Characterization and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Surface Water from Liaohe River, Northeast China

The silent threat: Nanopolystyrene and chrysene pollutants disrupt the intestinal mucosal barrier, new insights from juvenile Siniperca chuatsi

The intestinal mucosal barrier-comprising microbial, mechanical, chemical, and immunological barriers-is critical to protection against pathogens and maintenance of host health; however, it remains unclear whether it is affected by environmental contaminants. Therefore, the present study assessed whether exposure to ambient concentrations of nanopolystyrene (NP) and chrysene (CHR)-two ubiquitous environmental pollutants in the aquatic environment-affect the intestinal mucosal barrier in juvenile Siniperca chuatsi. After exposure for 21 days, S. chuatsi exhibited intestinal oxidative stress and imbalance of intestinal microbial homeostasis. NP and/or CHR exposure also disrupted the intestinal mechanical barrier, as evidenced by the altered intestinal epithelial cell morphology, disrupted structure of intercellular tight junctions, and decreased expression of tight junction proteins. Damage to the intestinal chemical barrier manifested as thinning of the mucus layer owing to the loss and damage of goblet cells. Furthermore, the intestinal immunological barrier was impaired as indicated by the loss of intestinal intraepithelial lymphocytes and increase in pro-inflammatory cytokines, chemokines, and immunoglobulins. These findings collectively suggest that the intestinal mucosal barrier was damaged. This study is, to the best of our knowledge, the first to report that exposure to NP and/or CHR at environmentally relevant concentrations disrupts the intestinal mucosal barrier in organisms and highlight the significance of nanoplastic/CHR pollution for intestinal health.

Association between exposure to water sources contaminated with polycyclic aromatic hydrocarbons and cancer risk: A systematic review

The recent scientific focus on polycyclic aromatic hydrocarbons (PAHs) has stemmed from their recognized genotoxic, mutagenic, and carcinogenic properties. This systematic review seeks to evaluate the nexus between exposure to water sources contaminated with PAHs and the associated cancer risk among global populations, encompassing both children and adults. Web of Science (WoS), Cochrane Library, PubMed, ProQuest, Scopus, and Google Scholar, were searched following the PRISMA guidelines, until December 31, 2023. Quality assessment of the selected studies was performed using the Newcastle-Ottawa Scale. The increased lifetime cancer risk (ILCR) attributed to PAH exposure through ingestion and dermal absorption was thoroughly examined across diverse age groups. After extensive searching, screening, and eligibility, 30 articles were included in this review, which was conducted in different parts of the world, including Nigeria (n = 11), China (n = 7), India (n = 4), Iran (n = 3), South Africa (n = 2), Italy (n = 1), Colombia (n = 1), and Iraq (n = 1). Our analysis underscores Nigeria's alarming prevalence of PAH contamination in its rivers, groundwaters, and seawater. Remarkably, the highest cancer risk was identified among children and adults, notably in proximity to the Atlas Cove jetty (seawater) and various Nigerian rivers. This elevated risk is primarily attributed to the combined effects of ingestion and dermal absorption. Furthermore, our findings emphasize the prominent role of combustion-derived and pyrogenic sources of PAH in the examined aquatic ecosystems. This study unequivocally establishes that PAH-contaminated water sources significantly amplify the risk of cancer among both children and adults. The extent of risk variation is influenced by the specific water source, duration of exposure, and age group. Consequently, proactive identification of contaminated water sources and their pollution origins, coupled with targeted educational campaigns, holds promise for reducing the global burden of PAH-related cancer.

Nanoplastics and chrysene pollution: Potential new triggers for nonalcoholic fatty liver disease and hepatitis, insights from juvenile Siniperca chuatsi

Nanopolystyrene (NP) and chrysene (CHR) are ubiquitous contaminants in the natural environment; however, research on their hepatotoxicity and associated adverse effects remains relatively inadequate. The present study aimed to investigate the hepatotoxic effects of NP and/or CHR at environmentally relevant concentrations, as well as the underlying molecular mechanisms, in juvenile Siniperca chuatsi (mandarin fish). After a 21-day exposure period, the livers of exposed S. chuatsi exhibited macrostructural and microstructural damage accompanied by oxidative stress. Importantly, our study provides the first evidence that NP exposure leads to the development of nonalcoholic fatty liver disease (NAFLD) and hepatitis in S. chuatsi. Similarly, CHR exposure has also been found, for the first time, to cause hepatic sinusoidal dilatation (HSD) and hepatitis. Exposure to the combination of NP and CHR alleviated the symptoms of NAFLD, HSD, and hepatitis. Furthermore, our comprehensive multi-omic analysis revealed that the pathogenesis of NP-induced NAFLD was mainly due to induction of the triglyceride synthesis pathway and inhibition of the very-low-density lipoprotein secretion process. CHR induced HSD primarily through a reduction in vasoprotective ability and smooth muscle contractility. Hepatitis was induced by activation of the JAK-STAT/NF-kappa B signaling pathways, which upregulated the expression of inflammation-specific genes. Collectively, results of this study offer novel insight into the multiple hepatotoxicity endpoints of NP and/or CHR exposure at environmentally relevant concentrations in organisms, and highlight the importance of nanoplastic/CHR pollution for liver health.

