Historical input and sources of polycyclic aromatic hydrocarbons in aquatic sediments†

Aili Li*^ab, Bingni Zhang^c, Jin Zhang^d and Christoph Schüth^b
aChina Coal Aerial Photogrammetry and Remote Sensing Group Co., Ltd, Xi'an, 710199, China. E-mail: 0619775@zju.edu.cn; Tel: +86 18209231789
^bInstitute of Applied Geosciences, Technical University of Darmstadt, Darmstadt, 64287, Germany. E-mail: schueth@geo.tu-darmstadt.de
^cDepartment of Environmental Engineering, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China. E-mail: 12014042@zju.edu.cn
^dThe National Key Laboratory of Water Disaster Prevention, Yangtze Institute for Conservation and Development, Hohai University, Nanjing, 210098, China. E-mail: jin.zhang@hhu.edu.cn

First published on 13th August 2025

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Environmental significance Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and mutagenic, particularly heavy-molecular compounds, posing serious threats to ecosystem safety and human health. The persistent presence of PAHs in environmental matrices provides insights into historical emissions and inputs from the surrounding sources. This study examines the sedimentation characteristics of PAHs in Taihu Lake, located in one of the most developed regions of China, and interprets the inputs based on emissions from local coal and wood combustion, vehicle exhaust, the adsorption of individual PAHs onto fine and ultrafine particles, and the effectiveness of environmental measures for particle interception. Additionally, PAH distributions in other global aquatic environments are analyzed to generalize PAH inputs and sources in environmental receptors.

1. Introduction

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants widely distributed in the environment, with 16 of them classified as priority pollutants by the US Environmental Protection Agency, due to their carcinogenic and mutagenic properties, particularly the heavier molecular weight PAHs.^1,2 These compounds pose significant risks to ecosystem integrity and human health. PAH emissions have occurred since prehistoric times through natural events such as wildfires or volcanic eruption, as well as anthropogenic activities.^3–5 In recent decades, the extensive use of fossil fuels has made pyrogenic processes, such as biomass and fossil fuel combustion, the dominant sources of PAH emissions in most regions.^6,7 Anthropogenic emissions have substantially increased PAH concentrations in the environment, particularly in areas near coal-fired power plants, transportation hubs and petroleum refineries,^8–10 with detectable levels even in remote regions like Antarctica.^11,12

Pyrogenic PAHs are released into the environment in both gas and particle phases. Gas-phase PAHs primarily contribute to the formation of PAH derivatives in the atmosphere,^13,14 while most particle-bound PAHs deposit on the ground through wet and dry deposition.¹⁵ Many processes influence PAH concentrations and patterns in environmental receptors, such as combustion, adsorption, partitioning, emission, transport, deposition and degradation. Even within a single process, multiple factors can affect the outcome. For instance, PAH formation is strongly influenced by both fuel type and combustion conditions.^16,17 During combustion, PAHs originate from two primary pathways: one involves the direct release of inherent light molecular PAHs from fuels (such as coal and oil) during pyrolysis, while the other involves the formation of PAHs, particularly heavier molecules, via the pyrosynthesis from precursors like benzene, cyclobutadiene, ethylene, propane, and acetylene.^18–20 Given the different compositions of wood, coal and oil, PAH patterns emitted from the combustion of these fuels should vary. Additionally, within a certain temperature range, higher temperatures tend to promote the formation and emission of heavier PAHs.^21,22 With industrialization, fuel sources have progressively shifted from wood to coal and oil, accompanied by improvements in combustion efficiency through advancements in equipment and operational conditions. As a result, PAH patterns in the environment have evolved accordingly, and these changes can be partially traced through PAH distributions in aquatic sediments.

Several methods are commonly employed to identify PAH sources in the environment, including isomer ratios,^23,24 chemical mass balance model^25,26 and statistical analyses.^27,28 However, these studies primarily focus on interpreting PAH distribution characteristics in environmental matrices without accounting for regional PAH emissions and input. The PAH patterns observed in environmental samples are influenced by multiple factors, including fuel types, combustion conditions, as well as transport and deposition processes. Moreover, environmental PAHs typically originate from a complex mixture of sources associated with anthropogenic activities, making it challenging to quantitatively trace specific sources based solely on statistical methods. For instance, isomer ratio ranges are often used to distinguish the different input sources, such as anthra/(anthra + phen) = 0.19 ± 0.04 for wood combustion, 0.11 ± 0.05 for diesel combustion, and 0.31 ± 0.36 for bituminous coal combustion.²⁴ Herein, we reviewed the isomer ratios of phen/anthra, fluor/pyrene, BaA/chry and INcdP/BghiP from various emission sources including coal coking, coal power plants, residential coal combustion, vehicle exhaust and wood combustion (Fig. S1†). Despite being derived from direct emission samples, minimizing the effects of long-range transport, deposition and degradation, these ratios show considerable variability and overlap among sources. Additionally, isomer ratios can be further altered in the environment due to differences in water solubility, vapor pressure and logK_ow of individual PAHs (Table S7†). Therefore, isomer ratios alone are not reliable indicators for accurately tracing PAH sources from emissions to environmental receptors, and PAH data from environmental matrices alone are insufficient to definitively backtrack their sources.²⁹

In this study, we selected Taihu Lake, located in one of China's most developed regions, as a representative case to explore the relationship between sedimentary PAH distribution patterns and local energy consumption associated PAH emissions. We compiled and analyzed literature data to characterize PAH emission profiles from different sources and the adsorption behavior of individual PAHs on particles of varying sizes. Furthermore, we reviewed PAH patterns from 19 other aquatic regions worldwide to gain broader insights into anthropogenic impacts on environmental PAH distributions.

