Historical trends of perfluoroalkyl substances (PFASs) in dated sediments from semi-enclosed bays of Korea

Downward migration of per- and polyfluoroalkyl substances (PFAS) in lake sediments: Reconsideration of temporal trend analysis

Using sediment cores to reconstruct the contamination history of per- and polyfluoroalkyl substances (PFAS) is essential for chemical management but poses challenge. Herein, sediment cores, as well as surface water and sediments were taken from two Chinese lakes to investigate the vertical distribution and migration of PFAS. Wind wave, properties of sediment and water, and chemical characters of PFAS were examined to clarify the main factors influencing PFAS migration. Total PFAS concentrations in sediment cores ranged from 0.12 to 5.28 ng g-1 dry weight (dw) in Dianchi Lake and from 0.19 to 2.51 ng g-1 dw in Taihu Lake, respectively. Strong hydrodynamic disturbance (wind-wave erosion depth up to 30 cm) in Taihu Lake resulted in consistent PFAS levels and profiles throughout the sediment core, limiting its use for retrospective analysis. In Dianchi Lake, an increasing trend of total organic carbon-normalized PFAS indicated their persistent emission in China over the past decades. Perfluorooctane sulfonic acid increased markedly from early 2000s; temporal trend in composition for perfluorocarboxylates coincided with the global production transition. Finally, we proposed a three-step conceptual framework, including lake selection, key time point assessment, and contamination history reconstruction, to further improve the reliability of PFAS retrospective analysis in lake.

Distributions and compositional characteristics of per- and polyfluoroalkyl substances (PFASs) in sediments of the regional seas of South Korea

This study investigated the distribution and composition of 28 per- and polyfluoroalkyl substances (PFASs) in surface and core sediments from the regional seas of South Korea. Surface sediments were collected from the Yellow Sea (YS, n = 10), East China Sea (ECS, n = 6), South Sea (SS, n = 5), and East Sea (ES, n = 12), and core sediments were obtained from the ES (n = 3, 0-30 cm). Sediment samples were extracted with methanol by shaking, followed by purification using solid-phase extraction cartridges. The purified extracts were then analyzed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) to quantify 11 perfluoroalkyl carboxylic acids, 9 perfluoroalkyl sulfonic acids, 5 precursors, and 3 emerging PFASs. The highest PFAS concentrations in surface sediments were observed in the YS (300 ng g-1 organic carbon (OC)), followed by the ES (150 ng g-1 OC), ECS (120 ng g-1 OC), and SS (14 ng g-1 OC). Core sediment analysis revealed the accumulation of PFASs within the top 10 cm depth at the dumpsite, along with elevated OC contents (2.7-4.4 %) and lighter carbon stable isotope ratios (δ13C, -23 to -22 ‰) indicating the influence of dumped wastes. Principal component analysis classified the sites into three groups based on chemical composition, reflecting regional differences in PFASs usage, transport, and deposition. These findings provide critical insights into the distribution and environmental behavior of PFASs in marine sediments and contribute to developing future regulatory frameworks and pollution management strategies.

Spatiotemporal Trend of PFAS in Estuarine Sediments: Insights into Chlorinated Polyfluoroalkyl Ether Sulfonate Transformation

Per- and polyfluoroalkyl substances (PFAS) are synthetic long-lasting chemicals. Marine sediment is a major repository for PFAS in the environment; accordingly, this work investigated 45 legacy and emerging PFAS in samples of surface sediments and sediment cores (1940s-2020s) collected in the Pearl River outlets, its estuary, and the adjacent northern South China Sea (NSCS), one of the global pollution hotspots. The range of total PFAS concentrations in surface sediments from the river outlets and the NSCS was 244-14400 pg/g dry weight (dw) and 31.6-363 pg/g dw, respectively. In sediment cores, perfluorooctanesulfonate (PFOS) concentrations initially increased and then declined around ten years ago. Levels of long-chain perfluorinated carboxylates have been increasing since the 1980s and experienced an accelerated rise in the 2000s. Hydrogen-substituted polyfluoroalkyl ether sulfonate (H-PFESA) was widely found in sediment samples for the first time. The ratios of 6:2 H-PFESA to 6:2 chlorinated (Cl-) PFESA in sediment cores exceeded those in surface sediment and exhibited an increasing trend with the sediment age, implying the gradual transformation of 6:2 Cl-PFESA to its hydrogen-substituted analog in sediments. A preliminary risk assessment indicated that ∑6:2 PFESAs and PFOS posed medium to high risks over recent decades.

Occurrence and distribution of brominated and fluorinated persistent organic pollutants in surface sediments focusing on industrially affected rivers

This study investigated legacy persistent organic pollutants, including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDs), and per- and polyfluoroalkyl substances (PFAS), as well as their alternatives, in sediments from five major rivers, to assess their contamination status and usage patterns. The concentration levels of ΣPBDEs (median 9.98 ng/g dry weight (dw), mean 190 ng/g dw), ΣHBCDs (median 9.35 ng/g dw, mean 39.8 ng/g dw), Σnovel brominated flame retardants (NBFRs) (median not detected, mean 821 ng/g dw), and ∑PFAS (median 1.14 ng/g dw, mean 13.9 ng/g dw) in river sediments affected by high industrial activity were statistically significantly higher than at other sites with less or no industrial activity (Kruskal-Wallis test, p < 0.05). The dominant compounds among legacy substances for brominated flame retardants (BFRs) and PFAS are decaBDE for PBDEs, γ-HBCD for HBCDs, and perfluorooctane sulfonate (PFOS) for PFAS. The detection frequencies of 1,2-Bis(2,4,6-tribromophenoxy)ethane (BTBPE) and 6:2 chlorinated perfluoroalkylether sulfonic acid (F53B), as alternative substances for PBDEs and PFOS, were 16% and 9%, respectively. Regarding substances used as alternatives for perfluorooctanoic acid (PFOA) were detected at only one site for hexafluoropropylene oxide dimer acid (Gen-X), while 4,8-dioxo-3H-perfluorononanoic acid (ADONA) was not detected. The hazard quotient (HQ) values from the ecological risk assessment were generally low (HQ < 1), except for ΣPBDEs and PFOS at several sites. The present study emphasizes the need for continuous monitoring and risk assessment of these pollutants in river sediments, particularly in industrial areas, and highlights the importance of addressing the ecological toxicity of these substances to safeguard aquatic ecosystems.

