PAH Pollution Research Articles

Dose-specific biochemical and erythrocytic morpho-pathological profiling of anthracene (Polycyclic Aromatic Hydrocarbon) in an air-breathing teleost Anabas testudineus (Bloch) for establishing biomarkers

This study investigates the impact of anthracene, PAH, on the bioenzymological activity in the tissues of Anabas testudineus, commonly known as the Climbing Perch. The research was grounded in the understanding that PAHs, such as anthracene, pose significant risks to aquatic life, necessitating detailed analysis of their effects on fish physiology. The experiment employed two anthracene concentrations, T1 (0.0075 mg/L) and T2 (0.015 mg/L), representing 25 % and 50 % of the LC50, respectively, over exposure periods of 1, 5, 10, 15, and 21 days. Throughout the study, water samples were analyzed for physicochemical parameters to ensure consistent conditions. Post-exposure, fish were humanely euthanized, and their tissues (stomach, intestine, liver, and kidney) were harvested for a dose-specific bioenzymological assessment, focusing on glucose (GLU), protein (PRO), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and triglycerides (Trig). Analyzing these enzymological factors in fish tissues emerged as a pivotal method for pinpointing the bioindicators that mirror the fish's physiological state, particularly responsiveness under the contamination of PAHs, with a specific focus on anthracene. Additionally, the study delved into detecting apoptosis (programmed cell death), erythrocytic anomalies, and alterations in bioenzymological aspects within A. testudineus tissues. These observed changes demonstrated both the exposure-specific and dose-specific characteristics of anthracene. This research provides novel insights into the bioenzymatic systems of Anabas testudineus (Bloch), commonly known as the climbing perch, respond to PAHs, with a special emphasize on anthracene exposure. By elucidating these bioenzymological responses, the study underscores the importance of monitoring and managing PAH levels in aquatic environments and it attributes to SDG 14, which aims to life below water. Such measures are crucial to safeguard the health and well-being of aquatic species like A. testudineus, highlighting the broader ecological implications of PAH pollution.

Photocatalysis: A Sustainable Approach for Removing Hazardous Polyaromatic Hydrocarbons

AbstractPolycyclic aromatic hydrocarbons (PAHs) are omnipresent toxic pollutants found in numerous ecosystems, including soil, water, and living organisms. Due to their hydrophobic nature, PAHs tend to accumulate in aquatic environments, leading to high concentrations in aquatic sediments and subsequent bioaccumulation in organisms. This accumulation poses substantial risks to humans and aquatic life. Recent advances in photocatalytic methods, particularly those using nanocomposite materials, have shown promising outcomes in the degradation of PAHs. Photocatalysis, a process that uses UV and visible light to accelerate a chemical reaction, is effectively breaking these harmful compounds. This review focuses on the recent advances in the degradation of PAHs, the toxicological effects of PAHs on living organisms, and the mechanisms underlying nanocomposite‐based photocatalysis. The utilization of nanocomposite for photocatalysis is an eco‐friendly substitute to traditional methods for remediating PAH pollution in the ecosystem. This green approach using nanocomposite‐based photocatalysis offers a sustainable and effective approach for the degradation of PAHs.

Migration of fluoranthene, phenanthrene, and pyrene in soil environment during the growth of Brassica rapa subsp. chinensis

The escalating concern surrounding fluoranthene (FLN), phenanthrene (Phe), and pyrene (Pyr), underscores the urgency to investigate their dynamics in the context of agricultural ecosystems. Brassica rapa subsp. chinensis (Bok choy), a globally consumed vegetable, holds particular significance in this scenario. This study explores the migration and transformation of FLN, Phe, and Pyr from soil to Brassica rapa subsp. chinensis during its growth. The germination rates of seeds in these treatments varied, with soil+Bok choy and soil+FLN+Bok choy treatments showing higher rates (77.8 %), while soil+mix+Bok choy exhibited the lowest rate (11.1 %) after 3 days. Analyzing the distribution of FLN, Phe, and Pyr in Brassica rapa subsp. chinensis parts after 30 days revealed a sequence of accumulation in stem> root> leaf. This study provides information on practical implications for regulating the soil-plant migration and transformation of FLN, Phe, and Pyr, offering valuable insights for migration of PAHs pollution in agricultural settings.

