Investigating industrial PAH air pollution in relation to population exposure in major countries: A scoring approach

Key role of extracellular vesicles in the induction of necroptosis and apoptosis by a mixture of polycyclic aromatic hydrocarbons in the context of a steatohepatitis-like state

A positive association between human exposure to environmental pollutants and progression from benign hepatic steatosis to advanced chronic liver diseases has been documented. Among chemicals found in air pollution, polycyclic aromatic hydrocarbons (PAHs) are of particular concern, due to their omnipresence in the environment. Ingestion of contaminated food is the primary route of exposure. Previous studies on the ability of PAHs to induce the pathological progression of liver steatosis have been limited to the analysis of individual PAHs. The aim of this study was therefore to examine the effects of a mixture of PAHs whose composition closely recapitulates that of contaminated food. The PAH mixture elicited both a steatohepatitis-like state in steatotic WIF-B9 hepatocytes (100 nM for 72 hours) and the progression of steatohepatitis in rats fed a lipid-enriched diet (0.8 mg/kg for 90 days). The PAH mixture induced transient necroptosis at 5 hours followed by a gradual increase in cellular apoptosis. PAH metabolism-dependent necroptosis appeared to be responsible for the development of the secondary apoptosis. Hepatocyte exposure induced a necroptosis-dependent release of extracellular vesicles (EVs), that appeared to be protective against necroptosis; however, those necroptotic EVs triggered apoptosis in recipient hepatocytes. Blocking of ASGR EV receptors with asialofetuin inhibited the interaction of EVs with hepatocytes and hence apoptosis. In conclusion, EV release seems to be crucial to avoid necroptosis, but inhibition of EV uptake can protect against apoptosis.

Populus × euramericana Accumulates More Organic Pollutants (PAHs and PCBs), While P. nigra 'Italica' Absorbs More Heavy Metals

The phytoremediation capacity of three common poplar species, white poplar (Populus alba L.), Lombardy poplar (Populus nigra 'Italica'), and Euro-American hybrid poplar (Populus × euramericana (Dode) Guinier cl. I-214), grown in a middle-sized city with a continental climate in Serbia was analyzed. For this purpose, 15 polycyclic aromatic hydrocarbons (PAHs), 10 polychlorinated biphenyls (PCBs), and 6 heavy metals (HMs) were tracked in leaves and one-year-old branches. P. × euramericana showed the highest PAH uptake capacity, with concentrations of 821.40 ng g-1 dry weight (DW) and 453.64 ng g-1 DW in leaves and branches, respectively. Likewise, P. euramericana accumulated the highest levels of PCBs in leaves (364.53 ng g-1 DW). Additionally, P. nigra 'Italica' demonstrated the greatest accumulation potential for HMs, particularly zinc, with 310.10 µg g-1 DW in leaves. Leaves accumulated ~30% more pollutants compared with branches. Significant differences in pollutant uptake capacities were found among species and plant organs. These findings highlight the importance of species selection in phytoremediation and clarify the role of poplar species in accumulating pollutants to mitigate urban pollution. Finally, this study provides valuable insights for future phytoremediation strategies using poplars, especially in urban environments with similar conditions.

Estimation of public exposure to PAH and environmental risks via wastewater-based epidemiology

The wastewater-based epidemiology (WBE) has the potential to monitor public health emergencies via the analysis of human urinary biomarkers in wastewater. This work proposes a novel approach utilizing WBE for the spatial and temporal evaluation of PAHs exposure using hydroxyl derivatives of PAHs. These are 1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 9-hydroxyfluorene, 9-hydroxyphenanthrene, 1-hydroxypyrene and 3-hydroxybenzo(a)pyrene. Most target markers were found at quantifiable concentrations in raw and treated wastewater. The total loads identified in raw sewage ranged from 88.33 g/day to 154.77 g/day during the summer period and from 137.66 g/day to 283.78 2 g/day during the winter period. The obtained results for the removal efficiencies of OH-PAHs indicate a seasonal dependency in their degradation. Removal efficiencies were higher in January compared to August. The results of the back calculations allowed to estimate that during the summer, on average, a resident of Krakow could absorb approximately 2.1 µg of the assessed OH-PAHs per day, while in winter, this value increased to 4.1 µg. This is close to the reported in the literature value that the total daily exposure to OH-PAHs is estimated at 3 µg/day. Moreover, the risk quotation (RQ) values on the base of acute and chronic data base for compounds present in effluents were calculated. The RQ values in January were relatively low, but in August the RQ values were higher, indicating a high concentration of effluent and nitrogen in summer as these compounds were removed in winter and summer. To the authors' knowledge, this is the first time wastewater profiling of OH-PAHs in wastewater for the evaluation of exposure to PAHs have been used, also their removal as well emission with effluent were determined.