Historical reconstruction of PFAS discharge into the Cooum River - Before and after the great Chennai flood in 2015

Despite widespread research on PFAS, less is known in developing countries like India. PFAS levels in sediment core samples from the Cooum River of Chennai City (India) in 2014 and 2016 were estimated to evaluate the effect of the major flood event in 2015. Among 22 target PFAS in this study, 11 and 12 of them were detected in the 2014 and 2016 samples, respectively. Total PFAS concentrations were 70-1402 pg/g dw (average: 503 pg/g dw) in 2014 and 188-3629 pg/g dw (average: 1103 pg/g dw) in 2016. PFBS, N-EtFOSA, and 6:2 FTUCA, which were not detected in any layers in 2014, exhibited a dramatic increase in DFs in 2016, showing 50%, 50%, and 88%, respectively. Hierarchical cluster analysis revealed that the subsurface to bottom sediment layers for both years were similar in PFAS pollution, suggesting originating from the same sources. In contrast, the PFAS pollution in the surface layers in 2014 (0-18 cm) was statistically different from that in 2016 (0-23 cm), likely due to significant disturbance of the sediment profile caused by a major flood event in 2015. Correlation matrix analysis indicates the industrial uses of C8-based PFAS and shorter-chain alternatives near the studied area can be the major source of PFAS in the sediment near the studied area. The present study evidenced the ongoing production and use of PFAS in India, warranting and recommending further environmental monitoring of PFAS. To our knowledge, this is the first report about the effect of a major flood event in India on historical reconstruction of PFAS dynamics in Cooum river.

Spatial and vertical distribution of per- and polyfluoroalkyl substances (PFASs) in the water columns of the regional seas of South Korea

This study focused on analyzing the spatial and vertical distributions of 28 per- and polyfluoroalkyl substances (PFASs), which comprised five precursors and three alternatives, in the water columns of the regional seas surrounding South Korea, such as the Yellow Sea (YS, Y1-Y10), East China Sea (ECS, EC1-EC6), South Sea (SS, S1-S5), and East Sea (ES, E1-E7). The concentrations of these PFASs detected in 204 seawater samples varied from below the limit of detection ( Collapse

Key Words

• Chemical tracer
• East Sea
• HPLC-MS/MS
• Ocean current
• PFASs
• Yellow Sea

Collapse

MESH Headings

• Fluorocarbons/analysis
• Republic of Korea
• Water Pollutants, Chemical/analysis
• Environmental Monitoring
• Seawater/chemistry
• Oceans and Seas
• Caprylates/analysis

Collapse

Grants Collapse

Affiliation(s)

Sunmi Yang Department of Earth, Environmental & Space Sciences, Chungnam National University, Daejeon 34134, Republic of Korea
Jiyun Gwak Department of Earth, Environmental & Space Sciences, Chungnam National University, Daejeon 34134, Republic of Korea
Mungi Kim Department of Earth, Environmental & Space Sciences, Chungnam National University, Daejeon 34134, Republic of Korea
Jihyun Cha Department of Earth, Environmental & Space Sciences, Chungnam National University, Daejeon 34134, Republic of Korea
Youngnam Kim Department of Earth, Environmental & Space Sciences, Chungnam National University, Daejeon 34134, Republic of Korea
Yeonjung Lee Ocean Climate Response & Ecosystem Research Department, Korea Institute of Ocean Science and Technology, Busan 49111, Republic of Korea
Hyo-Bang Moon Department of Marine Science and Convergence Engineering, Hanyang University, Ansan 15588, Republic of Korea
Seongjin Hong Department of Earth, Environmental & Space Sciences, Chungnam National University, Daejeon 34134, Republic of Korea.

Collapse

Collaborators Collapse

Targeted screening, characterization and sources of per- and polyfluoroalkyl substances in plateau lake Yangzonghai, China

Per- and polyfluoroalkyl substances (PFAS) have been detected in lake ecosystems globally, even in remote areas at high altitudes. Compared to plain lakes with short water change cycles and significant human influence, plateau lakes are primarily tectonic closed or semi-closed lakes with steep terrain. Their long water change cycles lead to an obvious cumulative effect on pollutants. In this study, a targeted screening method for 74 PFAS in aquatic environment was established. The contamination characteristics of PFAS in surface water samples (0.5 m below the water surface) and bottom samples (0.5 m above the lake bottom) of plateau Lake Yangzonghai were studied and compared to a reference site in Dianchi Lake which has been severely affected by anthropogenic sources. Results showed that 32 PFAS were detected in Lake Yangzonghai with the total concentration (∑32PFAS) ranging from 14.95 to 26.42 ng L-1. Among the 27 PFAS with available standards for accurate quantification, 22 PFAS were detected, with the concentration of ∑22PFAS ranging from 13.27 to 20.17 ng L-1. Significant differences (p < 0.05) in PFAS concentrations were observed between surface water (22.12 ng L-1) and bottom water (18.18 ng L-1), demonstrating a stratification phenomenon. The spatial differences in PFAS concentrations in surface water were minimal, indicating that the surface water was uniformly mixed with limited local disturbance from human pollution. The main PFAS monomers were perfluorooctanoic acid (PFOA), 8-3 fluorotelomer carboxylic acid (8-3 FTCA), perfluoroheptanoic acid (PFHpA) and 2H-perfluoro-2-decenoic acid (8-2 FTUCA), while PFBA was not detected. This distribution remarkably differed from many other plain lakes and the reference lake. Source apportionment analysis showed that PFAS primarily originated from atmospheric transport and precursor degradation. The results provide a background pollution level of PFAS in the plateau lake near the city and will benefit for formulating control policies.