Impacts of exposure to nanopolystyrene and/or chrysene at ambient concentrations on neurotoxicity in Siniperca chuatsi

Health risks caused by widespread environmental pollutants such as nanopolystyrene (NP) and chrysene (CHR) in aquatic ecosystems have aroused considerable concern. The present study established juvenile Mandarin fish (Siniperca chuatsi) models of NP and/or CHR exposure at ambient concentrations for 21 days to systematically investigate the underlying neurotoxicity mechanisms. The results showed that single and combined exposure to NP and CHR not only reduced the density of small neuronal cells in the grey matter layer of the optic tectum, but also induced brain oxidative stress according to physiological parameters including CAT, GSH-Px, SOD, T-AOC, and MDA. The co-exposure alleviated the histopathological damage, compared to NP and CHR single exposure group. These results indicate that NP and/or CHR causes neurotoxicity in S. chuatsi, in accordance with decreased acetylcholinesterase activity and altered expression of several marker genes of nervous system functions and development including c-fos, shha, elavl3, and mbpa. Transcriptomics analysis was performed to further investigate the potential molecular mechanisms of neurotoxicity. We propose that single NP and co-exposure induced oxidative stress activates MMP, which degrades tight junction proteins according to decreased expression of claudin, JAM, caveolin and TJP, ultimately damaging the integrity of the blood-brain barrier in S. chuatsi. Remarkably, the co-exposure exacerbated the blood-brain barrier disruption. More importantly, single NP and co-exposure induced neuronal apoptosis mainly activates the expression of apoptosis-related genes through the death receptor apoptosis pathway, while CHR acted through both death receptor apoptosis and endoplasmic reticulum apoptosis pathways. Additionally, subchronic CHR exposure caused neuroinflammation, supported by activation of TNF/NF-κB and JAK-STAT signaling pathways via targeting-related genes, while the co-exposure greatly alleviated the neuroinflammation. Collectively, our findings illuminate the underlying neurotoxicity molecular mechanisms of NP and/or CHR exposure on aquatic organisms.

Ecological pollution and health risk monitoring assessment of polycyclic aromatic hydrocarbons and heavy metals in surface water, southeastern Nigeria

Polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) are predominant pollutants linked with anthropogenic activities across a host of environmental mediums. The level of pollution, ecological and health risk were assessed in surface water from Ekulu in Enugu metropolis, Nigeria for 17 PAHs and selected HMs (As, Cd, Cr, Cu, Pb, Ni, Zn) components. PAHs and HMs were determined using a gas chromatography-flame ionization detector (GC-FID) and atomic adsorption spectrophotometer (AAS). The total PAHs in station A (3.17mg/l), B (1.51mg/l), and C (1.83mg/l) were due to high molecular weight (HMW) PAHs than low molecular weight (HMW) PAHs. HMs contents were within USEPA and WHO minimum contamination levels (MCL) except Cr and Pb. The molecular diagnostics of PAHs showed that incomplete combustion of carbonaceous compounds was dominant, while petrogenic was insignificant across all samples. The ecological indices of PAHs and HMs varied from medium to high pollution due to anthropogenic activities that pose a threat to the ecosystem. The non-carcinogenic models showed that hazard index (HI) ranged from PAHs (0.027 - 0.083) and HMs (0.0067 - 0.087) which is less than unity implying no adverse health issues. The lifetime cancer risk (LCR) for PAHs (4.21×10-4 - 9.61×10-4) and HMs (1.72×10-5 - 3.98×10-5) suggested significant cancer risk is possible over some time for a population of 1 in 10,000 and 100,000 for both PAHs and HMs exposure for 70 years. Therefore, there is an urgent need for proper pollution control and mitigation plan to preserve both age groups from being continuously exposed to anthropogenic activities in the Ekulu River and further study should be carried out to monitor the available toxicants.