Exposure to polycyclic aromatic hydrocarbons (PAHs) from domestic heating and cooking combustion of different fuel types for elders in rural China

Solid fuel combustion emitted abundant pollutants, especially polycyclic aromatic hydrocarbons (PAHs) which had significant minus impact on human health in rural China. PAHs in PM2.5 emitted from different fuels combustion and hydroxylated metabolites of PAHs (OH-PAHs) in urine samples of different fuel users were detected in this study. The indoor PAHs were higher than that in outdoors for solid fuel use households, and the concentration of PAHs in the indoor of liquefied petroleum gas (LPG) use household was not much lower than solid fuel use households. Biogas-use household produced the lowest PAHs, which significantly reduced 64-82% compared with those emitted by solid fuel combustion. The different combustion conditions influenced the gaseous PAHs in indoors between two sampling sites. The gas/particle partition indicated that PAHs tended to occur in the particle phase with increased molecular weight, and the absorption was the main mechanism. The relative higher contribution of high molecular weight PAHs (HMW-PAHs) in solid fuel use households than in clean fuel use households, induced more health risks of PAHs. The concentration of Σ10OH-PAHs in the urine samples for elders of different fuel-use households displayed the trend of coal (83.27 ng/mL) > wood (79.32 ng/mL) > LPG (51.61 ng/mL) > biogas (28.96 ng/mL), and OH-NaPs was the predominant metabolites, which accounted for more than 90% of the total concentration. The carcinogenic risk of PAHs based on internal exposure was greater than or close to 10-4, with serious carcinogenic risks. This was different with the incremental lifetime cancer risk based on the atmospheric concentrations. The exposure of PAHs from solid fuel combustion for human being especially for the elders in this region should be concerned, and more data should be done for the internal exposure of PAHs.

Characterising polycyclic aromatic hydrocarbons in road dusts and stormwater in urban environments

The presence of polycyclic aromatic hydrocarbons (PAHs) pollution on urban road surfaces is one of the major environmental concerns. However, knowledge on the distribution variability of PAHs in road dusts (RDS) and stormwater is limited, which would restrict the further risk evaluation and mitigation implementation of PAHs in road stormwater runoff. This study collected RDS samples and stormwater samples on fourteen urban roads in Shenzhen, China. This study investigated the variation of sixteen PAHs species in RDS and stormwater, and further evaluated the intrinsic and extrinsic factors which influence PAHs accumulation on urban road surfaces. The research outcomes showed significant differences on spatial distribution of PAHs in RDS and in stormwater. The land use types, industrial, commercial and port areas and vehicular volume have a positive relationship with PAHs abundance while dust particle size showed a negative correlation with PAHs abundance. For two phases in stormwater, fluctuation of PAHs with the rainfall duration in total dissolved solid (TDS) was more intensive than in dissolved liquid phase (DLP). This indicated when PAHs attached to RDS enter stormwater, most of PAHs still tend to be on solid particles than in liquid. The study outcomes are expected to contribute to efficient designs of PAHs polluted stormwater mitigation.