Fractionation and tidal characteristics of per- and polyfluoroalkyl substances in the estuarine maximum turbidity zone

Complex tidal processes and suspended particulate matter (SPM) behavior influence the land-sea transport of terrestrial contaminants in estuaries. Contaminants are generally trapped within the estuarine maximum turbidity zone (MTZ), where SPM concentrations peak, misleading flux estimation. Here, we conducted high-resolution continuous sampling over two tidal cycles within the MTZ of a semidiurnal estuary. Tidal variations of per- and polyfluoroalkyl substances (PFAS), a class of persistent organic pollutants, were analyzed in dissolved water and size-fractionated SPM. Results showed that variations in dissolved PFAS may related to the mixing of upstream and downstream. The predominant size range for SPM was found in 1-31 μm (75 %, mainly 10-31 μm), but the PFAS tended to be sorbed by 0.22-1 μm (60 %) and > 31 μm (37 %) fractions. Except during periods of sediment resuspension when particulate PFAS concentration decreased, the PFAS concentration in the 1-31 μm increased during flood tides and decreased during ebb tides, which may not be related to organic carbon/elemental carbon levels. The hourly dynamic flux of dissolved-phase and particulate-phase PFAS transport to the sea in the MTZ was calculated by combining it with a hydrodynamic model. This study first highlights the size-fractionated PFAS transport under tidal influences and provides hourly flux estimation with a hydrodynamic model.

Multi-compartment levels and distributions of per- and polyfluoroalkyl substances surrounding fluorochemical manufacturing parks in China: A review of the current literature

Fluorochemical manufacturing parks (FMPs) are important point sources of per- and polyfluoroalkyl substances (PFASs) emissions to the surrounding environment. With legacy PFASs being phased-out and restricted in developed countries, China has emerged as one of the world's leading producers of PFASs. However, the occurrence and distribution patterns of PFASs emitted from FMPs in China remain poorly understood. This knowledge gap may lead to an underestimation of the contribution of FMPs as a source of PFASs in the environment. In this study, we collected pertinent data from published studies of PFAS emissions from FMPs and explored the occurrence patterns and distribution characteristics of PFASs across various media, including surface water, groundwater, tap water, sediment, soil, air, dust, plants, and animals. Seventeen classes of PFASs containing 80 compounds were identified in different media around FMPs, with concentrations significantly greater than in other suspected PFAS-contaminated sites. Notably, the levels of ultra-short-chain and emerging PFASs in the areas surrounding some FMPs were comparable to those of legacy PFASs, highlighting an increasing prevalence for the use of PFAS alternatives. In terms of spatial distribution, there was a decline in the PFAS concentration in most environmental media as the distance from FMPs increased. In addition, the distribution patterns of PFASs were associated with PFAS characteristics, the properties of different media, migration pathways, and other relevant aspects. This information will provide valuable insights into the current contamination situation regarding PFASs surrounding FMPs and will have profound implications for the effective implementation of PFAS management at FMPs.

Per- and polyfluoroalkyl substances (PFASs) in Chinese surface water: Temporal trends and geographical distribution

PFAS, recognized as persistent organic pollutants, present risks to both the ecological environment and human health. Studying PFASs in surface water yields insights into pollution dynamics. However, existing research on PFASs surface water pollution in China often focuses on specific regions, lacking comprehensive nationwide analyses. This study examined 48 research papers covering PFAS pollution in Chinese surface water, involving 49 regions and 1338 sampling sites. The results indicate widespread PFAS contamination, even in regions like Tibet. Predominant PFAS types include PFOA and PFOS, and pollution is associated with the relocation of industries from developed to developing countries post-2010. The shift from long-chain to short-chain PFASs aligns with recent environmental policy proposals. Geographic concentration of PFAS pollution correlates with industry distribution and economic development levels. Addressing point source pollution, especially from wastewater plant tailwater, is crucial for combating PFAS contamination. Greater emphasis should be placed on addressing short-chain PFASs.

Emerging contaminants and their potential impacts on estuarine ecosystems: Are we aware of it?

Emerging contaminants (ECs) are becoming more prevalent in estuaries and constitute a danger to both human health and ecosystems. These pollutants can infiltrate the ecosystem and spread throughout the food chain. Because of the diversified sources and extensive human activities, estuaries are particularly susceptible to increased pollution levels. A thorough review on recent ECs (platinum group elements, pharmaceuticals and personal care products, pesticides, siloxanes, liquid crystal monomers, cationic surfactant, antibiotic resistance genes, and microplastics) in estuaries, including their incidence, detection levels, and toxic effects, was performed. The inclusion of studies from different regions highlights the global nature of this issue, with each location having its unique set of contaminants. The diverse range of contaminants detected in estuary samples worldwide underscores the intricacy of ECs. A significant drawback is the scarcity of research on the toxic mechanisms of ECs on estuarine organisms, the prospect of unidentified ECs, warrant research scopes.

Spatial distribution characteristics of perfluoroalkyl substances in bulk and grain size fractionated sediments in Shenzhen Bay

Understanding Perfluoroalkyl substances (PFASs) spatial distribution in natural environments is crucial due to their environmental persistence and potential bioaccumulation. However, limited research has investigated PFASs spatial distribution at a high resolution, especially in the Guangdong-Hong Kong-Macao Greater Bay Area. Here, we examined the composition and concentration of PFASs in 36 bulk surface sediments and grain-size fractionated sediments from 9 representative sites to determine the spatial distribution characteristics in Shenzhen Bay. We found that ΣPFASs decreased gradually from nearshore area to offshore area (0.680 and 0.297 ng g-1 dw, respectively). Furthermore, PFASs are easily adsorbed on fine-grained sediments, likely due to their chain length and hydrophobicity. We argue that the lateral movement of sediments may transport fine-grained sediments associated with ΣPFASs out of the bay, resulting in the spatial difference in ΣPFASs in Shenzhen Bay. Our findings provide important insights into explore the mechanisms associated with preservation and transport of PFASs.

