Poyang Lake was 4 rings > 5 rings > 6 rings > 3 rings > 2 rings; the composition of 4-ring PAHs was dominant, and its content accounted for 86.11% of ∑16PAHs. The 2- and 3-ring and some 4-ring PAHs, including Flua and Pyr, were more susceptible to SOM, and the 4 through 6-ring PAHs were more susceptible to ORP and heavy metals and other environmental factors. Spatially, the higher concentration of ∑16PAHs occurred in the area of the lake adjacent to Duchang County and Poyang County, where the terrain was relatively closed, and the water exchange with the surrounding area was less than that in other sections, which was not conducive to the migration, transformation, and degradation of pollutants. In the temporal distribution, the changes in PAHs concentration level and the development of GDP in Jiangxi Province showed high consistency, and the influence of economic development and human activities might have been the main reason for the increasing PAHs concentration level. The main sources of PAHs in surface sediments of Poyang Lake included petroleum pollution and oil and coal and biomass combustion sources, and there were some spatial differences in PAHs sources in different regions. This study can provide a reference for PAHs pollution in surface sediments of Poyang Lake, which is important for the ecological environmental protection and management of Poyang Lake.

Evaluating the impact of polycyclic aromatic hydrocarbon bioaccumulation in adipose tissue of obese women

Polycyclic aromatic hydrocarbons (PAHs) are widespread across the environment and humans are unavoidably and constantly exposed to them. As lipophilic contaminants, these substances tend to accumulate in fatty tissues as adipose tissue and exposure to these endocrine disruptors has been associated with severe health hazards including prevalence and incidence of obesity. Previous studies have shown significantly higher concentrations of PAHs in adipose tissue compared to other human samples, such as urine and plasma, which are typically used for PAHs assessment. Therefore, conducting biomonitoring studies in adipose tissue is essential, although such studies are currently limited. In this study, the concentrations of 18 PAHs were measured in subcutaneous (scAT) and visceral adipose tissue (vAT) of 188 Portuguese obese females by high performance liquid chromatography (HPLC). The obtained results were then associated with the patient's data namely: 13 clinical, 4 social, and 42 biochemical parameters. Seventeen PAHs were present, at least, in one sample of both scAT and vAT, most of them with detection frequencies higher than 80%. Indeno [1,2,3-cd]pyrene (InP) was the only PAH never detected. Overall higher concentrations of PAHs were observed in scAT. Median concentrations of ∑PAHs were 32.2 ± 10.0 ng/g in scAT and 24.6 ± 10.0 ng/g in vAT. Thirty-six significant associations (7 with social, 18 with clinical, and 11 with biochemical parameters), including 21 Spearman's correlations were identified (12 positive and 9 negative correlations). Indicating the potential effects of PAHs on various parameters such as obesity evolution, body fat, number of adipocytes, total cholesterol, alkaline phosphatase, macrominerals, uric acid, sedimentation velocity, and luteinizing hormone. This study underscores the significance of biomonitoring PAH levels in adipose tissue and their potential effects on metabolic health. Further research is essential to fully comprehend the metabolic implications of PAHs in the human body and to develop strategies for obesity prevention and treatment.

Multimedia distribution, dynamics, and seasonal variation of PAHs in Songhua wetland: Implications for ice-influenced conditions

The knowledge of polycyclic aromatic hydrocarbons (PAHs) in wetlands remains limited. There is a research need for the dynamics between interfaces of multimedia when ice is present in this fragile ecosystem. In this study, sediment, open-water, sub-ice water, and ice samples were collected from the Songhua wetland to study the behaviors of PAHs with and without influences from ice. The concentration of all individual PAHs in sub-ice water (370–1100 ng/L) were higher than the open-water collected from non-ice-covered seasons (50–250 ng/L). Enrichment of PAHs in the ice of wetland was found, particularly for high-molecular-weight PAHs (HMW). This could be attributed to the relatively lower polarity of hydrocarbons compounds, making them more likely to remain in the ice layer during freezing. Source assessments reveal common sources for sub-ice water and ice, which differ from those in the open water in non-ice-covered seasons. This difference is primarily attributed to heating activities in the Harbin during winter. The average percentage contributions were 79% for sub-ice water and 36% for ice related to vehicle exhausts and coal combustion. Additionally, wood burning contributed 25% to sub-ice water and 62% to ice. Sediment in the wetland was found to serve as a final deposit particularly for heavier PAHs, especially those with 6 rings. Sediment also has the potential to act as a source for the secondary emission of low-molecular-weight PAHs (LMW) congeners into the water. PAHs in wetland displayed low ecological risk, while HMW PAHs with relative higher ecological risk is recommended to be further monitored.

