Perfluorinated compounds in the Pearl River and Yangtze River of China

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.

A sensitive method for simultaneous determination of 12 classes of per- and polyfluoroalkyl substances (PFASs) in groundwater by ultrahigh performance liquid chromatography coupled with quadrupole orbitrap high resolution mass spectrometry

Per- and polyfluoroalkyl substances (PFASs) comprise a large group of chemicals with diverse physicochemical properties, which make their simultaneous determination a challenging task. A trace analytical method based on ultrahigh performance liquid chromatography-quadrupole Orbitrap high resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) was developed for simultaneous determination of 54 PFASs belonging to 12 classes in groundwater, including 24 perfluorocarbons and 30 precursors. This method provided good linearity of calibration standards (R² > 0.99), excellent method limits of quantification (MLOQs) (0.5-250 pg/L), satisfactory matrix spiking recoveries (63%-148%), high precision (intra-day relative standard deviations (RSDs) 1.4-11.4%, inter-day RSDs 1.6-12.9%, and inter-week RSDs 2.1-12.7%), and short runtime (13 min), suitable for high throughput studies. The newly established method was successfully applied to detect PFASs in the groundwater samples collected from Hebei Province, China. Twenty PFASs were detected with the total concentration of 0.3-32.9 ng/L, indicating the contamination level similar to that in drinking water. The dominant PFASs were perfluorobutanesulfonate (PFBS), perfluorobutanoic acid (PFBA), perfluoropentanoic acid (PFPeA) and perfluorooctanoic acid (PFOA). In addition, 6:2 fluorotelomer phosphate diester (6:2 diPAP) and 6:2 fluorotelomer sulfonate (6:2 FTS) were found as the major precursors. The total PFAS concentrations were lower than the cumulative permissible limit of 70 ng/L for PFOS and PFOA recommended by the United States Environmental Protection Agency (USEPA) for drinking water in 2016. In a nutshell, this study provided a fast and sensitive method based on HRMS for the simultaneous analysis of a wide range of PFASs, present at trace levels in groundwater samples.

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.

Destruction of Per- and Polyfluoroalkyl Substances (PFAS) with Advanced Reduction Processes (ARPs): A Critical Review

Advanced reduction processes (ARPs) have emerged as a promising method for destruction of persistent per- and polyfluoroalkyl substances (PFAS) in water due to the generation of short-lived and highly reductive hydrated electrons (e_aq^-). This study provides a critical review on the mechanisms and performance of reductive destruction of PFAS with e_aq^-. Unique properties of e_aq^- and its generation in different ARP systems, particularly UV/sulfite and UV/iodide, are overviewed. Different degradation mechanisms of PFAS chemicals, such as perfluorooctanoic acid (PFOA), perfluorooctanesulfonate (PFOS), and others (e.g., short chain perfluorocarboxylic acids (PFCAs) and perfluorosulfonic acids (PFSAs), per- and polyfluoro dicarboxylic acids, and fluorotelomer carboxylic acids), are reviewed, discussed, and compared. The degradation pathways of these PFAS chemicals rely heavily upon their head groups. For specific PFAS types, fluoroalkyl chain lengths may also affect their reductive degradation patterns. Degradation and defluorination efficiencies of PFAS are considerably influenced by solution chemistry parameters and operating factors, such as pH, dose of chemical solute (i.e., sulfite or iodide) for e_aq^- photoproduction, dissolved oxygen, humic acid, nitrate, and temperature. Furthermore, implications of the state-of-the-art knowledge on practical PFAS control actions in water industries are discussed and the priority research needs are identified.

Spatiotemporal distribution, sources and ecological risks of perfluorinated compounds (PFCs) in the Guanlan River from the rapidly urbanizing areas of Shenzhen, China

Limited studies have demonstrated the environmental concerns of perfluorinated compounds (PFCs) in the rivers flowing through the rapidly urbanizing areas. Therefore, this study aims to investigate the spatial and temporal distribution, major sources and ecological risks of PFCs in the surface water samples, collecting from the Guanlan River, Shenzhen, China. The concentrations of ∑PFCs ranged from 11.3 to 384 ng/L, with a mean value of 81.8 ng/L in the dry season, and ranged from 6.90 to 619 ng/L, with a mean value of 339 ng/L in the wet season. Short-chain PFCs such as perfluorohexane sulfonate (PFHxS) and perfluorobutane sulfonate (PFBS) were detected as the predominant compounds. Further, the spatiotemporal distribution revealed significantly higher levels of PFCs in the wet season than those in the dry season, and relatively higher levels in the tributaries than those in the mainstream. Source apportionment highlighted the industrial discharges, domestic wastewater, precipitation, and wastewater treatment plants as the major sources of PFCs. Moreover, the population density and associated urban sewage emissions observed as important indicators for PFCs uneven distribution in the area. The ecological risk assessment revealed perfluorotetradecanoic acid (PFTA, C14) posed high ecological risks to the aquatic organisms (especially for mysid) in the Guanlan River. Taken all together, this study not only unveiled the characteristics of PFCs contamination in the rapidly urbanizing catchment, but also provided the baseline data for policy makers to protect the ecological environment of the urban rivers in the rapidly growing area.

Transcriptomic Changes in Liver of Juvenile Cynoglossus semilaevis following Perfluorooctane Sulfonate Exposure

Perfluorooctane sulfonate (PFOS) is an increasingly important environmental pollutant that is pervasive in the environment. A number of studies have focused on the toxicological effects of PFOS on model fish species (zebrafish and medaka), but little is known about the impact of PFOS on commercially important marine fish. Thus, the present study examined transcriptome responses to PFOS exposure in the liver of juvenile Cynoglossus semilaevis, an important farmed flatfish in China. Then, in response to PFOS challenges, 1695 and 5244 genes were identified as significantly increased and depressed, respectively. Significant expression changes were observed in immune-related genes (cytokine-cytokine receptor interaction, T-helper [Th]17 cell differentiation, and the chemokine nuclear factor-kappa B and T-cell receptor signaling pathways), indicating that immunotoxicity is a key aspect of the effects of PFOS on C. semilaevis. Exposure to PFOS also altered the gene expression levels of hormones (inhibin, insulin, somatostatin, and glucagon), which could lead to severe metabolic and endocrine dysfunction. As expected from previous studies, several phase I and phase II detoxification enzymes were significantly up-regulated, which could facilitate the biotransformation and detoxification of PFOS in C. semilaevis. The present study provides new insights into the molecular toxicology of PFOS in a commercially important fish species. Environ Toxicol Chem 2020;39:556-564. © 2019 SETAC.

Regulation of Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonic Acid (PFOS) in Drinking Water: A Comprehensive Review

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are receiving global attention due to their persistence in the environment through wastewater effluent discharges and past improper industrial waste disposal. They are resistant to biological degradation and if present in wastewater are discharged into the environment. The US Environmental Protection Agency (USEPA) issued drinking water Health Advisories for PFOA and PFOS at 70 ng/L each and for the sum of the two. The need for an enforceable primary drinking water regulation under the Safe Drinking Water Act (SDWA) is currently being assessed. The USEPA faces stringent legal constraints and technical barriers to develop a primary drinking water regulation for PFOA and PFOS. This review synthesizes current knowledge providing a publicly available, comprehensive point of reference for researchers, water utilities, industry, and regulatory agencies to better understand and address cross-cutting issues associated with regulation of PFOA and PFOS contamination of drinking water.