Kinetic insights and pollution mitigation in waste tire pyrolysis: Targeting sulfur, nitrogen, and PAHs emissions

Waste tires have potential to be used for generation of fuel via thermal degradation because of their non-biodegradable nature. Nevertheless, the formation of various pollutants such as sulfur-based and nitrogen-based are inevitable due to presence of nitrogen and sulfur containing compounds during waste tires production. The main purpose was to examine the effect of variating heating rates on pollutants release because heating rate is an important parameter which influences the pollutants releasing profile. Moreover, Ar and CO2 as reaction medium were used to identify their behavior for restraining the PAHs in gas phase. The present study investigates the influence of heating rates and carrier gas environment (Argon and CO2) to reduce the pollutants emission. Thermogravimetry-Mass Spectrum coupled with Fourier transform infrared spectrometer was used to evaluate the thermal degradation and pollutants formation. The major degradation of waste tires occurred between 300 and 500 ℃. The sulfur-based (H2S, CS2, COS, SO2, and CH3SH), nitrogen-based (NH3, HNCO, NO, and HCN) and 9 series of PAHs pollutants were detected. The higher heating rates promoted the pollutants emission. The degradation of compounds having sulfur content formed -SH radials and -SH helped in further release of sulfur based-pollutants. The NH3 releasing profile started after 200 ℃ and released till around 800 ℃ for 30 ⁰C/min and 40 ⁰C/min but its emission was very low after 600 ⁰C for heating rates 5 ⁰C/min, 10 ⁰C/min, and 20 ⁰C/min. The aromatic compounds fraction was more at higher heating rate due to short residence time for pyrolytic products to go through secondary reaction. The 5 ℃/min and 10 ℃/min were considered favorable heating rates in terms of achieving lowest activation energy in both gas environments. The thermodynamic parameters analysis suggested that waste tires pyrolysis was non-spontaneous and endothermic reaction as well as feedstocks showed potential to be utilized for waste conversion.

Fishing Harbours as a Source of PAHs Pollution: A Case Study from Veraval Harbour, West Coast of India

Fishing Harbours as a Source of PAHs Pollution: A Case Study from Veraval Harbour, West Coast of India

Is Fucus a suitable biomonitoring organism for polycyclic aromatic hydrocarbon contamination? A study from the Faroe Islands

To evaluate seaweed as a biomonitoring organism, Fucus was sampled in the Faroe Islands. Nineteen PAHs, including the EPA 16, and four groups of alkylated PAHs were quantified using GC–MS analysis of extracts obtained using a modified QuEchERS method with ultrasonication in acetonitrile, back-extraction into hexane, and Florisil® cleanup. Samples from the harbor of Tórshavn collected at high tide were the most polluted with PAH concentrations between 1.3 × 102 and 1.7 × 102 ng/g wet weight. All samples contained a factor 10 higher concentrations of alkylated PAHs compared to their parent compounds. These results suggest that Fucus might be suitable as a biomonitoring organism for PAH pollution. Differences between samples collected in close proximity and on different days were observed (same range of RSD 14–120% and 60–102%, respectively), suggesting that water exchange, tide levels, and direct exposure to surface diesel pollution have a strong influence on pollutant uptake in Fucus. The findings stress the need for further evaluation of the sampling strategy.

Variations in the concentration, inventory, source, and ecological risk of polycyclic aromatic hydrocarbons in sediments of the Lake Chaohu

In this study, the ecological risk assessment of PAHs pollution, the existing S-T model was improved and applied to this PAHs pollution assessment in surface sediment in Lake Chaohu. The potential sources and contributions of PAHs in the surface sediment were estimated by molecular diagnostic ratio (MDR) and positive matrix factorization (PMF). The results showed that the average concentration of 16 priority PAHs in the surface sediment was 718.16 ng/g in 2009 and 334.67 ng/g in 2020. In 2020, PAHs concentration has decreased compared to 2009 and the dominant composition has changed from high- to low-molecular-weight PAHs. The estimated PAHs mass inventory of the top 2 cm surface sediment was 2712 tons in 2009 and 1263 tons in 2020. Ecosystem risk assessment by improved S-T models suggested that the overall ecosystem risk of the studied regions was acceptable.

