Temporal trends and transport of perfluoroalkyl substances (PFASs) in a subtropical estuary: Jiulong River Estuary, Fujian, China

Co-emissions of fluoride ion, fluorinated greenhouse gases, and per- and polyfluoroalkyl substances (PFAS) from different fluorochemical production processes

Fluorochemical industry is an emerging industry leading to environmental emissions of fluoride ion, fluorinated greenhouse gases (GHGs) and per- and polyfluoroalkyl substances (PFASs) globally. Chlorofluorocarbon (CFCs) and hydrochlorofluorocarbon (HCFCs) are the primary causes of ozone layer depletion, and together with hydrofluorocarbons (HFCs), they contribute to global climate warming. PFAS are emerging persistent organic pollutants, comprising thousands of materials including perfluoroalkyl acids (PFAAs), perfluoroalkane sulfonamides (FASAs), and fluoropolymers.As the implementation of the Montreal Protocol and the Stockholm Convention makes progress, fluorochemical industry is searching for alternatives like HFCs, perfluoroalkyl ether carboxylic acids (PFECAs) and etc. Even though studies on chemical processes and environmental influences of the fluorochemical industry are plentiful, research on emissions of fluorine chemicals from different fluorochemical industry is still scarce. In this study, we conducted on-site sampling to analyze the distribution of fluorine chemicals in the surrounding environment of the fluorochemical industrial sites. The sampling sites represent different stages of fluorochemical industry production, including fluorite mining, synthesis of fluorochemical raw materials like fluorocarbons, and fine fluorine product processing which is mostly PFAS. Results show that at the fluorite mining stage, concurrent emissions of fluoride ion and CFC-12 contribute to the primary environmental issue. Perfluorooctanoic acid (PFOA) and some short-chain PFASs like perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA), perfluoroheptanoic acid (PFHpA), and perfluorobutanesulfonic acid (PFBS) are the main pollutants from fluocarbons production, accompanied by emissions of fluorinated GHGs such as HFC-32, and HCFC-22. At the fine fluorine product synthesis stage where produces fluoropolymers, perfluoropolyethers and fluorinated surfactants, PFAS especially for emerging alternatives PFECAs like hexafluoropropylene oxide dimer acid (HFPODA) and Perfluoro-4-oxapentanoic acid (PF4OPeA), as well as fluorinated GHGs like HFC-23 and HFC-227ea, require increasing attention.

Influence of age on the concentrations of perfluoroalkyl acids (PFAA) in the tissues of perch (Percafluviatilis)

Globally, perfluoroalkyl acids (PFAA) are ubiquitous due to their almost unlimited applications in industry and households and are detected in a wide variety of matrices.Aquatic ecosystems are of particular importance due to the spread of PFAA via water fluxes. The majority of published studies describe PFAA concentrations in fish or aquatic mammals, but not the dependence of PFAA concentrations in tissues and organs in fish of different ages. Since this is very important for understanding the accumulation behavior of these substances our study systematically investigates the influence of age on the PFAA concentration in the tissues of 74 perches (Perca fluviatilis), a very popular edible fish. Fish are particularly suitable as indicators of PFAA contamination of water because of their uptake via water (gills and skin) and food (predominantly piscivorous diet). The mean total PFAA concentrations (as the sum of the individual concentrations of 11 compounds) were: 114 μg/kg (kidney), 112 μg/kg (heart), 79.9 μg/kg (liver), 78.4 μg/kg (spleen), 64.6 μg/kg (gills) and 21.7 μg/kg (muscle), with longer-chain compounds accounting for 90% of the substances. Perfluorooctanesulfoic acid (PFOS) accounted for the largest percentage of the total PFAA concentration in all tissues at 43-63%. With the exception of the heart and spleen, a significant increase in total concentrations was observed with increasing age of the perch. The strongest correlation was observed for the kidney, followed by the liver and gills. With regard to their consumption as human nutrition the tolerable weekly PFAA intake of 4.4 ng/kg bodyweight and week for the sum of the 4 EFSA PFAA in adults and children was exceeded many times over (860% and 1600% respectively) with an average fish consumption per week. The maximum PFAA levels set in the E.U. since January 2023 were exceeded five times.

Distribution and ecological risk assessment of perfluoroalkyl carboxylic acids (PFCAs) in the coastal river, China

Perfluoroalkyl carboxylic acids (PFCAs) enter surface waters through wastewater discharge and atmospheric deposition, accumulating within aquatic ecosystems and organisms, causing dysfunction or mortality. This study investigates the migration, sources and ecological risks of six PFCAs in the coastal Wulong River basin and the estuary along the eastern coast of China. The six PFCAs detected in the Wulong River included, at concentrations ranging from 17.36 to 57.92 ng/L. The distribution of PFCAs concentrations throughout the estuary were as follows: Northeast China (414.07 ng/L) > North China (325.97 ng/L) > East China (249.53 ng/L) > South China (63.61 ng/L), with perfluorooctanoic acid (PFOA) being the dominant PFCA. Toxicity data was collected for all detected PFCAs and the species sensitivity distribution (SSD) method was used to derive the predicted no effect concentrations (PNECs) for all six PFCAs. The risk quotient (RQ) method showed that the risk posed to aquatic organisms in the river basin from all six PFCAs was relatively low (RQ < 1). However, joint probability curve (JPC) analysis revealed that the probability of perfluoropentanoic acid (PFPeA) causing harm to 5% of aquatic species reached 41.13%. Considering the frequency of occurrence and persistence of PFCAs in aquatic environments, these findings indicate they have the potential to induce serious toxic effects on aquatic organisms.

Perfluoroalkyl substances: a risk for the aquatifc environment? A 1-year case study in river waters of central Italy

Perfluoroalkyl substances (PFASs) are a large class of persistent emerging pollutants, ubiquitous in different environmental compartments. In this study, twenty-one PFASs were determined in seventy-eight water samples collected from six different rivers in the Umbria region (central Italy) during a 13-month monitoring campaign. The sum of the twenty-one target analytes (Σ21PFASs) ranged from 2.0 to 68.5 ng L-1, with a mean value of 22.0 ng L-1. The highest concentrations of Σ21PFASs were recorded in the warmest months (from June to September) due to reduced river streamflow caused by low rainfall and high temperatures. PFASs with a number of carbon atoms between four and nine prevail over C10-C18 congeners due to their higher water solubility and to their increased use in industry. PFBA, followed by PFPeA, PFHxA, and PFOA, was the most abundant congeners detected in the analyzed river water samples. Finally, the calculation of risk quotients (∑RQs) has allowed to assess the risk for three aquatic organisms (fish, algae, and daphnid) deriving from the exposure to PFASs. The survey showed that the risk for the three aquatic organisms during the four seasons and throughout the year was always negligible. The only exception was a low risk for fish and daphnid in GEN river considering the annual exposure.

Does salinity mediate the toxicity of perfluorooctanesulfonic acid (PFOS) in an estuarine fish?