2. Materials and methods

2.1 Study area and sampling

The Taihu Lake catchment is one of the most urbanized and industrialized regions in China, contributing around 10% of the national GDP and housing 5% of the national population.^30,31 It is situated in the Yangtze River Delta plain, covering an area of approximately 36500 km², encompassing the southern part of the Jiangsu Province, the northern part of the Zhejiang Province and the whole Shanghai municipality (Fig. 1a). Taihu Lake, located at the center of the catchment (Fig. 1b), is the third largest freshwater lake in China, spanning about 2340 km² with an average water depth of 1.9 m. The lake is connected to over 110 inflow and outflow rivers, with the inflows primarily concentrated in the northern and western sections, which are part of Jiangsu Province.³² Driven by these river inputs, the predominant water flow direction in the lake is from northwest to southeast. In addition to atmospheric deposition, sediments and associated contaminants in the northern part of the lake are largely delivered by inflowing rivers originating from the southern part of Jiangsu Province. The sediment texture in Taihu Lake is predominantly composed of clayey silt and clay, with particle sizes mostly smaller than 0.1 mm.^33,34

Within the northern part of Taihu Lake, Meiliang Bay and Gonghu Bay are primarily surrounded by industrial and urban areas, whereas Zhushan Bay is bordered mainly by agricultural and rural landscapes. The rivers connected to Meiliang Bay and Zhushan Bay serve as inflows, while the Wangyu River, linked to Gonghu Bay, functions as an inflow during the dry season and as an outflow during the rainy season. To investigate PAH inputs from industrialized areas via inflowing rivers and their subsequent transport within Taihu Lake, sediment samples were mainly collected from Meiliang Bay. Eight sediment cores, ranging between 16 cm and 38 cm in length, were collected during three field campaigns conducted in June 2016, February 2017 and September 2017 (Fig. 1c) using a gravity corer equipped with a core loss preventer (Uwitec, Austria). Each core was sectioned into 2 cm intervals, resulting in a total of 106 segments and stored in aluminum screw-top jars. Prior to analysis, the samples were kept at −20 °C, except during air shipping from China to Germany. Each segment was then freeze-dried and homogenized by milling before PAH analysis.

2.2 Sample preparation and PAH measurement

PAHs were extracted from 7 to 12 g of each sediment sample using accelerated solvent extraction (Dionex ASE 300) under static conditions (100 °C and 10 MPa) for 30 min with 35 mL of acetone. Following extraction, each sample extract was spiked with 100 μL of internal standard solution (4002.25 μg L⁻¹). The extracts were subsequently cleaned to remove residual water and interfering compounds. For the clean-up procedure, the column was sequentially eluted with 15 mL of n-hexane, followed by 5 mL of a 9:1 (v/v) mixture of n-hexane and dichloromethane, and finally 20 mL of a 4:1 (v/v) mixture of n-hexane and dichloromethane. The eluate was concentrated to around 2 mL using an automated nitrogen evaporation system.

A 1 μL aliquot of each concentrated eluate was then injected into a gas chromatography-mass spectrometry (GC-MS) system (Agilent 7890A/5975C) for PAH concentration quantification. The GC-MS system was operated in pulsed splitless injection mode with helium as the carrier gas, and analytes were detected in selected ion monitoring (SIM) mode. Separation was achieved using an HP-5 MS capillary column (5% phenyl methyl siloxane, 30 m length, 250 μm internal diameter, and 0.25 μm film thickness). The oven temperature program was as follows: initial hold at 75 °C for 3 min, ramped to 235 °C at 20 °C min⁻¹ for 18 min, further increased to 300 °C at 15 °C min⁻¹ for 8 min, and finally to 320 °C at 10 °C min⁻¹. The total running time was 43.333 min.

For quantification, PAH standards (PAH-mix 14, PAH-mix 45 and deuterated PAH-mix 31) were obtained from Dr Ehrenstorfer Augsburg, Germany. The standards were diluted with cyclohexane to four concentration levels for external calibration and response factor calculation. The internal standard (a dilution of deuterated PAH-mix 31, containing 5 deuterated PAHs) was used for quantifying target analytes. All solvents and clean-up reagents were purchased from Carl Roth GmbH + Co.KG, Germany.

Quality control was ensured using a certified reference soil sample (European Reference Material ERM-CC013a), collected from a former gasworks site. The reported uncertainties for individual PAH concentrations in the certified sample range from 5% to 20%. The certified soil was extracted and analyzed following the same procedure as field samples, with nine replicate analyses yielding average recovery rates of 95% to 130%, confirming the reliability of the analytical method. The quantification limits for the GC-MS analysis ranged from 10 to 25 pg of injected mass per compound, depending on the specific PAH and chromatographic background noise. This corresponds to 3–7 ng g⁻¹ individual PAHs in sediment samples, based on the amount of soil extracted and the volume of eluates concentrated.

In total, ten PAH compounds were analyzed, including 3-ring compounds (phenanthrene (phen) and anthracene (anthra)); 4-ring compounds (fluoranthene (fluor) and pyrene); 5-ring compounds (benzo[b]fluoranthene (BbF), benzo[k]fluoranthene (BkF), benzo[e]pyrene (BeP) and benzo[a]pyrene (BaP)); 6-ring compounds (benzo[g,h,i]perylene (BghiP) and indeno[1,2,3 -cd]pyrene (INcdP)). The 3-ring and 4-ring PAHs are classified as light PAHs, while the 5-ring and 6-ring are heavy ones.

2.3 Profile of concentration fractions

The PAH patterns in sediment cores were characterized by the concentration fractions of four light PAHs (CFL) and six heavy PAHs (CFH), calculated according to eqn (1) and (2). Based on the profiles of these fractions, four distinct pattern types were identified:

Type 1 (T1): CFH shows a consistent increasing trend, while CFL decreases progressively upwards along the sediment core; Type 2 (T2): CFH remains consistently higher than CFL throughout the entire sedimentation period; Type 3 (T3): CFH steadily decreases, while CFL increases throughout the entire core; Type 4 (T4): CFH remains consistently lower than CFL throughout the entire core.

	(1)

	(2)

2.4 Literature data collection and analysis

The literature data used to illustrate PAH emission patterns from different sources (Fig. 5a), PAH distributions across particle sizes (Fig. 5b) and PAH isomer ratios from various sources (Fig. S1†) were compiled from 40 peer-reviewed publications (Table S2, ESI Literature Reference†), 10 peer-reviewed publications (Table S3†) and 51 peer-reviewed publications (Table S4†), respectively. In Fig. 5a, the y-axis (light/heavy) represents the emission concentration ratio of four light PAHs (phen, anthra, fluor, and pyrene) to five heavy PAHs (BkF, BaP, BbF, INcdP, and BghiP) across various emission sources, including heavy-duty vehicle exhaust, light-duty vehicle exhaust, coal coking, coal-fired power plants, residential coal combustion and wood combustion. In Fig. 5b, the y-axis (ultrafine/fine) indicates the concentration ratio of the ten selected PAHs associated with ultrafine particles (diameter < 1 μm, including +0.35 μm/−0.05 μm range) relative to those associated with fine particles (diameter > 1 μm).

In the boxplots, the whiskers represent the minimum and maximum values calculated as Q1 − 1.5 × (Q3 − Q1) and Q3 + 1.5 × (Q3 − Q1), respectively. The five key statistical markers (Q1, Q2, median, Q3, and Q4) reflect the distribution of the dataset from low to high values. Circles indicate outliers (values beyond the whiskers) and asterisks denote extreme outliers, which fall outside the range of Q1 − 3 × (Q3 − Q1) and Q3 + 3 × (Q3 − Q1).