Highly Efficient Photocatalytic Remediation of Carcinogenic Anthracene and Phenanthrene by green Synthesized N‐doped Prussian blue Analogues

AbstractPolycyclic aromatic hydrocarbons (PAHs) are classified as priority pollutants because of their persistent nature, carcinogenicity, and mutagenicity; therefore, they must be eliminated. Herein, synthesis of nitrogen‐doped metal hexacyanoferrate nanoparticles (N−MHCF; M=Cu, Zn) was achieved using the green protocol in co‐precipitation techniques for the oxidative removal of PAH pollutants, namely, anthracene (ANT) and phenanthrene (PHE). PXRD and XPS analysis confirmed the doping of Nitrogen in MHCF nanocomposite. The optimum conditions, concentration of PAHs (10 mg L−1), and catalyst dose (20 mg) at neutral pH under sunlight to eliminate PAHs were reported. The degradation followed the Langmuir model and Ist‐order kinetics. The highest photodegraFdation was found for N−CuHCF (ANT: 95 %; PHE: 93 %), as compared to N−ZnHCF (ANT: 90 %; PHE: 87 %), which might be due to a high negative zeta charge (−30.3 mV), surface area, and lower band gap energy (1.7 eV). The GC‐MS technique showed that photocatalysts (N−MHCF) break down PAH contaminants into minor metabolites in exposure to solar irradiation. Up to eight consecutive cycles of use were possible with nanocomposites without any appreciable decrease in activity. Largely because of favorable surface characteristics, N−MHCF nanostructure fabricated via the green method is of great importance with a bright future in industries.

Mechanism of phenanthrene degradation by the halophilic Pelagerythrobacter sp. N7

PAHs has shown worldwide accumulation and causes a significant environmental problem especially in saline and hypersaline environments. Moderately halophilic bacteria could be useful for the bioremediation of PAH pollution in hypersaline environments. Pelagerythrobacter sp. N7 was isolated from the PAH-degrading consortium 5H, which was enriched from mixed saline soil samples collected in Shanxi Province, China. 16S rRNA in the genomic DNA revealed that strain N7 belonged to Pelagerythrobacter. Strain N7 exhibited a high tolerance to a wide range of salinities (1–10%) and was highly efficient under neutral to weak alkaline conditions (pH 6–9). The whole genome of strain N7 was sequenced and analyzed, revealing an abundance of catabolic genes. Using the whole genome information, we conducted preliminary research on key enzymes and gene clusters involved in the upstream and downstream PAH degradation pathways of strain N7, thereby inferring its degradation pathway for phenanthrene and naphthalene. This study adds to our understanding of PAH degradation in hypersaline environments and, for the first time, identifies a Pelagerythrobacter with PAH-degrading capability. Strain N7, with its high efficiency in phenanthrene degradation, represents a promising resource for the bioremediation of PAHs in hypersaline environments.

Source-specific ecological and health risks of polycyclic aromatic hydrocarbons in the adjacent coastal area of the Yellow River Estuary, China.

Industrialization and urbanization have led to increasing levels of PAH pollution in highly urbanized estuaries and their adjacent coastal areas globally. This study focused on the adjacent coastal area of the Yellow River Estuary (YRE) and collected surface seawater, surface sediment, and clams Ruditapes philippinarum and Mactra veneriformis at four sites (S1 to S4) in May, August, and October 2021 to analyze the source-specific ecological and health risks and bioeffects. The findings revealed that the main sources of PAHs were traffic emission (25.2% to 28.5%), petroleum sources (23.3% to 29.5%), coal combustion (24.7% to 27.5%), and biomass combustion (19.8% to 20.7%). Further, the PMF-RQ and PMF-ILCR analyses indicated that traffic emission was the primary contributor to ecological risks in seawater and health risks in both clam species, while coal combustion was the major contributor in sediment. Taken together, it is recommended to implement control strategies for PAH pollution following the priority order: traffic > coal > petroleum > biomass, to reduce the content and risk of PAHs in the YRE.