Perfluorooctanesulfonic acid (PFOS) is detected in estuarine environments, where salinity levels fluctuate regularly. We investigated the effects of salinity on the toxicity of PFOS in embryos and larvae of Cyprinodon variegatus. We crossed six PFOS treatments (0, 1-10,000 μg/L) with two salinities (10, 30 ppt). Larvae exposed to the highest concentration of PFOS under high salinity accumulated over twice the amount of PFOS compared to larvae maintained under low salinity. Embryonic survival was unaffected by PFOS, salinity, or their interaction. PFOS delayed time to hatch and increased salinity reduced time to hatch regardless of PFOS treatment; however, no salinity by PFOS interactions were observed. Conversely, PFOS and salinity interacted in the larval stage, with decreased survival at 30 ppt salinity. This is one of the first studies evaluating interactive effects of PFOS and high salinity and highlights the importance of assessing PFAS toxicity across life stages.

Effects of developmental exposure to individual and combined PFAS on development and behavioral stress responses in larval zebrafish

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals known for their widespread use and persistence in the environment. Laboratory and epidemiological studies investigating these compounds have signaled their neurotoxic and endocrine-disrupting propensities, prompting further research into their effects on behavioral stress responses and their potential role as risk factors for stress-related disorders such as anxiety and depression. This study elucidates the ramifications of early developmental exposures to individual and combined PFAS on the development and behavioral stress responses of larval zebrafish (Danio rerio), an established model in toxicological research. Wild-type zebrafish embryos were enzymatically dechorionated and exposed to PFOS, PFOA, PFHxS, and PFHxA between 6 and 120 h post-fertilization (hpf). We targeted environmentally relevant concentrations stemming from the USEPA 2016 Hazard Advisory Limit (HAL, 0.07 μg/L) and folds higher (0.35, 0.7, 1.75, and 3.5 μg/L). Evaluations at 120 hpf encompassed mortality, overall development, developmental defects, and larval activity both at baseline stress levels and following exposure to acute stressors (acoustic and visual). Larval exposure to PFOA, PFOS, or PFHxS (0.07 μg/L or higher) elicited significant increases in mortality rates, which capped at 23.1%. Exposure to individual chemicals resulted in limited effects on overall development but increased the prevalence of developmental defects in the body axis, swim bladder, pigmentation, and eyes, as well as the prevalence of yolk sac and pericardial edemas. Larval activity at baseline stress levels and following exposure to acute stimuli was significantly altered. Combined exposure to all four chemicals intensified the breadth of developmental and behavioral alterations, suggesting possible additive or synergistic effects. Our findings shed light on the developmental and neurobehavioral disturbances associated with developmental exposure to PFAS at environmentally relevant concentrations, the added risks of combined exposures to these chemicals, and their possible role as environmental risk factors for stress-related disorders.

Unregulated Active and Closed Textile Mills Represent a Significant Vector of PFAS Contamination into Coastal Rivers

Despite concerns over the ubiquity of per- and polyfluoroalkyl substances (PFAS), little is known about the diversity of input sources to surface waters and their seasonal dynamics. Frequent use of PFAS in textiles means both active and closed textile mills require evaluation as PFAS sources. We deployed passive samplers at seven sites in an urban river and estuary adjacent to textile mills in Southern Rhode Island (USA) over 12 months. We estimated monthly mass flows (g month-1) of perfluorohexanoic acid (PFHxA: 45±56), and perfluorooctanoic acid (PFOA: 30±45) from the upstream river influenced by an active mill. Average mass flows were 73-155% higher downstream, where historical textile waste lagoons contributed long chain perfluoroalkyl acids (PFAA). Mass flows of PFNA increased from 7.5 to 21 g month-1 between the upstream and downstream portions of the rivers. Distinct grouping of the two main PFAS sources, active textile mills and historical waste lagoons, were identified using principal components analysis. Neither suspect screening nor extractable organofluorine analysis revealed measurable PFAS were missing beyond the targeted compounds. This research demonstrates that both closed and active textile mills are important ongoing PFAS sources to freshwater and marine regions and should be further evaluated as a source category.

Occurrence of metals, phthalate esters, and perfluoroalkyl substances in cellar water and their relationship with bacterial community in rural areas of China

Water cellars are traditional rainwater harvesting facilities that have been widely used in rural areas of northwest China. However, there are few reports about the water quality and health risk caused by the cellar water, especially phthalate esters (PAEs) and perfluoroalkyl substances (PFASs). This study investigated and assessed the health risks caused by the metals, PAEs, PFASs and bacterial communities in cellar water. The results showed that the turbidity and total number of bacterial colonies ranged from 4.7 to 58.5 NTU and 5-557 CFU/mL, respectively. The turbidity and total number of bacterial colonies were the main water quality problems. Due to high concentration of Tl (0.005-0.171 μg/L), the samples reached a high level of metal pollution. PAEs showed no non-carcinogenic and carcinogenic risk. The perfluorobutanoic acid (PFBA), perfluorobutanesulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonate (PFOS) were the main components of PFASs. PFOA and PFOS reached a moderate risk level in many cellar water samples. Moreover, Tl, Pb, As, PFBA and PFBS could change the bacterial community composition and induce the enrichment of bacterial functions related to human diseases. Besides these parameters, dissolved oxygen (DO) also affected the bacterial functions related to human diseases. Therefore, more attention should be paid to turbidity, DO, Tl, Pb, As, PFOA, PFOS, PFBA and PFBS in the cellar water. These results are meaningful for the water quality guarantee and health protection in rural areas of China.

Occurrence, partitioning and transport of perfluoroalkyl acids in gas and particles from the southeast coastal and mountainous areas of China

Perfluoroalkyl acids (PFAA) in gas and particles were analyzed in southeast coastal and mountainous cities, including Fuzhou, Xiamen, Zhangzhou and Nanping, to study the pollution characteristics, particle size distribution, phase partitioning and atmospheric transport. PFAA ranged from 7.8 to 290 pg m^-3 in gaseous phase, 27 - 1200 pg m^-3 in particulate phase, and perfluorobutanoic acid (PFBA), perfluorooctanoic acid (PFOA) were main compounds. PFAA had the highest concentration in Nanping with perfluorohexanoic acid (PFHxA) dominant, which could be related to the emission of PFAS from local industrial plants. Perfluorocarboxylic acids (PFCAs) and perfluoroalkyl sulfonic acids (PFSAs) exhibited different particle size distribution characteristics, with PFSAs preferring to distribute on coarse particles, which could be affected by the salt, minerals and organic matter in different particle sizes. The gas - particle partitioning coefficient (K_PA) had a line relationship with the fluorinated carbon chain length of PFAA, suggesting that long-chain PFAA tended to exist in particulate phase. The Winter Monsoon could transport to the study area and drive atmospheric PFAS to southern cities. HIGHLIGHTS: • Industrial plants contributed high concentrations of PFAA. • PFSAs tended to present in coarse particles. • Log K_PA increased linearly with increasing carbon chain length of PFAA. • Winter Monsoon drove atmospheric PFAA to southern cities.