Determination of polyfluoroalkyl substances in cosmetic products using dispersed liquid-liquid extraction coupled with UHPLC-MS/MS

Human exposure to polyfluoroalkyl substances (PFASs) via cosmetics has been of increasing concern due to the tremendous detrimental health impacts of PFASs. Developing an effective method for extracting and determining PFASs in cosmetics is crucial in accurately assessing their corresponding human exposure risk. Herein, this study developed a new sample pre-treatment method to address the challenges posed by the variety and complexity of cosmetic matrices. Seventeen PFASs in cosmetic products, including 9 perfluoro carboxylic acids and 8 perfluorosulfonic acids, were simultaneously determined using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The whole pre-treatment process can be divided into three steps. In step 1, cosmetics with diverse matrix types can be effectively dispersed during extraction by using saturated sodium chloride-acetonitrile and saturated sodium chloride-tetrahydrofuran as extraction solvents. In step 2, the pre-purification step employs a potassium ferrocyanide-zinc acetate co-precipitant to remove high molecular weight interferents from the extraction solution, thereby enhancing the efficiency of solid-phase extraction (SPE). In step 3, WAX-SPE is utilized to further eliminate interferents from the extraction solution while concentrating the analytes, meeting the trace analysis requirements for PFASs in cosmetics. The method detection limits were 0.09-0.26 ng g-1. The recoveries ranged from 70.1% to 114.7%, with relative standard deviations in the range of 2.0-19.1%. The method was applied to cosmetic samples in the Guangzhou market, and the total concentration of PFASs ranged from 0 to 10.8 ng g-1. This method has strong anti-interference ability, good applicability, high sensitivity, and good reproducibility, making it suitable for the analysis and detection of perfluorinated acids in cosmetic samples. It provides technical support for cosmetics safety regulation.

Spatial and temporal trends in polychlorinated naphthalenes in sediment from Ulsan and Onsan Bays of Korea: Potential sources and ecotoxicological concerns

Few studies have been conducted on spatial and temporal trends in polychlorinated naphthalenes (PCNs) in coastal environments. Here, we describe 18 PCN congeners found in surface and dated sediment samples collected from highly industrialized bays of Korea. Measurable levels of PCN congeners were detected in all sediment samples, suggesting concurrent and historical contamination. The highest PCN concentrations were observed in sediment from rivers, streams, and the inner portions of the bays, which are surrounded by industrial complexes and commercial harbors. CNs 73, 66/67, and 52 were dominant in surface and dated sediment samples. Congener patterns and diagnostic ratios revealed that PCN contamination is originated from combustion processes and the use of polychlorinated biphenyl (PCB) technical mixtures. PCN concentrations in dated sediment increased from the 1980s to the mid-2000s and then decreased to 2015. Although the toxic equivalent (TEQ) levels of PCNs in our study did not exceed sediment quality guidelines proposed by international authorities, the cumulative risks from the TEQ concentrations of polychlorinated dibenzo-p-dioxins, furans, PCBs, and PCNs can be expected for benthic organisms.

Vertical distribution, environmental occurrence, and risk assessment of organic pollutants in lacustrine sediments in southeast China

To clarify the impact of human activities on the natural environment, as well as the current ecological risks to the environment surrounding Zhushan Bay in Taihu Lake, the characteristics of deposited organic materials, including elements and 16 polycyclic aromatic hydrocarbons (∑₁₆PAHs), in a sediment core from Taihu Lake were determined. The nitrogen (N), carbon (C), hydrogen (H), and sulfur (S) contents ranged from 0.08 to 0.3%, 0.83 to 3.6%, 0.63 to 1.12%, and 0.02 to 0.24%, respectively. The most abundant element in the core was C followed by H, S, and N, while elemental C and the C/H ratio displayed a decreasing trend with depth. The ∑₁₆PAH concentration was in the range of 1807.48-4674.83 ng g^-1, showing a downward trend with depth, with some fluctuations. Three-ring PAHs dominated in surface sediment, while 5-ring PAHs dominated at a depth of 55-93 cm. Six-ring PAHs appeared in the 1830s and gradually increased over time before slowly decreasing from 2005 onward due to the establishment of environmental protection measures. The ratio of PAH monomers indicated that PAHs in samples from a depth of 0 to 55 cm were mainly derived from the combustion of liquid fossil fuels, while the PAHs in the deeper samples mainly originated from petroleum. The results of a principal component analysis (PCA) showed that the PAHs in the sediment core of Taihu Lake were mainly derived from the combustion of fossil fuels, such as diesel, petroleum, gasoline, and coal. The contributions of biomass combustion, liquid fossil fuel combustion, coal combustion, and unknown source were 8.99%, 52.68%, 1.65%, and 36.68%, respectively. The results of a toxicity analysis indicated that most of the PAH monomers had little impact on the ecology, and the annual increase of a small number of monomers might have toxic effects on the biological community, resulting in a serious ecological risks, that requires the imposition of control measures.

Optimizing the fugacity model to select appropriate remediation pathways for perfluoroalkyl substances (PFASs) in a lake

Increased anthropogenic activities have caused contamination of perfluoroalkyl substances (PFASs) in lakes worldwide. However, how to remediate their contamination remains unclear. In this study, a heavily polluted lake, Baiyangdian Lake in China, was selected to investigate current PFASs levels in multimedia, stimulate their transport fate based upon an optimized fugacity model, and finally identify appropriate remediation pathways. From 2008-2019, the average concentrations of PFASs in the lake increased approximately 7-40 times in the environment and biota. Spatially, with continuous import of perfluorohexane sulfonate (PFHxS) and perfluorooctanoic acid (PFOA), barring fish, a noticeable north-south difference was distinguished in the PFASs composition in multimedia from the lake. Based on the optimized fugacity model simulation, the water phase was the primary transport path (~76.5%) for PFASs, with a total flux of 333 kg y^-1. Compared with bioaccumulation fluxes in submerged plants (6.2 kg y^-1), emerged plants (2.6 kg y^-1), and fish (1.1 kg y^-1), the exchange flux of PFASs between water and sediment remained high (~94 kg y^-1). Considering remediation cost, sediment cleaning is currently the most cost-effective pathway, while harvesting submerged plant could be a promising pathway in the future. This study provides a basis for remediating PFASs-polluted lakes on a global scale.