Data on energy consumption and the number of vehicles in Jiangsu Province were obtained from official statistic websites (Fig. 4). Additionally, data describing PAH distribution patterns in 19 other aquatic areas (Table 1 and Fig. 7) were sourced from 20 peer-reviewed publications. It should be noted that PAH concentrations from different studies may vary due to differences in sample collection, processing and analytical methods. To minimize these discrepancies, concentration ratios between different PAH compounds (Fig. 5a, S1† and 7) and individual PAH concentration ratios (Fig. 5b) were employed to interpret PAH emissions and distributions, rather than directly comparing absolute PAH concentrations across studies.

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3. Results and discussion

3.1 PAH patterns in the cores

Given the wide variability and overlap in isomer ratios among individual sources (Fig. S1†), we further calculated these ratios in sediment cores from Taihu Lake (Fig. S2†). Notably, the sedimentary profiles of isomer ratios exhibit considerable differences within the same region, despite the proximity of sampling sites and the likelihood of consistent historical PAH input sources. Similar inconsistencies have been reported in water sample studies.³⁵ Although PAHs are persistent environmental contaminants, their distribution characteristics can still present some clues on their historical emissions and inputs. Light PAHs (3-ring and 4-ring) and heavy PAHs (5-ring and 6-ring) are generally associated with different pyrolytic and pyrosynthetic origins, and they exhibit distinct physicochemical properties affecting their environmental partitioning and fate (Table S7†).

In this study, four light PAHs (phen, anthra, fluor, and pyrene) and six heavy PAHs (BkF, BaP, BeP, BbF, INcdP, and BghiP) were identified as dominant pyrolytic compounds in the sediment cores (Table S1†). These two groups were therefore selected to characterize PAH distribution patterns in the sediments. Overall, the distribution patterns are relatively consistent across cores, with the concentrations of heavy PAHs increasing significantly more than those of the light ones above background levels, except in core ML7 whose deposition period corresponds only to the upper layers of the other cores (Fig. 2). According to the dating results of cores ML35, ML36 and ZS42 (Fig. S4†), the most significant rise in PAH concentrations began in the early 1960s, coinciding with the onset of industrialization in developed areas of China. This temporal trend indicates a clear influence of anthropogenic activities on PAH accumulation in the lake sediments.

The concentration fractions of the four light PAHs (CFL) and six heavy PAHs (CFH) were further calculated using eqn (1) and (2) to evaluate anthropogenic impacts on PAH inputs in the sediments of Taihu Lake (Fig. 3). The CFH values show a consistent increasing trend over the deposition period, while CFL values exhibit an opposite, decreasing trend. In the deeper sediment layers of cores ML35, ML36 and ZS42, deposited prior to industrialization,³⁶ CFL values are notably higher than CFH. Considering the predominant anthropogenic sources of PAHs, fossil fuel combustion in the areas surrounding the northern part of Taihu Lake is likely the primary contributor to the PAH concentration fractions in the sediment over recent decades.³⁷

The sampling area is located in the southern part of Jiangsu Province (Fig. 1a), one of the most economically developed regions in China, which has played a significant role in driving the country's GDP growth over recent decades.^38,39 Coal consumption in Jiangsu Province increased substantially from 85.6 million tons in 1985 to a peak of 275.8 million tons in 2013, primarily for power generation and industry, which together accounted for more than 75% of the total coal consumption over the past two decades (Fig. 4a). Additionally, coal consumption for heating and coking increased from 6.34 to 64.52 million tons, while residential coal use declined dramatically from 3.88 to 0.063 million tons. Oil consumption for transport and industrial sectors also grew, increasing from 7.63 million tons in 1995 to 20.52 million tons in 2015. In particular, oil consumption for transport showed a steady linear increase from 1.47 to 12.25 million tons (Fig. 4b). Notably, the number of light-duty vehicles increased exponentially from 1.02 million in 2002 to 25.80 million in 2016, while the number of heavy-duty vehicles increased more modestly, from 0.4 million to 0.96 million (Fig. 4c).

Given the dramatic increases in coal and oil consumption, along with the rapid growth in vehicle numbers in the region, the corresponding PAH emission patterns were analyzed to explain the observed profiles of PAH concentration fractions in the sediments. These patterns were derived using the ratios of emission concentrations between light and heavy PAHs from various sources, including heavy-duty vehicle exhaust (HDVE), light-duty vehicle exhaust (LDVE), coal coking (CC), coal-fired power plants (CPPs), residential coal combustion (RCC) and wood combustion (WC) (Fig. 5a). Among these sources, wood combustion exhibits generally higher light-to-heavy PAH emission ratios compared to others, which likely accounts for the higher CFL values observed in the deeper sediment layers of cores ML35, ML36, ML6, ZS42, and GH4, deposited before industrialization (Fig. 3). Afterward, coal and oil gradually became the dominant energy sources, affecting the profiles of CFL and CFH in the sediment. Oil consumption for transportation increased nearly tenfold, from 1.47 to 12.25 million tons (Fig. 4b), while the number of light-duty vehicles increased more than twentyfold, from 1.02 million to 25.80 million (Fig. 4c), suggesting that light-duty vehicles are the primary consumers of oil in the transport sector. Comparing light/heavy PAH emission ratios across different sources (Fig. 5a and Table S5†), LDVE exhibits the lowest ratios, indicating relatively higher emissions of heavy PAHs. This supports the inference that LDVE is a significant contributor to the increasing CFH observed in the sediment profiles (Fig. 3).

Since coal consumption is approximately an order of magnitude higher than oil consumption and CPPs account for more than 55% of the total coal use (Fig. 4a and b), emissions from CPPs have a substantial influence on PAH distributions in the environment. Due to limitations in data availability and differences in reporting units (e.g., vehicle emission rates are commonly reported in μg km⁻¹), this study focuses on estimating PAH emission rates from CPPs and CC based on literature data (Tables S8 and S9†). Subsequently, the total PAH emissions from these two sources in Jiangsu Province were estimated (Fig. 6). The results indicate that CPPs emit a higher amount of light PAHs relative to heavy PAHs, whereas CC shows the opposite, with heavier PAHs dominating emissions. Consequently, as coal consumption for CC increases, the relative fraction of light PAHs in total emissions tends to decrease. For environmental protection, a range of particle interception devices have been applied in CPPs and industrial boilers in China to mitigate emissions over recent decades.^40,41 However, these devices are generally more effective at capturing fine particles than ultrafine particles.^42–44 Meanwhile, it has been found that approximately 50% (or even more) of PAHs emitted from fuel combustion are bound to ultrafine particles.^45–50 Moreover, the six heavy PAHs are prone to adsorption onto ultrafine particles compared to the four light PAHs (Fig. 5b). Therefore, the light/heavy ratio for CPPs (Fig. 5a) should be lower than what is typically reported, as most emission studies rely on samples collected from intercepted ash rather than from ultrafine particles that escape into the atmosphere. This suggests that in actual environmental releases, a greater proportion of heavy PAHs may be emitted from coal combustion, contributing to the progressively increasing CFH observed in sediment cores (Fig. 3).