Effects of physicochemical properties and co-existing zinc agrochemicals on the uptake and phytotoxicity of PFOA and GenX in lettuce

Even though the potential toxicity and treatment methods for per- and polyfluoroalkyl substances (PFAS) have attracted extensive attention, the plant uptake and accumulation of PFAS in edible plant tissues as a potential pathway for human exposure received little attention. Our study in a hydroponic system demonstrated that perfluorooctanoic acid (PFOA) and its replacing compound, 2,3,3,3-tetrafluoro-2-(heptafluoropropoxy) propanoic acid (GenX) displayed markedly different patterns of plant uptake and accumulation. For example, the root concentration factor (RCF) of PFOA in lettuce is almost five times of that of GenX while the translocation factor (TF) of GenX is about 66.7% higher than that for PFOA. The co-presence of zinc amendments affected the phyto-effect of these two compounds and their accumulation in plant tissues, and the net effect on their plant accumulation depended on both the properties of Zn amendments and PFAS. Zinc oxide nanoparticles (ZnONPs) at 100 mg/L did not affect the uptake of PFOA in either lettuce roots or shoots; however, Zn2+ at the same concentration significantly increased PFOA accumulation in both tissues. In contrast, both Zn amendments significantly lowered the accumulation of GenX in lettuce roots, but only ZnONPs significantly hindered the GenX accumulation in lettuce shoots. The co-exposure to ZnONPs and PFOA/GenX resulted in lower oxidative stress than the plants exposed to PFOA or GenX alone. However, both zinc agrochemicals with or without PFAS led to lower root dry biomass. The results shed light on the property-dependent plant uptake of PFAS and the potential impact of co-existing nanoagrochemicals and their dissolved ions on plant uptake of PFOA and GenX.

Boosting degradation and defluorination efficiencies of PFBS in a vacuum-ultraviolet/S(Ⅳ) process with iodide involvement

Perfluorobutane sulfonate (PFBS) is considered to be a promising alternative of perfluorooctane sulfonates (PFOS), while it is also hazardous. The UV/S (Ⅳ) system has been confirmed to be effective for PFOS removal from water, while it is inefficient for PFBS decomposition. A hybrid vacuum-ultraviolet (VUV)/S (Ⅳ)/KI process was investigated for the degradation of PFBS in aqueous solution. With KI involvement, the degradation rate of PFBS was boosted from 1.8802 μg h^-1 up to 3.5818 μg h^-1 in the VUV/S (Ⅳ) process. Alkaline conditions significantly increased the degradation efficiency of PFBS, which can be explained that S (Ⅳ) was dominated by SO₃^2- rather than HSO₃^- and H₂SO₃ in alkaline conditions. Cl^-, HCO₃^-, NO₃^-, NO₂^-, and HA would inhibit the performance of the VUV/S (Ⅳ)/KI process via various reactions. In addition, the toxicity of PFBS was significantly reduced by the VUV/S (Ⅳ)/KI process. Even in actual waters, the VUV/S (Ⅳ)/KI process also presented a satisfying performance in the degradation of PFBS.

Co-occurrence of phthalate esters and perfluoroalkyl substances affected bacterial community and pathogenic bacteria growth in rural drinking water distribution systems

The adverse health effects of phthalate esters (PAEs) and perfluoroalkyl substances (PFAS) in drinking water have attracted considerable attention. Our study investigated the effects of PAEs and PFAS on the bacterial community and the growth of potential human pathogenic bacteria in rural drinking water distribution systems. Our results showed that the total concentration of PAEs and PFAS ranged from 1.02 × 10² to 1.65 × 10⁴ ng/L, from 4.40 to 1.84 × 10² ng/L in rural drinking water of China, respectively. PAEs concentration gradually increased and PFAS slowly decreased along the pipeline distribution, compared to concentrations in the effluents of rural drinking water treatment plants. The co-occurrence of higher concentrations of PAEs and PFAS changed the structure and function of the bacterial communities found within these environments. The bacterial community enhanced their ability to respond to fluctuating environmental conditions through up-regulation of functional genes related to extracellular signaling and interaction, as well as genes related to replication and repair. Under these conditions, co-occurrence of PAEs and PFAS promoted the growth of potential human pathogenic bacteria (HPB), therefore increasing the risk of the development of associated diseases among exposed persons. The main HPB observed in this study included Burkholderia mallei, Mycobacterium tuberculosis, Klebsiella pneumoniae, Acinetobacter calcoaceticus, Escherichia coli, and Pseudomonas aeruginosa. Contaminants including particles, microorganisms, PAEs and PFAS were found to be released from corrosion scales and deposits of pipes and taps, resulting in the increase of the cytotoxicity and microbial risk of rural tap water. These results are important to efforts to improve the safety of rural drinking water.

Sources, occurrence, and treatment techniques of per- and polyfluoroalkyl substances in aqueous matrices: A comprehensive review

Per- and polyfluoroalkyl substances (PFAS), a class of synthetic organic pollutants, have prompted concerns about their global prevalence and possible health effects. This review consolidates the most recent data on different aspects of PFAS, such as their occurrence, and prominent sources. The current literature analysis of PFAS occurrence suggests significant variation in their concentration ranging from 0.025 to 1.2 × 10⁸ ng/L in wastewater, 0.01 to 8.9 × 10⁵ ng/L in surface water, and <0.01 to 1.3 × 10⁴ ng/L in groundwater globally. Since conventional treatment techniques are inadequate in remediating PFAS, innovative treatment approaches based on their removal or mineralization mechanism have been comprehensively reviewed. Advanced treatment technologies have shown degradation or removal of PFAS to be around 6 and > 99.9% in different aqueous matrices. However, due to significant drawbacks in their applicability in wastewater treatment plants (WWTPs), a novel treatment train approach has emerged as an effective alternative. This approach synergistically integrates multiple remediation techniques while addressing the impediments of individual treatments. Furthermore, nanofiltration (NF270) combined with electrochemical degradation has been demonstrated to be the most efficient (>98%) treatment train approach in PFAS remediation. If implemented in WWTPs, nanofiltration followed by adsorption using activated carbon is also a viable method for PFAS removal.

Legacy and emerging persistent organic pollutants in the marginal seas of China: Occurrence and phase partitioning

Emerging per-and polyfluoroalkyl substances (PFASs) and traditional organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs) in the marginal seas of China were analyzed to study the occurrence, transport and phase partitioning. The influence of organic carbon (OC) and element carbon (EC) on particulate emerging pollutants in seawater was studied for the first time. The concentrations of PFASs, OCPs and PAHs in the seawater (dissolved phase plus particulate phase) ranged from 1.4 to 8.6, 0.76 to 4.3 and 8.4 to 130 ng L^-1, respectively. Pollutants in the northern East China Sea were generally higher than that in the southern East China Sea and South China Sea, which may be attribute to river discharges and land sources in the Yangtze River Delta. The Yellow Sea Coastal Current and Yangtze River Dilute Water drove the transport of contaminants from north to south marginal seas. Positive correlations between EC and PAHs were found, which can be explained by co-emission of them during combustion. Moreover, positive correlations between OC, EC and Log K_d for BkF, BeP, HCB, 6:2 FTSA were found, which demonstrated that OC and EC promoted the partitioning of these high oleophilic compounds to suspended particle.