Evidences for replacing legacy per- and polyfluoroalkyl substances with emerging ones in Fen and Wei River basins in central and western China

Legacy per- and polyfluoroalkyl substances (PFASs), mainly long-chain ones, are being substituted by short-chain homologues and novel fluorinated alternatives, whereas their occurrence, spatial distribution, sources and substitution characteristics are not well understood. For the first time, the occurrence and replacing trend of the legacy and novel fluorinated alternatives were examined in the surface water from Fen and Wei rivers, which are the two major rivers located in the underdeveloped and ecology vulnerable areas of central and western China. Results showed that the contamination of legacy and emerging PFASs in both river basins was widespread, and mainly caused by industrial activities. In both rivers, perfluorohexane sulfonic acid (PFHxS), as a substitute for perfluorooctane sulfonic acid (PFOS), was predominant in the urban areas. In the Fen River, more substitutes of PFOS, such as 6:2 fluorotelomer sulfonate (6:2 FTS) and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA), were distinct, while significant replacing for PFOA with short-chain perfluoroalkyl carboxylic acids (C4-C7) and Ammonium salt of 4,8-dioxa-3H-per-fluorononanoate (ADONA) was observed in Wei River. Besides, advanced oxidation experiment indicated that there were unknown PFASs which could be the precursors of perfluorocarboxylic acids in Wei River. Isomeric analyses indicated that there was contribution of telomerization related sources for PFOA in both rivers, whereas PFOS was mainly from ECF. The estimated total mass discharge of PFASs derived from Wei and Fen River to the Yellow river were 239 and 62.6 kg/year, respectively.

Occurrence of perfluoroalkyl substances in selected Victorian rivers and estuaries: An historical snapshot

This reconnaissance study was undertaken in 2012 to examine the occurrence of common perfluoroalkyl substances (PFAS), including perfluoroalkyl sulphonic acids and perfluoroalkyl carboxylic acids in rivers and estuaries in Port Philip Bay, Victoria, Australia. In total, 19 PFAS were screened in grab samples of water using a combination of solid phase extraction and liquid chromatography - mass spectrometry measurement techniques. Eighteen of the PFAS screened were observed in samples. The highest level of PFOS observed at a freshwater site was 0.045 μg/L; this concentration is approximately half the draft Australian 95% species protection level for total PFOS. The highest level of PFOA in the study (0.014 μg/L) was some four orders of magnitude lower than the draft Australian trigger value for PFOA (220 μg/L). However, none of the PFAS observed at the freshwater sites had research quotient (RQ) or toxicity unit (TU) values above 1 or -3, respectively. The highest concentration of PFOS observed at an estuarine site was 0.075 μg/L; the highest level of PFOA, 0.09 μg/L). There are no Australian marine water quality trigger values for PFAS, so potential risk was assessed using the European environment quality standards (EQS) adopted in EU Directive 2013/39/EU, RQ and TU methods. In that context, none of the PFAS observed at estuary sites had concentrations higher than the EU standards, or RQ above 1 or Log 10 TU above -3. Together these assessments suggest none of the PFAS screened would have posed an acute risk to organisms in the fresh or estuary waters studied at the time of sampling on an individual or collective basis. However, the detection of these PFAS in Victorian estuaries highlights that the issue is not just an issue for more densely populated countries in the northern hemisphere, but also potentially of concern in Australia. And, in that context, more sampling campaigns in Port Philip Bay are of paramount importance to assess the potential risk pose by these compounds to aquatic ecosystems.

Distribution and Bioaccumulation of Perfluoroalkyl Acids in Xiamen Coastal Waters

Since perfluoroalkyl acids (PFAs) are widely used and harmless to organisms, they have attracted great attention in recent years. The distribution of PFAs in the oceans all around the world is well documented. However, the study of PFAs in Xiamen could be a beneficial complement, for its unique geologies of no rivers that originate from other cities to influence the concentration of PFAs in this area. In this paper, six PFAs were analyzed in water, sediments, and organisms from both freshwater and seawater and the bioaccumulation factors (BAFs) were calculated with the quantity of PFAs in different trophic levels of aquatic organisms. The results showed that the ΣPFA concentrations ranged from 7.66 to 11.98 ng·L−1 for seawater samples and from 2.12 to 8.61 ng·L−1 for freshwater. The concentration of ΣPFAs in sediments was 7.43–12.89 ng·g−1 and 4.53–5.80 ng·g−1 in seawater and freshwater, respectively. The PFA concentration in water is highly positive correlated with the PFA concentration in sediments (R2 = 0.85). The calculated bioaccumulation factors (BCFs) were 6412–14254 L·kg−1 and 2927–7959 L·kg−1 for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonates (PFOS), respectively. PFOA seems more bioaccumulative than PFOS in seawater. The results illustrated the PFA pollution in the Xiamen sea area, and it is useful for the protection and control of the organic pollutants in this area.

Characterization and source identification of tetracycline antibiotics in the drinking water sources of the lower Yangtze River

The occurrence and spatio-temporal patterns of five tetracyclines (TCs) and six of their degradation products were investigated in twenty-eight drinking water sources along the lower Yangtze River (LYR) over dry, normal and flood seasons. Tetracycline (TC), oxytetracycline (OTC) and doxytetracycline (DXC) were the dominant antibiotics detected with the highest occurrence. The maximum concentrations of TC, OTC and DXC were found in dry season as 11.16, 18.98, and 56.09 ng/L, respectively, because of the low dilution, low degradation, and high consumption in this season. Cluster analysis indicated distinct variations in the TCs' compositional profiles in both space and time. OTC and its metabolites contributed 18.5-59.6% of the TC load in dry season, possibly due to the seasonally increased release of pharmaceutical OTCs from sewage effluents, but they were seldom detected in other seasons. Pollution load index analysis showed that tributaries carrying large amounts of veterinary TCs derived from breeding wastewater and untreated rural sewage contributed larger proportions of the TC load for most drinking water sources than sewage outlets. The contribution ratio of the TC load from tributaries (74.5%) was approximately three times higher than that from sewage discharges (25.5%). The study demonstrated that the control of load from tributaries is the key to mitigating TC pollution of the drinking water sources in the LYR. An effective source tracking method for evaluating the contribution of antibiotic load from multiple diffuse pollution origins and identifying the high-risk contamination sources was established for antibiotic management and control.

Field-scale evaluation of the uptake of Perfluoroalkyl substances from soil by rice in paddy fields in South Korea

The concentrations of 17 perfluoroalkyl substances (PFASs) were investigated in paddy soil, void water, and brown rice collected from 30 paddy fields to examine the uptake of PFASs from soil by rice. The total concentrations of PFASs ranged from 7.76 to 3020 ng/L (average = 166 ng/L) in void water, 0.120 to 13.9 ng/g dry-weight (dw) (1.92 ng/g dw) in paddy soils, and from not-detected to 1.85 ng/g (0.403 ng/g) in brown rice samples. The highest PFAS concentrations were observed in brown rice cultivated in a paddy field where high levels of PFASs were observed in void water and paddy soil. Among target PFAS compounds, perfluorocarboxylic acids were dominant and detected in all matrices, and perfluorooctanoic acid (PFOA) was the most predominant compound in brown rice and void water. Significant positive correlations were examined for some detected PFASs between each matrix. PFOA in brown rice was positively correlated with PFOA in void water as well as perfluorodecanoic acid (PFDA) in paddy soil (p < 0.01). PFOA in void water also had correlated with PFDA in paddy soil. However, there was no correlation of other compounds between each matrix, except for correlations of perfluorononanoic acid (PFNA) and PFDA in paddy soil with those in void water, respectively (p < 0.05). Moreover, PFOA concentration in brown rice (0.093 ng/g) was much higher than one in white rice detected with a non-detectable level.

Detection and Treatment Methods for Perfluorinated Compounds in Wastewater Treatment Plants

We surveyed the variation in perfluorinated compound (PFC) concentrations entering urban wastewater treatment plants and then designed an optimal PFCs treatment method based on a pilot test. The PFCs influent concentration was found to be affected by the types of industries and operating rate. The concentration of PFCs in the wastewater treatment effluent was slightly lower than that of the influent. Thus, PFCs had not been adequately removed by the existing biological treatments. The pilot test results showed that about 10% of PFCs was removed by coagulation and precipitation, and the ozone and chlorine test showed that few, if any, PFCs were removed regardless of the oxidant dose. The activated carbon adsorption test showed that the removal significantly increased with empty bed contact time, with about a 60% removal in five minutes and over 90% removal in over 15 minutes. Therefore, a more stable and higher PFCs removal would result from continuous oxidation processes, such as ozone and adsorption processes involving activated carbon, rather than a single biological treatment.