In addition, several other factors may contribute to the higher fraction of heavy PAHs relative to lighter ones in sediments. Light PAHs are generally more susceptible to photodegradation during atmospheric transport and to biodegradation following deposition in soils or aquatic environments.^51–54 Moreover, individual PAH compounds exhibit distinct physicochemical properties. Heavy PAHs tend to have lower water solubility and higher logK_ow values (Table S7†), indicating greater hydrophobicity and environmental persistence. Consequently, heavy PAHs are more likely to accumulate and be retained in the environment, particularly as total PAH emissions increase.

3.2 Anthropogenic impacts on PAH patterns in global areas

Based on the interpretation of PAH patterns and input sources in the sediments of Taihu Lake, we further reviewed the profiles of PAH concentration fractions from 19 other aquatic areas to provide a broader, global perspective on PAH distribution. Across these areas, four types of CFL and CFH profiles were identified (Fig. 7), with Taihu Lake's profile classified as type 1 (T1), as defined in Section 2.3. Comparing the PAH concentration ranges among the 19 areas, high concentrations (above 1000 ng g⁻¹) are predominantly found in developed regions, corresponding to the T1, T2 and T3 profiles (Table 1). In these areas, PAH concentrations tend to decrease in the surface sediment layers (Fig. S3†). In contrast, increasing PAH concentrations in the upper sediment layers are mostly observed in developing regions, such as in sediment cores from the continental shelf of the East China Sea, Haizhou Bay, and the adjacent Thane Creek of Mumbai. This divergence in trends likely reflects differences in the implementation of environmental policies and technologies. Despite continued growth in fossil fuel consumption, developed regions often show decreasing PAH trends in surface sediment, likely due to stricter environmental regulations and more advanced emission control technologies. For example, in New Zealand, fossil fuel consumption increased from approximately 250 to 450 PJ between 1974 and 2014, largely driven by coal and oil, yet reductions in PAH concentrations have been reported.⁵⁵ These contrasting concentration profiles underscore the influence of socio-economic development stages and environmental governance on PAH accumulation.

In the five cores from the Baltic Sea, Mangere Inlet, and the adjacent Thane Creek (representing T1 and T2 profiles), PAH concentrations in the sediment layers are relatively low, yet their CFH remains higher than CFL. This differs from the fraction profiles observed in Taihu Lake but still indicates a predominant influence of fossil fuel combustion, alongside greater degradation losses of light PAHs during transport and deposition. However, interpretation of emission sources in these areas is limited by the absence of sediment dating, leaving the sedimentation periods and the corresponding energy usage patterns unclear.

Interestingly, two sediment cores from the Seine Estuary tributary in France and Nagaike Pond in Japan exhibit exceptionally high PAH concentrations in their deep layers, which correspond to the period of World War II, as evidenced by sediment dating. Notably, these two cores present contrasting trends in CFL and CFH fractions. The profile from Nagaike Pond likely reflects both the early industrialization of Osaka City and intense air raids during the war.⁵⁶ Additionally, Nagaike Pond is unique among the reviewed cores, showing a decline in CFH in the upper sediment layers, likely due to increased fossil fuel use alongside the adoption of emission controls from the 1960s to the 2000s.

For T4 profiles, PAH concentrations and CFH fractions in most cores only begin to increase in the upper sediment layers, except for one core from Las Matas near an oil refinery. This is consistent with the fact that these sampling sites are typically located in developing areas experiencing growing energy demands. Furthermore, in these areas, PAH sources may extend beyond fossil fuel combustion. For example, Phayao Lake is surrounded by agricultural land, and its sediment PAHs likely originate mainly from biomass combustion.⁵⁷ In Las Matas, PAHs may largely be input through oil leakage instead of combustion emissions, resulting in relatively stable CFL and CFH fractions, as light PAHs are more abundant in crude oil.⁵⁸ Notably, the Rhine River sediment core exhibits a distinctive two-part profile: the upper 20 cm of sediment, deposited after 1900, shows a sharp increase in total PAH concentrations, with CFH levels surpassing CFL in the uppermost segments (Fig. S3†).

In China, sediment cores from 6 areas exhibit fraction profiles of T1 and T4. Cores from the continental shelf of the East China Sea, Haizhou Bay and Taihu Lake present T1 profiles, as these areas in Southeast China are highly developed. By contrast, cores from the Dahuofang Reservoir, Liaohe River Delta and Bohai Sea in Northeast China correspond to T4 profiles, reflecting relatively less development. Overall, these findings suggest that the PAH concentration fraction profiles can, to some extent, reflect regional characteristics related to fossil fuel consumption and socio-economic development.

4. Conclusion

In this study, an extensive review of literature and data was conducted on PAH emissions from various sources, PAH partitioning across particle sizes, fossil fuel consumption, and PAH concentration fractions in sediments, with the aim of interpreting the impacts of anthropogenic activities on PAH distributions in aquatic environments. Including the Taihu Lake, sediment concentration fraction profiles from 20 global aquatic areas are categorized into four types, reflecting close association with regional development and industrialization levels. In developed regions, CFH is generally higher than CFL in sediments, consistent with greater fossil fuel consumption and emission control. In contrast, relatively lower CFH is commonly observed in sediments deposited during earlier, less developed periods, or in regions with industrialization and lower pyrosynthetic PAH emissions. Additionally, PAH concentrations tend to decrease in surface sediments of developed countries, whereas increasing concentrations are typically observed in developing countries. This divergence highlights the influence of different developmental stages, energy consumption patterns, and the effectiveness of environmental regulations on PAH accumulation in aquatic sediments.

Data availability

The original data used in this manuscript have been attached in the ESI.†

Conflicts of interest

There are no conflicts of interest to declare.

Acknowledgements

This work was supported by BMBF-SIGN 02WCL1336C, the International Science & Technology Cooperation Program of China (No. 2016YFE0123700), and the Qinchuangyuan high-level innovation and entrepreneurship project (No. QCYRCXM-2022-251). The author Aili Li sincerely thanks the Chinese Scholarship Council.