Particle size distribution, wet deposition and scavenging effect of per- and polyfluoroalkyl substances (PFASs) in the atmosphere from a subtropical city of China

Per- and polyfluoroalkyl substances (PFASs) as emerging organic pollutants have received great attention, but the scavenging efficiency of particulate PFASs by wet deposition was rarely studied. For the first time, we reported the scavenging efficiency of PFASs on different particle sizes. In this study, both rainwater and particle samples were collected for a whole year from Xiamen, a subtropical city of China. Particulate PFASs ranged from 4.11 to 67.41 pg m^-3, with an average value of 26.56 pg m^-3, and perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA) were the main compounds. Perfluorocarboxylic acids (PFCAs) were predominantly observed on fine particles (<1 μm), while PFOS and 6:2 chlorinated polyfluoroalkyl ether sulfonic acid (6:2 Cl-PFESA) had large proportions on coarse particles (1-2.5 μm and 2.5-10 μm). In the rainwater, PFASs ranged from 0.20 to 180.65 ng L^-1, with an average value of 10.71 ng L^-1, and perfluorobutanoic acid (PFBA), PFOA were the main compounds. The wet deposition flux of ∑PFASs was 5200 mg km^-2 yr^-1, exhibiting high fluxes during the wet season (March to September). The scavenging efficiency of particulate PFOS and PFOA ranged from 68%-98% during the rainfall, and wash-out of the raindrops was found to be one of the main scavenging mechanisms. In addition, the precipitation duration and intensity influenced the scavenging efficiency. The scavenging capacity of PFCAs was large on fine particles, while for per-and polyfluoroalkyl sulfonic acids, the scavenging capacity was high on coarse particles. Our results showed that wet deposition effectively removed medium to long carbon chain (≥C6) PFASs in the atmosphere.

Perfluoroalkyl Substances (PFASs) in Rivers and Drinking Waters from Qingdao, China

Perfluoroalkyl substances (PFASs) in rivers; drinking water sources (reservoirs and groundwater); and various types of drinking waters (tap waters, barreled pure waters, and bottled mineral waters) in Qingdao, Eastern China were quantified by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The total concentrations of PFASs (ΣPFASs) in the river waters ranged from 28.3 to 292.2 ng/L, averaging 108 ± 70.7 ng/L. PFBS was the most abundant compound, with a maximum concentration of 256.8 ng/L, followed by PFOA (maximum concentration: 72.4 ng/L) and PFBA (maximum concentration: 41.6 ng/L). High levels of PFASs were found in rivers in the suburban and rural areas. The estimated annual mass loading of the total PFASs to Jiaozhou Bay (JZB) was 5.9 tons. The PFASs in the drinking water reservoirs were relatively low. The ΣPFASs in the tap water ranged from 20.5 ng/L to 29.9 ng/L. Differences in the PFAS levels and composition profiles were found among barreled water at different market sites and for different brands of mineral water products. The sequence of the contamination levels of the waters related to drinking water was reservoir water > tap water > barrel water > groundwater > bottled mineral water. The PFASs in drinking water may not pose a serious risk to the drinking water consumers of Qingdao City.

Spatiotemporal distribution, partitioning behavior and flux of per- and polyfluoroalkyl substances in surface water and sediment from Poyang Lake, China

Thirty-five legacy and emerging per- and polyfluoroalkyl substances (PFAS) were analyzed in surface water and sediments collected from Poyang Lake, the largest freshwater lake in China. The ƩPFAS concentrations ranged from 23 to 1000 ng/L in water dissolved phase, 1.3-9.8 ng/L in suspended particulate matters, and 0.26-2.9 ng/g dry weight in sediments. Short-chain and emerging PFAS were predominant in surface water and sediments, rather than legacy perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Hexafluoropropylene oxide dimer/trimer acid (HFPO-DA/TA), 6:2 and 8:2 chlorinated polyfluorinated ether sulfonic acids (6:2 and 8:2 Cl-PFESAs), 6:2 fluorotelomer sulfonate (6:2 FTS), and sodium p-perfluorous nonenoxybenzene sulfonate (OBS) were detected in all samples, indicating that these emerging PFAS have been widely produced and used in this region. The high concentrations of HFPO-DA/TA, 6:2 FTS, 6:2, 8:2 Cl-PFESAs, and OBS in sediments and their higher water-sediment distribution coefficients than those of predecessors (PFOA or PFOS) suggest that lake sediments could be an important long-term sink for these emerging alternatives. The positive matrix factorization model demonstrated that food packaging and textile treatments (50%) and fluoropolymer manufacturing (26% for alternative sources and 8.2% for legacy sources) were the two major sources of PFAS in Poyang Lake. The influx and outflux of total PFAS in Poyang Lake were 9.0 and 12.8 ton/year, respectively, and the OBS flux was estimated for the first time. The results provide insights into the environmental behavior and fate of emerging PFAS in freshwater ecosystems.

Review on Per- and Poly-Fluoroalkyl Substances’ (PFASs’) Pollution Characteristics and Possible Sources in Surface Water and Precipitation of China

In recent years, due to the production and use of per- and poly-fluoroalkyl substances (PFASs), the research on the pollution characteristics and sources of PFASs in surface water and precipitation in China has attracted increasing attention. In this study, the related published articles with sampling years from 2010 to 2020 were reviewed, and the concentration levels, composition characteristics and possible sources of PFASs in surface water (rivers and lakes) and precipitation in China were summarized, including those in the Tibetan Plateau region. The results show that the concentrations of PFASs in surface water in different areas of China vary greatly, ranging from 0.775 to 1.06 × 106 ng/L. The production processes of fluorinated manufacturing facilities (FMFs) and sewage discharge from wastewater treatment plants (WWTPS) were the main sources of PFASs in surface water in China, and the concentrations of PFASs in water flowing through cities with high urbanization increased significantly compared with those before water flowed through cities with high urbanization. The compositions of PFASs in surface water gradually changed from long-chain PFASs, such as per-fluoro-octanoic acid (PFOA) and per-fluoro-octanesulfonic acid (PFOS) to short-chain PFASs, such as per-fluorobutanoic acid (PFBA), per-fluorobutanesulfonic acid (PFBS), perfluorohexanoic acid (PFHxA) and per-fluoropentanoic acid (PFPeA). The concentrations of PFASs in precipitation in China ranged from 4.2 to 191 ng/L, which were lower than those of surface water. The precipitation concentrations were relatively high around a fluorination factory and in areas with high urbanization levels. PFASs were detected in the surface water and precipitation in the Tibetan Plateau (TP), which is the global “roof of the world”, but the concentrations were low (0.115–6.34 ng/L and 0.115–1.24 ng/L, respectively). Local human activities and surface runoff were the main sources of PFASs in the surface water of the Tibetan Plateau. In addition, under the influence of the Southeast Asian monsoon in summers, marine aerosols from the Indian Ocean and air pollutants from human activities in Southeast Asia and South Asia will also enter the water bodies through dry and wet depositions. With the melting of glaciers caused by global warming, the concentration of PFASs in the surface water of the TP was higher than that before the melting of glaciers flowed into the surface water of the TP. Generally, this study summarized the existing research progress of PFAS studies on surface water and precipitation in China and identified the research gaps, which deepened the researchers’ understanding of this field and provided scientific support for related research in the future. The concentrations of PFASs in the water bodies after flowing through FMFs were significantly higher than those before water flowed through FMFs, so the discharge of the FMF production process was one of the main sources of PFASs in surface water.