Occurrence, sources and health risk of polyfluoroalkyl substances (PFASs) in soil, water and sediment from a drinking water source area

Polyfluoroalkyl substances (PFASs) enter into environmental metric via various pathways in the process of manufacturing and consuming the products containing PFASs. Yuqiao reservoir (YQR) is a major drinking water source in Tianjin of China, where little attention was given to PFASs. To explore the occurrence, source and risk of 17 PFASs, multi-media environmental including soil, water, and sediment were sampled from this water source area. The ∑PFASs concentrations of surface water, groundwater, soil and sediment ranged from 5.839 to 120.885 ng/L, 1.426 to 17.138 ng/L, 0.622 to 5.089 μg/kg dw, and 0.240 to 1.210 μg/kg dw respectively. Some short-chained (C4-C8) PFASs were detected widely such as PFOA, PFBA, PFHxA, PFBS, PFHpA and PFPeA in surface water and groundwater, with the detection frequency of ＞78%, and PFBA and PFOA dominated in the 17 PFASs. In addition, the correlations between total PFASs and TOC were significant at 0.05 level, especially in surface water with R² = 0.9165 (p = 0.011). In terms of vertical distribution characteristics of ∑PFASs, the ∑PFASs in four sediment cores showed a decreasing trend at first, and then an increasing trend from the bottom to the top associated with TOC. PFBA/PFOA and PFHpA/PFOA showed better linear correlations with R² of 0.5541 (p = 0.039), and for PFNA/PFOA and PFHpA/PFOA with R² of 0.6312 (p = 0.032) at the 0.05 level in the surface water, which indicated that sewage and atmospheric precipitation were the major sources. Though the RQ results based on the measured concentrations and reference values in environmental media revealed lower risks, the potential hazard may occur due to accumulation characteristics and long-distance transmission capability of PFASs. Hence, the corresponding management strategies should be taken, such as control over emission at source, product substitution and strengthening legislation, to eliminate potential risks to human health.

Dietary intake, drinking water ingestion and plasma perfluoroalkyl substances concentration in reproductive aged Chinese women

BACKGROUND

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a group of synthetic chemicals that are widely used in industrial and consumer products. A growing body of literature suggests that exposure to these chemicals are associated with adverse reproductive outcomes in women. However, the sources of PFAS exposure are often poorly characterized in women of child-bearing age.

OBJECTIVES

To examine the association of plasma PFAS concentrations with dietary intake and drinking water sources in reproductive aged women in Shanghai, one of the high PFAS polluted regions in China.

METHODS

Concentrations of ten PFAS in plasma samples were measured in 933 women. Information on dietary intake and type of drinking water was collected by questionnaire. We used multivariable linear regression models to assess the association of PFAS concentrations with dietary intake and drinking water.

RESULTS

After controlling for potential confounders, a higher frequency of intake of aquatic products (freshwater fish, marine fish, shellfish, shrimp and crab) was positively and significantly associated with concentrations of PFOS, PFOA, PFNA, PFDA, PFUA and PFDoA in 900 reproductive aged women. Intake of freshwater fish showed the strongest association with PFAS. Compared with the lowest intake group of freshwater fish, the intermediate intake group had 8-32% increase in the concentrations of these pollutants; and the highest group had 11-57% increase. Conversely, intake of soy products was associated with lower levels of PFDA, PFUA, PFNA, PFOS, and PFDoA. In addition, compared with women drinking tap water, drinking bottled water was associated with significantly decreases in PFHpA, PFDA, PFOA, PFUA and PFBS blood levels by 9-13% in 905 reproductive aged women.

CONCLUSIONS

Intake of freshwater fish, marine fish, shrimp and crab was positively associated with plasma PFAS concentrations, while intake of soy products and bottled water was associated with lower PFAS concentrations in the Chinese women of reproductive age.

Bioconcentration and tissue distribution of shorter and longer chain perfluoroalkyl acids (PFAAs) in zebrafish (Danio rerio): Effects of perfluorinated carbon chain length and zebrafish protein content

Perfluoroalkyl acids (PFAAs) are a class of emerging pollutants. However, the bioconcentration and tissue distribution of shorter chain PFAAs in aquatic animals are not well understood. Here, we investigated the effects of perfluorinated carbon chain length of PFAAs and protein content of tissues on the bioconcentration and tissue distribution of both shorter chain PFAAs (linear C-F = 3-6) and longer chain PFAAs (linear C-F = 7-11) in zebrafish. The results showed that the uptake rate constants (k_u) and the bioconcentration factors (BCF_ss) of the shorter chain PFAAs (0.042-32 L·kg_ww^-1·d^-1 and 0.12-24 L·kg_ww^-1, respectively) in tissues were significantly lower than those of the longer chain PFAAs (2.8-1.4 × 10³ L·kg_ww^-1·d^-1 and 9.7-1.9 × 10⁴ L·kg_ww^-1, respectively). Moreover, the concentrations of both longer and shorter chain PFAAs were lowest in the muscle where the protein content was lowest, and they were highest in blood and liver where the protein content was highest among tissues except brain. The protein content of the brain was higher than that of the liver but the concentrations of PFAAs in the brain were significantly lower than those in the liver because of the blood-brain barrier. In addition, the ovary/blood and brain/blood ratios of concentrations for the shorter chain PFAAs were lower than those for the longer chain PFAAs. Generally, both log k_u and log BCF_ss showed a significantly positive correlation with either perfluorinated carbon number of PFAAs or protein content of tissues (P < 0.05). Further nonlinear surface fitting revealed that the effect of perfluorinated carbon number was more significant than protein content on the PFAA bioconcentration in zebrafish tissues. These results suggest that there are differences in the bioconcentration and tissue distribution between longer and shorter chain PFAAs and the shorter chain PFAAs seem to be safe compared with the longer chain PFAAs.

Simulating transport, flux, and ecological risk of perfluorooctanoate in a river affected by a major fluorochemical manufacturer in northern China

Perfluoroalkyl acids (PFAAs) have been widely detected and pose potential risks to both human and ecosystem health. Since the probation of perfluorooctane sulfonate (PFOS) by the Stockholm Convention, perfluorooctanoate (PFOA) has frequently been used as a chemical intermediate and processing aid. Owing to a lack of effective treatment technologies for PFOA, surrounding environments have been highly affected. Previous studies by our group have reported elevated PFOA levels in the Xiaoqing River, which receives sewage from a major fluorochemical manufacturer in northern China. To further explore the transport, flux, and ecological risk of the perfluorooctanoate in the river, this study conducted a 2-year sampling campaign of surface water from 2014 to 2015. An extremely high PFOA concentration (mean: 62.3 μg L^-1) was observed for the Xiaoqing River in comparison with other studies. The highest average concentration and flux of PFOA were recorded in the autumn and summer, respectively. With data on selected hydrological parameters and cross-sections, PFOA concentrations were modeled using DHI MIKE 11. To explore the current loads and environmental capacity of PFOA, two scenarios (i.e., emissions based on observed concentrations and on the predicted no-effects concentration, PNEC) were set. The simulation results based on observed data showed that PFOA loads in the Xiaoqing River were 11.4 t in 2014, and 12.5 t in 2015. Based on the PNEC, the environmental carrying capacity of PFOA was estimated to be 13.9 t in 2014, and 13.8 t in 2015. The current loads of PFOA were found to approach the maximum environmental carrying capacity. Relatively high risks around both the fluorine industrial park (FIP) and estuary area were identified. In comparison with other suggested guidelines, threats to the ecological status of the river would be severe, which suggests that stringent management and emission criteria are needed for this industry.

Accumulation of perfluorinated alkyl substances (PFAS) in agricultural plants: A review

PFASs are a class of compounds that include perfluoroalkyl and polyfluoroalkyl substances, some of the most persistent pollutants still allowed - or only partially restricted - in several product fabrications and industrial applications worldwide. PFASs have been shown to interact with blood proteins and are suspected of causing a number of pathological responses, including cancer. Given this threat to living organisms, we carried out a broad review of possible sources of PFASs and their potential accumulation in agricultural plants, from where they can transfer to humans through the food chain. Analysis of the literature indicates a direct correlation between PFAS concentrations in soil and bioaccumulation in plants. Furthermore, plant uptake largely changes with chain length, functional group, plant species and organ. Low accumulations of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) have been found in peeled potatoes and cereal seeds, while short-chain compounds can accumulate at high levels in leafy vegetables and fruits. Significant variations in PFAS buildup in plants according to soil amendment are also found, suggesting a particular interaction with soil organic matter. Here, we identify a series of challenges that PFASs pose to the development of a safe agriculture for future generations.