Development of human health criteria in China for benzo[a]pyrene: A comparison of deterministic and probabilistic approaches

Human health water quality criteria (HHWQC) for benzo[a]pyrene (BaP) in Chinese rivers and lakes were established using both deterministic and probabilistic approaches. Results showed that the national bioaccumulation factor (BAF) values for BaP at trophic levels 2, 3, and 4 were 342 L/kg, 199 L/kg, and 196 L/kg, respectively. The probabilistic HHWQC for BaP was 0.00407 μg/L for both water and organisms consumption and 0.00488 μg/L for organisms consumption only, which provide a more adequate protection than the deterministic HHWQC. Approximately 32.1% of the studied waters in China exceeded the derived HHWQC, which is likely to have adverse health effects and need be considered more attention. The derived HHWQC for BaP is soly based on Chinese exposure-related activity patterns and field-measured BAFs in surface freshwaters in China, which is important to provide a scientific basis for establishing or revising water quality standards (WQS) and risk management of BaP in water.

Mn oxides enhanced pyrene removal with both rhizosphere and non-rhizosphere microorganisms in subsurface flow constructed wetlands

The polycyclic aromatic hydrocarbons (PAHs) are substantial wastewater pollutants emitted mostly by petroleum refineries and petrochemical industries, and their environmental fate has been of increasing concern among the public. Consequently, subsurface flow constructed wetlands (SFCWs) filled with Mn oxides (W-CW) or without Mn oxides (K-CW) were established to investigate the performance and mechanisms of pyrene (PYR) removal. The average removal rates of PYR in W-CW and K-CW were 96.00% and 92.33%, respectively. The PYR removal via other pathways (microbial degradation, photolysis, volatilisation, etc.) occupied a sizeable proportion, while the total PYR content in K-CW plant roots was significantly higher than that of W-CW. The microorganisms on the root surface and rhizosphere played an important role in PYR degradation in W-CW and K-CW and were higher in W-CW than that in K-CW in all matrix zones. The microorganisms between the 10-16 cm zone from the bottom of W-CW filled with Mn oxides (W-16) were positively correlated with PYR-degrading microorganisms, aerobic bacteria and facultative anaerobes, whereas K-16 without birnessite-coated sand was negatively correlated with these microorganisms.

Assessing potential risks of aquatic polycyclic aromatic compounds via multiple approaches: A case study in Jialing and Yangtze Rivers in downtown Chongqing, China

To better evaluate the potential risks of aquatic polycyclic aromatic compounds (PACs), multiple approaches have been implemented in this study to assess the human health and ecological risks of parent, nitrated and oxygenated polycyclic aromatic hydrocarbons (PAHs, NPAHs and OPAHs) in the surface water of Jialing and Yangtze Rivers in downtown Chongqing in southwestern China. The concentrations of ∑PAHs (334 ± 125 ng L^-1) were much higher than those of ∑OPAHs (20.2 ± 7.49 ng L^-1) in the two rivers, while NPAHs were barely detected. Concentrations of detected PACs were higher in wet season than dry season, probably resulted from the elevated particle input due to heavy rainfall in wet season. Concentrations of PAHs were higher in the particulate phase than dissolved phase, while OPAHs levels showed a reverse pattern. The partition coefficients (K_p) of PACs in the water-SPM (suspended particulate matter) system were mainly affected by SPM concentrations and octanol/water partition coefficients of specific PACs. Human health risks calculated from non-probabilistic risk assessment model and probabilistic risk assessment model based on Monte Carlo simulation showed similar data pattern with slight difference in absolute values. Both models revealed potential or even severe human health risks contributed mainly by dermal exposure to aquatic PACs in this study. Furthermore, these models also manifested that infant stage was highly sensitive for PAC exposure. Sensitivity analysis indicated that health risk results was most sensitive to Benzo[a]pyrene equivalent toxic concentration (BaP_eq), followed by showering time and daily water intake volume. Levels of ecological risks and contributions of individual PACs differed from models based on different quality values. The adequacy of toxicity data was crucial for the reliability of ecological risk assessment.