References

1. F. Tomasetig, C. Tebby, V. Graillot, F. Zeman, A. Pery, J. P. Cravedi and M. Audebert, Comparative genotoxic potential of 27 polycyclic aromatic hydrocarbons in three human cell lines, Toxicol. Lett., 2020, 326, 99–105,  DOI:10.1016/j.toxlet.2020.03.007 .
2. M. Vijayanand, A. Ramakrishnan, R. Subramanian, P. K. Issac, M. Nasr, K. S. Khoo, R. Rajagopal, B. Greff, A. N. I. Wan, B. H. Jeon, S. W. Chang and B. Ravindran, Polyaromatic hydrocarbons (PAHs) in the water environment: A review on toxicity, microbial biodegradation, systematic biological advancements, and environmental fate, Environ. Res., 2023, 227, 1–20,  DOI:10.1016/j.envres.2023.115716 .
3. E. Argiriadis, R. F. Denniston, S. Ondei, D. M. J. S. Bowman, G. Genuzio, H. Q. A. Nguyen, J. Thompson, M. Baltieri, J. Azenon, J. Cugley, D. Woods, W. F. Humphreys and C. Barbante, Polycyclic aromatic hydrocarbons in tropical Australian stalagmites: a framework for reconstructing paleofire activity, Geochim. Cosmochim. Acta, 2024, 366, 250–266,  DOI:10.1016/j.gca.2023.11.033 .
4. S.-l. Jiao, H. Zhang, Y.-f. Cai, C.-f. Jin and S.-z. Shen, Polycyclic aromatic hydrocarbons (PAHs) evidence for frequent combustion events on land during the Permian–Triassic transition in Northwest China, Palaeogeogr., Palaeoclimatol., Palaeoecol., 2024, 642, 1–10,  DOI:10.1016/j.palaeo.2024.112152 .
5. K. Nordberg, G. Björk, K. Abrahamsson, S. Josefsson and L. Lundin, Historic distribution of polycyclic aromatic compounds (PAC) in a Skagerrak fjord, Swedish west coast as reflected in a high-resolution sediment record and compared to the Environmental Quality Standards (EQS), Mar. Pollut. Bull., 2024, 199, 1–13,  DOI:10.1016/j.marpolbul.2023.116014 .
6. Y. P. Chen, Y. Zeng, Y. F. Guan, Y. Q. Huang, Z. Liu, K. Xiang, Y. X. Sun and S. J. Chen, Particle size-resolved emission characteristics of complex polycyclic aromatic hydrocarbon (PAH) mixtures from various combustion sources, Environ. Res., 2022, 214, 1–10,  DOI:10.1016/j.envres.2022.113840 .
7. D. Wu, F. Zhang, W. Lou, D. Li and J. Chen, Chemical characterization and toxicity assessment of fine particulate matters emitted from the combustion of petrol and diesel fuels, Sci. Total Environ., 2017, 605, 172–179,  DOI:10.1016/j.scitotenv.2017.06.058 .
8. A. C. Ruiz-Fernández, M. Sprovieri, R. Piazza, M. Frignani, J. A. Sanchez-Cabeza, M. L. Feo, L. G. Bellucci, M. Vecchiato, L. H. Pérez-Bernal and F. Páez-Osuna, 210Pb-derived history of PAH and PCB accumulation in sediments of a tropical inner lagoon (Las Matas, Gulf of Mexico) near a major oil refinery, Geochim. Cosmochim. Acta, 2012, 82, 136–153,  DOI:10.1016/j.gca.2011.02.041 .
9. Y. Wu, Z. Xu, X. Huang, S. Liu, M. Tang and S. Lu, A typical 300 MW ultralow emission coal-fired power plant: source, distribution, emission, and control of polycyclic aromatic hydrocarbons, Fuel, 2022, 326, 1–10,  DOI:10.1016/j.fuel.2022.125052 .
10. X. Zhang, H. Zhang, Y. Wang, P. Bai, L. Zhang, A. Toriba, S. Nagao, N. Suzuki, M. Honda, Z. Wu, C. Han, M. Hu and N. Tang, Estimation of gaseous polycyclic aromatic hydrocarbons (PAHs) and characteristics of atmospheric PAHs at a traffic site in Kanazawa, Japan, J. Environ. Sci., 2025, 149, 57–67,  DOI:10.1016/j.jes.2023.09.009 .
11. P. Van Overmeiren, K. Demeestere, P. De Wispelaere, S. Gili, A. Mangold, K. De Causmaecker, N. Mattielli, A. Delcloo, H. V. Langenhove and C. Walgraeve, Four years of active sampling and measurement of atmospheric polycyclic aromatic hydrocarbons and oxygenated polycyclic aromatic hydrocarbons in Dronning Maud Land, East Antarctica, Environ. Sci. Technol., 2024, 58, 1577–1588,  DOI:10.1021/acs.est.3c06425 .
12. L. Wei, J. Lv, P. Zuo, Y. Li, R. Yang, Q. Zhang and G. Jiang, The occurrence and sources of PAHs, oxygenated PAHs (OPAHs), and nitrated PAHs (NPAHs) in soil and vegetation from the Antarctic, Arctic, and Tibetan Plateau, Sci. Total Environ., 2024, 912, 1–10,  DOI:10.1016/j.scitotenv.2023.169394 .
13. W. Deng, M. Wen, J. Xiong, C. Wang, J. Huang, Z. Guo, W. Wang and T. An, Atmospheric occurrences and bioavailability health risk of PAHs and their derivatives surrounding a non-ferrous metal smelting plant, J. Hazard. Mater., 2024, 470, 1–12,  DOI:10.1016/j.jhazmat.2024.134200 .
14. M. Tsapakis and E. G. Stephanou, Diurnal Cycle of PAHs, Nitro-PAHs, and oxy-PAHs in a high oxidation capacity marine background atmosphere, Environ. Sci. Technol., 2007, 41, 8011–8017,  DOI:10.1021/es071160e .
15. J. Fu, H. Zhang, R. Li, T. Shi, H. Gao, S. Jin, Q. Wang, H. Zong and G. Na, Occurrence, spatial patterns, air-seawater exchange, and atmospheric deposition of polycyclic aromatic hydrocarbons (PAHs) from the Northwest Pacific to Arctic Ocean, Mar. Environ. Res., 2023, 183, 1–10,  DOI:10.1016/j.marenvres.2022.105793 .
16. E. Reizer, B. Viskolcz and B. Fiser, Formation and growth mechanisms of polycyclic aromatic hydrocarbons: A mini-review, Chemosphere, 2022, 291, 1–15,  DOI:10.1016/j.chemosphere.2021.132793 .
17. W. Sun, A. Hamadi, S. Abid, N. Chaumeix and A. Comandini, Probing PAH formation chemical kinetics from benzene and toluene pyrolysis in a single-pulse shock tube, Proc. Combust. Inst., 2021, 38, 891–900,  DOI:10.1016/j.proci.2020.06.077 .