Removal of polar organic micropollutants by pilot-scale reverse osmosis drinking water treatment

The robustness of reverse osmosis (RO) against polar organic micropollutants (MPs) was investigated in pilot-scale drinking water treatment. Experiments were carried in hypoxic conditions to treat a raw anaerobic riverbank filtrate spiked with a mixture of thirty model compounds. The chemicals were selected from scientific literature data based on their relevance for the quality of freshwater systems, RO permeate and drinking water. MPs passage and the influence of permeate flux were evaluated with a typical low-pressure RO membrane and quantified by liquid chromatography coupled to high-resolution mass spectrometry. A strong inverse correlation between size and passage of neutral hydrophilic compounds was observed. This correlation was weaker for moderately hydrophobic MPs. Anionic MPs displayed nearly no passage due to electrostatic repulsion with the negatively charged membrane surface, whereas breakthrough of small cationic MPs could be observed. The passage figures observed for the investigated set of MPs ranged from less than 1%-25%. Statistical analysis was performed to evaluate the relationship between physicochemical properties and passage. The effects of permeate flux were more pronounced for small neutral MPs, which displayed a higher passage after a pressure drop.

Combining the assessment of apical endpoints and gene expression in the freshwater snail Physa acuta after exposure to reclaimed water

Post-treatment wastewater reuses are diverse. Recreational and environmental restoration uses of reclaimed water (RW) can be potentially harmful to aquatic organisms. In this work the freshwater snail Physa acuta was exposed to RW (100%) and its dilution (RW 50%). A simple laboratory mixture of three emerging pollutants was used to address the complex problem of mixture toxicity of RW. Hence fortified reclaimed water (FRW), obtained by adding fluoxetine (400 μg FLX/L), perfluorooctane sulphonic acid (90 μg PFOS/L) and methylparaben (9 μg MP/L), was tested at two dilution percentages: 100% and 50%. The effects of the laboratory mixture of FLX, PFOS and MP on the test medium were also studied. Long-lasting effects, together with early molecular responses, were assessed. Fecundity (cumulative egg production) over 21 days and the hatching of produced eggs (F1) after another 21-day embryonic exposure were monitored. The gene expression of three genes was analysed after 24 h of exposure: two endocrine-related nuclear receptors (ERR and RXR) and one stress protein gene (Hsp70). This reproduction test, with additional assessments of the F1 recovered eggs' hatching success, showed that both RW and FRW significantly reduced fecundity. F1 hatching was affected only by FRW. The gene expression results showed that the RXR response was strikingly similar to the fecundity response, which suggests that this nuclear receptor is involved in the reproductive pathways of gastropods. ERR remained virtually unaltered. Hsp70 was overexpressed by the laboratory mixture in the test medium, but no effect was observed in the fortification of RW. This opposite effect and lack of response for F1 hatching produced by the laboratory mixture in the test medium highlighted the difficulty of predicting mixture effects. The experimental approach allowed us to test the effects caused by RW on P. acuta at different biological organisation levels. Thus, the combination of molecular biomarkers and ecological relevant endpoints is a good strategy to test complex mixtures like RW as it provides a framework to link mechanisms of action and whole organism effects when it is almost impossible to detect the pollutant(s) that cause toxic effects.

Perfluoroalkyl Substances in Water from the Yangtze River and Its Tributaries at the Dividing Point Between the Middle and Lower Reaches

The Yangtze River drainage basins are China's most important economic development zones and also the locations of several large-scale fluorine chemical industries. In order to reveal the contribution from the tributaries at the dividing point between the middle and lower reaches of the Yangtze River with respect to perfluorinated substances (PFASs), 17 PFAS compounds in surface water, groundwater, and tap water samples were analyzed in the tributary system of the Jiujiang section of the Yangtze River. The total concentrations of PFASs in the surface waters ranged from 7.8 to 586.2 ng/L. High proportion of short-chain compound PFBS in surface waters in Nanchang City, Poyang Lake, and the Yangtze River was observed which is likely of WWTPs' origin.

Worldwide Distribution of Novel Perfluoroether Carboxylic and Sulfonic Acids in Surface Water

Driven by increasingly stringent restrictions on long-chain per- and polyfluoroalkyl substances (PFASs), novel fluorinated compounds have emerged on the market. Here we report on the occurrences of several perfluoroalkyl ether carboxylic and sulfonic acids (PFECAs and PFESAs), including hexafluoropropylene oxide dimer and trimer acids (HFPO-DA and HFPO-TA), ammonium 4,8-dioxa-3 H-perfluorononanoate (ADONA), chlorinated polyfluorinated ether sulfonic acid (6:2 Cl-PFESA), and its hydrogen-substituted analogue (6:2 H-PFESA) in surface waters from China ( n = 106), the United States ( n = 12), the United Kingdom ( n = 6), Sweden ( n = 10), Germany ( n = 14), The Netherlands ( n = 6), and Korea ( n = 6). Results showed that HFPO-DA, HFPO-TA, and 6:2 Cl-PFESA (median = 0.95, 0.21, and 0.31 ng/L, respectively) were frequently detected in all countries, indicating ubiquitous dispersal and distribution in global surface waters. The presence of 6:2 H-PFESA was widely detected in China (detection rate > 95%) but not in any other country. Only trace levels of ADONA (0.013-1.5 ng/L) were detected in the Rhine River flowing through Germany. The estimated total riverine mass discharges of HFPO-DA, HFPO-TA, and ΣPFESAs reached 2.6, 6.0, and 4.3 ton/year in five of the major river systems in China. Our results indicated that novel PFECAs and PFESAs might become global contaminants, and future investigations are warranted.

Role of the Nrf2-ARE pathway in perfluorooctanoic acid (PFOA)-induced hepatotoxicity in Rana nigromaculata

Perfluorooctanoic acid (PFOA) is widely distributed in various environmental media and is toxic to organisms. This study demonstrated that PFOA induces hepatotoxicity in the frog and evaluated the role of CYP3A and the Nrf2-ARE signaling pathway in regulating responses to PFOA-induced hepatotoxicity. Rana nigromaculata were exposed to 0, 0.01, 0.1, 0.5, or 1 mg/L PFOA solutions in a static-renewal system for 14 days. Liver tissue samples were collected 24 h after the last treatment. Hepatic histology was observed by HE staining and transmission electron microscopy. The oxidative stress levels in the liver were measured. The expression levels of CYP3A, Nrf2, NQO1, and HO-1 mRNA were measured by quantitative reverse transcription-polymerase chain reaction. PFOA-treated frog liver tissue exhibited diffuse cell borders, cytoplasmic vacuolization, broken nuclei, nuclear chromatin margination, and swollen mitochondria. In addition, the livers of PFOA-treated frogs showed a significantly elevated content of reactive oxygen species, malondialdehyde, glutathione and glutathione S-transferase activity compared to the livers of control frogs. However, the glutathione peroxidase activities concomitantly decreased in PFOA-treated frogs compared to those in the control group. Furthermore, compared with control frogs, the expression levels of CYP3A, Nrf2, and NQO1 mRNA significantly increased in PFOA-treated frogs. HO-1 mRNA expression remarkably increased only in groups treated with 0.5 or 1 mg/L PFOA. Our results indicate that PFOA induces hepatotoxicity in a dose-dependent manner. Furthermore, the results of the comparison analysis between different gender groups illustrated that PFOA is more toxic to female frogs than male frogs. Our results demonstrated that PFOA causes liver damage and that CYP3A enhances PFOA-induced female frogs hepatotoxicity are more virulent than male through biotransformation, and the activation of the Nrf2-ARE pathway is induced to protect against hepatotoxicity in Rana nigromaculata, all of which provide the scientific basis for the protection of amphibians against environmental contaminants.

