Distribution of perfluorinated compounds in water, sediment, biota and floating plants in Baiyangdian Lake, China

Tissue distribution of emerging per- and polyfluoroalkyl substances in wild fish species from Qiantang river, east China: Comparison of 6:2 Cl-PFESA with PFOS

This study argued for the first time that 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and perfluorooctanesulfonic acid (PFOS) might have different tissue distribution mechanisms in wild fish species. Nine emerging and legacy per- and polyfluoroalkyl substances (PFASs) were detected in the water and wild fish tissues samples collected from the Qiantang River. Perfluorooctanoic acid (213 ng/L) was the predominant PFAS contaminant, and the other contaminants included perfluorohexanoate (19 ng/L), perfluorobutanoate (199 ng/L) and hexafuoropropylene oxide dimer acid (55 ng/L), which are the main fluorinated alternatives used in various industries located along the Qiantang River. Furthermore, PFOS (742 ng/g) and 6:2 Cl-PFESA (9.0 ng/g) were the predominant PFAS contaminants detected in the fish tissue samples. The differences in the potential molecular mechanism of the tissue distribution of PFOS and 6:2 Cl-PFESA in wild fish species are discussed. Additionally, we hypothesize that phospholipid partitioning is the primary mechanism underlying the tissue distribution of PFOS, and that a specific protein-binding mechanism is involved in the tissue distribution of 6:2 Cl-PFESA.

Poly- and perfluoroalkyl substances (PFASs) in amphibians and reptiles - exposure and health effects

Poly- and perfluoroalkyl substances (PFASs) are commonly used in various industries and everyday products, including clothing, electronics, furniture, paints, and many others. PFASs are primarily found in aquatic environments, but also present in soil, air and plants, making them one of the most important and dangerous pollutants of the natural environment. PFASs bioaccumulate in living organisms and are especially dangerous to aquatic and semi-aquatic animals. As endocrine disruptors, PFASs affect many internal organs and systems, including reproductive, endocrine, nervous, cardiovascular, and immune systems. This manuscript represents the first comprehensive review exclusively focusing on PFASs in amphibians and reptiles. Both groups of animals are highly vulnerable to PFASs in the natural habitats. Amphibians and reptiles, renowned for their sensitivity to environmental changes, are often used as crucial bioindicators to monitor ecosystem health and environmental pollution levels. Furthermore, the decline in amphibian and reptile populations worldwide may be related to increasing environmental pollution. Therefore, studies investigating the exposure of amphibians and reptiles to PFASs, as well as their impacts on these organisms are essential in modern toxicology. Summarizing the current knowledge on PFASs in amphibians and reptiles in a single manuscript will facilitate the exploration of new research topics in this field. Such a comprehensive review will aid researchers in understanding the implications of PFASs exposure on amphibians and reptiles, guiding future investigations to mitigate their adverse effects of these vital components of ecosystems.

Ecotoxicity of perfluorooctanoic acid and perfluorooctane sulfonate on aquatic plant Vallisneria natans

Perfluorinated compounds (PFCs) are persistent organic contaminants that are highly toxic to the environment and bioaccumulate, but their ecotoxic effects on aquatic plants remain unclear. In this study, the submerged plant Vallisneria natans was treated with short-term (7 days) and long-term (21 days) exposures to perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) at concentrations of 0, 0.01, 0.1, 1.0, 5.0, and 10 mg/L, respectively. The results showed that both high concentrations of PFOA and PFOS inhibited the growth of V. natans and triggered the increase in photosynthetic pigment content in leaves. The oxidative damage occurred mainly in leaves, but both leaves and roots gradually built up tolerance during the stress process without serious membrane damage. Both leaves and roots replied to short-term stress by activating superoxide dismutase (SOD), catalase (CAT) and polyphenol oxidase (PPO), while peroxidase (POD) was involved under high concentration stress with increasing exposure time. Leaves showed a dose-effect relationship in integrated biomarker response (IBR) values under short-term exposure, and the sensitivity of roots and leaves to PFOS was higher than that of PFOA. Our findings help to increase knowledge of the toxic effects of PFCs and have important reference value for risk assessment and environmental remediation of PFCs in the aquatic ecosystem.

Per- and polyfluoroalkyl substances (PFAS) in grocery store foods: method optimization, occurrence, and exposure assessment

Dietary exposure to per- and polyfluoroalkyl substances (PFAS) is poorly understood. Evaluating PFAS in food is complicated by the need to evaluate varied matrices and a lack of a standard, matrix-specific sample extraction methods. Prior food studies implemented universal rather than matrix-specific extraction approaches, which may yield false negatives and an underestimation of PFAS dietary exposure if methods are not suitable to all matrices. Here the objectives were to screen and optimize PFAS extraction methods for plants, tissues, and dairy; apply optimized extraction methods to a grocery store food survey; and compare estimated exposure to published reference doses (RfDs). Optimized, matrix-specific extractions generally yielded internal standard recoveries of 50-150% and matrix spike recoveries of 70-130%. The frequency of PFAS detection in grocery store foods (16 of 22 products) was higher than in previous work. PFAS were detected at concentrations of 10 ng kgdw-1 (perfluorobutane sulfonate; washed green beans and perfluorohexanoic acid; unwashed tomato) to 2680 ng kgdw-1 (perfluorohexane sulfonate; radish). Concentrations of perfluorooctanoic acid (PFOA) in carrots, lettuce, radish, and canned green beans yielded median exposure intake (EI) values of 0.016-0.240 ng per kgbw-day, which exceeded the EPA RfD (0.0015 ng per kgbw-day). Washing reduced radish PFOA concentrations below detection, but EIs at the reporting limit still exceeded the RfD. The combination of improved data quality and greater frequency of PFAS detection vs. prior studies plus EI > RfD for some PFAS suggests a need for matrix-specific extractions and analysis of PFAS in additional grocery store foods from broader geographic regions.

Distribution and potential health risks of perfluoroalkyl substances (PFASs) in water, sediment, and fish in Dongjiang River Basin, Southern China

Per- and polyfluoroalkyl substances (PFASs) have attracted worldwide attention due to their high stability, refractory degradation, and bioaccumulation. The Dongjiang River is one of the most important water sources in the Pearl River Delta region. It flows from Jiangxi Province to Guangdong Province and finally into the Pearl River, providing domestic water for cities such as Guangzhou, Shenzhen, and Hong Kong. In this study, 17 PFASs in water, sediment, and fish in the Dongjiang River Basin in southern China were investigated using high-performance liquid chromatography-mass spectrometry. Total PFAS concentrations ranged from 20.83 to 372.8 ng/L in water, from 1.050 to 3.050 ng/g in sediments, and from 12.28 to 117.4 ng/g in fish. Among six species of fish, Oreochromis mossambicus (mean: 68.55 ng/g) had the highest concentration of PFASs, while Tilapia zillii (36.90 ng/g) had the lowest concentration. Perfluorooctanoic acid (PFOA) predominates in water and sediments, while perfluorooctanesulfonic acid (PFOS) predominates in fish. Long-chain perfluorocarboxylates (PFCAs) and perfluorosulfonates (PFSAs) showed higher bioaccumulation, and the field-sourced sediment-water partition coefficients (Kd) and bioaccumulation factors (BAFs) of PFASs increased with the length of perfluorocarbon chains. PFAS concentration in the lower reaches (urban area) of the Dongjiang River is higher than that in the upper and middle reaches (rural area). The calculated hazard ratio (HR) of PFOS and PFOA levels in fish in the Dongjiang River Basin was far less than 1; hence, the potential risk to human health was limited.