The occurrence, sources, and health risks of substituted polycyclic aromatic hydrocarbons (SPAHs) cannot be ignored

Similar to parent polycyclic aromatic hydrocarbons (PPAHs), substituted PAHs (SPAHs) are prevalent in the environment and harmful to humans. However, they have not received much attention. This study investigated the occurrence, distribution, and sources of 10 PPAHs and 15 SPAHs in soil, water, and indoor and outdoor PM2.5 and dust in high-exposure areas (EAH) near industrial parks and low-exposure areas (EAL) far from industrial parks. PAH pollution in all media was more severe in the EAH than in the EAL. All SPAHs were detected in this study, with alkylated and oxygenated PAHs being predominant. Additionally, 3-OH-BaP and 1-OH-Pyr were detected in all dust samples in this study, and 6-N-Chr, a compound with carcinogenicity 10 times higher than that of BaP, was detected at high levels in all tap water samples. According to the indoor-outdoor ratio, PAHs in indoor PM2.5 in the EAH mainly originated from indoor pollution sources; however, those in the EAL were simultaneously affected by indoor-outdoor air exchange and indoor sources. Most target PAHs tended to deposit from air to dust, and this tendency was significantly negatively associated with the octanol-air partitioning coefficient of PAHs. SPAHs in the environment are primarily derived from the petroleum industry and the mixed combustion of gasoline, biomass, and coal. The toxicity equivalence factors of SPAHs were predicted using QSAR models to assess their lifetime carcinogenic risk (ILCR). The ILCRtotal from PAHs for adults in the EAH was >10−4. Though the levels of 6-N-Chr and 1-Me-Pyr in the environment were markedly lower than those of PPAHs, their ILCRs from PM2.5 inhalation and dermal contact with water exceeded 10−6. This study is significant for recognizing and controlling the health risks associated with SPAHs in humans.

Potential of a novel endophytic diazotrophic Serratia sp. Wed4 for pyrene biodegradation

Endophytic diazotrophic Serratia sp. Wed4 with high nitrogenase activity (1260.9 ± 8.3 nmol C2H4 mL−1h−1) was isolated from Glycine max Linn growing in PAH contaminated soil for improving PAH removal and crop growth. Strain Wed4 biodegraded 37.0% of pyrene within 14 d via phthalate pathway in vitro and could biodegraded other PAHs with 2–5 rings effectively. Its capabilities on promoting crop growth included indole acetic acid (IAA) production (30.8 ± 3.3 μg mL−1), iron carrier production (A/Ar = 0.841 ± 0.002), inorganic phosphate dissolution (D/d = 1.184 ± 0.032) and organic phosphate dissolution (D/d = 1.154 ± 0.025). Strain Wed4 successfully colonized in barley tissues (>104 CFU g−1 FW), significantly promoted barley growth and nitrogen nutrition, reduced pyrene residues especially in shoots. Under sufficient nitrogen condition, strain Wed4 significantly promoted the dry weight of barley by 18.9%–33.9%, and decreased the pyrene residues by 46.4% in shoots and by 32.1% in roots. Meanwhile, under the deficient nitrogen condition, strain Wed4 significantly promoted the dry weight of barley by 40.1%–63.3% and decreased the pyrene residues by 39.0% in shoots and by 28.0% in roots. The pyrene contents were significantly negatively correlated with the total nitrogen contents in barley tissues, suggesting that nitrogen fixation of strain Wed4 also stimulated the pyrene removal. Based on its performance, Serratia sp. Wed4 provided a great potential to increasing crop yield and reducing PAH pollution in nitrogen deficient soils.

Correction to: PAH Pollution in Particulate Matter and Risk in Chinese Cities

Correction to: PAH Pollution in Particulate Matter and Risk in Chinese Cities

PAHs pollution in the outdoor air of areas with various land uses in the industrial city of Iran: distribution, source apportionment, and risk assessment

Shahryar city regions with various land uses had their outdoor air concentrations of PM2.5-bound PAHs determined. Totally, 32 samples were taken - eight samples from the industrial region air (IS), eight samples from the high-traffic urban regions air (HTS), eight samples from the air of commercial regions (CS), and eight samples from residential areas (RS), which were analyzed by GC-MS. According to the study's findings, in the outdoor air of IS, HTS, CS, and RS, there were mean ƩPAHs concentrations of 23.25 ± 20.22, 38.88 ± 26.53, 6.97 ± 4.26, and 4.48 ± 3.13 ng/m3, respectively. As comparison to CS and RS, mean concentration of ƩPAHs in samples from HTS and IS was substantially greater (p < 0.05). Using the Unmix.6 receptor model, sources of PAHs in the air of Shahryar were allocated. The model's results show that 42% of PAHs come from diesel vehicles and industrial activities, 36% from traffic and other transportation sources, and 22% from heating sources and coal burning. The carcinogenicity suffering resulting from exposure to PAHs was as follows: This value for children of the ingestion, inhalation pathways and dermal contact is (1.90 × 10−6-1.38 × 10−4), (5.5 × 10−11-2.67 × 10−9) and (2.36 × 10−6-1.72 × 10−4), respectively. Also, for adults were (1.47 × 10−6 - 1.07 × 10−4), (1.14 × 10−10 - 5.27 × 10−9) and (3.68 × 10−6- 2.87 × 10−4), respectively. In general, the analyzed region's carcinogenicity risk estimates fell within the range of acceptable limit.