Distribution of perfluorinated compounds (PFASs) in the aquatic environment of the industrially polluted Vaal River, South Africa

Perfluorinated alkyl substances (PFASs) are highly persistent chemicals, which have a bioaccumulative potential and can be found in wildlife around the world. Although multiple studies have been performed on PFASs pollution of the aquatic environment, little is known on PFASs pollution on the African continent and their possible risks for human health. In the present study, we examined the distribution of 15 PFASs in fish, invertebrates, sediment and water, collected at three sites, representing a gradient of industrial and mining pollution, along the Vaal River, South Africa. Furthermore, possible risks for human health through consumption of contaminated fish were examined. Perfluorooctane sulfonate (PFOS) was the most dominant PFAS measured in biota, whereas perfluoropentanoic acid (PFPeA) was measured in higher concentrations in water. Mean PFAS concentrations in water ranged from <LOQ to 38.5ng/L. PFAS concentrations in water decreased along the gradient and were similar or lower compared to other studies in Europe, Asia and America. PFAS measurements in sediment were <LOQ, with the exception of PFOS at Thabela Thabeng (2.36ng/g dry weight (dw)). Average ∑PFAS concentrations in biota increased along the gradient and ranged from <LOQ to 34.5ng/g wet weight (ww) in invertebrates, <LOQ to 289ng/g ww in liver and <LOQ to 34.0ng/g ww in muscle tissue. Although PFOS concentrations were relatively high compared to literature, concentrations of other PFASs were rather low. A potential risk for humans through consumption of PFAS-contaminated fish was assessed. Tolerable daily intake values (grams of fish that can be eaten daily without risking health effects) were much lower than the average South African fish consumption per day, implying a potential risk for human health through consumption of PFAS contaminated fish. CAPSULE: Concentrations of perfluorinated compounds in water, sediment, fish and invertebrates from the Vaal River were low or intermediate and posed a potential risk for human health through consumption of contaminated fish.

Circulating levels of perfluoroalkyl substances and left ventricular geometry of the heart in the elderly

AIMS

Some persistent organic pollutants (POPs) such as hexachlorobenzene (HCB) and some polychlorinated biphenyls (PCBs) have been shown to interfere with myocardial function and geometry. We therefore investigated if also another group of POPs: per- and polyfluoroalkyl substances (PFASs) were associated with alterations in left ventricular geometry.

METHODS

801 subjects aged 70 years were investigated in a cross-sectional study within the scope of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Eight PFASs were detected in >75% of participants´ plasma by ultra-performance liquid chromatograph/tandem mass spectrometry. Left ventricular geometry was determined by echocardiography. Multivariable linear regression was used to investigate the associations between PFASs and left ventricular geometry of the heart after exclusion of subjects with previous myocardial infarction (n = 72).

RESULTS

When adjusting for multiple comparisons, none of the eight PFASs evaluated were significantly related to left ventricular mass. However, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA) were related to relative wall thickness (RWT) in a negative fashion (p < 0.0021). Besides being inversely related to RWT, PFNA was also positively related to left ventricular end-diastolic volume (LVEDD) (p < 0.0021). These analyses were adjusted for traditional cardiovascular risk factors.

CONCLUSION

In this cross-sectional study, several of the PFASs evaluated, especially PFNA, were related to myocardial geometry: a reduction in relative wall thickness and an increase in left ventricular diameter following adjustment for traditional cardiovascular risk factors, suggesting a role for PFASs in cardiac remodeling.

Validation and determination of nine PFCS in surface water and sediment samples using UPLC-QTOF-MS

In this study, an analytical method for the routine determination of nine perfluorinated compounds (PFCs), using ultra performance liquid chromatography coupled to a quadrupole time-of-flight mass spectrometer (UPLC-QTOF-MS), was developed, validated, and used for their assay in surface water and sediments. The method yielded good linearity with a correlation coefficient (R²) ranging between 0.991 and 0.999 for all the compounds investigated. Limits of detection (LOD) ranged between 0.02 and 0.08 ng/l, while the limit of quantification (LOQ) ranged from 0.065 to 0.261 ng/l. Recovery studies were carried out in replicate assays, and percentage recoveries ranged between 56 and 112% for the nine perfluorinated compounds investigated. The method was applied to determine levels of perflurooctanoic acid (PFOA) and PFOS in surface water and sediment samples collected along the Plankenburg River in Stellenbosch, South Africa. Samples were pre-treated, extracted, and cleaned up via offline solid-phase extraction (SPE) procedures, using hydrophilic-lipophilic balance (HLB) C-18 cartridges. Levels of PFOA and PFOS found in surface water ranged between (12.8 ± 4.24 and 62.62 ± 4.86 ng/l) and (<LOD and 3.8 ng/l), respectively, while levels measured in corresponding sediment samples ranged between 0.14-0.33 ng/g (PFOA) and <LOD and 0.7 ± 0.013 ng/g (PFOS). Concentrations of PFOA and PFOS were suspected to be associated with anthropogenic activities in the vicinity of the sampling areas.

Risk exposure assessment of per- and polyfluoroalkyl substances (PFASs) in drinking water and atmosphere in central eastern China

We examined per- and polyfluoroalkyl substances (PFASs) in air from eight cities, and in water from six drinking-water treatment plants (DWTPs), in central eastern China. We analyzed raw and treated water samples from the DWTPs for 17 ionic PFASs with high-performance liquid chromatography/negative-electrospray-ionization tandem mass spectrometry (HPLC/(-)ESI-MS/MS), and analyzed the gas and particle phases of atmospheric samples for 12 neutral PFASs by gas chromatography-mass spectrometry (GC-MS). Perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) were the dominant compounds in drinking water, and fluorotelomer alcohols (FTOHs) dominated in atmospheric samples. Of all the compounds in the treated water samples, the concentration of PFOA, at 51.0 ng L^-1, was the highest. Conventional treatments such as coagulation (COA), flocculation (FOC), sedimentation (SED), and sand filtration (SAF) did not remove PFASs. Advanced treatments, however, including ultrafiltration (UF) and activated carbon (AC), removed the majority of PFASs except for shorter-chain PFASs such as perfluorobutanoic acid (PFBA) and perfluoropentanoic acid (PFPA). We also investigated human exposure to PFASs via drinking water and the atmosphere and found that the mean daily intake of PFASs was 0.43 ng kg^-1 day^-1.

Occurrence and Partition of Perfluorinated Compounds (PFCs) in Water and Sediment from the Songhua River, China

This study provided the first evidence that perfluorinated compounds (PFCs) were widely detected in the Songhua River, China. Seventeen surface water and sediment samples were collected and analyzed for the determination of 14 PFCs. The total concentrations of PFCs (Σ PFCs) ranged from 0.143 to 1.41 ng L^-1 in water samples. Perfluorooctanoic acid (PFOA) was detected with the highest detection frequency (%) ranging from below LOQ to 0.678 ng L^-1. Σ PFCs were relatively low in sediments, and only four individual homologues were detected. Perfluorooctane sulfonate (PFOS) and PFOA were detected with the lowest levels in this study compared with other PFCs detected in all the rivers of China in previous studies. The concentrations of PFCs were highly influenced by distribution of wastewater treatment plants (WWTPs). The effluents from WWTPs, which are discharged into the Songhua River, are regarded as the main contamination sources of PFCs in this study. Even though low risk for the concentrations of PFOS and PFOA to aquatic ecosystem of the Songhua River was found in the analysis of potential adverse effect, further experimental studies on occurrence of PFCs and their potential adverse effects to wildlife and humans should be conducted continuously in the Songhua River basin because of the increasing discharge. The mean partition coefficients (log K _oc) of PFOS between sediment and water was 4.49 cm³ g^-1, which was probably influenced by the sediment characteristics and hydrodynamic parameters. PFCs tend to accumulate in water compared with other persistent organic pollutants.