Spatiotemporal distribution, ecological risk assessment and source analysis of legacy and emerging Per- and Polyfluoroalkyl Substances in the Bohai Bay, China

The Bohai Sea is one of the most polluted hotspots by per- and Polyfluoroalkyl substances (PFASs) in the world and studies on the vertical distribution of PFASs at different water layers and phase partitioning between water and suspended particulate matter (SPM) were still limited. 23 legacy and emerging PFASs were investigated in seawater and SPM throughout the Bay in this study. The average concentrations of ∑PFASs in seawater were 48.21 ng/L and 52.71 ng/L during the periods of wet and normal water, respectively. In general, the concentrations of ∑PFASs in surface water were higher than that in deep water. Legacy PFASs in seawater were dominated by PFOA and short-chain PFASs, while the emerging alternative HFPO-DA was detected in the whole water layer of the Bohai Bay with an average concentration of 1.09 ng/L. The spatial distribution showed that ∑PFASs were higher nearshore than inside the bay and higher in the south than that in the north of the bay. The average concentration of ∑PFASs in SPM was 9.02 ng/g. Long-chain PFASs and the emerging alternative 6:2 Cl-PFESA accounted for the major contaminants. The partition coefficients log K_d and φ_spm-w showed a linear positive correlation with carbon chain length. Preliminary risk assessments revealed that the ecological risk of common PFASs in the Bohai Bay was low, while PFOA was at moderate risk. The principal component analysis demonstrated that the production process of traditional fluorochemical factories, fire-fighting and emerging electroplating industries were the main sources of PFASs. This was the first comprehensive survey of emerging PFASs in different water depths and in SPM of the Bohai Bay during different seasons, which provided important scientific data for studying the ecological risks and pollution prevention of PFASs.

Historical record of legacy and alternative halogenated flame retardants in dated sediment from a highly industrialized saltwater lake in Korea

Legacy and alternative halogenated flame retardants (HFRs), such as polybrominated diphenyl ethers (PBDEs), novel brominated flame retardants (NBFRs), and dechlorane plus (DP), were measured in dated sediments from a highly industrialized lake in Korea. All HFRs were detected in almost all of the sediment depth layers for more than 70 years, indicating a history of long-term contamination. Similar historical trends in PBDEs, 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), and DP were observed in dated sediments, whereas decabromodiphenylethane (DBDPE), and 2-ethylhexyl-2,3,4,5-octabromo-1,3,3-trimethyl-1-phenylindane (OBIND) concentrations sharply increased since the 1990s. Moreover, the concentration ratios of DBDPE/BDE 209 increased from the early 1990s to the present. Our findings suggest that DBDPE and OBIND have been used as HFR alternatives. The historical record of the concentrations and profiles of legacy and alternative HFRs corresponded with industrial activities, consumption of FRs, and coastal development activities. Inventories of legacy and alternative HFRs were similar to those reported for highly industrialized regions around the globe.

Levels and profiles of perfluorinated alkyl acids in liver tissues of birds with different habitat types and trophic levels from an urbanized coastal region of South Korea

Contamination status and characteristics of perfluorinated alkyl acids (PFAAs) including perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonic acids (PFSAs) was examined using liver tissue of birds - black-tailed gulls (Larus crassirostris), domestic pigeons (Columba livia var. domestica), pacific loons (Gavia pacifica), herons (Ardea cinerea), and egrets (Egretta garzetta and Ardea alba) - with different trophic levels, habitat types and migratory behaviors from an industrialized coastal region of South Korea. A wide range of PFAAs (1.09 ng/g to 1060 ng/g; median = 52.6 ng/g) were detected in bird livers from the Korean coasts with high detection frequency. Accumulation features of PFAAs in birds indicated that primarily trophic position and secondly habitat type influence the levels and composition of PFAAs, e.g., relatively high PFAA levels and high composition of odd-numbered long carbon chain PFCAs (perfluoroundecanoic acid (PFUnDA) and perfluorotridecanoic acid (PFTriDA)) and PFOS in higher trophic and marine birds. The prevalence of long carbon chain (≥14) PFCAs likely implies a wide use of fluorotelomer-based substances in Korea. Interspecies comparison in the accumulation profile of persistent organic pollutants (including polychlorinated biphenyls (PCBs), organochlorine pesticides, polybrominated diphenylethers (PBDEs), and PFAAs) reveals relatively high load of PFAAs in inland (pigeons) and estuarine (egrets/herons) species compared to marine bird species, indicating wide use of PFAAs in the terrestrial environment.

Assessment of regional and temporal trends in per- and polyfluoroalkyl substances using the Oriental Magpie (Pica serica) in Korea

Per- and polyfluoroalkyl substances (PFASs) are used in industrial and commercial products due to their amphiphilic properties. Birds have been utilized as biomonitoring species due to their environmental pollutant vulnerability and wide distribution. The Oriental Magpie (Pica serica) is a representative residential species inhabiting terrestrial environments. In this study, we measured PFAS concentrations in Magpie liver tissue (n = 253) collected from 12 Korean regions in 2004 and 2017. The predominant compounds were perfluorooctanesulfonic acid (PFOS; mean: 23.8 ng/g wet weight), perfluorotridecanoic acid (PFTrDA; 2.79 ng/g), and perfluoroundecanoic acid (PFUnDA: 2.11 ng/g). We observed significant correlations between Magpie PFAS measurements, indicating similar sources and bioaccumulation processes. Adult females showed significantly lower PFOS concentrations than adult males and young males and females, indicating that avian sex is a crucial physiological factor of PFAS accumulation. PFOS, perfluorodecanoic acid (PFDA), and perfluorotetradecanoic acid (PFTeDA) concentrations in urban regions were significantly higher than rural regions. PFOS concentrations in Magpie livers increased significantly between sampling years, whereas C11-C13 carboxylic acids (PFCAs) decreased. This suggests that urbanization and population are major factors in Magpie PFAS accumulation. Almost all hepatic PFOS concentrations were below the threshold values proposed by previous studies, implying limited risks. Our findings suggest that the Oriental Magpies are PFAS sentinel in residential environments. This is the first comprehensive report on biomonitoring of PFASs using the Oriental Magpie.