Spatial Distribution and Sources of Polycyclic Aromatic Hydrocarbons in Sediments from Dachan Bay, Shenzhen City

The study investigated the composition and content of Σ15PAH in the surface and core sediments from Dachan Bay (DCB) in Shenzhen city and discussed the effects of urban development and regional energy structure on the marine environment through the spatial distribution, vertical profile, and sources of Σ15PAH. The results indicated that the concentrations of Σ15PAH in the sediments of DCB ranged between 299 ng/g and 2336 ng/g in the surface sediments and between 65 ng/g and 994 ng/g in the core sediments. The horizontal spatial distribution of PAHs content with decreasing concentrations from the coastal to central areas implied the land-based input of PAHs. The vertical profile of high PAHs concentration in 0 cm–60 cm suggested that the PAHs pollution is attributed to the urban development of Shenzhen since 1950, especially after the 1980s. According to features of the low molecular weight (LMW)/high molecular weight (HMW), PAHs diagnostic ratios and their relationships with total organic carbon (TOC) and oil, the pyrogenic PAHs were mainly from the combustion of petroleum and byproducts in the surface and 0 cm–60 cm sediments but from the combustion of biomass in 60 cm–190 cm sediments, which corresponded with the variation of energy structure in surrounding areas. This study suggested that urban development and regional energy structure have a great impact on PAHs distribution in DCB and further controls of land-based pollutant emissions are still needed.

PAH Pollution in Particulate Matter and Risk in Chinese Cities

PAH Pollution in Particulate Matter and Risk in Chinese Cities

Distribution of the new functional marker gene (pahE) of aerobic polycyclic aromatic hydrocarbon (PAHs) degrading bacteria in different ecosystems

Understanding the degradation potentials in PAHs-contaminated sites is significant for formulating effective bioremediation strategies. pahE encoding PAHs hydratase-aldolase has been proven as a better new functional marker gene of aerobic PAHs-degrading bacteria to assess the biodegradation potential of indigenous PAHs-degrading bacterial population. However, the distribution of pahE and its relationship with environmental factors remain unknown. The present study observed spatial variations in the diversity and abundance of pahE across oilfield soils, mangrove sediments, and urban roadside soils. nahE from Pseudomonas, bphE from Hyphomonas oceanitis, nagE from Comamonas testosterone, and novel pahE genes were widely present in these PAHs-polluted ecosystems. The abundance of pahE in PAHs-contaminated sites was in the range of 105–106 copies·g−1 (dry weight). Redundancy analysis and Pearson's correlation analysis implied that the distribution of pahE in the PAHs-contaminated environment was mainly shaped by environmental factors such as PAHs pollution level, nutrient level, salinity, and water content. This work was the first to explore the distribution of the new functional marker gene (pahE) and its links with environmental parameters, which provided new insights into the ecophysiology and distribution of indigenous aerobic PAHs-degrading bacteria in contaminated sites.

Occurrence, sources, and potential risk of polycyclic aromatic hydrocarbons in southern Xinjiang, China

Abstract Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants of global concern, mainly originating from industrial activities, biomass combustion, and vehicle emissions. With the acceleration of industrialization, the surrounding environment of the industrial area may have potential health effects on the population. Therefore, we focused on the occurrence, source, and health risk assessment of PAHs in soil, plants, and water near industrial areas in southern Xinjiang, China. The occurrence of PAHs in different soil layers (0–10, 10–30, and 30–50 cm) was studied, with PAHs mainly concentrated in the topsoil (11.50–34.68 ng/g). In plants, PAHs varied from 56.63 to 597.28 ng/g, with the highest concentrations in reed (267.29–597.28 ng/g). Total PAHs in water ranged from 4183.85 to 24803.45 ng/L, with an average of 10,240 ng/L. 3-ring PAHs were the dominant species in soil, plants, and water with 55, 69, and 59%, respectively. PAHs isomer ratio results indicated that PAHs in soil, plants, and water mainly came from fossil fuels and biomass combustion. Incremental lifetime cancer risk estimation results demonstrated that adults might face higher potential health risks than children. Adults’ dermal contact was the dominant route of exposure, while oral ingestion was the dominant exposure pathway for children. The total carcinogenic risk value of corn is much higher than that of walnuts and red dates, indicating that PAHs pollution in corn must be taken seriously. The results can clarify the local pollution situation, and provide suggestions for improving pollution prevention and control measures.