Distribution profiles of per- and poly fluoroalkyl substances (PFASs) and their re-regulation by ocean currents in the East and South China Sea

We investigated the distribution of 17 individual per- and polyfluoroalkyl substances (PFASs) in 42 surface water samples collected from the East and South China Seas (7.0-36.0°N, 110.0°N-123.0°E). Concentrations of 7 individual PFASs, including perfluorobutane sulfonate (PFBS), perfluorohexane sulfonate (PFHxS), perfluoropentanoic acid (PFPA), perfluorohexanoate (PFHxA), perfluoroheptanoate (PFHpA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonamide (FOSA), were quantified in the East China Sea, but only concentrations of PFOA and FOSA were quantified in the South China Sea. The total concentrations of the 17 PFASs ranged from 181 to 2658pg/L in the East China Sea and from 62 to 494pg/L in the South China Sea. We also show that river fluxes and ocean currents had a strong influence on the distribution of PFASs in the East China Sea. Using ArcGIS 10.1, we show how ocean currents control the spatial distribution of PFOA in the central South China Sea.

Perfluoroalkyl and polyfluoroalkyl substances in the lower atmosphere and surface waters of the Chinese Bohai Sea, Yellow Sea, and Yangtze River estuary

Polyfluoroalkyl and perfluoroalkyl substances (PFASs), in the forms of neutral polyfluoroalkyl substances in the gas phase of air and ionic perfluoroalkyl substances in the dissolved phase of surface water, were investigated during a sampling campaign in the Bohai Sea, Yellow Sea, and Yangtze River estuary in May 2012. In the gas phase, the concentrations of neutral ∑PFASs were within the range of 76-551pg/m³. Higher concentrations were observed in the South Yellow Sea. 8:2 fluorotelomer alcohol (FTOH) was the predominant compound as it accounted for 92%-95% of neutral ∑PFASs in all air samples. Air mass backward trajectory analysis indicated that neutral ∑PFASs came mainly from the coast of the Yellow Sea, including the Shandong, Jiangsu, and Zhejiang provinces of China, and the coastal region of South Korea. The fluxes of gas phase dry deposition were simulated for neutral PFASs, and neutral ∑PFASs fluxes varied from 0.37 to 2.3pg/m²/s. In the dissolved phase of the surface water, concentrations of ionic ∑PFASs ranged from 1.6 to 118ng/L, with the Bohai Sea exhibiting higher concentrations than both the Yellow Sea and the Yangtze River estuary. Perfluorooctanoic acid (PFOA) was the predominant compound accounting for 51%-90% of the ionic ∑PFAS concentrations. Releases from industrial and domestic activities as well as the semiclosed geographical conditions increased the level of ionic ∑PFASs in the Bohai Sea. The spatial distributions of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) were different significantly. The Laizhou Bay was the major source region of PFCAs and the Yangtze River estuary was the major source of PFSAs.

Investigation of Perfluoroalkyl Substances (PFASs) in Sediments from the Urban Lakes of Anqing City, Anhui Province, China

Fifteen individual perfluoroalkyl substances (PFASs) were analyzed in 22 sediment samples collected from Anqing urban lakes (Anhui province, China) by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Total PFAS concentration was between 0.61 and 26 ng g^- 1 dry weight. Perfluorooctane sulfonate (PFOS) was the dominant PFAS contaminant, with a concentration range of < 0.040-13 ng g^- 1. Results indicated higher total PFAS concentrations in lakes located to the northwest of Anqing City than in other regions. Adjacent chemical and industrial factories were hypothesized to be responsible for these higher PFAS levels in those lakes. In comparison to other measurements obtained from other lakes, PFAS concentrations in the urban lakes of Anqing City were relatively high.

Long-Chain Perfluoroalkyl acids (PFAAs) Affect the Bioconcentration and Tissue Distribution of Short-Chain PFAAs in Zebrafish (Danio rerio)

Short- and long-chain perfluoroalkyl acids (PFAAs), ubiquitously coexisting in the environment, can be accumulated in organisms by binding with proteins and their binding affinities generally increase with their chain length. Therefore, we hypothesized that long-chain PFAAs will affect the bioconcentration of short-chain PFAAs in organisms. To testify this hypothesis, the bioconcentration and tissue distribution of five short-chain PFAAs (linear C-F = 3-6) were investigated in zebrafish in the absence and presence of six long-chain PFAAs (linear C-F = 7-11). The results showed that the concentrations of the short-chain PFAAs in zebrafish tissues increased with exposure time until steady states reached in the absence of long-chain PFAAs. However, in the presence of long-chain PFAAs, these short-chain PFAAs in tissues increased until peak values reached and then decreased until steady states, and the uptake and elimination rate constants of short-chain PFAAs declined in all tissues and their BCF_ss decreased by 24-89%. The inhibitive effect of long-chain PFAAs may be attributed to their competition for transporters and binding sites of proteins in zebrafish with short-chain PFAAs. These results suggest that the effect of long-chain PFAAs on the bioconcentration of short-chain PFAAs should be taken into account in assessing the ecological and environmental effects of short-chain PFAAs.

Distribution characteristics of poly- and perfluoroalkyl substances in the Yangtze River Delta

In this work, a method was developed and optimized for the analysis of polyfluoroalkyl and/or perfluoroalkyl substances (PFASs) content in surface water and sediment samples with high instrumental response and good separation. Surface water and sediment samples were collected from the Yangtze River Delta (YRD) to analyze the distribution characteristics of perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkane sulfonic acids (PFSAs), perfluoroalkyl phosphonic acids (PFPAs), perfluoroalkyl phosphinic acids (PFPiAs), and polyfluoroalkyl phosphoric acid diesters (diPAPs). The results showed that the total concentrations of PFCAs and PFSAs in YRD varied from 31 to 902ng/L. PFCAs (≥11 carbons) and PFSAs (≥10 carbons atoms) were not detected in any surface water samples. The mean concentrations of all PFCAs and PFSAs in surface water from the sampling areas decreased in the following order: Yangtze river (191ng/L)≈Taihu lake (189ng/L)>Huangpu river (122ng/L)≈Qiantang river (120ng/L)>Jiaxing urban river (100ng/L). Strong significant (p<0.05) correlations between the concentrations of many of the compounds were found in the sampling areas, suggesting a common source for these compounds. Only perfluorooctanoic acid (PFOA) was observed in all sediment samples, at concentrations varying from 0.02 to 1.35ng/g. Finally, detection rates of two diPAPs were only 8% and 10%, respectively and the concentration of diPAPs was two to three times lower compared to PFCAs and PFSAs.

Global distribution of perfluorochemicals (PFCs) in potential human exposure source-A review

Human exposure to perfluorochemicals (PFCs) has attracted mounting attention due to their potential harmful effects. Breathing, dietary intake, and drinking are believed to be the main routes for PFC entering into human body. Thus, we profiled PFC compositions and concentrations in indoor air and dust, food, and drinking water with detailed analysis of literature data published after 2010. Concentrations of PFCs in air and dust samples collected from home, office, and vehicle were outlined. The results showed that neutral PFCs (e.g., fluorotelomer alcohols (FTOHs) and perfluorooctane sulfonamide ethanols (FOSEs)) should be given attention in addition to PFOS and PFOA. We summarized PFC concentrations in various food items, including vegetables, dairy products, beverages, eggs, meat products, fish, and shellfish. We showed that humans are subject to the dietary PFC exposure mostly through fish and shellfish consumption. Concentrations of PFCs in different drinking water samples collected from various countries were analyzed. Well water and tap water contained relatively higher PFC concentrations than other types of drinking water. Furthermore, PFC contamination in drinking water was influenced by the techniques for drinking water treatment and bottle-originating pollution.