Nationwide health risk assessment of juvenile exposure to polycyclic aromatic hydrocarbons (PAHs) in the water body of Chinese lakes

The high emissions of polycyclic aromatic hydrocarbons (PAHs) pose a serious threat to the lake ecosystem and human health, and the human health risk assessment of PAH exposure is expected as an urgent project in China. This paper focused on 44 Chinese lakes in 6 lake zones to investigate the occurrence, composition and source of 19 PAHs in water body and estimate the human health risk under PAH exposure. The "List of PAH Priority Lakes" in China was generated based on the combination of incremental lifetime cancer risk (ILCR) model and Monte Carlo simulation. Our results showed that the Σ₁₇ PAHs ranged from 3.75 ng·L^-1 to 368.68 ng·L^-1 with a median of 55.88 ng·L^-1. Low-ring PAHs were the predominant compounds. PAH profiles varied significantly at lake zone level. Diagnostic ratios showed that PAHs might derive from petroleum and coal or biomass combustion. Benzo[a]pyrene-equivalent toxic concentrations (BaPeq) of the Σ₁₇ PAHs ranged from 0.07 ng·L^-1 to 2.26 ng·L^-1 (0.62 ± 0.52 ng·L^-1, mean ± standard deviation) with a median of 0.47 ng·L^-1. Benzo[a]anthracene (BaA), benzo[a]pyrene (BaP) and benzo[e]pyrene (BeP) were the main toxic isomers. Juvenile exposure to PAHs via oral ingestion (drinking) and dermal contact (showering) had negligible and potential health risks, respectively. Juveniles were the sensitive population for PAH exposure. 15 lakes were screened into the "List of PAH Priority Lakes" in three priority levels: first priority (Level A), moderate priority (Level B) and general priority (Level C). Lake Taihu, Lake Chaohu and Lake Hongze were the extreme priority lakes. Optimizing the economic structures and reducing the combustion emissions in these areas should be implemented to reduce the population under potential health risk of PAHs.

Levels of persistent organic pollutants in pine tree components and ambient air

Pine needles are employed as alternative biomonitoring agents in atmospheric studies. In this study, pine (Pinus Pinea) components (needles and branches) and air samples were collected simultaneously to monitor polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs) from Gemlik, Turkey between January and December 2016. The relationship between ambient air and pine needles were examined to enlighten the usability of pine components as passive samplers for persistent organic pollutants (POPs) in the Marmara region. Average ∑₁₄PAH concentrations for the ambient air, pine needles, and pine branches were 23.1 ± 18.3 ng/m³, 626 ± 306 ng/g DW and 548 ± 261 ng/g DW respectively. PCB concentrations were 118 ± 74 pg/m³, 7.5 ± 2.1 ng/g DW and 6.8 ± 2.9 ng/g DW and ∑₁₀ OCP concentrations were 122 ± 89 ng/m³,1.3 ± 1.5 ng/g DW and 10.0 ± 3.8 ng/g DW in the same order. Levels of PAHs and PCBs were higher in needles than branches. PAH, PCB and OCP concentrations in pine components tended to decrease with increasing temperatures in spring. PAH compounds with medium and light molecular weighted ones were found to be dominant. On the other hand, the predominant PCB components were the medium-weighted congeners while γ-HCH, Heptachlor endo. Epox. Iso A, endrin aldehyde, and methoxychlor were the dominant OCP species.

Determination of polycyclic aromatic hydrocarbons (PAHs) in drinking water of Samsun and it's surrounding areas, Turkey

BACKGROUND

Polycyclic aromatic hydrocarbons (PAH) are considered to be one of the major contaminants of drinking water and natural water bodies. Some of the well documented polycyclic aromatic hydrocarbons that are water pollutants and were considered for analysis in this study included benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[a]pyrene (BaP), benzo[g,h,i]perylene (BgP), and indeno[1,2,3-c,d]pyrene (InD). This study aimed at determining the levels of concentrations of basically five polycyclic aromatic hydrocarbons in 57 drinking water bodies located around Samsun, Ordu, Giresun, Çorum, Amasya, Kastamonu and Sinop provinces.

MATERIALS AND METHOD

In this study, the Environmental Protection Agency (EPA) method 550.1 for the determination of polycyclic aromatic hydrocarbons in drinking by Liquid-Solid Extraction (LSE) and High Performance Liquid Chromatography (HPLC) with Coupled Ultraviolet (CD) and Fluorescence Detection (FD) was used. Sampling procedures were done according to the validated method specified by the Turkish Ministry of Enivironment and Forestry. Prior to the determination of concentrations by HPLC, PAHs contained in the samples were separated from the solid phase by Solid-Phase Extraction (SPE). All data analyses were conducted using SPSS and Excel.