Legacy and emerging per- and polyfluoroalkyl substances (PFAS) in sediments from the East China Sea and the Yellow Sea: Occurrence, source apportionment and environmental risk assessment

The Yellow Sea (YS), the East China Sea (ECS) and their coastal areas have undergone rapid urbanization and industrialization. These areas are important sinks for many persistent organic pollutants. In this study, the concentration of legacy and emerging per- and polyfluoroalkyl substances (PFAS) in marine sediments from the YS and ECS were investigated. Nineteen PFAS were identified, ranging in concentration from 0.21 ng/g to 4.74 ng/g (mean: 1.60 ng/g). Legacy long-chain PFAS [e.g., perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), and perfluorooctane sulfonate (PFOS)] were the dominant contaminants. Alternative PFAS such as 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and 2,3,3,3-tetrafluoro-2-(1,1,2,2,3,3,3-heptafluoropropoxy) propanoic acid (HFPO-DA) were identified within the detection range of 16%-100%. HFPO-DA was measured in all sediments in equivalent levels to PFOS (0.119 ng/g and 0.139 ng/g, respectively). This is the first reported occurrence of perfluoro-1-butanesulfonamide (FBSA) and HFPO-DA in marine sediments, indicating a replacement in the production of PFAS from legacy to emerging ones along with eastern coastal cities of China. The results of the potential source identification demonstrated that metal plating plants, textile treatments, fluoropolymer products, food packaging, and the degradation of volatile precursor substances were the main sources of PFAS in the ECS and YS. The environmental risk assessment based on the risk quotient demonstrated that PFOA and PFOS in the ECS and YS may present a low to medium risk at most sampling points.

Identification, quantification, and prioritization of new emerging pollutants in domestic and industrial effluents, Korea: Application of LC-HRMS based suspect and non-target screening

The present study was designed to identify recently (or rarely) recognized or unreported substances (RRS or URS) contained in the effluents from water treatment plants in two industrialized urban areas, Gumi and Daegu, in Korea. In addition to 30 initial targets, 72 substances were identified through suspect and non-target screening (SNTS). Among them were 4 RRSs and 22 URSs, respectively. The quantitative analyses were applied to 35 pharmaceuticals, 15 pesticides, 13 poly-/perfluorinated alkyl substances (PFASs), 2 organophosphate flame retardants (OPFRs), 2 corrosion inhibitors, and 3 metabolites. The highest average concentration was observed for benzotriazole, followed by those for niflumic acid, and metformin. Effluents from Gumi mainly contained benzotriazole and metformin whereas niflumic acid and tramadol were the major components in effluents from Daegu. According to a scoring system based on risk relevant parameters, higher priorities were given to telmisartan, PFOA, and cimetidine. Yet, priorities for some substances were area specific (e.g., benzotriazole from Gumi, PFASs from Daegu), reflecting differences in industry profiles and populations. Many of the RRSs and URSs were recognized as potential hazards. The new identifications and evaluations should be taken into consideration for constant monitoring and management, as do the previously recognized contaminants.

Environmental Risk Assessment Resulting from Sediment Contamination with Perfluoroalkyl Substances

Due to wide use of perfluoroalkyl substances (PFASs) (e.g., in metal-plating, in fire-fighting foam, lubricants) and their resistance to degradation, they occur widely in the environment. The aim of this study was to estimate the environmental risk resulting from the presence of PFASs in the Gulf of Gdansk. Therefore, 17 PFASs concentrations were determined using ultra performance liquid chromatography with tandem mass spectrometry detection (UPLC-MS/MS). Additionally, sediment ecotoxicity was investigated. The results of the chemical analysis were used to asses environmental risk of PFASs. In samples collected around discharge collectors from a wastewater treatment plant and the Vistula mouth, Σ17PFASs values were 0.00403 ÷ 40.6 and 0.509 ÷ 614 ng/g d.w., respectively. In samples collected around discharge collectors, PFHxA, PFPeA, PFHpA, and PFOA were dominating, while at the Vistula River mouth, PFHxS, PFDS, and PFBS were prevalent. For most sediments, no toxic effect was observed in the toxicity tests with Heterocypris inconguens and Aliivibrio ficsheri. There was no observed correlation between the PFASs level and their ecotoxicity. Generally, the results of environmental risk assessment indicate that the PFASs would not generate high impact on the aquatic life (five water samples have shown medium risk related to PFBS and PFDoA).

Spatiotemporal variations, sources and health risk assessment of perfluoroalkyl substances in a temperate bay adjacent to metropolis, North China

Fourteen perfluoroalkyl substances (PFASs) in fishery organism, surface seawater, river water, rainwater, and wastewater samples collected from Jiaozhou Bay (JZB) in China and its surrounding area were determined to understand their contamination status, sources, health risk, and causes of spatiotemporal variations in the aquatic environment of a temperate bay adjacent to a metropolis. The total concentration of PFASs in 14 species of fishery organisms ranged from 1.77 ng/g to 31.09 ng/g wet weight, and perfluorooctane sulfonate (PFOS) was the dominant PFAS. ∑PFASs concentration in surface seawater ranged from 5.54 ng/L to 48.27 ng/L over four seasons, and dry season (winter and spring) had higher levels than wet season (summer and autumn). Perfluorooctanoic acid (PFOA) was the predominant individual PFAS in seawater, indicating that notorious C8 homologs remained the major PFASs in this region. The seasonal variation in seawater concentrations of three major PFASs, namely, PFOA, perfluoroheptanoic acid, and perfluorononanoic acid, was similar to that of ∑PFASs. However, the seasonal variation of PFOS concentration was different from that of ∑PFASs, with the lowest in winter and the highest in spring. In general, seasonal variations of terrigenous input and water exchange capacity were the main reasons for the spatiotemporal variation of PFASs in the aquatic environment of JZB. Moreover, bioselective enrichment for individual PFAS affected the partition of PFASs in different environment medium. Wet precipitation, sewage discharge, and surface runoff were the main sources of PFASs in this area. Nevertheless, the contribution of different sources to individual PFAS indicated a clear difference, and wastewater and river water were not consistently the most important source for every PFAS. Preliminary risk assessment revealed that the consumption of seafood, especially fish, from JZB might pose a certain extent of health risk to local consumers based on their estimated daily intake of PFASs.