Cellular adaptations of the scleractinian coral Madracis pharensis to chronic oil pollution in a Mediterranean shipwreck

Chemical pollution in marine ecosystems is a factor of stress interacting in multiple and complex ways with other major causes of deterioration, such as warming seas due to climate change. Here we surveyed epibenthic communities from a shipwreck in the Levantine Basin for temporal and spatial changes in the community in relation to chronic oil pollution, comparing results collected from an area of the wreck characterized by chronic oil leakage with another area not affected by oil. Polycyclic aromatic hydrocarbons (PAHs) bioaccumulation analyses were integrated with characterization of the efficiency of xenobiotics biotransformation processes and antioxidant network of the scleractinian coral Madracis pharensis, chosen as bioindicator species. Results highlighted the two areas hosting different epibenthic communities over a period of 11 years. Significant changes in the percentage cover of M. pharensis could be the result of recent mass mortality associated to Marine Heat Waves. Biological investigation conducted in M. pharensis tissues revealed an increased content of PAHs in specimens collected from the oil-impacted area, coupled with an increased capability of oxyradicals scavenging capacity and a lower functionality of phase II biotransformation mechanisms associated to glutathione S-transferase. Overall, the results suggest that M. pharensis has the capability to develop cellular and physiological adaptations to chemical-mediated stress, with yet unknown possible energy trade-offs to sustain stress response.

Humoral immunosuppression of exposure to polycyclic aromatic hydrocarbons and the roles of oxidative stress and inflammation

Previous studies have indicated adverse health effects of exposure to polycyclic aromatic hydrocarbons (PAHs), but evidence on the association between PAH exposure and immunity is scarce and its underlying mechanism is largely unknown. This study assessed human exposure to PAHs by determining the concentrations of PAHs in serum and their metabolites in paired urine. The oxidative stress and inflammation levels were evaluated by urinary DNA damage biomarker 8-hydroxydeoxyguanosine, white blood cell counts and C-reaction protein. We investigated the relationship between PAH exposure and seven immunological components, and explored the indirect roles of oxidative stress and inflammation by mediation and moderation analysis. Multivariate regression analysis revealed that 1-hydroxynaphthalene and 2-hydroxyfluorene were negatively associated with immunoglobulin A, and 3-hydroxyphenanthrene was negatively correlated with complement component 3. Restricted cubic spline analysis demonstrated nonlinear relationships between some individual PAHs or their metabolites with immunological components. Bayesian kernel machine regression and quantile g-computation revealed significant associations of higher PAH exposure with decreased immunoglobulin G and kappa light chain levels. Phenanthrene was the compound that contributed the most to reduced immunoglobulin G. Mediation analysis demonstrated significant indirect effects of 8-hydroxydeoxyguanosine and white blood cell counts on the association between higher PAH exposure and decreased immunological components. Moderation analysis revealed that PAH exposure and decreased immunological components are significantly associated with higher levels of C-reaction protein and white blood cell counts. The results demonstrated significant immunosuppression of PAH exposure and highlighted the indirect roles of oxidative stress and inflammation. Interventions to reduce systemic inflammation may mitigate the adverse immune effects of PAH exposure.