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

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

Per- and polyfluoroalkyl substances (PFASs) in groundwater from a contaminated site in the North China Plain: Occurrence, source apportionment, and health risk assessment

Per-and polyfluoroalkyl substances (PFASs) are manmade chemicals that have wide industrial and commercial application. However, little research has been carried out on PFASs pollution in groundwater from a previously contaminated site. Here, we investigated 43 PFASs in a monitoring campaign from two different aquifers in the North China Plain. Our results revealed that total PFASs concentrations (∑₄₃PFASs) ranged from 0.22 to 3,776.76 ng/L, with no spatial or compositional differences. Moreover, perfluorooctanoic acid (PFOA) and perfluoroheptane sulfonate (PFHpS) were the dominant pollutants with mean concentrations of 177.33 ng/L and 51 ng/L, respectively. ∑₄₃PFAS decreased with well depth due to the adsorption of PFASs to the aquifer materials. Water temperature, total organic carbon, dissolved oxygen, and total phosphorus concentrations were correlated to the PFAS concentrations. Principal component analysis indicated that the main sources of PFASs in groundwater were untreated industrial discharge, untreated domestic wastewater, food packaging, aqueous film forming foams and metal plating, and surface runoff, which overlapped with the industries that previously existed in a nearby city. Human health risks from drinking contaminated groundwater were low to the local residents, with children aged 1-2 years being the most sensitive group. One specific site with a high PFOA concentration was of concern, as it was several orders higher than the 70 ng/L recommended by US Environmental Protection Agency health advisory. This study provided baseline data for PFASs in a previously-contaminated site, which will help in the development of effective strategies for controlling PFASs pollution in the North China Plain.

Plant uptake of perfluoroalkyl substances in freshwater environments (Dongzhulong and Xiaoqing Rivers, China)

This study provides new knowledge on the mobility, behavior, and partitioning of 17 perfluoroalkyl substances (PFASs) in the water-sediment-plant system along the Dongzhulong and Xiaoqing Rivers. The fate of PFASs in these rivers is also discussed. The study area is affected by the industrial production of perfluorooctanoic acid (PFOA). The ∑PFASs in water and sediments close to the industrial discharge were 84,000 ± 2000 ng/L and 2300 ± 200 ng/g dw, respectively, with the concentrations decreasing along the river due to dilution. PFOA was the dominant compound (74-97% of the ∑PFASs), although other PFASs were identified close to urban areas. Principal component analysis and solid-liquid distribution coefficients revealed that long-chain PFASs accumulated in the sediment whereas short-chain PFASs remained in the water all along the river. PFASs were taken up by plants and remobilized to different plant compartments according to shoot concentration factors (SCFs), root concentration factors (RCF), and transfer factors (TFs). Among the four plant species studied, floating plants absorbed high levels of PFASs, while rooted species translocated short-chain PFASs from the roots to the shoots. Therefore, floating species, due to their high uptake capacity and large proliferation rate, could eventually be used for phytoremediation.

Estimating the dietary exposure and risk of persistent organic pollutants in China: A national analysis

Substantial heterogeneities have been found in previous estimations of the risk from dietary exposures to persistent organic pollutants (POPs) in China, mainly due to spatiotemporal variations. To comprehensively evaluate the dietary risks of POPs listed in the Stockholm Convention, more than 27,580 data records from 753 reports published over the last three decades were examined. Respectively, for various food categories, the results obtained for the range of mean concentrations of POPs are as follows: total dichlorodiphenyltrichloroethanes (DDTs: 1.4-27.1 μg/kg), hexachlorocyclohexanes (HCHs: 1.8-29.3 μg/kg), polybrominated diphenyl ethers (PBDEs: 0.046-2.82 μg/kg), polychorinated biphenyls (PCBs: 0.05-7.57 μg/kg), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD&Fs: 2.9-210 pg toxic equivalent (TEQ)/kg), perfluorooctanoic acid (PFOA: 0.02-0.97 μg/kg), perfluoroctane sulfonate (PFOS: 0.00082-2.76 μg/kg) and short-chain chlorinated paraffins (SCCPs: 64-348.92 μg/kg). Temporal decreasing trends were observed for DDTs, HCHs, PBDEs, PCDD&Fs, and PFOA, with no significant change for other POPs. Meanwhile, the estimated daily intake for adults were 75.2 ± 43.6 ng/kg/day for DDTs, 123 ± 87 ng/kg/day for HCHs, 0.37 ± 0.17 pg TEQ/kg/day for PCDD&Fs, 17.8 ± 9.5 ng/kg/day for PCBs, 3.3 ± 1.8 ng/kg/day for PBDEs, 3.6 ± 1.9 ng/kg/day for PFOA, 3.3 ± 2.0 ng/kg/day for PFOS, and 2.5 ± 1.6 μg/kg/day for SCCPs. Furthermore, non-carcinogenic risks were the highest for PCBs (0.89) and PCDD&Fs (0.53), followed by PFOA (0.18), PFOS (0.17), HCHs (0.062), SCCPs (0.025), DDTs (0.0075), and PBDEs (0.00047). These findings illustrated that exposure to POPs declined due to the control policies implemented in China, while the cumulative risk of POPs was still higher than 1, indicating continuous efforts are required to mitigate associated contamination.

Bioaccumulation, Biodistribution, Toxicology and Biomonitoring of Organofluorine Compounds in Aquatic Organisms

This review is a survey of recent advances in studies concerning the impact of poly- and perfluorinated organic compounds in aquatic organisms. After a brief introduction on poly- and perfluorinated compounds (PFCs) features, an overview of recent monitoring studies is reported illustrating ranges of recorded concentrations in water, sediments, and species. Besides presenting general concepts defining bioaccumulative potential and its indicators, the biodistribution of PFCs is described taking in consideration different tissues/organs of the investigated species as well as differences between studies in the wild or under controlled laboratory conditions. The potential use of species as bioindicators for biomonitoring studies are discussed and data are summarized in a table reporting the number of monitored PFCs and their total concentration as a function of investigated species. Moreover, biomolecular effects on taxonomically different species are illustrated. In the final paragraph, main findings have been summarized and possible solutions to environmental threats posed by PFCs in the aquatic environment are discussed.

Concentration, spatial distribution, and health risk assessment of PFASs in serum of teenagers, tap water and soil near a Chinese fluorochemical industrial plant

Discharges released from fluorochemical industrial plants lead to severe contamination of the environment with per- and polyfluoroalkyl substances (PFASs), which may pose risks to human health. In this study, 187 serum samples from teenagers (age = 14 years), 22 tap water samples and 40 soil samples were collected in areas within 0-11 km of a fluorochemical industrial plant in Huantai County, Shandong Province, and concentrations of 18 PFASs were quantified by UPLC-MS/MS. Perfluorooctanoic acid (PFOA) was found to be predominant, concentrations of which ranged from 40.4 to 845 ng/mL in serum, from 2.88 to 19.3 ng/L in tap water, from 4.40 to 189 ng/g in soil, and accounting for 84.1-98.6%, 15.9-79.8%, and 73.8-96.7% of the total PFASs, respectively. Statistical analysis demonstrated that concentrations of perfluorinated carboxylic acids (PFCAs) in soil (C5-C9) and serum (C8-C10) were associated with the industrial plant. And PFOA concentrations in tap water were not relevant to the industrial plant, which were comparable with the non-contaminated area and lower than the threshold value recommended by U.S. EPA (70 ng/mL), indicating that the contribution to the high concentration of serum PFOA of local teenagers by drinking water was limited. Moreover, PFCAs in soil only made a limited contribution to the serum PFCAs of local residents by direct inhalation and dermal exposure, but the potential health risk by the soil via food chain should be paid attention to. Furthermore, health risk assessment demonstrated that high concentrations of PFOA in serum could pose potential health risk to local teenagers. Therefore, effective measures should be taken to attenuate the health risks caused by the industrial plant to local residents, and further epidemiological studies should be carried out in the future.

Occurrence, partition and environmental risk assessment of per- and polyfluoroalkyl substances in water and sediment from the Baiyangdian Lake, China

This work examined the contamination of poly- and perfluorinated compounds (PFASs) in the water and sediment of the Baiyangdian Lake. The total concentration of PFASs in the surface water varied from 140.5 to 1828.5 ng/L, and the highest concentration of PFASs were observed near the entrance of Fuhe river. The topmost contaminant was sodium perfluorohexanesulfonate (PFHxS) and perfluorooctanoic acid (PFOA) in the north and south of the Baiyangdian Lake respectively, which indicated different contamination sources. The total concentration of PFASs in the sediment varied from 0.48 to 30 ng/g, and the distribution of PFASs in the sediment was similar with that in the surface water. The concentrations of polyfluoroalkyl phosphoric diesters (diPAPs) were three to four orders of magnitude lower than those of perfluorocarboxylates (PFCAs) and PFSAs. Although the pore water and the surface water had similar ΣPFASs, the concentration of perfluorodecanoic acid (PFDA) in pore water was 1.4 to 4.4 times higher than that in surface water, and the concentration of perfluoropentanoic acid (PFPeA) in pore water was 20–70% that in surface water. The results of ecological risk assessment showed that the PFASs were currently of no immediate risk to the aquatic life.