18. A. M. Mastral and M. S. Callén, A review on polycyclic aromatic hydrocarbon (PAH): emissions from energy generation, Environ. Sci. Technol., 2000, 34, 3051–3057,  DOI:10.1021/es001028d .
19. Y. Wang, A. Raj and S. H. Chung, A PAH growth mechanism and synergistic effect on PAH formation in counterflow diffusion flames, Combust. Flame, 2013, 160, 1667–1676,  DOI:10.1016/j.combustflame.2013.03.013 .
20. Y. Han, Y. Chen, Y. Feng, W. Song, F. Cao, Y. Zhang, Q. Li, X. Yang and J. Chen, Different formation mechanisms of PAH during wood and coal combustion under different temperatures, Atmos. Environ., 2020, 222, 1–9,  DOI:10.1016/j.atmosenv.2019.117084 .
21. N. E. Sánchez, A. Callejas, Á. Millera, R. Bilbao and M. U. Alzueta, Polycyclic aromatic hydrocarbon (PAH) and soot formation in the pyrolysis of acetylene and ethylene: Effect of the reaction temperature, Energy Fuels, 2012, 26, 4823–4829,  DOI:10.1021/ef300749q .
22. P. Devi and A. K. Saroha, Effect of pyrolysis temperature on polycyclic aromatic hydrocarbons toxicity and sorption behaviour of biochars prepared by pyrolysis of paper mill effluent treatment plant sludge, Bioresour. Technol., 2015, 192, 312–320,  DOI:10.1016/j.biortech.2015.05.084 .
23. R. X. S. Tulcan, L. Liu, X. Lu, Z. Ge, D. Y. Fernández Rojas and D. Mora Silva, PAHs contamination in ports: status, sources and risks, J. Hazard. Mater., 2024, 475, 1–12,  DOI:10.1016/j.jhazmat.2024.134937 .
24. M. B. Yunker, R. W. Macdonald, R. Vingarzan, R. H. Mitchell, D. Goyette and S. Sylvestre, PAHs in the Fraser River basin: a critical appraisal of PAH ratios as indicators of PAH source and composition, Org. Geochem., 2002, 33, 489–515,  DOI:10.1016/S0146-6380(02)00002-5 .
25. K. Bao, C. Zaccone, Y. Tao, J. Wang, J. Shen and Y. Zhang, Source apportionment of priority PAHs in 11 lake sediment cores from Songnen Plain, Northeast China, Water Res., 2020, 168, 1–12,  DOI:10.1016/j.watres.2019.115158 .
26. A. Hanedar, K. Alp, B. Kaynak, J. Baek, E. Avsar and M. T. Odman, Concentrations and sources of PAHs at three stations in Istanbul, Turkey, Atmos. Res., 2011, 99, 391–399,  DOI:10.1016/j.atmosres.2010.11.017 .
27. P. Siudek, Polycyclic aromatic hydrocarbons in coarse particles (PM10) over the coastal urban region in Poland: Distribution, source analysis and human health risk implications, Chemosphere, 2023, 311, 1–12,  DOI:10.1016/j.chemosphere.2022.137130 .
28. Y. Zhang, C. Guo, J. Xu, Y. Tian, G. Shi and Y.-C. Feng, Potential source contributions and risk assessment of PAHs in sediments from Taihu Lake , China : Comparison of three receptor models, Water Res., 2012, 46, 3065–3073,  DOI:10.1016/j.watres.2012.03.006 .
29. A. L. C. Lima, J. W. Farrington and C. M. Reddy, Combustion-derived polycyclic aromatic hydrocarbons in the environment - A review, Environ. Forensics, 2005, 6, 109–131,  DOI:10.1080/15275920590952739 .
30. C. Li, W. Feng, F. Song, Z. He, F. Wu, Y. Zhu, J. P. Giesy and Y. Bai, Three decades of changes in water environment of a large freshwater lake and its relationship with socio-economic indicators, J. Environ. Sci., 2019, 77, 156–166,  DOI:10.1016/j.jes.2018.07.001 .
31. Y. Tao, Z. Li, X. Sun, J. Qiu, S. G. Pueppke, W. Ou, J. Guo, Q. Tao and F. Wang, Supply and demand dynamics of hydrologic ecosystem services in the rapidly urbanizing Taihu Lake Basin of China, Appl. Geogr., 2023, 151, 1–12,  DOI:10.1016/j.apgeog.2022.102853 .
32. B. Qin, Lake Taihu, China: Dynamics and Environmental Change, Springer Science & Business Media, 2008 Search PubMed .
33. X. Jin, S. Wang, Y. Pang and F. Wu, Phosphorus fractions and the effect of pH on the phosphorus release of the sediments from different trophic areas, Environ. Pollut., 2006, 139, 288–295,  DOI:10.1016/j.envpol.2005.05.010 .
34. B. Qin, W. Hu, G. Gao, L. Luo and J. Zhang, Dynamics of sediment resuspension and the conceptual schema of nutrient release in the large shallow Lake Taihu , China, Chinese Sci. Bull., 2004, 49, 54–64,  DOI:10.1360/03wd0174 .
35. R. Lohmann, B. Vrana, D. Muir, F. Smedes, J. Sobotka, E. Y. Zeng, L. J. Bao, I. J. Allan, P. Astrahan, T. Bidleman, D. Crowley, E. Dykyi, N. Estoppey, G. Fillmann, L. Jantunen, S. Kaserzon, K. A. Maruya, B. McHugh, B. Newman, R. M. Prats, M. Tsapakis, M. Tysklind, B. L. van Drooge and C. S. Wong, AQUA-GAPS/MONET-derived concentrations and trends of PAHs and polycyclic musks across global waters, Environ. Sci. Technol., 2024, 58, 13456–13466,  DOI:10.1021/acs.est.4c03099 .
36. A. Li, T. Beek, B. aus der, M. Schubert, Z. Yu, T. Schiedek and C. Schüth, Sedimentary archive of polycyclic aromatic hydrocarbons and perylene sources in the northern part of Taihu Lake, China, Environ. Pollut., 2019, 246, 198–206,  DOI:10.1016/j.envpol.2018.11.112 .
37. M. U. Ali, L. Siyi, B. Yousaf, Q. Abbas, R. Hameed, C. Zheng, X. Kuang and M. H. Wong, Emission sources and full spectrum of health impacts of black carbon associated polycyclic aromatic hydrocarbons (PAHs) in urban environment: A review, Crit. Rev. Environ. Sci. Technol., 2021, 51, 857–896,  DOI:10.1080/10643389.2020.1738854 .