Perfluoroalkyl substances in water, sediment, and fish from a subtropical river of China: Environmental behaviors and potential risk

Perfluoroalkyl substances (PFAS) in water, sediment and fish were analyzed from a subtropical river, Jiulong River in the southeast of China, to character the sources, seasonal variations, bioconcentration and potential risk. PFAS in water, sediment, muscle and liver tissues of fish ranged from 2.5 to 410 ng L^-1, 0.24-1.9 ng g^-1 dw, 25-100 and 35-1100 ng g^-1 ww, respectively. Generally, perfluorohexanoic acid (PFHxA) was the dominant compound in water, while, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were the dominant compounds in sediment and fish tissues. High concentrations of PFAS in water were found near the machinery manufacturing and paper packaging plants in the north branch of Jiulong River. PFAS during the dry season were significantly (P < 0.01) higher than that during the normal season and wet season. The K_d of PFAS increased with the carbon chain length, and perfluoroalkyl sulfonic acids (PFSAs) exhibited higher K_d values than perfluoroalkyl carboxylic acids (PFCAs), indicating these long chain PFAS tended to be adsorbed by sediment. Long chain PFAS exhibited high bioconcentration factors (BCFs), while short and medium carbon chain PFAS had weak bioconcentration capacity. The hazard ratios (HR) suggested that frequent consumption of river fish may pose health risks to local population.

Spatial and temporal trends of perfluoroalkyl acids in water bodies: A case study in Taihu Lake, China (2009-2021)

Perfluoroalkyl acids (PFAAs) have been ubiquitously detected in water bodies and are a cause of great public concern due to their adverse effects. This study investigated the long-term temporal-spatial trends of PFAAs in the water bodies of the entire Taihu Lake, and predicted PFAA concentrations for 2024. A field investigation conducted in 2021 and previous data allowed to derive trends over a broad temporal-spatial scale, which is often not feasible in short-term studies. In the 2009-2021 period, the most quantifiable PFAAs increased, among which perfluorooctanoic acid and perfluorohexanoic acid were predominant. As of 2021, the mean total concentration of ten PFAAs (∑₁₀PFAA) showed a distinct spatial decreasing trend, moving from north to south within the lake, and similar spatial distribution patterns were also noted in other years. The main PFAA input and most serious contamination were concentrated in the northern region, due to the riverine inputs and clustering of PFAA-related industries. The ∑₁₀PFAA concentration in the wet season was greater and presented a more uniform distribution pattern than that in the dry season, possibly due to the combined effects of the degradation of PFAA precursors, water inflow, rainfall, shipping activities, and a shallow water column. From 2009 to 2021 the ∑₁₀PFAA concentration of the entire lake showed an increasing trend, but the rate of increase was significantly reduced. In addition, a grey model predicted that the mean ∑₁₀PFAA concentration in the entire Taihu Lake will reach 431 ng/L in 2024, and the northern region will be affected by a more serious PFAA pollution in the future because it exhibited a high mean ∑₁₀PFAA concentration of 426 ng/L in 2021. These findings provide novel insights into the temporal-spatial distribution of PFAAs in Taihu Lake, and could help regulators to formulate policy decisions in response to PFAA pollution.

Occurrence of legacy and emerging poly- and perfluoroalkyl substances in water: A case study in Tianjin (China)

Due to the water solubility and environmentally persistent properties of poly- and perfluoroalkyl substances (PFAS), the contamination of PFAS in drinking water is raising widespread concerns for their potential adverse health risks. In the present study, the behavior of PFAS from source waters to effluent water was analyzed by taking samples from three drinking water sources (Yuqiao Reservoir, Beidagang Reservoir, and Yangtze River) and effluent of several treatment processes used in one drinking water treatment plant (DWTP) of Tianjin (China), including pre-chlorination, coagulation, sand filtration, and chlorination. The range of total concentration of PFAS (∑₂₁PFAS) in three source water was 6.64-19.80 ng/L (Yuqiao Reservoir), 80.00-119.86 ng/L (Beidagang Reservoir), and 15.87 ng/L (Yangtze River), respectively. As for individual PFAS, PFBA (perfluorobutanoic acid) was the most abundant PFAS, followed by PFOA (perfluorooctanoic acid), PFBS (perfluorobutane sulfonate), and PFOS (perfluorooctane sulfonate), especially, 6:2 Cl-PFESA (6:2 Cl-polyflurinated ether sulfonate) was detected in all samples. During treatment, the removal rate of ∑₂₁PFAS was 11%, and the removal rate of long-chain PFAS such as PFNA (perfluorononanoic acid), PFOS, and PFDS (perfluorodecane sulfonate) were relatively higher than short-chain PFAS due to their hydrophobic characteristic. Besides, the influence of seasonal factor (precipitation) on the occurrence and composition characteristics of PFAS in the aquatic environment was also investigated, and the results demonstrated that precipitation affected the total concentrations of PFAS in the aquatic environment, but barely on the composition characteristics of PFAS. Furthermore, the ecological risks could be negligible based on the concentration of PFAS measured in surface water. In the meanwhile, the health risks were also assessed based on the concentration of PFAS detected in drinking water, the result indicated that the concentrations of PFAS were less than the suggested drinking water advisories. In addition, more attention should be paid to the risk caused by the frequently detected emerging PFAS such as 6:2 Cl-PFESA and HFPO-DA (hexafluoropropylene oxide-dimer acid).

Per and poly-fluoroalkyl substances (PFAS) as a contaminant of emerging concern in surface water: A transboundary review of their occurrences and toxicity effects

Per and poly-fluoroalkyl substances (PFAS) have been recognized as contaminants of emerging concerns by the United States Environmental Protection Agency (US EPA) due to their environmental impact. Several advisory guidelines were proposed worldwide aimed at limiting their occurrences in the aquatic environments, especially for perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA). This review paper aims to provide a holistic review in the emerging area of PFAS research by summarizing the spatiotemporal variations in PFAS concentrations in surface water systems globally, highlighting the possible trends of occurrences of PFAS, and presenting potential human health impacts as a result of PFAS exposure through surface water matrices. From the data analysis in this study, occurrences of PFOA and PFOS in many surface water matrices were observed to be several folds higher than the US EPA health advisory level of 70 ng/L for lifetime exposure from drinking water. Direct discharge and atmospheric deposition were identified as primary sources of PFAS in surface water and cryosphere, respectively. While global efforts focused on limiting usages of long-chain PFAS such as PFOS and PFOA, the practices of using short-chain PFAS such as perfluorobutanoic acid (PFBA) and perfluorobutane sulfonic acid (PFBS) and PFAS alternatives increased substantially. These compounds are also potentially associated with adverse impacts on human health, animals and biota.

Occurrence and ecotoxicological risk assessment of perfluoroalkyl substances in water of lakes along the middle reach of Yangtze River, China

Polyfluoroalkyl substances (PFASs) are widely distributed in aquatic environment, and the potential ecological risk of PFASs has become a new challenge in recent years. But there were few integrated studies about the distribution, source appointment and risk assessment of PFASs in water of lakes along the middle reach of Yangtze River, China. Hence, this study investigated the pollution characteristics, source apportionment, ecological risks assessment of eleven PFASs from the surface water in this region. The total concentrations of PFASs (∑PFASs) ranged from 12.43 to 77.44 ng L^-1 in this region. The ∑PFASs in Hong and Poyang Lakes were higher than those in Dongting Lake and middle reach of Yangtze River (p < 0.05). The compositions of PFASs in the middle reach of Yangtze River and along three lakes were similar, being with a larger proportion of short-chain PFACs. The food packaging and metal plating sources were identified as the main sources by two models. The total risk quotients (∑RQs) showed the ecological risk for algae in the middle reach of Yangtze River, Dongting and Poyang Lakes were negligible, but the low risk in some sites of Hong Lake. The EDIs of ∑PFASs were much lower than the tolerable daily intake recommended by the European Food Safety Authority. The results of this study were significant for developing effective strategies (e.g. short-chain substitution and restriction) of controlling PFASs pollution in the middle reach of Yangtze River and along lakes.