Legacy and emerging persistent organic pollutants in the freshwater system: Relative distribution, contamination trends, and bioaccumulation

In this study, a comprehensive investigation was performed to understand the overall occurrence, relative distribution, and bioaccumulation of seven different groups of POPs, comprising 27 polybrominated diphenyl ethers (PBDEs), 76 polychlorinated biphenyls (PCBs), 23 organochlorine pesticides (OCPs), three hexabromocyclododecanes (HBCDs), and 13 perfluoroalkyl substances (PFASs) as legacy POPs, and 41 polychlorinated naphthalenes (PCNs) and 24 short-chain chlorinated paraffins (SCCPs) as emerging POPs, by monitoring crucian carp, sediment, and river water in the freshwater system. Among the targeted POPs, SCCPs were predominant in sediment and crucian carp (more than 95%), while a dominance of PFASs was observed in river water (92%). Principal component analysis revealed four different groups/patterns of POPs in all media: one for PBDEs, PCBs, and OCPs, another for HBCDs and PFASs, and the two others for PCNs and SCCPs. Also, sexually dimorphic growth-dependent accumulation of legacy POPs was observed in crucian carp such that POPs concentration increased with increasing fish size and males recorded significantly higher levels of POPs compared to females.

Concentration and distribution of per- and polyfluoroalkyl substances (PFAS) in the Asan Lake area of South Korea

Seasonal and spatial variations in per- and polyfluoroalkyl substances (PFAS) concentrations in different environmental media in the Asan Lake area of South Korea were investigated by measuring liquid chromatography-tandem mass spectrometry (LC-MS/MS). The mean concentrations of Σ₁₆ PFAS in the different media were in the ranges of 20.7-98.2 pg/m³ in air, 17.7-467 ng/L in water, 0.04-15.0 ng/g dry weight (dw) in sediments, and not detected (n.d.)-12.9 ng/g dw in soils, and the mean concentrations of Σ₁₉ PFAS in fish ranged from n.d. to 197 ng/g wet weight. The most frequently detected PFAS were perfluorooctanoic acid (PFOA) in air and soils, perfluoropentanoic acid (PFPeA) in water, and perfluorooctane sulfonate (PFOS) in sediment and fish. Long-chain PFAS species dominated over short-chain PFAS in most media samples except for the water phase. Sediment-water partition coefficients (log K_d) and bioaccumulation factors (log BAF) of PFAS were calculated using measured concentrations in water, sediments, and fish. Log K_d of PFAS tended to increase with increasing CF₂ units of PFAS, and perfluorodecanoic acid (PFDA) and PFOS showed the highest log BAF value (> 3.0) in all fish species. These results indicate that longer-chain PFAS, especially PFOS, can be effectively accumulated in biota such as fish.

Quinolones antibiotics in the Baiyangdian Lake, China: Occurrence, distribution, predicted no-effect concentrations (PNECs) and ecological risks by three methods

The occurrence, distribution, and ecological risk of 10 quinolones (QNs) were investigated in the water and sediment samples from Baiyangdian Lake, China. The field samplings were conducted in April (dry season) and August (wet season) 2018, the results showed that QNs was extensively distributed in the Baiyangdian Lake. For the occurrence, Flumequine (FLU) and Ofloxacin (OFL) were the most detected QNs in Baiyangdian Lake. For the temporal variation, the sum concentration of QNs in water and sediment were ranged from 153 ng/L to 3093 ng/L and from 40.1 ng/g to 1475 ng/g in April, while ranged from 3.83 ng/L to 769 ng/L and from 20.3 ng/g to 373 ng/g in August. For the spatial variation, all of QNs exhibited significance difference in concentration at different sampling areas. Furthermore, PNEC plays an important role in ecological risk assessment, thus the PNECs of FLU and OFL were derived by assessment factors (AF), species sensitivity distribution (SSD), and AQUATOX model methods. The results showed that: PNEC_AFs, PNEC_SSDs, and PNEC_AQUATOXs were 18.7 μg/L, 196 μg/L, and 128 μg/L for FLU, respectively; and were 0.021 μg/L, 4.40 μg/L, and 3.00 μg/L for OFL, respectively. The PNECs for FLU and OFL derived by three approaches showed the rank of: PNEC_SSDs > PNEC_AQUATOXs > PNEC_AFs; while the risk quotients (RQs) followed the other rank of: RQ_SSDs < RQ_AQUATOXs < RQ_AFs. The results was indicated that the indirect ecological effects plays an important role in the derived PNECs for QNs, without considering the indirect ecological effects in natural ecosystem can lead to under-protective or over-protective PNECs (RQs) for chemicals. Therefore, AQUATOX model can be applied in deriving PNECs during the ecological risk assessment.

Increasing perfluoroalkyl substances and ecological process from the Yongding Watershed to the Guanting Reservoir in the Olympic host cities, China

Perfluoroalkyl substances (PFASs) have raised great attention, particularly in regions of rapid urbanization. Zhangjiakou and Beijing will jointly host the Winter Olympic Games in 2022, which will likely increase local PFASs pollution and their associated risks over the coming period. In this study, we identified ecological process of PFASs, including sources, environmental fate, and risks, from the Yongding Watershed to the Guanting Reservoir. The concentrations of total 12 PFASs in water of the Guanting Reservoir were higher than that from the Yongding Watershed, with mean of 48.9 and 33.7 ng/L, respectively. The concentrations of PFASs in sediment of the Yongding Watershed and the Guanting Reservoir were similar, with mean of 1.01 and 0.827 ng/g dry weight, respectively. Detected levels of PFASs in the Guanting Reservoir significantly increased during the past eight years, possibly due to an improving economy and a rapidly developed service industry. Moderate PFASs levels in fish of the Guanting Reservoir were detected relative to other lakes and reservoirs. The daily intake of PFASs via fish and water ranged from 4.96 to 15.0 ng/kg bw/day, with higher levels found in children relative to adults. In total, approximately 9.06 kg of PFASs from riverine flow and atmospheric deposition annually entered the Guanting Reservoir. PFASs from the Yongding River significantly contributed to the pollution of Guanting Reservoir, with predominance of perfluorobutanoic acid (PFBA) in water, and long-chain perfluorinated carboxylic acids (PFCAs) and perfluorooctane sulfonate (PFOS) in sediment in both the Yongding Watershed and the Guanting Reservoir. Most of the PFASs (23.5 kg) were stored in water of the Guanting Reservoir, while the annual storage of PFASs in sediment and fish was only 4.68 × 10^-2 kg and 4.36 × 10^-2 kg via deposition and accumulation, respectively. The results suggest that water quality management of the Yongding Watershed is necessary for effective control on PFASs pollution in the Guanting Reservoir.

High contamination, bioaccumulation and risk assessment of perfluoroalkyl substances in multiple environmental media at the Baiyangdian Lake

The contamination of perfluoroalkyl substances (PFASs) in the Baiyangdian Lake has exacerbated readily since 2008. This study analyzed the perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonic acids (PFSAs) in the surface water, sediment, and fish of the Baiyangdian Lake. In the surface water, the total concentration of PFASs ranged in 1193-3462 ng L^-1 (mean 1734 ng L^-1) in the rainy season and 469-1724 ng L^-1 (mean 876 ng L^-1) in the dry season. The total concentration of PFASs in the sediment ranged in 1.97-13.3 ng g^-1 (mean 6.53 ng g^-1). It was found that PFCAs and PFSAs with longer chains were more easily adsorbed in the sediment. Among the collected fish samples, the enrichment of PFASs in the tissues fell in the order of liver > cheek > muscle. For the muscle, stomach, and liver tissues of the fish samples, significant correlations existed between the δ¹⁵N values and the concentration of perfluorooctane sulfonic acid (PFOS). The contents of PFOS and perfluorooctanoic acid (PFOA) in the fish were not at a level high enough to significantly risk human health.

Are perfluoroalkyl substances in water and fish from drinking water source the major pathways towards human health risk?