Analysis of nationwide soil pesticide pollution: Insights from China

China is a typical agricultural country that heavily relies on pesticides. Some pesticides can remain in the soil after application and thus pose a significant threat to human health. In order to characterize the status and hazards of nationwide soil contamination, this study extracted concentration data from published literature and analyzed them by a scoring approach, standard comparison and health risk assessment. For the soil pollution score, northern regions got the highest values, such as Henan (0.63), Liaoning (0.55), Heilongjiang (0.54) and Jilin (0.53), which implies high soil pesticide residues in these provinces. In contrast, Qinghai (-0.77), Guizhou (-0.64) and Tibet (-0.63) had lower scores. China's soil pesticide standards cover only 16 pesticides, and these pesticide concentrations were all below the corresponding standards. Direct exposure to soil pesticides in this study generally posed a negligible risk to children. Furthermore, pesticide dissipation and usage intensity in each province were analyzed as they were possible influences on pollution. The result showed that soil in the northern regions could accumulate more pesticides than those in the southern regions, and this geographic pattern was basically consistent with the distribution of soil pollution. However, the relationship between agricultural activities and soil pollution was less well characterized. It is recommended to establish a long-term monitoring database for pesticides and include more pesticides in regulatory frameworks. Additionally, efforts to accelerate pesticide degradation and shift the planting structure to reduce pesticide usage can help alleviate the pressure on soil from pesticides. This study can serve as a critical reference for policymakers and stakeholders in the field of agriculture.

Profiling population-wide exposure to environmental chemicals: A case study of naphthalene

Long-term exposure to environmental chemicals can detrimentally impact human health, and understanding the relationship between age distribution and levels of external and internal exposure is crucial. Nonetheless, existing methods for assessing population-wide exposure across age groups are limited. To bridge this research gap, we introduced a modeling approach designed to assess both chronic external and internal exposure to chemicals at the population level. The external and internal exposure assessments were quantified in terms of the average daily dose (ADD) and steady-state blood concentration of the environmental chemical, respectively, which were categorized by age and gender groups. The modeling process was presented within a spreadsheet framework, affording users the capability to execute population-wide exposure analyses across a spectrum of chemicals. Our simulation outcomes underscored a salient trend: younger age groups, particularly infants and children, exhibited markedly higher ADD values and blood concentrations of environmental chemicals compared to their older counterparts. This observation is due to the elevated basal metabolic rate per unit of body weight characteristic of younger individuals, coupled with their diminished biotransformation kinetics of xenobiotics within their livers. These factors collectively contribute to increased intake rates of environmental chemicals per unit of body weight through air and food consumption, along with heightened bioaccumulation of these chemicals within their bodies (e.g., blood). Furthermore, we augmented the precision of the external and internal exposure assessment by incorporating the age distribution across the population. The simulation outcomes unveiled that, to estimate the central tendency of the population's exposure levels, employing the baseline value group (age group 21-30) or the surrogate age of 25 serves as a simple yet dependable approach. However, for comprehensive population protection, our recommendation aligns with conducting exposure assessments for the younger age groups (age group 0-11). Future studies should integrate individual-level exposure assessment, analyze vulnerable population groups, and refine population structures within our developed model.

Assessing pesticides in the atmosphere: A global study on pollution, human health effects, monitoring network and regulatory performance

Pesticides are widely used in agriculture, but their impact on the environment and human health is a major concern. While much attention has been given to their presence in soil, water, and food, there have been few studies on airborne pesticide pollution on a global scale. This study aimed to assess the extent of atmospheric pesticide pollution in countries worldwide and identify regional differences using a scoring approach. In addition to analyzing the health risks associated with pesticide pollution, we also examined agricultural practices and current air quality standards for pesticides in these countries. The pollution scores varied significantly among the countries, particularly in Europe. Asian and Oceanic countries generally had higher scores compared to those in the Americas, suggesting a relatively higher level of air pollution caused by pesticides in these regions. It is worth noting that the current pollution levels, as assessed theoretically, pose minimal health risks to humans. However, studies in the literature have shown that excessive exposure to pesticides present in the atmosphere has been associated with various health problems, such as cancer, neuropsychiatric disorders, and other chronic diseases. Interestingly, European countries had the highest overall pesticide application intensities, but this did not necessarily correspond to higher atmospheric pesticide pollution scores. Only a few countries have established air quality standards specifically for pesticides. Furthermore, pollution scores across states in the USA were investigated and the global sampling sites were mapped. The findings revealed that the scores varied widely in the USA and the current sampling sites were limited or unevenly distributed in some countries, particularly the Nordic countries. These findings can help global relevant environmental agencies to set up comprehensive monitoring networks. Overall, the present research highlights the need to create a pesticide monitoring system and increase efforts to enhance pesticide regulation, ensure consistency in standards, and promote international cooperation.