RESULTS

Obtained results from the investigation revealed that the average total PAH and benzo[a]pyrene (BaP) concentration levels in drinking water samples taken from the central districts of Samsun were 2.73 ± 1.51 and 0.35 ± 0.24 ng/L respectively. In drinking water samples taken from Ordu, Giresun, Çorum, Amasya, Kastamonu and Sinop, the average total PAH concentrations were found to be 5.85 ± 3.82 ng/L, 3.79 ± 1.27 ng/L, 1.08 ± 0.62 ng/L, 2.42 ± 1.04 ng/L; 1.92 ± 0.35 ng/L and 4.07 ± 2.33 ng/L respectively. The average (BaP) concentrations for the same named locations were determined as 0.97 ± 0.75 ng/L; 0.55 ± 0.29 ng/L; 0.11 ± 0.08 ng/L; 0.35 ± 0.10 ng/L; 0.14 ± 0.04 ng/L; 0.39 ± 0.23 ng/L, respectively. It is therefore evident that the values ​​of PAH and BaP in drinking water were below the limits of 100 and 10 ng/L ​​specified in the Regulation on Water Intended for Human Consumption. These values are below the set limits proposed by Turkish legislation and WHO.

CONCLUSION

All the results for drinking water, usable water and natural spring water were below the values ​​specified in the Regulation on Water Intended for Human Consumption and WHO. The PAH content of the studied river waters as well were below the limits proposed by Turkish legislation and WHO.

Spatiotemporal distribution, source apportionment and ecological risk assessment of PBDEs and PAHs in the Guanlan River from rapidly urbanizing areas of Shenzhen, China

In this study, nine congeners of polybrominated diphenyl ethers (PBDEs) and sixteen congeners of polycyclic aromatic hydrocarbons (PAHs) were measured in water samples to elucidate their spatial distribution, congener profiles, sources and ecological risks in the Guanlan River during both the dry season (DS) and the wet season (WS). The concentration of Σ₉PBDE ranged from 58.40 to 186.35 ng/L with an average of 115.72 ng/L in the DS, and from 8.20 to 37.80 ng/L with an average of 22.15 ng/L in the WS. Meanwhile, the concentration of Σ₁₆PAHs was ranged from 121.80 to 8371.70 ng/L with an average of 3271.18 ng/L in the DS and from 1.85 to 7124.25 ng/L with an average of 908.11 ng/L in the WS. The concentrations of PBDEs and PAHs in the DS were significantly higher than those in the WS, probably due to the dilution of the river during the rainy season. Moreover, the spatial distribution of pollutants revealed decreasing trend in the concentration from upstream to downstream and almost identical pattern was observed during both seasons. The source apportionment suggested that penta-BDE and to some extent octa-BDE commercial products were major sources of PBDEs in the study area. However, the sources of PAHs were mainly comprised of fossil fuels and biomass burning, followed by the petroleum products and their mixtures. The results of the ecological risk assessment indicated PBDEs contamination posed high ecological risks, while PAHs exhibited low or no ecological risks in the study area. Consistent with the environmental levels, the ecological risks of pollutants were relatively lower in the WS, compared to that in the DS. The results from this study would provide valuable baseline data and technical support for policy makers to protect the ecological environment of the Guanlan River.

Spatiotemporal distributions of polycyclic aromatic hydrocarbons close to a typical medical waste incinerator

Environmental contaminations by polycyclic aromatic hydrocarbons (PAHs) especially from incinerators occur subtly, and PAH contribution from this source is underestimated. However, as environmental PAH concentrations build up, this may be a serious concern around the incinerator vicinity due to the potential consequences of PAHs on ecosystems and human health. Thus, the contribution of selected (12) PAHs from the Obafemi Awolowo University Teaching Hospital medical waste incinerator (or source, HWI_0) was determined by sampling stack gas and ambient air around incinerator vicinity from June 2014 to May 2015. Results showed that the 12 PAH source (HWI_0) concentrations were in the range of NA (for phenanthrene, pyrene, anthracene, benz[e]acephenanthrylene, and indeno[2,1-b]chromene) to 10.9 ng/m³ (pyrelene) and generally higher than the receptor points (hospital waste incinerators (HWIs)). The average total PAH concentrations per month at HWI_0 and the receptors-HWI_1, HWI_2, HWI_3, HWI_4 and HWI_5-were 73.0 ± 27.9, 60.4 ± 30.8, 42.5 ± 23.6, 38.7 ± 21.9, 35.0 ± 27.2, and 39.2 ± 22.9 ng/m³, respectively. These results and multivariate receptor model analysis indicated high correlations between source PAH contributions and the receptor points. The PAH concentrations in the dry season were higher than the wet season suggesting that hydrological condition affects ambient PAH concentrations. The average PAH concentrations in the HWIs as well as the cumulative exposure concentrations observed throughout the period are of major health concern because PAH concentrations detected are several times higher than both the European Union standard and the WHO guideline level.