Due to potential adverse effects and bioaccumulation in biota and humans, perfluoroalkyl substances (PFASs) have raised wide attention in recent years. Ingestion is a vital pathway for PFASs to transmit to humans especially through water and fish. In present study, PFASs in water and fish from the drinking water source of Beijing in China were investigated. Three layers of water were collected in order to find the connection between concentrations of PFASs and depth of water, which showed no prominent correlation. PFASs in water from Miyun Reservoir with concentrations of 5.30-8.50 ng/L, were relatively lower compared with other reports on raw drinking water. Perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) were the dominant PFASs. In addition, six species of fish (including Cyprinus carpio, Carassius auratus, Erythroculter dabryi, Pseudohemiculter dispar, Hypophthalmichthys molitrix and Siniperca chuatsi) were analyzed, with concentrations of PFASs ranging from 1.70 to 14.32 ng/g wet weight (w.w.). Due to relatively stronger bioaccumulation potential, long chain perfluorinated carboxylates (PFCAs) and perfluorinated sulfonates (PFSAs) were detected with higher concentrations, especially perfluoroundecanoic acid (PFUdA) and perfluorodecanoic acid (PFDA). The estimated daily intake (EDI) of PFASs through drinking water and fish consumption were 0.20-0.34 and 3.44-12.61 ng/kg bw/day based on Exposure Factors Handbook of Chinese Population, respectively. In addition, the EDI of high-priority concern PFASs via pork, chicken and dust were also calculated, with value of 0.015-0.043, 0.003-0.013 and 0.074-0.390 ng/kg bw/day, respectively. The total EDI of PFOS and PFOA via diverse pathways were less than suggested tolerable daily intake (PFOS, 150 ng/kg bw/day; PFOA, 1500 ng/kg bw/day), indicating that the detected levels would not cause severe health effects on Beijing residents.

Occurrences, levels and risk assessment studies of emerging pollutants (pharmaceuticals, perfluoroalkyl and endocrine disrupting compounds) in fish samples from Kalk Bay harbour, South Africa

A comprehensive analysis of 15 target chemical compounds (pharmaceuticals and personal care product, perfluoroalkyl compounds and industrial chemicals) were carried out to determine their concentrations in selected commercially exploited, wild caught small and medium sized pelagic fish species and their organs (Thyrsites atun (snoek), Sarda orientalis (bonito), Pachymetopon blochii (panga) and Pterogymnus laniarius (hottentot)) obtained from Kalk Bay harbour, Cape Town. Solid phase extraction (SPE) method based on Oasis HLB cartridges were used to concentrate and clean-up the samples. Liquid chromatography-mass spectrometry analysis of these chemical compounds revealed the simultaneous presence of at least 12 compounds in different parts of the selected fish species in nanogram-per-gram dry weight (ng/g dw) concentrations. The results revealed that perfluorodecanoic acid, perfluorononanoic acid and perfluoroheptanoic acid were the most predominant among the perfluorinated compounds and ranged between: (20.13-179.2 ng/g), (21.22-114.0 ng/g) and (40.06-138.3 ng/g). Also, diclofenac had the highest concentration in these edible fish species out of all the pharmaceuticals detected (range: 551.8-1812 ng/g). The risk assessment values were above 0.5 and 1.0 for acute and chronic risk respectively which shows that these chemicals have a high health risk to the pelagic fish, aquatic organisms and to humans who consume them. Therefore, there is an urgent need for a precautionary approach and the adequate regulation of the use and disposal of synthetic chemicals that persist in aquatic/marine environment in this province and other parts of South Africa, to prevent impacts on the sustainability of our marine environment, livelihood and lives.

Removal of perfluoalkyl acids (PFAAs) through fluorochemical industrial and domestic wastewater treatment plants and bioaccumulation in aquatic plants in river and artificial wetland

The fluorochemical industry has shifted to the production of short chain homologues of perfluoalkyl acids (PFAAs) in recent years. Yet the effective removal of short-chain PFAAs from wastewater is still a major challenge. In this study, the removal efficiencies (RM) of short- and long-chain PFAAs emitted from two fluorochemical industrial parks were evaluated in one industrial and two domestic waste water treatment plants (WWTPs), and bioaccumulation factors (BAF) of PFAAs in various emerged and submerged aquatic plants in adjacent river and an artificial wetland were also calculated. Perfluorobutanoic acid (PFBA), perfluorobutane sulfonic acid (PFBS) and perfluorooctanoic acid (PFOA) were dominant in the whole area. The source water of the fluorochemical industrial WWTP (F-WWTP) gathered from the facilities in Park 2 contained total PFAAs (∑PFAAs) of 5,784 ng/L. Among the four main technologies, the biological aerated filter, combined with upflow sludge bed processes presented the greatest RM of ∑PFAAs in the F-WWTP, respectively. The source water of the wetland from the river brought ∑PFAAs to 21,579 ng/L, emerged plants showed higher BAF of PFBA and PFBS, while lower BAF of PFOA and PFOS than submerged plants. J. serotinus showed both the highest ∑PFAAs and the highest BAF for short chain PFAAs. With the increasing production capacity, this study provided valuable information for risk assessment and management of PFAA emission from point sources.

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.

Effects of fluorescent dissolved organic matters (FDOMs) on perfluoroalkyl acids (PFAAs) in lake and river water

This study presents the effects of fluorescent dissolved organic matters (FDOM) on perfluoroalkyl acids (PFAAs) in western Lake Chaohu and its inflow rivers. The surface water samples from the 27 sites in western Lake Chaohu and its inflow rivers were collected in March and September 2013. The contents of PFAAs and the FDOM in the water samples were measured by a high-performance liquid chromatograph - mass spectrometer (HPLC-MS) and by a fluorescence spectrophotometer, respectively. The temporal-spatial distributions of PFAAs and FDOM, as well as their interrelationships, were investigated. Eleven PFAA components were detected, and the mean concentration of total PFAAs (TPFAAs) in western Lake Chaohu and its inflow rivers were 12.93 ± 5.19 ng/L and 11.84 ± 9.50 ng/L, respectively. PFOA was the predominant contaminant in two regions (7.13 ± 3.07 ng/L and 4.30 ± 2.14 ng/L) followed by PFHxA (1.72 ± 0.80 ng/L and 1.42 ± 1.41 ng/L) and PFBA (1.44 ± 0.78 ng/L and 1.37 ± 0.78 ng/L). The mean concentration of total FDOM in western Lake Chaohu and its inflow rivers were 220.0 ± 40.30 μg quinine sulfate units (Q.S.)/L and 406.3 ± 213.1 μg Q.S./L, respectively. The significant, positive correlations were observed between the PFAAs and FDOMs in both the lake area and the inflow rivers. However, no significant correlation was observed between PFAAs and the dissolved organic carbon (DOC) in the lake area. This finding indicated that the residues and distributions of PFAAs were significantly dependent on the compositions of dissolved organic matters (DOM) and not on the total content of DOM.

Bioaccumulation of perfluoroalkyl substances in marine echinoderms: Results of laboratory-scale experiments with Holothuria tubulosa Gmelin, 1791

Bioaccumulation of six perfluoroalkyl substances (PFAS) was assessed using the marine echinoderm Holothuria tubulosa Gmelin, 1791. Batch experiments were conducted to establish the relationship between concentrations in water, sediment and biota over 197 days. The sample treatment for the determination of compounds involves steps of lyophilization, solvent extraction and clean-up of the extracts with dispersive sorbents. PFAS were then analysed by liquid chromatography-tandem mass spectrometry. During contaminant exposure, detectable levels of compounds were found in all samples collected. Mean concentrations of selected PFAS were higher in sediments than in water samples. This fact is explained by the strong adsorption of these compounds into sediments. Sediment-water distribution coefficients (log Kd) were in the range 0.11 (PFBuA) to 2.46 (PFOA). Beside this, PFAS accumulation was observed in Holothuria tubulosa organisms. The uptake of PFAS was very rapid, reaching the maximum between 22 and 38 days of assay. Bioaccumulation factors (mean log BAF: 1.16-4.39) and biota sediment accumulation factors (mean log BSAF: 1.37-2.89) indicated a high bioaccumulation potential for the target compounds. Both parameters increased with perfluoroalkyl chain length (R2 > 0.93; p < 0.05). In organ-specific distributions of PFAS, greater concentrations were found in intestine than in gonads. Also, male specimens showed higher concentration levels than female (student t-test: tcal = 2.788, ttab = 2.262; p < 0.05). These data provide a detailed accounting of PFAS fate and distribution in the marine environment highlighting accumulation at lower trophic levels, a potential source for contamination in higher organisms.