38. G. Long and M. K. Ng, The political economy of intra-provincial disparities in post-reform China: A case study of Jiangsu province, Geoforum, 2001, 32, 215–234,  DOI:10.1016/S0016-7185(00)00030-0 .
39. G. Shi, N. Jiang, Y. Li and B. He, Analysis of the dynamic urban expansion based on multi-sourced data from 1998 to 2013: A case study of Jiangsu Province, Sustainability, 2018, 10, 1–18,  DOI:10.3390/su10103467 .
40. W. Chen and R. Xu, Clean coal technology development in China, Energy Policy, 2010, 38, 2123–2130,  DOI:10.1016/j.enpol.2009.06.003 .
41. X. Yuan, M. Zhang, Q. Wang, Y. Wang and J. Zuo, Evolution analysis of environmental standards: Effectiveness on air pollutant emissions reduction, J. Clean. Prod., 2017, 149, 511–520,  DOI:10.1016/j.jclepro.2017.02.127 .
42. Y. Xu, X. Liu, Y. Zhang, W. Sun, Z. Zhou, M. Xu, S. Pan and X. Gao, Field measurements on the emission and removal of PM_2.5 from coal-fired power stations: 3. direct comparison on the PM removal efficiency of electrostatic precipitators and fabric filters, Energy Fuels, 2016, 30, 5930–5936,  DOI:10.1021/acs.energyfuels.6b00425 .
43. H. Yi, X. Guo, J. Hao, L. Duan and X. Li, Characteristics of inhalable particulate matter concentration and size distribution from power plants in China, J. Air Waste Manage. Assoc., 2006, 56, 1243–1251,  DOI:10.1080/10473289.2006.10464590 .
44. Y. Zhao, S. Wang, C. P. Nielsen, X. Li and J. Hao, Establishment of a database of emission factors for atmospheric pollutants from Chinese coal-fired power plants, Atmos. Environ., 2010, 44, 1515–1523,  DOI:10.1016/J.ATMOSENV.2010.01.017 .
45. Y. Chen, X. Bi, B. Mai, G. Sheng and J. Fu, Emission characterization of particulate/gaseous phases and size association for polycyclic aromatic hydrocarbons from residential coal combustion, Fuel, 2004, 83, 781–790,  DOI:10.1016/j.fuel.2003.11.003 .
46. G. Shen, W. Wang, Y. Yang, C. Zhu, Y. Min, M. Xue, J. Ding, W. Li, B. Wang, H. Shen, R. Wang, X. Wang and S. Tao, Emission factors and particulate matter size distribution of polycyclic aromatic hydrocarbons from residential coal combustions in rural Northern China, Atmos. Environ., 2010, 44, 5237–5243,  DOI:10.1016/j.atmosenv.2010.08.042 .
47. G. Shen, W. Wang, Y. Yang, J. Ding, M. Xue, Y. Min, C. Zhu, H. Shen, W. Li, B. Wang, R. Wang, X. Wang, S. Tao and A. G. Russell, Emissions of PAHs from indoor crop residue burning in a typical rural stove: Emission factors, size distributions, and gas-particle partitioning, Environ. Sci. Technol., 2011, 45, 1206–1212,  DOI:10.1021/es102151w .
48. C. Venkataraman, J. M. Lyons and S. K. Friedlander, Size Distributions of polycyclic aromatic hydrocarbons and elemental carbon. 1. sampling, measurement methods, and source characterization, Environ. Sci. Technol., 1994, 28, 555–562,  DOI:10.1021/es00053a005 .
49. C. Venkataraman, G. Negi, S. Brata Sardar and R. Rastogi, Size distributions of polycyclic aromatic hydrocarbons in aerosol emissions from biofuel combustion, J. Aerosol Sci., 2002, 33, 503–518,  DOI:10.1016/S0021-8502(01)00185-9 .
50. R. Wang, B. Yousaf, R. Sun, H. Zhang, J. Zhang and G. Liu, Emission characterization and ¹³C values of parent PAHs and nitro-PAHs in size-segregated particulate matters from coal-fired power plants, J. Hazard. Mater., 2016, 318, 487–496,  DOI:10.1016/j.jhazmat.2016.07.030 .
51. J. Li, Y. Zhu, X. Ji, D. Huang, M. Ge, W. Wang, J. Li, M. Li, C. Chen and J. Zhao, Oxidation of polycyclic aromatic hydrocarbons (PAHs) triggered by a photochemical synergistic effect between high- and low-molecular-weight PAHs, Environ. Sci. Technol., 2024, 17807–17816,  DOI:10.1021/acs.est.4c08661 .
52. M. Arekhi, L. G. Terry and T. P. Clement, Characterizing the efficiency of low-cost LED lights for conducting laboratory studies to investigate polycyclic aromatic hydrocarbon photodegradation processes, Environ. Res., 2023, 217, 1–10,  DOI:10.1016/j.envres.2022.114951 .
53. J. Mu, Q. Leng, G. Yang and B. Zhu, Anaerobic degradation of high-concentration polycyclic aromatic hydrocarbons (PAHs) in seawater sediments, Mar. Pollut. Bull., 2021, 167, 1–8,  DOI:10.1016/j.marpolbul.2021.112294 .
54. S. H. Yu, L. Ke, Y. S. Wong and N. F. Y. Tam, Degradation of polycyclic aromatic hydrocarbons by a bacterial consortium enriched from mangrove sediments, Environ. Int., 2005, 31, 149–154,  DOI:10.1016/j.envint.2004.09.008 .
55. P. Verma, N. Patel, N. K. C. Nair and A. C. Brent, Improving the energy efficiency of the New Zealand economy: A policy comparison with other renewable-rich countries, Energy Policy, 2018, 122, 506–517,  DOI:10.1016/j.enpol.2018.08.002 .
56. M. Ishitake, H. Moriwaki, K. Katahira, O. Yamamoto, K. Tsuruho, H. Yamazaki and S. Yoshikawa, Vertical profile of polycyclic aromatic hydrocarbons in a sediment core from a reservoir in Osaka City, Environ. Geol., 2007, 52, 123–129,  DOI:10.1007/s00254-006-0465-0 .
57. Y. Han, B. A. M. Bandowe, T. Schneider, S. Pongpiachan, S. S. H. Ho, C. Wei, Q. Wang, L. Xing and W. Wilcke, A 150-year record of black carbon (soot and char) and polycyclic aromatic compounds deposition in Lake Phayao, north Thailand, Environ. Pollut., 2021, 269, 1–9,  DOI:10.1016/j.envpol.2020.116148 .