Characterization of occurrence, sources and sinks of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in a tropical urban catchment

Understanding the sources, occurrence and sinks of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in the urban water cycle is important to protect and utilize local water resources. Concentrations of 22 target PFASs and general water quality parameters were determined monthly for a year in filtered water samples from five tributaries and three sampling stations of an urban water body. Of the 22 target PFASs, 17 PFASs were detected with a frequency >93% including PFCAs: C4-C12 perfluoroalkyl carboxylates, C4, C6, C8, and C10 perfluoroalkane sulfonates, perfluorooctane sulfonamides and perfluorooctane sulfonamide substances (FOSAMs), C10 perfluoroalkyl phosphonic acid (C10 PFPA), 6:2 fluorotelomer sulfonic acid (6:2 FTSA) and C8/C8 perfluoroalkyl phosphinic acid (C8/C8-PFPIA). The most abundant PFASs in water were PFBS (1.4-55 ng/L), PFBA (1.0-23 ng/L), PFOS (1.5-24 ng/L) and PFOA (2.0-21 ng/L). In the tributaries, PFNA concentrations ranged from 1.2 to 87.1 ng/L except in the May 2013 samples of two tributaries, which reached 520 and 260 ng/L. Total PFAS concentrations in the sediment samples ranged from 1.6 to 15 ng/g d.w. with EtFOSAA, PFDoA, PFOS and PFDA being the dominant species. Based on water and sediment data, two types of sources were inferred: one-time or intermittent point sources and continuous non-point sources. FOSAMs and PFOS released continually from non-point sources, C8/C8 PFPIA, PFDoA and PFUnA was released from point sources. The highly water soluble short-chain PFASs including PFBA, PFPeA and PFBS remained predominantly in the water column. The factors governing solution phase concentrations appear to be compound hydrophobicity and sorption to suspended particles. Correlation of the dissolved phase concentrations with precipitation data suggested stormwater was a significant source of PFBA, PFBS, PFUnA and PFDoA. Negative correlations with precipitation indicated sources feeding FOSAA and FOSA directly into the tributaries.

Perfluoroalkyl substances in waters along the Grand Canal, China

The Grand Canal, also known as the Beijing-Hangzhou Grand Canal, is a UNESCO World Heritage Site and the longest canal in the world. It is an important trunk line of the South-to-North Water Diversion Project in China. The contamination status and spatial distributions of perfluoroalky substances (PFASs) in waters of the Grand Canal were investigated. The total concentrations of PFASs (∑PFASs) range from 7.8 ng/L to 218.0 ng/L, with high ∑PFASs occurring in the southern part of the Grand Canal which is located in a highly urbanized and economically developed region. The dominance of PFOA showed a decreasing trend toward north while shorter chain homologue proportions increased in the northern part of the Canal which mainly traverses underdeveloped and rural areas in Eastern China. Positive correlations were observed between ∑PFASs and the population density as well as GDP per capita. Intersection with large rivers may affect the contamination levels and composition of PFASs in the water of the Grand Canal near the intersection sites.

Spatiotemporal distribution and potential sources of perfluoroalkyl acids in Huangpu River, Shanghai, China

Perfluoroalkyl acids (PFAAs) have been found to be ubiquitously disseminated in the environment due to their widespread use in recent decades. In this study, the occurrence and spatiotemporal distribution of PFAAs in the surface water of Huangpu River, Shanghai, China were investigated from 2012 to 2014. The total concentration of 14 PFAAs (ΣPFAAs) ranged from 39.8 to 596.2 ng L^-1, with a mean value of 226.3 ng L^-1. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) were dominant, with their mean concentrations of 139.6 and 46.5 ng L^-1, respectively. The concentration of ΣPFAAs increased greatly downstream especially in the lower reach of an industrial and urbanized area. Samples collected in different seasons were used to analyze the seasonal variation. The results showed that higher concentration of ΣPFAAs occurred in the wet season, especially downstream. Therefore, industrial discharges, municipal wastewater and surface runoff were identified as major potential sources. The annual discharge load of ΣPFAAs from Huangpu River to Yangtze River was estimated to be 2263.4 kg yr^-1. The hazard assessment suggested that the contamination of PFAAs in Huangpu River could pose risks to the aquatic environment and drinking water safety, which should draw more attention.

Removal of PFOA and PFOS from aqueous solutions using activated carbon produced from Vitis vinifera leaf litter

The removal of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) from aqueous solutions using agro-waste biomass of Vitis vinifera (grape) leaf litter was studied. Activated carbons were produced from the biomass and chemical activation achieved by using phosphoric acid (H₃PO₄) and potassium hydroxide (KOH) for the modification of the carbons' surface morphology. Activated carbons were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy and Brunauer-Emmett-Teller (BET) in order to understand removal mechanisms of the contaminants by activated carbons. The effect of solution concentration, pH, adsorbent dosage, contact time and temperature was evaluated to optimize the removal efficiency of activated carbons. Adsorption isotherm models were used to analyse the equilibrium data obtained, and kinetic models were applied to study sorption mechanisms. The results fitted well into Freundlich isotherm with both AC-KOH and AC-H₃PO₄ having high K _f values. Maximum adsorption capacities for AC-H₃PO₄ were 78.90 and 75.13 mg/g for PFOA and PFOS, respectively. Equilibrium was reached before 60 min on both adsorbents, and thermodynamic studies indicated that the process was exothermic and spontaneous. Surface morphology showed the abundance of microspores (>60%) with BET total surface area of 295.488 and 158.67 m²/g for AC-H₃PO₄ and AC-KOH activated carbons, respectively. Removal efficiencies were 95 and 90% for PFOA using AC-H₃PO₄ and AC-KOH, respectively; corresponding values for PFOS were 94 and 88%. Adsorbents' removal capacities depended on the physicochemical characteristics of adsorbents.

Perfluoroalkyl acids (PFAAs) in sediments from rivers of the Pearl River Delta, southern China

Having been largely used in industrial and household products, perfluoroalkyl acids (PFAAs) appear in environmental and biological systems with prevalence and persistence and have raised great concern in recent years. The present study is aimed at studying concentrations and composition profiles of 16 PFAAs in surface sediments collected from 51 sampling locations in 4 main rivers of the Pearl River Delta, one of the economy-developed areas in China. The total PFAA concentrations (∑ PFAAs) were determined in a wide range of 1.89-15.1 ng g^-1 dw (dry weight) with an average concentration to be 3.54 ng g^-1 dw. Higher ∑ PFAAs were observed in the downstream of Dongjiang River and the Pearl River, possibly due to the discharge of industrial wastewater. Perfluoropentanoic acid (PFPeA) and perfluorooctane sulfonate (PFOS) were the dominant PFAAs, accounting for 51 to 85% of ∑ PFAAs in 27% of the samples. High PFPeA concentrations in sediments of urban river were scarcely observed in previous studies worldwide. The sources of short-chain perfluoroalkyl carboxylic acids (PFCAs) were significantly different from those of other PFAAs. Preliminary hazard assessment proved negligible for PFOS, perfluorooctanoic acid (PFOA), PFPeA, and perfluorohexanoic acid (PFHxA) concentrations in sediments from rivers of the Pearl River Delta.

Perfluoroalkyl acids (PFAAs) in water and sediment from the coastal regions of Shandong peninsula, China

Perfluoroalkyl acids (PFAAs) have been observed in various environmental matrices globally in recent years. In this study, the levels, spatial distribution tendencies, and partitioning characteristics of the target 12 PFAAs were investigated in water and sediment from the coastal regions of Shandong peninsula in China, and two sediment core samples were also collected to study the vertical and historical variation of PFAAs. The ranges (means) of total PFAA concentrations were 23.69-148.48 ng/L (76.11 ng/L) in the water and 1.30-11.17 ng/g (5.93 ng/g) in the surface sediment, respectively. Among the target 12 PFAAs, perfluorooctanoic acid (PFOA) was the dominant component in water, followed by perfluorooctane sulfonate (PFOS) and perfluorohexanoic acid (PFHxA). PFOS, perfluoroundecanoic acid, and PFOA were the dominant components in sediment. For their spatial distribution, higher levels of PFAAs were found at the locations close to much developed cities. The PFAA concentrations showed an overall decreasing tendency with depth increase in the two sediment cores, which indicates that the extent of PFAAs pollution is aggravating trend in recent years. Results of the partition coefficient (K _d ) show that the compounds with longer carbon chains (C ≥ 7) generally had higher K _d values, which suggest that long-chain PFAAs are prone to be adsorbed by sediment. In addition, the Log K _d of PFHxA, PFOA, and PFOS were significantly and positively correlated to the salinity of the water. The results of risk assessment suggest appreciable risk of PFAAs to the local ecosystem.