Elevated concentrations of perfluorohexanesulfonate and other per- and polyfluoroalkyl substances in Baiyangdian Lake (China): Source characterization and exposure assessment

Novel 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) and legacy PFASs, such as perfluorohexane sulfonate (PFHxS), have been used to replace perfluorooctane sulfonate (PFOS), a known persistent organic pollutant. Thus, it is critical to understand these PFOS alternatives regarding their sources and concentrations in the natural environment. In this study, 41 surface water samples as well as edible aquatic organisms were collected from Baiyangdian Lake, the largest freshwater lake in Hebei Province, China. Perfluorooctanoate acid (PFOA) and PFHxS were the predominant PFASs detected in the surface water, reaching concentrations of 8 397.23 ng/L and 1 478.03 ng/L, respectively, with PFHxS accounting for the greatest proportion (∼80.00%) in most water samples. PFHxS (mean: 87.53 ng/g) and PFOS (mean: 35.94 ng/g) were also the most prevalent compounds detected in aquatic organisms. Estimated daily intake (EDI) values of PFOS (16.56 ng/kg bw/d) and PFHxS (16.11 ng/kg bw/d) via aquatic food and drinking water were the highest among PFASs, indicating potential exposure risks to residents. In addition, fish product consumption was the important exposure pathway for residents to PFOA, PFHxS, PFOS, and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA). This study reports on the highest PFHxS levels ever recorded in surface water, suggesting that further quantification of PFHxS in human serum and assessment of its health risks to local residents are warranted and critical.

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.

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.

Geographical trends of PFAS in cod livers along the Norwegian coast

The level of perfluorinated alkyl substances (PFAS) was determined in North East Arctic cod (Gadus morhua) liver samples from 15 Norwegian fjords and harbors. Five harbors in the eastern part of Norway, six harbors in the western part and four harbours in the northern part. A total of 200 samples were analyzed for 16 PFAS. Determination of PFAS were carried out by LC-MS/MS following sample clean up by solid phase extraction and ultracentrifugation. The predominating PFAS was PFOS, which was found to be higher than the level of quantification (1.5 μg kg-1 wet weight) in 72% of the samples. The highest level of PFOS found was 21.8 μg kg-1 wet weight in a sample from Kragerø in the eastern part of Norway. A significantly higher level of PFOS was found in the eastern fjords and harbors compared to fjords and harbors in the western and northern part of Norway. Within the northern fjords and harbors elevated PFOS levels were found in Narvik, which may indicate a local source there. Variations in PFOS of the cod livers thus reflect differences in levels of pollution between the areas.

Influence of the natural colloids on the multi-phase distributions of antibiotics in the surface water from the largest lake in North China

Understanding antibiotic adsorption on natural colloids is crucial for prediction of the behavior, bioavailability and toxicity of antibiotics in natural waters. In the present study, the filtered water (dissolved phase, <0.7μm) was further separated into colloidal phase (1kDa-0.7μm) and soluble phase (<1kDa) by cross-flow ultrafiltration (CFUF), and the spatial-temporal variation and distribution of six antibiotics in multi-phases were investigated in Baiyangdian Lake. Results indicated that antibiotic concentrations differed significantly with sampling location and time. The mean concentrations of antibiotics ranged between 13.65 and 320.44ngL^-1 in the dissolved phase, and the colloidal phase accounted for 4.7-49.8% of all antibiotics, suggesting that natural colloids play an important role as carriers of antibiotics in aquatic environments. Because of the influence of colloids, the partition coefficients of antibiotics between suspended particulate matter (SPM) and soluble phase (intrinsic partition coefficients, K_p^int) were found to be 6.18-109.60% higher than corresponding observed partition coefficients (K_p^obs, between SPM and dissolved phase). The mean partition coefficients between colloidal and soluble phase (K_col.) ranged between 6218 and 117,374Lkg^-1, which were 1-2 orders of magnitude greater than K_p^int values. In order to explore the adsorption mechanism of antibiotics on colloids, Pearson's correlations were performed. The results showed that log K_col. were negatively correlated with cations in natural colloids; especially with Mg (r, -0.643, P<0.01) for oxytetracycline (OTC), and with both Ca (-0.595, P<0.01) and Mg (-0.593, P<0.01) in the case of ofloxacin (OFL). This result revealed that the competitive effect between cations and antibiotics was the main factor influencing the adsorption behavior of antibiotics on natural colloids in the lake.

Ecological effect and risk towards aquatic plants induced by perfluoroalkyl substances: Bridging natural to culturing flora

In the present study, the concentrations and proportions of perfluoroalkyl substances (PFASs) in water and sediments (in different seasons) from the Qing River were investigated. The highest concentration of PFASs in water (207.59 ng L^-1) was found in summer. The composition of PFASs in water changed with time, perfluorobutane sulfonate (PFBS) was the predominant compound in spring and summer, while long-chain PFASs, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), started to increase in autumn and winter. The PFASs concentration in sediments ranged from 0.96 to 4.05 ng g^-1 dw. The proportion of long-chain PFASs was higher than that of short-chain PFASs in sediments, the dominant component in sediments was PFOA with a contribution of 24.6-75.4% to total PFASs in sediments, followed by PFOS. The concentrations of PFASs in roots of emergent plants were relatively higher than those in submerged plants. However, the translocation effect of PFASs was not remarkable. Bioaccumulation factors (BAFs) of the aquatic plants indicated the absorption of PFASs were effective. BAFs in submerged plants basically increased with increasing chain length accordingly. In general, aquatic plants had the absorption preference for long-chain PFASs, especially PFOS, which was the predominant compounds in both submerged and emergent plants. Based on the results above, hornworts were selected to be cultivated indoor in the nutrient solution spiked gradient concentrations of PFOS to assess the general ecological risk. The results revealed that hornworts were resistant to PFOS and might be used as remediation flora to eliminate PFOS contamination.

The Investigation of Perfluorinated Compounds in Surface Waters of the Xixi Wetland, Hangzhou, China

The distribution patterns of perfluorinated compounds (PFCs) in the surface waters of Xixi wetland, China, were investigated for the first time. Among the eight PFCs investigated, only perfluorooctanoic acid (PFOA), perfluoroheptanoic acid (PFHpA) and perfluorononanoic acid (PFNA) were detected. PFOA was the most prominent PFC, and detected in all of the samples with higher PFOA concentrations (maximum: 197.8 ng L^-1), followed by PFHpA (maximum: 3.97 ng L^-1). Geographical differences in PFC levels were not observed among various sampling locations except for the YanShan River location, but seasonal changes have been observed for PFOA. The study suggested that the water diversion project from the Qiantang River to the Xixi Wetland may have significantly contributed to the increase of PFOA level, and that domestic sewage and farmland irrigation runoff are constant pollution sources to the Xixi Wetland.

Perfluoroalkyl Acid Concentrations in Livers of Fox (Vulpes vulpes) and Chamois (Rupicapra rupicapra) from Germany and Austria

The concentrations of 11 perfluorinated alkyl acids (PFAAs) were measured in the livers of foxes (Vulpes vulpes) from Germany, a primarily carnivorous species, and chamois (Rupicapra rupicapra) from Austria, an herbivorous species. Perfluorooctanesulfonate (PFOS) at concentrations [all results refer to wet weight (ww)] of 3.2-320 µg/kg were detected in all 40 fox livers tested, yielding an arithmetic mean of 46.6 µg/kg and a median of 29.8 µg/kg. Long-chain PFAAs were detected at concentrations of 1.7 µg/kg perfluorononanoic acid (PFNA) to 2.4 µg/kg perfluorodecanoic acid (PFDA) and perfluorododecanoic acid (PFDoDA). Of the short-chain PFAAs tested, only perfluorohexanoic acid (PFHxA) was found in 1 fox liver at a concentration of 1.4 µg/kg, and perfluorohexane sulfonate (PFHxS) was found in 2 fox livers at a concentration of 1 µg/kg each. PFOS and PFNA concentrations higher than limit of quantification (LOQ) were detected in 90.9 and 81.8 % of chamois livers, respectively. The arithmetic mean for PFOS concentrations was 2.2 µg/kg (median 2.4 µg/kg), a factor of 21 (median factor of 12) lower than in fox livers. The arithmetic mean for PFNA concentrations was 2.0 µg/kg (median 1.9 µg/kg). Perfluorobutanoic acid, PFHxA, perfluorooctanoic acid, perfluorobutanesulfonate, and PFHxS were not detected at concentrations higher than the LOQ in any of the samples. The various results are compared with one another and with the results of other studies of herbivorous, carnivorous, and omnivorous wild animals. The highest concentrations of PFAA, in particular PFOS, were found in omnivorous animals followed by carnivores. The lowest levels were present in herbivores.