Levels, distribution, sources and children health risk of PAHs in residential dust: A multi-city study in China

BackgroundPolycyclic aromatic hydrocarbons (PAHs) are typical residential pollutants mainly from biofuel combustion that impose inevitable risk to children. The PAHs in residential dust is universal in most Chinese households with an obvious public health concern. MethodsIn this observational study, a total of 235 residential dust samples from 8 Chinese cities (Panjin, Shijiazhuang, Lanzhou, Luoyang, Xi'an, Wuxi, Mianyang, and Shenzhen) were collected from April 2018 to March 2019, which were extracted and analyzed for 16 priority PAHs by HPLC/FD-UV. Diagnostic ratios, hierarchical clustering analysis and principal component analysis were applied simultaneously for source apportionments. Incremental lifetime cancer risk was employed to estimate children's health risks based on the assumed exposure scenarios. Spearman correlation, Mann-Whitney U test, Kruskal-Wallis H test and Partial Least Squares were used to screen the factors affecting the concentration of PAHs in residential dust. ResultsThe median concentration of ∑16PAHs in residential dust from 8 cities was 44.11 μg/g (0.04 - 355.79 μg/g). ∑16PAHs were found both higher in dust samples in heating season and from downwind households only in Mianyang (p < 0.05). The leading two sources of PAHs were combustion processes and automobile exhaust emissions based on four principal components that accounted for 74.29 % of the total variance. Indoor air environmental factors, household characteristics, and residents' behavioral lifestyles may be the influencing factors of residential dust PAHs. The carcinogenic risk of children aged 0 - 5 years, under the moderate exposure level of PAHs in residential dust, exceeded the acceptable level (10−5 - 10−4 for dermal contact and 10−6 - 10−5 for ingestion). ConclusionsThere was serious PAHs pollution in residential dust under actual living conditions in eight cities across China. More evidence-based measures were needed to control PAHs pollution to safeguard children's health according to appointed sources and influencing factors in residential dust.

Dissolved polycyclic aromatic hydrocarbons (PAHs-d) in response to hydrology variation and anthropogenic activities in the Yangtze River, China

Owing to their bioavailability and toxicity, the dissolved polycyclic aromatic hydrocarbons (PAHs-d) loaded in rivers are harmful to both inland and marine ecosystems. Thus, exploring the changes in PAHs-d levels and sources is important for controlling PAHs pollution. In this study, the concentration of PAHs-d in the mainstream of the Yangtze River during dry and wet seasons was investigated and the source was analyzed using the positive matrix factorization (PMF) model to assess the response of PAHs-d to hydrological and anthropogenic activities changes. The concentration of PAHs-d in the wet season (166.2 ± 52.51 ng/L) was significantly higher than that in the dry season (89.05 ± 20.89 ng/L) (ANOVA, P < 0.001), and the sampling sites with high pollution were mainly distributed in the downstream urban agglomeration. Herein, 2–3 rings were identified to play a dominant role in the composition of PAHs-d. Compared with the dry season, the proportion of the low molecular weight (LMW) PAHs-d were relatively depleted and the high molecular weight (HMW) PAHs-d were accumulated in the wet season. Coal and coke combustion were identified as the main sources of PAHs-d (65.9% in the dry season and 59.2% in the wet season), followed by vehicle emissions, petroleum sources, and biomass combustion. Owing to the change in energy consumption structure and climate characteristics, the sources of PAHs-d displayed seasonal variation and spatial heterogeneity. Further, flow was identified as the most important factor affecting PAHs-d in the hydrological parameters. Increases of flow, pH, and SPM decreased the proportion of LMW PAHs-d, and increased that of HMW PAHs-d. The increase in anthropogenic activities intensified the residual levels of 2-3rings and 5–6 rings in water, but had no significant impact on the levels of 4 rings.