Identify biosorption effects of Thiobacillus towards perfluorooctanoic acid (PFOA): Pilot study from field to laboratory

The concentration of Perfluoroalkyl acids (PFAAs) and the bacterial community composition along the Xiaoqing River were explored with HPLC-MS/MS and Illumina high-throughput sequencing in present study. The results showed that perfluorooctanoic acid (PFOA) was the predominant PFAAs in all sediment samples, and high level of PFOA could lead to an evident increase in the abundance of Thiobacillus. Thiobacillus was identified with the survival ability in high concentrations of PFOA accordingly. Therefore, Thiobacillus thioparus and Thiobacillus denitrificans were selected as receptors to design indoor biosorption experiment. The growth curves under different PFOA concentrations and residual rates of PFOA in the processes of cultivation were analyzed. The results showed that upwards concentrations of PFOA below 5000 ng/L led to an obvious increase in the growth rate of T. thioparus. Whereas PFOA promoted the growth of T. denitrificans in a relatively limited range of concentration, and the effect was not obvious. The addition of different concentrations of PFOA had no apparent effects on pH values in the media of both T. thioparus and T. denitrificans. The concentrations of PFOA in liquid media reduced after the process of bacteria culturing. The removal rates of T. thioparus and T. denitrificans to PFOA were 21.1-26.8% and 13.5-18.4%, respectively. The current findings indicated that T. thioparus could play a significant role as potential biosorbent with the ability to eliminate PFOA effectively in aquatic environment, which would provide novel information for PFOA ecological decontamination and remediation.

Perfluorinated alkyl substances in serum of the southern Chinese general population and potential impact on thyroid hormones

In this study, eight perfluorinated alkyl substances (PFASs) and five thyroid hormones (TSH, FT4, FT3, TGAb, and TMAb) were determined in 202 human serum samples of the general population of Guangdong, Guangxi and Hainan provinces in southern China. Σ₈PFASs concentrations ranged from 0.85 to 24.3 ng/mL with a mean value of 4.66 ng/mL. The PFASs composition profiles of human serum samples nearly make no difference at different locations. A significant increase was observed for ∑₈PFASs, PFOS, and PFHxS concentrations with age (p < 0.01). Gender-related differences were found; PFOS, PFHxS, PFBS, and PFOA levels were higher in males (p < 0.05), and the mean concentration of ∑₈PFASs was 1.5 times greater in males (6.02 ng/mL) than in females (4.15 ng/mL). PFOS and ∑₈PFASs were significantly negatively correlated with FT3 and FT4 and positively correlated with TSH while PFPeA and PFHxA were significantly positively correlated with TGAb and TMAb in all the samples. The opposite associations between FT3, TSH and PFOS, PFOA and PFHxS levels in hypothyroidism and hyperthyroidism group indicate that the PFOS, PFOA and PFHxS enhance the negative feedback mechanisms of the thyroid gland.

A nationwide survey of perfluorinated alkyl substances in waters, sediment and biota collected from aquatic environment in Vietnam: Distributions and bioconcentration profiles

Water, sediment, various tissues of fish, crustacean, gastropod and bivalve were collected from major river basins in Vietnam and analyzed for the presence of perfluorinated alkyl substances (PFASs). Furthermore, the occurrence of PFASs in coastal, tap and well waters collected from eight different regions in Vietnam was investigated. PFOA and PFOS were consistently detected as the dominant PFASs in surface waters. The greatest concentrations of PFOA (53.5ngL^-1) and PFOS (40.2ngL^-1) were found in a surface water sample collected from a channel that receives wastewater treatment plant discharges. PFOS and PFHxS were found as the predominant PFASs in sediments. The greatest PFAS concentration in biota was 16.9ng PFUnDA g^-1 wet weight found in a fish liver. Some long-chain PFCAs including PFNA, PFUnDA and PFTrDA as well as PFHxS were more abundant than short-chain PFASs in biota tissues. The measured concentrations of PFOS and PFOA in surface and tap waters were below the provisional health advisory. The rank order of mean bioconcentration factor of PFOS in biota was; crustacean (115L/kg), gastropod (1117L/kg), fish (1120L/kg) and bivalve (2110L/kg). This study provides baseline information for a better understanding of PFASs contamination in Vietnam.

Concentrations of select dissolved trace elements and anthropogenic organic compounds in the Mississippi River and major tributaries during the summer of 2012 and 2013

The Mississippi River drainage basin includes the Illinois, Missouri, Ohio, Tennessee, and Arkansas rivers. These rivers drain areas with different physiography, population centers, and land use, with each contributing a different suites of metals and wastewater contaminants that can affect water quality. In July 2012, we determined 18 elements (Be, Rb, Sr, Cd, Cs, Ba, Tl, Pb, Mg, Al, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) and chlorophyll-a (Chl-a) in the five major tributaries and in the Upper Mississippi River. The following summer, we determined both trace elements and 25 trace organic compounds at 10 sites in a longitudinal study of the main stem of the Mississippi River from Grafton, Illinois to Natchez, Mississippi. We detected wastewater contaminants, including pharmaceuticals and endocrine disrupting compounds, throughout the river system, with the highest concentrations occurring near urban centers (St. Louis and Memphis). Concentrations were highest for atrazine (673 ng L^-1), DEET (540 ng L^-1), TCPP (231 ng L^-1), and caffeine (202 ng L^-1). The Illinois, Missouri, and Yazoo rivers, which drain areas with intense agriculture, had relatively high concentrations of Chl-a and atrazine. However, the Ohio River delivered higher loads of contaminants to the Mississippi River, including an estimated 177 kg day^-1 of atrazine, due to higher flow volumes. Concentrations of heavy metals (Ni, V, Co, Cu, Cd, and Zn) were relatively high in the Illinois River and low in the Ohio River, although dissolved metal concentrations were below US EPA maximum contaminant levels for surface water. Multivariate analysis demonstrated that the rivers can be distinguished based on elemental and contaminant profiles.

Oxidative Damage and Cytotoxicity of Perfluorooctane Sulfonate on Chlorella vulgaris

We studied the effects of perfluorooctane sulfonate (PFOS) on the chlorophyll content, cell permeability, and antioxidant defense systems of the green alga Chlorella vulgaris. The results showed that the production of reactive oxygen species increased in a concentration-dependent manner after exposure to PFOS for 96 h. Superoxide dismutase and catalase activity was elevated after exposure to the lower concentrations and then decreased with higher concentrations. Malondialdehyde content was significantly higher than that of controls at the higher PFOS concentrations. Cell membrane permeability increased. These results indicate that PFOS exposure leads to oxidative damage in C. vulgaris. At these concentrations, chlorophyll and the structure of chloroplasts were destroyed.

Occurrence investigation of perfluorinated compounds in surface water from East Lake (Wuhan, China) upon rapid and selective magnetic solid-phase extraction

Using a novel magnetic nanocomposite as adsorbent, a convenient and effective magnetic solid-phase extraction (MSPE) procedure was established for selective separation and concentration of nine perfluorinated compounds (PFCs) in surface water sample. Then an ultra high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) system was employed for detection of PFCs. Good linearity of the developed analytical method was in the range of 0.5-100 ng L^-1 with R² > 0.9917, and the limits of detection (LODs) ranged from 0.029 to 0.099 ng L^-1. At three fortified concentrations of 0.5, 5 and 50 ng L^-1, the spiked recoveries of PFCs were in the range of 90.05-106.67% with RSDs < 12.62% (n = 3). The proposed analytical method was applied for determination of PFCs in surface water from East Lake (Wuhan, China). The total concentrations of nine PFCs ranged from 30.12 to 125.35 ng L^-1, with perfluorooctane sulfonate and perfluoroctanoic acid as the most prevalent PFCs, and the greatest concentrations of PFCs were observed in Niuchao lakelet. The concentrations of the PFCs (C ≥ 11) were mostly less than the limits of quantification (LOQs), attributed to the possibility that the more hydrophobic long-chain PFCs are potential to accumulate in sediment and aquatic biota.