Review on plant uptake of PFOS and PFOA for environmental cleanup: potential and implications

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) have gained increasing concern due to their persistent characteristics, wide distribution, biotoxicity, and bioaccumulative properties. The current remediation technologies for PFOA and PFOS are primarily focused on physical and chemical techniques. Phytoremediation has provided promising alternatives to traditional cleanup technologies due to their low operational costs, low maintenance requirements, end-use value, and aesthetic nature. In this review, uptake, translocation, and toxic effects of PFOS and PFOA are summarized and discussed. Several potential hyperaccumulators of PFOS and PFOA are provided according to the existing data. Biomass, chlorophyll, soluble protein, enzyme activities, oxidative stress, and other variables are assessed for potential indicator of PFOS/PFOA biotoxicity. The various studies on multiple scales are compared for identifying the threshold values. Several important implications and recommendations for future research are proposed at the end. This review provides an overview of current studies on plant uptake of PFOS and PFOA from the perspective of phytoremediation.

Per- and polyfluoroalkyl substances (PFAS) as contaminants of emerging concern in Asia's freshwater resources

The occurrence of per- and polyfluoroalkyl substances (PFAS) in water resources is an emerging concern because of their environmental persistence and bioaccumulation in humans. In Western countries, health advisories regarding PFAS exposure have been released to warn the public of its potential adverse effects. However, awareness regarding PFAS exposure in Asia is still at its infancy as reflected by the minimal safeguards imposed to protect the population from exposure. Here, we reviewed studies on PFAS contamination in Asia with a focus on freshwater resources to determine whether PFAS is also a concern in this part of the globe. Peer reviewed articles which included information on PFAS levels from 2000 to 2020 were compiled. The highest PFAS contamination was detected in surface water relative to ground, tap, and drinking water. PFAS levels in water resources in several countries in Asia, such as China, Japan, and South Korea, were above the recommended level, similar to that in the United States. PFAS in South and Southeast Asia were just below the recommended level, but the rise of PFAS in China in the recent decade, alongside its remarkable economic and industrial growth, suggests that increased PFAS contamination in South and Southeast Asia may soon follow, as these countries compete with the global economy. Hence, there is a need for these countries to also implement measures that will reduce the exposure of their population to PFAS.

Behavior Effects of Structurally Diverse Per- and Polyfluoroalkyl Substances in Zebrafish

Per- and polyfluoroalkyl substances (PFAS) are ubiquitously detected in the environment, and some pose significant human and environmental health concerns globally. While some PFAS induce adverse health effects, relatively few toxicological studies adequately address the broad structural diversity of this chemical class. In the current study, we evaluated 58 individual PFAS spanning 14 structural subclasses and 2 mixtures at single concentrations for developmental toxicity in zebrafish using highly sensitive behavior endpoints. Following developmental exposure to PFAS, zebrafish were assessed for mortality and challenged with an embryonic photomotor response (EPR) assay at 24 h postfertilization (hpf) and with larval photomotor response (LPR) and larval startle response assays at 120 hpf. We found that none of the tested PFAS exposures elicited significant mortality or aberrant EPR; however, exposure to 21 individual PFAS from multiple structural subclasses and 1 mixture induced aberrant larval behavior. We then evaluated developmental toxicity across a concentration range of 0-100 μM for 10 perfluoroalkyl carboxylic acids (PFCAs; 4-carbon perfluorobutanoic acid through the 13-carbon perfluorotridecanoic acid). Exposure to the PFCAs did not cause significant mortality or morphological effects, with the exception of perfluorooctanoic acid and perfluorononanoic acid, and did not induce aberrant EPR. All PFCAs, except for longer-chain perfluorododecanoic acid caused abnormal LPR following exposure to at least one concentration. In this study, we evaluated a broad set of PFAS not previously assessed for in vivo sublethal behavior endpoints and confirmed previous findings that exposure to some PFAS induces abnormal behavior in developing zebrafish. The data from this study will guide the selection of PFAS for which to investigate modes of toxic action.

Perfluoroalkyl substances in drinking water sources along the Yangtze River in Jiangsu Province, China: Human health and ecological risk assessment

Perfluoroalkyl substances (PFASs) in source water is of growing concern for its adverse effects on human health and wildlife as well. The Yangtze River is the vital drinking water source in Jiangsu Province of China, but little attention has been paid on PFASs. The occurrence, spatial distribution and temporal trend of PFASs in 21 water sources along the Jiangsu section of the Yangtze River was investigated with sampling from 2018 to 2020. Moreover, health risk of PFASs was assessed by estimated intake dose and derived tolerable intake dose, while ecological risk was assessed by selected effect concentration and environmental exposure. PFASs concentrations in source water ranged from 12.0 to 128 ng/L, with perfluorooctanoic acid (PFOA) as the dominated congener. Fluorine chemical industry lead to a great increase of perfluorohexanoic acid (PFHxA) in its nearest water source. The estimated daily intake of PFASs through drinking was 0.54 and 0.82 ng/kg bw/day for adults and children. The major health risk was from perfluorooctane sulfonate (PFOS) and PFOA for their toxicity on liver, reproduction, development and immunity, with the maximum hazard quotient of 0.029 and 0.043 for adults and children in the worst scenario. The ecological risks from PFASs on nine species groups ranged from 2.7 × 10-10 to 5.2. PFOA and Perfluorobutane sulfonate (PFBS) were causing significant risk on wildlife, particularly on worms, mussels, and fish, which may further influence the structure and processes in the foodweb. Overall, PFASs, especially PFOS, PFOA and PFBS, induced considerable risk on human health and aquatic species in some hotspot area. It would be necessary to include them into monitoring in China and develop standards for different protection purposes.

PFAS Exposure Pathways for Humans and Wildlife: A Synthesis of Current Knowledge and Key Gaps in Understanding

We synthesize current understanding of the magnitudes and methods for assessing human and wildlife exposures to poly- and perfluoroalkyl substances (PFAS). Most human exposure assessments have focused on 2 to 5 legacy PFAS, and wildlife assessments are typically limited to targeted PFAS (up to ~30 substances). However, shifts in chemical production are occurring rapidly, and targeted methods for detecting PFAS have not kept pace with these changes. Total fluorine measurements complemented by suspect screening using high-resolution mass spectrometry are thus emerging as essential tools for PFAS exposure assessment. Such methods enable researchers to better understand contributions from precursor compounds that degrade into terminal perfluoroalkyl acids. Available data suggest that diet is the major human exposure pathway for some PFAS, but there is large variability across populations and PFAS compounds. Additional data on total fluorine in exposure media and the fraction of unidentified organofluorine are needed. Drinking water has been established as the major exposure source in contaminated communities. As water supplies are remediated, for the general population, exposures from dust, personal care products, indoor environments, and other sources may be more important. A major challenge for exposure assessments is the lack of statistically representative population surveys. For wildlife, bioaccumulation processes differ substantially between PFAS and neutral lipophilic organic compounds, prompting a reevaluation of traditional bioaccumulation metrics. There is evidence that both phospholipids and proteins are important for the tissue partitioning and accumulation of PFAS. New mechanistic models for PFAS bioaccumulation are being developed that will assist in wildlife risk evaluations. Environ Toxicol Chem 2021;40:631-657. © 2020 SETAC.