Co-PBK: a computational biomonitoring tool for assessing chronic internal exposure to chemicals and metabolites

Toxic chemicals are released into the environment through diverse human activities. An increasing number of chronic diseases are associated with ambient pollution, thus posing a threat to people. Given the high consumption of resources for human biomonitoring, this study proposed coupled physiologically-based kinetic (co-PBK) modeling matrices as a biomonitoring tool for simplifying chronic internal exposure estimates of environmental chemicals and their metabolites using naphthalene (NAP) and its metabolites (i.e., 1-OHN and 2-OHN) as simulation examples. According to the simulation of the steady-state mass among various organs/tissues via the co-PBK modeling matrices, fat had the highest potential bioaccumulation of NAP and its metabolites. With respect to body fluids, 1-OHN and 2-OHN tended to bioaccumulate more in the bile than in the urine. According to the sensitivity analysis, the calculated sensitivity factors for the first-order kinetics-based rate constants imply that due to the biotransformation process, target organs/tissues (e.g., liver and kidneys) would be continuously exposed to more NAP metabolites under chronic exposure. Meanwhile, 1-OHN may be more stably transported to the urine than 2-OHN for further human biomonitoring during long-term internal exposure. According to the case study of simulating population chronic exposure to NAP in Shenzhen, the co-PBK modeling estimated the population exposure to NAP with an intake rate of 8.77 × 10-2 mg d-1 and the aggregated urinary concentration of NAP metabolites of 2.60 μg L-1. Furthermore, the accuracy of the urinary levels between the real-world data and the values simulated by the co-PBK modeling was assessed and the root-mean-square error of c1-OHN,urine was found to be lower than that of c2-OHN,urine.

Air pollution prevention in central China: Effects on particulate-bound PAHs from 2010 to 2018

Long-term trends in particulate-bound polycyclic aromatic hydrocarbon (PAH) concentrations in air in Zhengzhou (a severely polluted city in central China) between 2010 and 2018 were studied to assess the effectiveness of an air pollution prevention and control action plan (APPCAP) implemented in 2013. The PM2.5, sum of 16 PAHs (Σ16 PAHs), benzo[a]pyrene (BaP), and BaP toxic equivalent concentrations were high before 2013 but 41%, 77%, 77%, and 78% lower, respectively, after the APPCAP. The maximum daily Σ16 PAHs concentration between 2014 and 2018 was 338 ng/m3, 65% lower than the maximum of 961 ng/m3 between 2010 and 2013. The ratio between the Σ16 PAHs concentrations in winter and summer decreased over time and was 8.0 in 2011 and 1.5 in 2017. The most abundant PAH was benzo[b]fluoranthene, for which the 9-year mean concentration was 14 ± 21 ng/m3 (15% of the Σ16 PAHs concentration). The mean benzo[b]fluoranthene concentration decreased from 28 ± 27 ng/m3 before to 5 ± 4 ng/m3 after the APPCAP (an 83% decrease). The mean daily BaP concentrations were 0.1-62.8 ng/m3, and >56% exceeded the daily standard limit of 2.5 ng/m3 for air. The BaP concentration decreased from 10 ± 8 ng/m3 before to 2 ± 2 ng/m3 after the APPCAP (a 77% decrease). Diagnostic ratios and positive matrix factorization model results indicated that coal combustion and vehicle exhausts were important sources of PAHs throughout the study period, contributing >70% of the Σ16 PAHs concentrations. The APPCAP increased the relative contribution of vehicle exhausts from 29% to 35% but decreased the Σ16 PAHs concentration attributed to vehicle exhausts from 48 to 12 ng/m3. The PAH concentration attributed to vehicle exhausts decreased by 79% even though vehicle numbers strongly increased, indicating that pollution caused by vehicles was controlled well. The relative contribution of coal combustion remained stable but the PAH concentration attributed to coal combustion decreased from 68 ng/m3 before to 13 ng/m3 after the APPCAP. Vehicles made dominant contributions to the incremental lifetime cancer risk (ILCRs) before and after the APPCAP even though the APPCAP decreased the ILCRs by 78%. Coal combustion was the dominant source of PAHs but contributed only 12-15% of the ILCRs. The APPCAP decreased PAH emissions and changed the contributions of different sources of PAHs, and thus strongly affected the overall toxicity of PAHs to humans.