Evaluation of single and joint toxicity of perfluorooctane sulfonate and zinc to Limnodrilus hoffmeisteri: Acute toxicity, bioaccumulation and oxidative stress

Perfluorooctane sulfonate (PFOS) and zinc have been detected in aquatic environment widely. In order to study the combined effects of PFOS and Zn, a series of experiments was conducted to explore the acute mortality, bioaccumulation and antioxidant status of Limnodrilus hoffmeisteri. The acute toxicity was evaluated by calculating 24h-EC50 values, and it was observed that 24h-EC50 values in single and joint treatments decreased with decreasing pH value or increasing exposure concentration. Toxic unit analysis suggested that the combined effects of the PFOS+Zn binary mixture were mostly simple addition, with 8 groups showing synergism and only one group showing antagonism. The analysis of internal Zn and PFOS concentration showed that the possible interaction between Zn and PFOS can affect the bioaccumulation of the two chemicals in L. hoffmeisteri. In addition, oxidative stress status was assessed by measuring oxidation-related biochemical parameters such as superoxide dismutase, glutathione peroxidase and malondialdehyde, and the integrated biomarker response index was estimated to rank the toxicity order. Exposures to Zn and PFOS were found to evoke some changes in the antioxidant defense system, and a strong self-adaptive ability was noticed for L. hoffmeisteri after 10 d exposure.

Exploring the fate, transport and risk of Perfluorooctane Sulfonate (PFOS) in a coastal region of China using a multimedia model

Perfluorooctane Sulfonate (PFOS) and related substances have been widely applied in both industrial processes and domestic products in China. Exploring the environmental fate and transport of PFOS using modeling methods provides an important link between emission and multimedia diffusion which forms a vital part in the human health risk assessment and chemical management for these substances. In this study, the gridded fugacity based BETR model was modified to make it more suitable to model transfer processes of PFOS in a coastal region, including changes to PFOS partition coefficients to reflect the influence of water salinity on its sorption behavior. The fate and transport of PFOS in the Bohai coastal region of China were simulated under steady state with the modified version of the model. Spatially distributed emissions of PFOS and related substances in 2010 were estimated and used in these simulations. Four different emission scenarios were investigated, in which a range of half-lives for PFOS related substances were considered. Concentrations of PFOS in air, vegetation, soil, fresh water, fresh water sediment and coastal water were derived from the model under the steady-state assumption. The median modeled PFOS concentrations in fresh water, fresh water sediment and soil were 7.20ng/L, 0.39ng/g and 0.21ng/g, respectively, under Emission Scenario 2 (which assumed all PFOS related substances immediately degrade to PFOS) for the whole region, while the maximum concentrations were 47.10ng/L, 4.98ng/g and 2.49ng/g, respectively. Measured concentration data for PFOS in the Bohai coastal region around the year of 2010 were collected from the literature. The reliability of the model results was evaluated by comparing the range of modeled concentrations with the measured data, which generally matched well for the main compartments. Fate and transfer fluxes were derived from the model based on the calculated inventory within the compartments, transfer fluxes between compartments and advection fluxes between sub-regions. It showed that soil and costal water were likely to be the most important sinks of PFOS in the Bohai costal region, in which more than 90% of PFOS was stored. Flows of fresh water were the driving force for spatial transport of PFOS in this region. Influences of the seasonal change of fresh water fluxes on the model results were also analyzed. When only seasonal changes of the fresh water flow rates were considered, concentrations of PFOS in winter and spring were predicted to be higher than that under annual average conditions, while the concentrations in summer and autumn were lower. For PFOS fluxes entering the sea, opposite conclusions were drawn compared to the concentrations. Environmental risks from the presence of PFOS in fresh water were assessed for this region through comparison with available water quality criteria values. The predicted concentrations of PFOS in the Bohai coastal region provided by the model were lower than the water quality criteria published by the United States Environmental Protection Agency and Chinese researchers, while the concentrations in more than 80% of the sampling locations exceeded the European Union Water Framework Directive Environmental Quality Standards values. Seasonal variations of flow rate might cause a significant increase in environmental risks.

Assessment on the distribution and partitioning of perfluorinated compounds in the water and sediment of Nansi Lake, China

In this study, the distribution and partitioning of nine perfluorinated compounds (PFCs) in the water and sediment of Nansi Lake were systematically investigated. The total concentration of PFCs was in the range of 38.4-91.4 ng/L in the water and 0.47-1.81 ng/g in the sediment. The concentration of perfluorooctanoic acid (PFOA) was the highest in all the homologues in the water and was in the range of 34.9-84.6 ng/L. However, perfluorooctane sulfonate (PFOS), PFOA, and perfluoroundecanoic acid (PFUnDA) were the predominant PFCs in the sediment, and their levels were similar. The levels of PFOA, PFHpA, PFOS, PFNA, and the total PFCs in the water were relatively higher in the upper region than those in the lower region of Nansi Lake. In the sediment, the levels of PFOA, PFOS, and PFUnDA showed the similar distribution tendency. Industrial wastewater discharged from the cities around Nansi Lake was the main sources of PFCs. The partitioning coefficients (K d ) of PFOA, PFNA, PFDA, and PFOS were in the range of 0.29-0.87, 1.43-2.18, 2.08-3.15, and 2.20-2.80, respectively. Therefore, the log K d of PFDA and PFOS was apparently high as compared to two other compounds. The organic matter content of the sediment had no effect on the partitioning of PFCs between sediment and water in Nansi Lake.

Perfluoroalkyl substances in the Daling River with concentrated fluorine industries in China: seasonal variation, mass flow, and risk assessment

In the present study, we investigated concentrations and composition profiles of perfluoroalkyl substances (PFASs) in surface water from the Daling River in different seasons. The highest concentration of ΣPFASs (9540 ng L(-1)) and dominant homologues were found in surface water collected in summer. Perfluorobutanoic acid (PFBA), perfluorobutane sulfonate (PFBS), and perfluorooctanoic acid (PFOA) were the dominant PFASs in four seasons with a total contribution of over 90%. The discharge of two fluorine chemical industry parks was predicted to be the main contamination source of PFASs in the study area. The daily and annual mass flows were calculated according to data of detected PFAS concentrations and water discharge, and the annual mass loading of PFASs into the Bohai Sea from the Daling River reached to 461 kg year(-1). Hazard assessment indicated that concentrations of PFASs in study area had little risk to aquatic organisms and wildlife. However, the multiple health risk would be relatively high if the water was served as drinking water in the study area.

Nano-Sized Cyclodextrin-Based Molecularly Imprinted Polymer Adsorbents for Perfluorinated Compounds-A Mini-Review

Recent efforts have been directed towards the design of efficient and contaminant selective remediation technology for the removal of perfluorinated compounds (PFCs) from soils, sediments, and aquatic environments. While there is a general consensus on adsorption-based processes as the most suitable methodology for the removal of PFCs from aquatic environments, challenges exist regarding the optimal materials design of sorbents for selective uptake of PFCs. This article reviews the sorptive uptake of PFCs using cyclodextrin (CD)-based polymer adsorbents with nano- to micron-sized structural attributes. The relationship between synthesis of adsorbent materials and their structure relate to the overall sorption properties. Hence, the adsorptive uptake properties of CD-based molecularly imprinted polymers (CD-MIPs) are reviewed and compared with conventional MIPs. Further comparison is made with non-imprinted polymers (NIPs) that are based on cross-linking of pre-polymer units such as chitosan with epichlorohydrin in the absence of a molecular template. In general, MIPs offer the advantage of selectivity, chemical tunability, high stability and mechanical strength, ease of regeneration, and overall lower cost compared to NIPs. In particular, CD-MIPs offer the added advantage of possessing multiple binding sites with unique physicochemical properties such as tunable surface properties and morphology that may vary considerably. This mini-review provides a rationale for the design of unique polymer adsorbent materials that employ an intrinsic porogen via incorporation of a macrocyclic compound in the polymer framework to afford adsorbent materials with tunable physicochemical properties and unique nanostructure properties.