Temporal and spatial analysis of per and polyfluoroalkyl substances in surface waters of Houston ship channel following a large-scale industrial fire incident

Firefighting foams contain per- and polyfluoroalkyl substances (PFAS) - a class of compounds widely used as surfactants. PFAS are persistent organic pollutants that have been reported in waterways and drinking water systems across the United States. These substances are of interest to both regulatory agencies and the general public because of their persistence in the environment and association with adverse health effects. PFAS can be released in large quantities during industrial incidents because they are present in most firefighting foams used to suppress chemical fires; however, little is known about persistence of PFAS in public waterways after such events. In response to large-scale fires at Intercontinental Terminal Company (ITC) in Houston, Texas in March 2019, almost 5 million liters of class B firefighting foams were used. Much of this material flowed into the Houston Ship Channel and Galveston Bay (HSC/GB) and concerns were raised about the levels of PFAS in these water bodies that have commercial and recreational uses. To evaluate the impact of the ITC incident response on PFAS levels in HSC/GB, we collected 52 surface water samples from 12 locations over a 6-month period after the incident. Samples were analyzed using liquid chromatography-mass spectrometry to evaluate 27 PFAS, including perfluorocarboxylic acids, perfluorosulfonates and fluorotelomers. Among PFAS that were evaluated, 6:2 FTS and PFOS were detected at highest concentrations. Temporal and spatial profiles of PFAS were established; we found a major peak in the level of many PFAS in the days and weeks after the incident and a gradual decline over several months with patterns consistent with the tide- and wave-associated water movements. This work documents the impact of a large-scale industrial fire, on the environmental levels of PFAS, establishes a baseline concentration of PFAS in HSC/GB, and highlights the critical need for development of PFAS water quality standards.

Dam operation altered profiles of per- and polyfluoroalkyl substances in reservoir

Information on the impact of dam operation on per- and polyfluoroalkyl substances (PFASs) distribution in reservoirs is very limited. In the present study, water, riparian soils and floating wastes samples were collected from the Three Gorges Reservoir, China during the storage and the discharge periods to characterize the PFASs distribution. The total PFASs concentrations of water samples in the storage period (50.4-146 ng/L) were 4.7 times higher than those in the discharge period (1.40-38.6 ng/L). The main types of PFASs in water samples changed from PFOA in the discharge period to short-chain species in the storage period. The main analogues in riparian soils and floating wastes were PFOA and PFOS. Wastes contributed little to PFASs mass in the reservoir, while PFASs accumulated in soils accounted for 49.7 % of the total mass when the riparian zone was submerged during the storage period. Changes in profiles of PFASs caused by dam operation suggested that the potential water safety and the shift of riparian soils between source and sink of PFASs may vary with the annual operation cycle of dam. The water resources protection in reservoirs needs strategies that consider the variation of dam operation cycle.

Perfluoroalkyl substances (PFASs) in special management sea areas of Korea: Distribution and bioconcentration in edible fish species

Thirteen PFASs in water (n = 58), sediment (n = 58) and edible fish samples (n = 81) collected from three special management sea areas of Korea including Gwangyang bay, Masan bay and Busan harbor in July 2018 were investigated. The mean PFASs concentration in water (ng/L) were in order Masan (5.09) > Busan (2.82) > Gwangyang (1.74). PFASs levels were found as the low concentration in sediment. The greatest total PFASs concentration in each fish tissue was found as 3.04 (ng/g ww) in a Japanese amberjack fish for muscle in Busan, 66.23 (ng/mL) in Japanese amberjack fish for blood in Masan and 125.03 (ng/g ww) flathead grey mullet in Busan bay. The BCF (L/kg) of PFDoDA was found as the highest in muscle of all species with values from 30,922 (grey mullet in Gwangyang) to 69,131 (grey mullet in Busan). PFDS was the highest BCF's PFASs (110,599 L/kg) in muscle which was found in Japanese amberjack in Busan bay.

Legacy per- and polyfluoroalkyl substances (PFASs) and alternatives (short-chain analogues, F-53B, GenX and FC-98) in residential soils of China: Present implications of replacing legacy PFASs

With the worldwide regulation of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), the alternatives (short chain analogues and emerging per- and polyfluoroalkyl substances, PFASs) have gradually attracted global attention. This study analysed the replacing of legacy PFASs in China using PFASs data from residential soils, which might be good environmental indicators of their present usage. The total concentrations of 21 PFASs ranged from 244 to 13564 pg/g, and PFOA was the dominant compound among the studied PFASs, with a concentration of 354 ± 439 pg/g. Serious PFASs pollution in residential soils mainly occurred in Eastern Coastal China as a result of locally developed industry and economies. Weak but significant correlations were found between PFASs and environmental and socioeconomic factors, suggesting that various factors determine PFASs contamination in residential soils. The concentration and detection frequency (DF) of short-chain analogues (C < 8) (375 ± 509 pg/g and 100%), and F-53B (216 ± 306 pg/g and 98.9%) were higher than those for PFOS (193 ± 502 pg/g and 85.4%), indicating that these compounds have been widely used as PFOS alternatives and their consumption has already exceeded that of PFOS in China. In addition, GenX (the PFOA alternative) had a concentration and DF of 19.1 ± 104 pg/g and 40.5%, respectively. These values were much lower than those for PFOA (354 ± 439 pg/g and 96.6%), indicating GenX consumption is still limited at the national scale of China, despite its use as a PFOA replacement. Moreover, the low concentration and DF of FC-98 (2.31 ± 11.1 pg/g and 27.0%) indicate that its consumption might be negligible. Our study demonstrated that short chain analogues and emerging alternatives have become the dominant PFAS pollutants in Chinese residential soils, and further studies need to be conducted to understand their toxicity and environmental risks.

Occurrence and partitioning behavior of per- and polyfluoroalkyl substances (PFASs) in water and sediment from the Jiulong Estuary-Xiamen Bay, China

Twenty-four per- and polyfluoroalkyl substances (PFASs) were analyzed in water and sediment from the Jiulong Estuary-Xiamen Bay to study their seasonal variations, transport, partitioning behavior and ecological risks. The total concentration of PFASs in water ranged from 11 to 98 ng L^-1 (average 45 ng L^-1) during the dry season, 0.19-5.7 ng L^-1 (average 1.5 ng L^-1) during the wet season, and 3.0-5.4 ng g^-1 dw (average 3.9 ng g^-1 dw) in sediment. In water samples, short-chain PFASs were dominated by perfluorooctanoic acid (PFBA) in the dry season and perfluorobutane sulfonate (PFBS) in the wet season, while long chain PFASs, such as perfluorooctane sulfonate (PFOS), dominated in the sediment. The highest concentration of PFASs in water were found in the estuary; in contrast, the highest level of PFASs in sediment were found in Xiamen Bay. These spatial distributions of PFASs indicate that river discharge is the main source of PFASs in estuarine water, while the harbor, airport and wastewater treatment plant near Xiamen Bay may be responsible for the high PFBS and PFOS concentrations in water and sediment. The partition coefficients (log K_d) of PFASs between sediment and water (range from 1.64 to 4.14) increased with carbon chain length (R² = 0.99) and also showed a positive relationship with salinity. A preliminary environmental risk assessment indicated that PFOS and perfluorooctanoic acid (PFOA) in water and sediment pose no significant ecological risk to organisms.