Diluted bitumen weathered under warm or cold temperatures is equally toxic to freshwater fish

Canada is one of the main petroleum producers in the world. Through its oil sands exploitation, a viscous bitumen mixed with sand, water, and clay is being produced. This bitumen is so viscous that approximatively 20%–30% of diluent needs to be added to ease transportation, resulting in a mixture called diluted bitumen (dilbit). The transport of dilbit through North America comes with a potential risk for oil spills in freshwater ecosystems at any time of the year. In this study, a mesoscale spill tank was used to study dilbit spills in freshwater to understand the effect of cold (winter-like) vs. warmer (spring- and fall-like) water temperatures on its natural weathering and their toxicity to fathead minnow (Pimephales promelas) embryos. Water samples were collected weekly during two consecutive 35-day experiments ran at either 2 or 15 °C. Each week, fish larvae were exposed for 7 days, and water analysis was performed. Chemical analysis showed that the volatile organic compound, total organic carbon, and polycyclic aromatic hydrocarbon concentrations decreased in both experiments with time, while fish larvae exposed to both temperature settings yielded increased abnormalities, EROD activity, CYP1A, and glutathione S-transferase mRNA expression levels, and decreased heart rate. Importantly, there were no major differences between the temperature regimes on dilbit weathering, highlighting that if a spill occurs in colder waters, it would be equally toxic to organisms. This work provides new data on the potential risk of oil spill for use during response planning and modelling.

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

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

The cross-linking between DNA damage, oxidative stress and epidermal barrier in keratinocytes after exposure to particulate matters and carbon black.

As the largest organ, the skin provides the first line of defence against environmental pollutants. Different pollutants have varied damage to the skin due to their own physical-chemical properties. A previous epidemiological study by our team revealed that eczema was positively correlated with different air pollutants. However, the mechanism of action from different pollutants on the skin is less known. In this work, the differences among the genotoxicity, intracellular reactive oxygen species, and barrier-related parameters caused by two kinds of air pollutants, that is, S1650b and carbon black (CB) were investigated by Western blot, TUNEL, comet assay and RNA-sequences. The results indicated that both S1650b and CB caused DNA damage of keratinocytes. With the content of lipophilic polycyclic aromatic hydrocarbons (PAH), S1650b leaked into the keratinocytes easily, which activated the aromatic hydrocarbon receptor (AhR) in keratinocytes, leading to worse damage to barrier-related proteins than CB. And CB-induced higher intracellular ROS than S1650b due to the smaller size which make it enter the keratinocytes easier. RNA-sequencing results revealed that S1650b and CB both caused DNA damage of keratinocytes, and the intervention of S1650b significantly upregulated AhR, cytochrome oxidase A1 and B1 (CYP1A1 and CYP1B1) genes, while the results showed oppositely after CB intervention. The mechanism of keratinocyte damage caused by different air particle pollutants in this study will help to expand our understanding on the air pollutant-associated skin disease at cell levels.

Contribution of combined stressors on density and gene expression dynamics of the copepod Temora longicornis in the North Sea.

The impact of multiple environmental and anthropogenic stressors on the marine environment remains poorly understood. Therefore, we studied the contribution of environmental variables to the densities and gene expression of the dominant zooplankton species in the Belgian part of the North Sea, the calanoid copepod Temora longicornis. We observed a reduced density of copepods, which were also smaller in size, in samples taken from nearshore locations when compared to those obtained from offshore stations. To assess the factors influencing the population dynamics of this species, we applied generalised additive models. These models allowed us to quantify the relative contribution of temperature, nutrient levels, salinity, turbidity, concentrations of photosynthetic pigments, as well as chemical pollutants such as polychlorinated biphenyls and polycyclic aromatic hydrocarbons (PAHs), on copepod density. Temperature and Secchi depth, a proxy for turbidity, were the most important environmental variables predicting the densities of T. longicornis, followed by summed PAH and chlorophyll concentrations. Analysing gene expression in field-collected adults, we observed significant variation in metabolic and stress-response genes. Temperature correlated significantly with genes involved in proteolytic activities, and encoding heat shock proteins. Yet, concentrations of anthropogenic chemicals did not induce significant differences in the gene expression of genes involved in the copepod's fatty acid metabolism or well-known stress-related genes, such as glutathione transferases or cytochrome P450. Our study highlights the potential of gene expression biomonitoring and underscores the significance of a changing environment in future studies.