A review of sources, multimedia distribution and health risks of perfluoroalkyl acids (PFAAs) in China

Perfluoroalkyl acids (PFAAs) have been recognized as emerging pollutants because of their ubiquitous occurrence in the environment, biota and humans. In order to investigate their sources, fate and environmental effects, a great number of surveys have been carried out over the past several years. In the present review, we summarized the status of sources and emission, concentration, distribution and risks of PFAAs in China. Concentrations of PFAAs, especially perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in various environmental media including water, sediment, soil, rain, snow and organisms, as well as human tissues are summarized based on the available data. Concentrations of PFAAs in aquatic systems are higher in relatively more industrialized and urbanized areas than those from the less populated and remote regions in China, indicating that their emission and distribution are closely related to regional urbanization and industrialization. PFAAs and related products have been widely used over the past several decades, which have brought about high concentrations detected in environmental matrixes, biota and even local residents. Ecological risk assessment of PFAAs is still less developed in China. Most existing studies compared concentrations of PFAAs to guideline values derived for single species to evaluate the risk. In order to reveal the transport, partitioning and degradation of PFAAs in the environment, further studies on their behavior, fate, bioaccumulation and adverse effects in different trophic levels should be conducted.

Distribution, source characterization and inventory of perfluoroalkyl substances in Taihu Lake, China

The levels, distribution, possible sources, and inventory of perfluoroalkyl acids (PFAAs) in the eutrophic freshwater Taihu Lake, East China were investigated in this study. Among the target 11 PFAAs, perfluorooctanoic acid (PFOA) (2.15-73.9 ng L(-1)) and perfluorohexanoic acid (PFHxA) (<LOQ-22.2 ng L(-1)) were the dominant components in surface water, followed by perfluorooctanesulfonic acid (PFOS) with the maximum concentration of 10.5 ng L(-1). PFOS was also dominant (0.13-6.95 ng g(-1) dw) in the sediments, accounting for 15-85% of ΣPFAAs concentrations in 70% of the sediment samples. Sediment-water partitioning coefficients showed that logKOC increased linearly with the increasing chain length, with the logKOC values increased by 0.1-0.4 log unit with each CF2 moiety from C8 to C12 perfluorinated carboxylic acids. Three specific molecular ratios, PFOS/PFOA, PFOA/PFNA and PFHpA/PFOA were used to characterize the potential sources. It indicated that the majority of pollutants was from direct emissions from manufacturing processes. The PFOA/PFNA ratios between 1.7 and 56.8 in surface water suggested the influence of secondary sources such as the degradation of volatile precursor substances. Given the high ratios of PFHpA/PFOA (0.05-7.93), it also indicated the influence from atmospheric deposition to the epilimnion. The predicted environmental concentrations were calculated from European Union system for the evaluation of substances model (EUSES). As expected, the predicted environmental concentration (PEC) of PFOS in sediment fit well to the monitored level of PFOS in this region, and the inventory of ΣPFCA and PFOS were estimated to be 989 kg and 646 kg in Taihu Lake.

Occurrence and fate of perfluoroalkyl substances in marine sediments from the Chinese Bohai Sea, Yellow Sea, and East China Sea

In this study, 166 surface sediments and 3 sediment cores from the Bohai Sea (BS), Yellow Sea (YS) and East China Sea (ECS) in China were collected to investigate the spatial and temporal distributions and the transport of PFASs. PFASs concentrations in the surface sediments ranged from below detection limit (<LOD) to 2.78 ng g(-1) with an average value of 0.55 ng g(-1) on a dry weight basis (dw). A general decreasing trend of PFASs from the coast areas to the open sea was found. Multivariate regression analysis indicated pH and longitude were the major factors influencing surficial distributions of PFASs in the sampling areas (R(2) = 0.29, p < 0.01). Total PFASs concentrations in the sediment cores ranged from <LOD to 1.65 ng g(-1) dw, with an increasing trend from the lower to the upper layers, corresponding well to the increasing production and usage in China in recent years.

Distribution of perfluoroalkyl substances (PFASs) with isomer analysis among the tissues of aquatic organisms in Taihu Lake, China

The distribution of perfluoroalkyl substances (PFASs) and the isomers of perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) was investigated among various tissues (including muscle, gill, kidney, liver) and eggs, in aquatic organisms in Taihu Lake, China. Highest concentration of ΣPFASs was mostly found in liver (278-685 ng/g ww) and eggs (66.0-467 ng/g ww) while the lowest was in muscle (40.6-165 ng/g ww). n-PFOS was the predominant PFOS isomer in most of the tissues with a proportion of 46.3-96.5%. Ratios of PFAS concentrations in eggs to those in liver (E/L) increased positively with the protein-water partition coefficient. The E/L of PFOS isomers descended in the order: linear > monomethyl > diperfluoromethyl isomers. The liver/muscle and kidney/muscle ratios of n-PFOS were higher than branched isomers, suggesting that n-PFOS has higher binding affinity with hepatic proteins or branched isomers are preferentially excreted though liver and kidney.

Endocrine disruption effects of long-term exposure to perfluorodecanoic acid (PFDA) and perfluorotridecanoic acid (PFTrDA) in zebrafish (Danio rerio) and related mechanisms

Perfluoroalkyl acids (PFAAs) have been frequently detected in both the environment and biota, however the endocrine disruption potentials and underlying mechanism of long-chain PFAAs have not yet been fully understood in fish. In the present study, the effects of perfluorodecanoic acid (PFDA) and perfluorotridecanoic acid (PFTrDA) on sex steroid hormones and expression of mRNA of selected genes in hypothalamic-pituitary-gonad (HPG) axis were evaluated after 120 d exposure of zebrafish. In addition, production of sex hormones and transcription of steroidogenic genes were measured after in vitro exposure of H295R cells for 48 h. Exposure to PFTrDA resulted in reduced production of testosterone (T) along with lesser expression of CYP17A mRNA in H295R cells. In zebrafish, significant up-regulation of vtg1 was observed in males exposed to PFDA, whereas down-regulation was observed in females exposed to PFTrDA. In male zebrafish, concentrations of 17β-estradiol (E2) were significantly increased at 0.01 mg L(-1) PFTrDA. Significant increases in ratios of E2/T and E2/11-ketotestosterone (11-KT) were observed in male zebrafish after exposure to PFDA or PFTrDA, indicating estrogenic potentials of these compounds. The results of this study showed that long-term exposure to PFDA or PFTrDA could modulate sex steroid hormone production and related gene transcription of the HPG axis in a sex-dependent manner. Consequences of endocrine disruptions in reproduction performances of the fish warrant further investigation.

High levels of perfluoroalkyl acids in sport fish species downstream of a firefighting training facility at Hamilton International Airport, Ontario, Canada

A recent study reported elevated concentrations of perfluorooctane sulfonic acid (PFOS) and other perfluoroalkyl acids (PFAAs) in surface water, snapping turtles, and amphipods in Lake Niapenco, downstream of Hamilton International Airport, Ontario, Canada. Here, our goals were to 1) determine the extent of PFAA contamination in sport fish species collected downstream of the airport, 2) explore if the airport could be a potential source, and 3) compare fish PFOS concentrations to consumption advisory benchmarks. The PFOS levels in several sport fish collected from the three locations closest to the airport (<40km) were among the highest previously published in the peer-reviewed literature and also tended to exceed consumption benchmarks. The only other fish that had comparable concentrations were collected in a region affected by inputs from a major fluorinated chemical production facility. In contrast, PFOS concentrations in the two most downstream locations (>70km) were comparable to or below the average concentrations in fish as observed in the literature and were generally below the benchmarks. With regards to perfluorocarboxylates (PFCAs), there was no significant decrease in concentrations in fish with distance from the airport and levels were comparable to or below the average concentrations observed in the literature, suggesting that the airport is not a significant source of PFCAs in these fish species. PFOS-based aqueous film-forming foam (AFFF) was used at a firefighting training facility at the airport in the 1980s to mid-1990s. Taken together, our results provide evidence that the historical use of AFFF at the airport has resulted in fish PFOS concentrations that exceed the 95th percentile concentration of values reported in the literature to date.