Seasonal variation and spatial transport of polycyclic aromatic hydrocarbons in water of the subtropical Jiulong River watershed and estuary, Southeast China

Riverine runoff is one of the most important pathways of pollutants entering the oceans. To study the seasonal variations, spatial transports, sources and mass fluxes of polycyclic aromatic hydrocarbons (PAHs) from the subtropical Jiulong River watershed to estuary, water samples were collected in wet and dry seasons. PAH concentrations showed significant temporal-spatial variations (ANOVA, p < 0.05). In the watershed, PAH concentrations in wet season (48.6 ± 18.2 ng L^-1) were significantly lower than in dry season (90.3 ± 18.5 ng L^-1). In contrast, estuarine PAH concentrations in wet season (67.1 ± 24.6 ng L^-1) were significantly higher than in dry season (27.4 ± 10.6 ng L^-1) (p < 0.0001). The spatial variations of PAH concentrations in wet and dry seasons reflected positive and restricted transport processes occurred in the river. These findings might be subjected to seasonal changes in precipitation, water discharge, hydrodynamic conditions, and human activities. The compositional patterns of PAHs illustrated that fluorene and phenanthrene were the dominant compounds in the watershed, while phenanthrene was predominant in the estuary. Source analysis by molecular diagnostic ratios and PMF model indicated that fossil fuel and biomass combustion and petroleum both contributed to the presence of PAHs, and the high contributions of pyrogenic PAHs might be related to urban rainstorm runoff in winter and atmospheric inputs in winter. Although the estimated flux of PAHs from watershed to estuary was about 676 kg yr^-1 with a low level by comparing the data obtained in the worldwide, continue concern of PAHs in the Jiulong River is recommended due to the intense human activities.

Temporal variations of perfluoroalkyl substances partitioning between surface water, suspended sediment, and biota in a macrotidal estuary

A one-year monitoring study was conducted in a macrotidal estuary to assess the temporal variations and partitioning behavior of perfluoroalkyl and polyfluoroalkyl substances (PFASs). Surface water, suspended particulate matter (SPM), and invertebrates including zooplankton (copepods, mysids) and shrimps were sampled on a monthly basis in the Gironde Estuary (SW France). Environmental parameters such as suspended solid loads, salinity, and river water flow rate were highly variable at the study site. However, moderate seasonal variations were observed in terms of PFAS levels and profiles. Summed PFAS (Σ₂₂PFASs) concentrations averaged 6.5 ± 2.7 ng L^-1 in the dissolved phase and 3.0 ± 1.2 ng g^-1 dry weight in the SPM. The Σ₂₂PFASs was in the range of 1.7-13 ng g^-1 wet weight in invertebrates. C₅-C₈ perfluoroalkyl carboxylates (PFCAs) generally prevailed in the dissolved phase, while perfluorooctane sulfonate (PFOS) was dominant in the SPM and biota. Suspended sediment-water partitioning coefficients Log K_D and Log K_OC were correlated with the perfluoroalkyl chain length, as were the particle-bound fraction and bioaccumulation factors (Log BAF). Compound-specific Log BAFs varied within a limited range over the period surveyed. Biomagnification factors (mysids/copepods) were consistently >1 for PFOS, perfluorooctane sulfonamide, and long-chain PFCAs (perfluorodecanoate and perfluorododecanoate), suggesting biomagnification at the base of the estuarine food web.

Occurrence and distribution of perfluorooctane sulfonate and perfluorooctanoic acid in three major rivers of Xinjiang, China

Drinking water is a main pathway of human exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA). These two compounds have been identified in environmental waters worldwide, but little is known about their occurrence in Xinjiang. In this study, 155 water samples were obtained from 37 locations across Ulungur River, Manasi River, and Tarim River in Xinjiang, and were assessed by using liquid chromatography tandem-mass spectrometry. PFOS and PFOA were detected in over 50% of the samples with mean concentrations of 3.194 ng/L for PFOS and 3.460 ng/L for PFOA. Spatial and regional distribution differences do exist among the three analyzed rivers. PFOS and PFOA in Manasi River were observed at the highest levels (especially in M10 and M11), but no aggravation occurred from 2014 to 2017. Seasonal variations of PFOS and PFOA concentrations showed that water samples collected during summer were higher than those in other three seasons. The occurrence, levels, and distribution patterns of PFOS and PFOA were investigated in the present study, which provides useful theory and data support for human health risk assessment. The findings of the present study can be considered for controlling these water pollutants in environmental waters.

Dietary Exposure of Chinese Adults to Perfluoroalkyl Acids via Animal-Origin Foods: Chinese Total Diet Study (2005-2007 and 2011-2013)

Diet has been regarded as the main exposure source of perfluoroalkyl acids (PFAAs), but the national dietary survey of PFAAs in China was limited. Here, eight typical PFAAs were detected in milk, aquatic food, meat, and eggs from the Chinese Total Diet Studies (TDSs) during 2005-2007 and 2011-2013. Aquatic food was found to be the main source of PFAAs among animal-origin foods. The estimated dietary intakes of ∑PFAAs from animal foods (EDI_{animal-origin foods}) in coastal areas were relatively higher than in inland areas. The highest EDI_{animal-origin foods} of PFOS [4.07 and 2.02 ng kg^-1 of body weight (bw) day^-1] and PFOA (2.19 ng kg^-1 of bw day^-1) found in Shanghai and perfluorononanoic acid (PFNA, 2.72 ng kg^-1 of bw day^-1) in Fujian approach or exceed current minimal risk levels from the Agency for Toxic Substances and Disease Registry and tolerable weekly intakes from the European Food Safety Authority, suggesting potential risk of PFAA exposure from animal-origin foods in these areas.

Propensity of Tagetes erecta L., a Medicinal Plant Commonly Used in Diabetes Management, to Accumulate Perfluoroalkyl Substances

It has been extensively demonstrated that plants accumulate organic substances emanating from various sources, including soil and water. This fact suggests the potentiality of contamination of certain vital bioresources, such as medicinal plants, by persistent contaminants, such as perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), and perfluorobutane sulfonate (PFBS). Hence, in this study, the propensity of Tagetes erecta L. (a commonly used medicinal plant) to accumulate PFOA, PFOS, and PFBS was determined using liquid chromatography/tandem mass spectrometry (LC⁻MS/MS-8030). From the results, PFOA, PFOS, and PFBS were detected in all the plant samples and concentration levels were found to be 94.83 ng/g, 5.03 ng/g, and 1.44 ng/g, respectively, with bioconcentration factor (BCF) ranges of 1.30 to 2.57, 13.67 to 72.33, and 0.16 to 0.31, respectively. Little evidence exists on the bioaccumulative susceptibility of medicinal plants to these persistent organic pollutants (POPs). These results suggest that these medicinal plants (in particular, Tagetes erecta L., used for the management of diabetes) are also potential conduits of PFOA, PFOS, and PFBS into humans.