Effects on of Blended Biodiesel and Heavy Oil on Engine Combustion and Black Carbon Emissions of a Low-Speed Two-Stroke Engine

Abstract The effects of heavy fuel oil and biodiesel blends on engine combustion and emissions were studied in a marine two-stroke diesel engine. The engine was operated under propeller conditions using five different fuels with biodiesel blends of 10% (B10), 30% (B30), 50% (B50), and sulphur contents of 0.467% low sulphur fuel oil (LSFO) and 2.9% high sulphur fuel oil (HSFO). Tests have shown that using a biodiesel blend increases the engine fuel consumption due to its lower calorific value. Heavy fuel oil has a high Polycyclic aromatic hydrocarbons (PAH) content, which leads to higher exhaust temperatures due to severe afterburning in the engine. A comparison of engine soot emissions under different fuel conditions was carried out, and it was found that the oxygen content in biodiesel promoted the oxidation of soot particles during the combustion process, which reduced the soot emissions of biodiesel. Compared to HSFO, B10, B30, B50 and LSFO, the soot emission concentrations were reduced by 50.2%, 56.4%, 61% and 37.4%, respectively. In our experiments, the soot particles in the engine exhaust were sampled with a thermal float probe. Using Raman spectroscopy analysis, it was found that as the biodiesel ratio increased, the degree of carbonisation of the soot particles in the exhaust became less than that in the oxygenation process, resulting in a decrease in the degree of graphitisation.

Source analysis and health risk assessment of polycyclic aromatic hydrocarbon (PAHs) in total suspended particulate matter (TSP) from Bengbu, China

The polycyclic aromatic hydrocarbon (PAH) concentrations in total suspended particulate matter (TSP) samples collected from October, 2021 to September, 2022 were analyzed to clarify the pollution characteristics and sources of 16 PAHs in the atmospheric TSP in Bengbu City. The ρ(PAHs) concentrations ranged from 1.71 to 43.85 ng/m3 and higher concentrations were detected in winter, followed by spring, autumn, and summer. The positive matrix factorization analysis revealed that, in spring and summer, PAH pollution was caused mainly by industrial emissions, gasoline and diesel fuel combustion, whereas in autumn and winter, it was coal, biomass and natural gas combustion. The cluster and potential source factor analyses showed that long-range transport was a significant factor. During spring, autumn, and winter, the northern and northwestern regions had a significant impact, whereas the coastal area south of Bengbu had the greatest influence in summer. The health risk assessment revealed that the annual total carcinogenic equivalent concentration values for PAHs varied from 0.0159 to 7.437 ng/m3, which was classified as moderate. Furthermore, the annual incremental lifetime cancer risk values ranged from 1.431 × 10−4 to 3.671 × 10−3 for adults and from 6.823 × 10−5 to 1.749 × 10−3 for children, which were higher than the standard.

Characterization of persistent organic contaminants in the atmosphere of Gadani's ship breaking yards and its surrounding: Implications for sustainable ship recycling practices