Legacy and emerging per- and polyfluoroalkyl substances (PFASs) in the coastal environment of Korea: Occurrence, spatial distribution, and bioaccumulation potential

Contamination by per- and polyfluoroalkyl substances (PFASs) is of great concern in global environments. Due to strong regulation of legacy PFASs, emerging PFASs including alternatives and precursors have been introduced to the industrial market. In this study, legacy and emerging PFASs were measured in seawater, sediment, and bivalves collected along the Korean coast to investigate the occurrence, distribution, contamination sources, and bioaccumulation potential of PFASs. Wide concentration ranges of legacy PFASs were detected in multiple environmental samples, indicating widespread contamination. C8-based PFASs (e.g., PFOA and PFOS) were still major contaminants in all of the environmental samples. Some precursors, such as 8:2 fluorotelomer sulfonate (8:2 FTS) and N-ethyl-perfluorooctane sulfonamidoacetic acid (N-EtFOSAA), and perfluoro-2-propoxypropanoic potassium 9-chlorohexadecafluoro-3-oxanonane-1-sulfonate (F-53B), an alternative to PFOS, were detected in sediment or bivalve samples, implying a shift in consumption patterns from legacy to emerging PFASs. The highest concentrations of PFASs in environmental samples were found at the locations near industrial complexes, such as those for the semi-conductor, paper mill, automobile, and metal-plating industry. This result indicates that PFAS contamination is associated with intensive industrial activities in the coastal environment. Matrix-dependent contamination and profiles of PFASs were observed. Seawater was dominated by short-chained PFASs as a prompt reflection of regulation, while the sediment and bivalves were dominated by long-chained PFASs. Carbon-chain length was a major factor governing environmental behavior and bioaccumulation of PFASs. This was the first nation-wide survey on legacy and emerging PFASs in the coastal environment of Korea.

Perfluoroalkyl substances in sediments from the Bering Sea to the western Arctic: Source and pathway analysis

Although perfluoroalkyl substances (PFASs) are ubiquitous in the Arctic, their dominant pathways to the Arctic remain unclear. Most modeling studies support major oceanic transport for PFASs in the Arctic seawater, but this conclusion contradicts the rapid response of PFASs to global emissions in some biota species. Sediments, which act as important PFAS sinks for seawater and potential PFAS source to the benthic food web, are important for interpreting the fate of PFASs in the Arctic. Here we investigate the occurrence of 9 PFASs in one core (1945-2014) and 29 surface sediments from the Bering Sea to the western Arctic. Total PFAS concentrations (0.06-1.73 ng/g dw) in surface sediments were dominated by perfluorooctane sulfonate (PFOS), perfluorononanoic acid (PFNA) and perfluorobutyl sulfonate (PFBS), with higher levels in the Bering Sea slope and the northeast Chukchi Sea. Historical trends in PFASs varied among individuals, with PFOS declining in the early 2000s while PFNA showing an increasing up-core trend. Analysis of positive matrix factorization model identified that the major PFAS sources in the sediment core were dominated by the atmospheric oxidation of consumer use of PFOS precursor-based products (45.0%), while the oceanic transport of fluoropolymer manufacture of polyvinylidene fluoride (mainly PFNA) exhibited an increasing trend over time, becoming dominant in surface sediments (42.8%). Besides, local input of possible aqueous fire-fighting foams (mainly PFOS and PFBS) also acted as an important source currently (30.1%) and historically (34.9%). Our study revealed that the pathways of PFASs in Arctic sediments varied greatly for individuals and the conclusion of PFOS originating from mainly atmospheric oxidation was different from seawater modeling results. This, together with the high possibility of sediments as direct source to Arctic food web (supported by similar PFAS compositions and temporal variations), help provide additional evidence regarding PFAS pathways to the Arctic.

Spatial distribution of perfluoroalkyl acids (PFAAs) and their precursors and conversion of precursors in seawater deeply affected by a city in China

Conversion of perfluoroalkyl acid (PFAA) precursors in the environment has been a hotspot research in recent years. This study firstly determined the spatial distribution of PFAAs and their precursors including 8:2 fluorotelomer unsaturated acid (8:2 FTUCA), perfluorooctane sulfoneamide (FOSA), and diperfluorooctane sulfonamido ethanol-based phosphate (di-SAmPAP), then investigated the conversion of the potential precursors in the seawater and sewage treatment plants (STPs) effluents. The results indicated that the target pollutants showed a typical concentration gradient from nearshore to offshore. And the obviously increased concentration of perfluorinated carboxylic acids (△[PFCAs]) after oxidation treatment can verify the existence of PFAA precursors in the seawater and STP effluents. The concentrations of PFCAs with carbon atom numbers 4-9 (PFCA_C4-C9) revealed the most increase. Moreover, the levels of △[PFCAs] and the ratios of △[PFCAs] to their concentration before oxidation (△[PFCA]/[PFCA]_{before oxidation}) indicated obvious spatial variations in the seawater and STP effluents. The higher levels of △[PFCA_C4-C12] and the lower ratios of ∑△[PFCA_C4-C12]/∑[PFAA]_{before oxidation} were observed in the STP effluents, which implied that precursors might be decomposed during the sewage treatment process. These results suggested the STP effluents might have an important effect on the PFAAs levels of seawater.

Phthalates and non-phthalate plasticizers in sediment from Korean coastal waters: Occurrence, spatial distribution, and ecological risks

Due to regulations on phthalates, non-phthalate plasticizers (NPPs) are now used as an alternative. Limited studies have been conducted on the occurrence and distribution of NPPs. In this study, sediment samples were collected from 50 locations along the Korean coast to assess the occurrence, distribution, sources, and ecological risks of phthalates and NPPs. Phthalates and NPPs were detected in all sediments, indicating ubiquitous contamination of the coastal environment. Di(2-ethylhexyl)phthalate (DEHP) and di(2-ethylhexyl)terephthalate (DEHT) were dominant, suggesting that DEHT could be an emerging contaminant of concern. The highest concentrations of phthalates and NPPs were found in sediment samples from harbors, implying they are contaminated hotspots. Sedimentary organic carbon was a major factor governing the distribution of phthalates and NPPs. Significant correlations were observed among phthalates and NPPs, suggesting similar sources and geochemical behavior. DEHP concentration exceeded threshold values, indicating potential health risks to benthic organisms in sediments.