58. S. Kuppusamy, N. R. Maddela, M. Megharaj and K. Venkateswarlu, Total petroleum hydrocarbons: environmental fate, toxicity, and remediation, 2019, pp. 1–264,  DOI:10.1007/978-3-030-24035-6 .
59. Y. Cai, X. Wang, Y. Wu, Y. Li and M. Ya, Over 100-year sedimentary record of polycyclic aromatic hydrocarbons (PAHs) and organochlorine compounds (OCs) in the continental shelf of the East China Sea, Environ. Pollut., 2016, 219, 774–784,  DOI:10.1016/j.envpol.2016.07.053 .
60. R. Zhang, F. Zhang and T. C. Zhang, Sedimentary records of PAHs in a sediment core from tidal flat of Haizhou Bay, China. Sci. Total Environ., 2013, 450(451), 280–288,  DOI:10.1016/j.scitotenv.2013.02.029 .
61. C. H. Vane, B. G. Rawlins, A. W. Kim, V. Moss-Hayes, C. P. Kendrick and M. J. Leng, Sedimentary transport and fate of polycyclic aromatic hydrocarbons (PAH) from managed burning of moorland vegetation on a blanket peat, South Yorkshire, UK, Sci. Total Environ., 2013, 449, 81–94,  DOI:10.1016/j.scitotenv.2013.01.043 .
62. M. Ricking and H. M. Schulz, PAH-profiles in sediment cores from the Baltic Sea, Mar. Pollut. Bull., 2002, 44, 565–570,  DOI:10.1016/S0025-326X(02)00062-0 .
63. T. Gardes, F. Portet-Koltalo, M. Debret, K. Humbert, R. Levaillant, M. Simon and Y. Copard, Temporal trends, sources, and relationships between sediment characteristics and polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in sediment cores from the major Seine estuary tributary, France, Appl. Geochem., 2020, 122, 1–14,  DOI:10.1016/j.apgeochem.2020.104749 .
64. S. G. Wakeham and E. A. Canuel, Biogenic polycyclic aromatic hydrocarbons in sediments of the San Joaquin River in California (USA), and current paradigms on their formation, Environ. Sci. Pollut. Res., 2016, 23, 10426–10442,  DOI:10.1007/s11356-015-5402-x .
65. R. J. Wilcock and G. L. Northcott, Polycyclic aromatic hydrocarbons in deep cores from Mangere inlet, New Zealand, N. Z. J. Mar. Freshwater Res., 1995, 29, 107–116,  DOI:10.1080/00288330.1995.9516645 .
66. N. Basavaiah, R. D. Mohite, P. U. Singare, A. V. R. Reddy, R. K. Singhal and U. Blaha, Vertical distribution, composition profiles, sources and toxicity assessment of PAH residues in the reclaimed mudflat sediments from the adjacent Thane Creek of Mumbai, Mar. Pollut. Bull., 2017, 118, 112–124,  DOI:10.1016/j.marpolbul.2017.02.049 .
67. N. Itoh, S. Tamamura and M. Kumagai, Distributions of polycyclic aromatic hydrocarbons in a sediment core from the north basin of Lake Biwa, Japan, Org. Geochem., 2010, 41, 845–852,  DOI:10.1016/j.orggeochem.2010.04.002 .
68. H. Tsuji, W. A. Jadoon, Y. Nunome, H. Yamazaki, S. Asaoka, K. Takeda and H. Sakugawa, Distribution and source estimation of polycyclic aromatic hydrocarbons in coastal sediments from Seto Inland Sea, Japan, Environ. Chem., 2020, 17, 488–497,  DOI:10.1071/EN20005 .
69. P. N. Taylor and J. N. Lester, Polynuclear aromatic hydrocarbons in a river Thames sediment core, Environ. Technol., 1995, 16, 1155–1163,  DOI:10.1080/09593331608616351 .
70. T. Lin, Y. Qin, B. Zheng, Y. Li, L. Zhang and Z. Guo, Sedimentary record of polycyclic aromatic hydrocarbons in a reservoir in Northeast China, Environ. Pollut., 2012, 163, 256–260,  DOI:10.1016/j.envpol.2012.01.005 .
71. C. Ma, T. Lin, S. Ye, X. Ding, Y. Li and Z. Guo, Sediment record of polycyclic aromatic hydrocarbons in the Liaohe River Delta wetland, Northeast China: Implications for regional population migration and economic development, Environ. Pollut., 2016, 222, 146–152,  DOI:10.1016/j.envpol.2016.12.065 .
72. T. Gocht, K. M. Moldenhauer and W. Püttmann, Historical record of polycyclic aromatic hydrocarbons (PAH) and heavy metals in floodplain sediments from the Rhine River (Hessisches Ried, Germany), Appl. Geochem., 2001, 16, 1707–1721,  DOI:10.1016/S0883-2927(01)00063-4 .
73. L. Hu, Z. Guo, X. Shi, Y. Qin, K. Lei and G. Zhang, Temporal trends of aliphatic and polyaromatic hydrocarbons in the Bohai Sea, China: Evidence from the sedimentary record, Org. Geochem., 2011, 42, 1181–1193,  DOI:10.1016/j.orggeochem.2011.08.009 .
74. A. C. Ruiz-Fernández, M. Sprovieri, R. Piazza, M. Frignani, J. A. Sanchez-Cabeza, M. L. Feo, L. G. Bellucci, M. Vecchiato, L. H. Pérez-Bernal and F. Páez-Osuna, ²¹⁰Pb-derived history of PAH and PCB accumulation in sediments of a tropical inner lagoon (Las Matas, Gulf of Mexico) near a major oil refinery, Geochim. Cosmochim. Acta, 2012, 82, 136–153,  DOI:10.1016/j.gca.2011.02.041 .
75. E. Heath, N. Ogrinc, J. Faganeli and S. Covelli, Sedimentary record of polycyclic aromatic hydrocarbons in the Gulf of Trieste (Northern Adriatic Sea), Water, Air, Soil Pollut.:Focus, 2006, 6, 605–614,  DOI:10.1007/s11267-006-9045-2 .
76. M. Notar, H. Leskovšek and J. Faganeli, Composition, distribution and sources of polycyclic aromatic hydrocarbons in sediments of the Gulf of Trieste, Northern Adriatic Sea, Mar. Pollut. Bull., 2001, 42, 36–44,  DOI:10.1016/S0025-326X(00)00092-8 .
77. W. Deelaman, C. Choochuay, S. Pongpiachan and Y. Han, Ecological and health risks of polycyclic aromatic hydrocarbons in the sediment core of Phayao Lake, Thailand, J. Environ. Exposure Assess., 2023, 2, 1–15,  DOI:10.20517/jeea.2022.29 .

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