Gadani is internationally renowned for its extensive ship-breaking operations, positioning it as one of the globe's primary ship-breaking hubs. A comprehensive study was conducted to evaluate the presence of organic contaminants in the air within Gadani, encompassing the areas surrounding ship-breaking facilities, proximate residential settlements, and adjacent roadways. Passive air samplers were employed to collect a total of 30 air samples. The analytical results unveiled a notably elevated concentration of specific organic compounds, with a pronounced prevalence of polycyclic aromatic hydrocarbons (PAHs), short-chain chlorinated paraffins (SCCPs), and polychlorinated biphenyls (PCBs) at the ship-breaking yard. Notably, dichlorodiphenyltrichloroethanes (DDTs) and DDE were detected at substantially lower levels. In particular, sites in close proximity to ship-breaking activities exhibited elevated concentrations of PCBs (Σ7PCB 0.065429 to 7.345714 ng/sample), PAHs (Σ8PAH 2.44 to 134.23 ng/sample), and SCCPs (0.18 to 25.6 ng/sample). Conversely, DDTs and DDE demonstrated higher concentrations near residential settlements. The evaluation of Molecular Diagnostic Ratios for PAHs revealed anthracene/anthracene + phenanthrene ratios of 0.88, 0.69, and 0.5 for ship-breaking areas, roadside locations, and community surroundings, respectively. Furthermore, the benz[a]anthracene/benz-[a]anthracene + chrysene molecular ratios were measured at 0.77 (ship-breaking sites), 0.82 (roadside), and 0.83 (community), respectively. The molecular ratio of fluoranthene/fluoranthene + pyrene at ship-breaking sites was 0.23, while roadside and community ratios were 0.36 and 0.89, respectively. These findings underscore the significant contribution of ship-recycling activities to the atmospheric release of SCCPs, PCBs, and PAHs, emphasizing the global imperative for responsible ship recycling practices.

Ecological risk of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) in the sediment of a protected karst plateau lake (Caohai) wetland in China

Understanding PAH and OCP distributions and sources in lakes is necessary for developing pollutant control policies. Here, we assessed the occurrence, risk, and sources of PAHs and OCPs in the sediment of Caohai Lake. The PAHs were predominantly high-molecular-weight compounds (mean 57.5 %), and the diagnostic ratios revealed that coal, biomass burning, and traffic were the sources of PAHs. HCHs (6.53 ± 7.22 ng g−1) and DDTs (10.86 ± 12.16 ng g−1) were the dominant OCPs and were primarily sourced from fresh exogenous inputs. RDA showed that sediment properties explained 74.12 % and 65.44 % of the variation in PAH and OCP concentrations, respectively. Incremental lifetime cancer risk (ILCR) assessment indicated that hazardous PAHs in Caohai Lake sediment posed moderate risks to children and adults (ILCR>1.0 × 10−4), while the risk from OCPs was low; however, the recent influx of HCHs and DDTs requires additional attention.

Long-term (1993–2018) particulate polycyclic aromatic hydrocarbons (PAHs) concentration trend in the atmosphere of Seoul: Changes in major sources and health effects

This study assessed the long-term concentration trend and profiles of twelve polycyclic aromatic hydrocarbons (PAHs) occurring as airborne particulate matter in Seoul, Republic of Korea (Korea) between 1993 and 2018 to evaluate the human health effect and the effectiveness of air quality management policies. Total PAHs (∑PAHs of 12 compounds), benzo [a]pyrene (BaP), and BaP toxic equivalent (BaPTEQ) concentrations increased from 1993 to 1999 but decreased thereafter. Moreover, the BaP concentration has remained below 1 ng/m3 since 2010–2011. Benzo [b+k]fluoranthene (B [b+k]F) accounted for the largest ∑PAHs fraction (approximately 24%) for the entire period. Based on the PAH profiles, as well as the Principal Component Analysis (PCA) results and diagnostic ratio analysis, vehicular emissions and coal combustion were identified as major sources of the PAHs in Seoul. Additionally, contribution of vehicular emissions increased from 2002 to 2003 to 2018, whereas that of solid fuel combustion decreased in the same period. PAH levels increased 8-fold in winter compared to summer mainly due to increases in local and regional emissions. The implementation of policies to regulate the use of solid fuels and vehicular emissions in Korea effectively reduced Elemental Carbon (EC) and PAH emissions, as demonstrated by CO, EC, and PAHs reductions and a good correlation between EC and PAHs. Moreover, aggressive air quality management policies in China have also contributed to decreasing PAH concentration trend in Seoul. Following the incremental lifetime cancer risk (ILCR) estimations method for 8 different population groups, males in the 0–1 age group was the only group still at potential risk of PAH inhalation in 2018, while other groups have been in the acceptable risk since 2012–2013.