Seasonal variation and sediment-water exchange of antibiotics in a shallower large lake in North China

The occurrence of four antibiotics, including oxytetracycline (OTC), tetracycline (TC), norfloxacin (NOR) and ofloxacin (OFL), in surface water, overlying water, pore water and sediment samples were studied in the Baiyangdian Lake from February to November in 2009. The total concentrations of these antibiotics ranged among 17.73-281.82, 22.98-258.45, 22.43-198.95 ng L(-1) and 131.65-750.27 ng g(-1) in surface water, overlying water, pore water and sediments, respectively. Seasonal variation might be impacted by the frequency of different pattern of antibiotics and the water temperatures of different seasons, where the higher concentrations appeared at different seasons. In addition, the regions with significant sewage discharge or human agricultural activities exhibited high concentrations of antibiotics in water and sediments. The highest accumulation rates of the four antibiotics ranged from 11.27 to 29.71%, which indicated that these compounds exhibited strong adsorption to the sediment. However, higher concentrations of antibiotics in pore water and even overlying water may result in the release of these compounds from the sediment acting as a secondary contaminant source in a certain time period, especially for TC. The pseudo-partitioning values of fluoroquinolones (FQs) ranged from 4493 to 47,093 L kg(-1) and were much higher than those of tetracyclines (TCs), which ranged from 277 to 1880 L kg(-1) indicating that the FQs are prone to accumulation in the sediment.

Bioaccumulation and trophic transfer of perfluorinated compounds in a eutrophic freshwater food web

In this study, the bioaccumulation of perfluorinated compounds from a food web in Taihu Lake in China was investigated. The organisms included egret bird species, carnivorous fish, omnivorous fish, herbivorous fish, zooplankton, phytoplankton, zoobenthos and white shrimp. Isotope analysis by δ(13)C and δ(15)N indicated that the carnivorous fish and egret were the top predators in the studied web, occupying trophic levels intermediate between 3.66 and 4.61, while plankton was at the lowest trophic level. Perfluorinated carboxylates (PFCAs) with 9-12 carbons were significantly biomagnified, with trophic magnification factors (TMFs) ranging from 2.1 to 3.7. The TMF of perfluorooctane sulfonate (PFOS) (2.9) was generally comparable to or lower than those of the PFCAs in the same food web. All hazard ratio (HR) values reported for PFOS and perfluorooctanoate (PFOA) were less than unity, suggesting that the detected levels would not cause any immediate health effects to the people in Taihu Lake region through the consumption of shrimps and fish.

Field study on the uptake and translocation of perfluoroalkyl acids (PFAAs) by wheat (Triticum aestivum L.) grown in biosolids-amended soils

Field experiments were performed to evaluate the uptake and translocation of perfluoroalkyl acids (PFAAs) in wheat (Triticum aestivum L.) grown in soils amended with biosolids at different rates. Nine perfluorocarboxylic acids (PFCAs) and three perfluorosulfonic acids (PFSAs) were detected in the soils and wheat tissues. Total concentrations of PFAAs in the soils and wheat root, straw, husk and grain increased with increasing application of biosolids. PFCA concentrations in grain increased logarithmically with increasing PFCA concentrations in soils (P < 0.01) while PFSAs in grain were correlated linearly with PFSA concentrations in soils (P < 0.01), indicating that PFCAs and PFSAs may have different transport pathways from soil to grain. While no significant correlation was found between the root concentration factors (Croot/Csoil) and PFAA carbon chain length, the transfer factors from roots to straws (Cstraw/Croot) and from straws to grains (Cgrain/Cstraw) correlated negatively with PFAA carbon chain length (P < 0.01).

Bioaccumulation of perfluoroalkyl substances by Daphnia magna in water with different types and concentrations of protein

Perfluoroalkyl substances (PFASs) are sometimes regarded as proteinophilic compounds, however, there is no research report about the effect of environmental protein on the bioaccumulation of PFASs in waters. In the present study we investigated influences of protein on the bioaccumulation of six kinds of PFASs by Daphnia magna in water; it included perfluorooctane sulfonate, perfluorooctanoic acid, perfluorononanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, and perfluorododecanoic acid. Two types of protein including bovine albumin from animal and soy peptone from plant were compared and the effects of protein concentration were investigated. Both types of protein at high concentrations (10 and 20 mg L(-1)) suppressed the bioaccumulation of PFASs. When protein concentration increased from 0 to 20 mg L(-1), the decreasing ratios of the PFAS body burden (35.3-52.9%) in Daphnia magna induced by bovine albumin were significantly higher than those (22.0-36.6%) by soy peptone. The dialysis bag experiment results showed that the binding of PFASs to protein followed the Freundlich isotherm, suggesting it is not a linear partitioning process but an adsorption-like process. The partition coefficients of PFASs between bovine albumin and water were higher compared to soy peptone; this resulted in higher reducing rates of freely dissolved concentrations of PFASs with increasing bovine albumin concentration, leading to a stronger suppression of PFAS bioaccumulation. However, the presence of both types of protein with a low concentration (1 mg L(-1)) enhanced the bioaccumulation of PFASs. Furthermore, the water-based bioaccumulation factor based on the freely dissolved concentrations of PFASs even increased with and the depuration rate constants of PFASs from Daphnia magna decreased with protein concentration, suggesting that protein would not only reduce the bioavailable concentrations and uptake rates of PFASs but also lower the elimination rates of PFASs in Daphnia magna. Because these two opposite effects would change with different protein concentrations in water, the net effect of protein on PFAS bioaccumulation would also vary with protein concentration.

Occurrence and transport of perfluoroalkyl acids (PFAAs), including short-chain PFAAs in Tangxun Lake, China

Short-chain perfluoroalkyl acids (PFAAs), which have less than seven fluorinated carbons, have been introduced as substitutes for eight-carbon homologue products. In this study, water, sediment, and biological samples (fish and plant) were collected from Tangxun Lake, which is located near a production base of the fluorochemical industry in Wuhan, China. Perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) were the predominant PFAAs in surface water, with average concentrations of 3660 ng/L and 4770 ng/L, respectively. However, perfluorooctane sulfonate (PFOS) was the most abundant PFAA in sediments, with an average concentration of 74.4 ng/g dw. The organic carbon normalized distribution coefficients (KOC) indicated that short-chain PFAAs (CF2 < 7) tended to have lower adsorption potentials than PFOS, perfluorooctanoic acid (PFOA), and longer perfluoroalkyl chain compounds. PFBS and PFBA could transport to a farther distance in the horizontal direction along the water flow and infiltrate into deeper depths in the vertical direction. However, levels of PFOS and PFOA in water dropped exponentially along the current, and their proportions were decreased gradually with the increasing depth in sediment cores. Furthermore, values of log bioconcentration factor (BCF) of the short-chain PFAAs were all relatively low (<1), indicating no bioaccumulation potentials for short-chain PFAAs in aquatic species.

Perfluoroalkyl acids (PFAAs) in riverine and coastal sediments of Laizhou Bay, North China

This study investigates the concentrations and distributions of perfluoroalkyl acids (PFAAs), including perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulphonates (PFSAs), in surface sediments from Laizhou Bay and its adjacent rivers. ∑PFAAs showed much higher levels in the river sediment (with a mean of 5.25 ng/g dw) than in the coastal sediment (with a mean of 0.76 ng/g dw). Perfluorooctanoic acid (PFOA) was the predominant compound, accounting for 50% to 97% of ∑PFAA concentrations in 70% of the samples. The highest concentrations were detected in the Xiaoqing River, possibly due to the rapid development of the nearby fluorochemical industry. Hydrodynamics strongly influenced the distribution of PFAAs in Laizhou Bay. The hydrophilic property of shorter-chained PFAAs (C≤8) allowed them to be transported to the inner bay via currents, to adsorb onto suspended sediment and then to be deposited. The Xiaoqing River showed the highest PFOA concentration (76.9 ng/g dw) among the bodies of sediment that had been studied worldwide, which might pose a potential threat for the benthic organisms of this river.