Long-term trends of persistent toxic substances and potential toxicities in sediments along the west coast of South Korea

For decades, in response to industrialization and urbanization, environmental qualities of estuarine and coastal areas of the west coast of Korea have been deteriorating. Long-term changes in concentrations of persistent toxic substances (PTSs) in sediments, including PAHs, styrene oligomers, nonylphenols, and metals and their potential toxicities via AhR- and ER-mediated potencies, and bioluminescent bacterial inhibition, were investigated. Long-term monitoring in five estuarine and coastal areas (2010-2018; 10 sites) showed that concentrations of PAHs and nonylphenols in sediments have declined while concentrations of some metals, Cd, Cr, and Hg have increased. Similarly, AhR-mediated potencies in sediments have declined, but inhibitions of bioluminescent bacteria have increased. Concentrations of sedimentary PAHs and AhR-mediated potencies were significantly (p < 0.01) and positively correlated. Sources of PAHs from combustion have been gradually declining while inputs from vehicle exhaust by-products have been increasing. Overall, this study brought our attention a balanced regulation in chemical-specific manner.

Trends in the risk of second primary malignancies among survivors of chronic lymphocytic leukemia

With improving survivorship in chronic lymphocytic leukemia (CLL), the risk of second primary malignancies (SPMs) has not been systematically addressed. Differences in risk for SPMs among CLL survivors from the Surveillance, Epidemiology, and End Results (SEER) database (1973–2015) were compared to risk of individual malignancies expected in the general population. In ~270,000 person-year follow-up, 6487 new SPMs were diagnosed with a standardized incidence ratio (SIR) of 1.2 (95% CI:1.17–1.23). The higher risk was for both solid (SIR 1.15; 95% CI:1.12–1.18) and hematological malignancies (SIR 1.61; 95% CI:1.5–1.73). The highest risk for SPMs was noted between 2 and 5 months after CLL diagnosis (SIR 1.57; 95% CI:1.41–1.74) and for CLL patients between 50- and 79-years-old. There was a significant increase in SPMs in years 2003–2015 (SIR 1.36; 95% CI:1.3–1.42) as compared to 1973–1982 (SIR 1.19; 95% CI:1.12–1.26). The risk of SPMs was higher in CLL patients who had received prior chemotherapy (SIR 1.38 95% CI:1.31–1.44) as compared to those untreated/treatment status unknown (SIR 1.16, 95% CI:1.13–1.19, p < 0.001). In a multivariate analysis, the hazard of developing SPMs was higher among men, post-chemotherapy, recent years of diagnosis, advanced age, and non-Whites. Active survivorship plans and long-term surveillance for SPMs is crucial for improved outcomes of patients with a history of CLL.

Contamination by perfluoroalkyl substances and microbial community structure in Pearl River Delta sediments

Environmental microbiota play essential roles in the maintenance of many biogeochemical processes, including nutrient cycling and pollutant degradation. They are also highly susceptible to changes in environmental stressors, with environmental pollutants being key disruptors of microbial dynamics. In the present study, a scientific cruise was launched on July 2017 around Pearl River Delta, a suitable studying site for perfluoroalkyl substances (PFASs) in the wake of the severe PFAS pollution. Surface sediment samples were collected from 18 representative stations to assess PFAS accumulation and profile microbial community. PFAS concentrations ranged from 24.2 to 181.4 pg/g dry weight in sediment, and perfluorooctanesulfonic acid (PFOS) was the dominant homologue. The concentrations of PFAS homologues in the current study were much lower than those reported in previous studies, implying effective management and control of pollution from PFAS-related industries. 16S rRNA gene amplicon sequencing revealed that Proteobacteria was the dominant phylum, while nitrogen-metabolizing Nitrosopumilus and sulfate-reducing Desulfococcus genera were the most abundant. Variations in microbial communities among sampling stations were mainly due to the differences in abundances of Escherichia, Nitrosopumilus, and Desulfococcus. The outbreak of Escherichia bacteria at specific coastal stations potentially indicated the discharge of fecal matter into the marine environment. Dissolved oxygen (DO) in bottom seawater significantly influenced the structure of microbial communities in the sediment, while current study failed to observe significant effects from PFAS pollutants. Positive correlations were found between DO and sulfate-reducing bacteria in Desulfococcus and GOUTA19 genera. Overall, this study explored relationships between environmental variables (e.g., PFAS pollutants) and sediment bacteria. Biogeochemical parameters significantly influenced the structure and composition of microbial communities in sediment.

Accumulation and exposure assessment of persistent chlorinated and fluorinated contaminants in Korean birds

To date, information is scarce on the accumulation and potential risks of persistent chlorinated and fluorinated contaminants in birds. In this study, organohalogen contaminants (OHCs), such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), and perfluoroalkyl substances (PFASs), were measured in the liver tissues of 10 bird species (n = 69) from Korea. Among the OHCs, PFASs showed the highest concentration, ranging from 5.40 to 11,300 (median: 294) ng/g wet weight. The median concentrations of OCPs and PCBs in all the bird samples were 147 and 81.9 ng/g lipid weight, respectively. The maximum concentration of perfluorooctane sulfonate (PFOS) observed in our bird samples was highest reported so far. Concentrations of OHCs in predatory birds were significantly greater than those measured in non-predatory birds, indicating the importance of diet and trophic position for bioaccumulation of these contaminants. In addition, different accumulation patterns of OHCs were found between predatory and non-predatory birds. Significant correlations were found between organochlorine concentrations and stable nitrogen isotope ratio (δ¹⁵N) measurements, whereas no correlation was found between PFASs and δ¹⁵N. Although the concentrations of PCBs and DDTs in birds were lower than the threshold levels, 25% and 49% of birds exceeded the toxicity reference value and predicted no effect concentration for PFOS, respectively, implying potential health risks to Korean birds.