Perfluorinated organic contaminants in sediment and aquatic wildlife, including sharks, from Georgia, USA

Species-specific profiles of per- and polyfluoroalkyl substances (PFAS) in small coastal sharks along the South Atlantic Bight of the United States

Per- and polyfluoroalkyl substances (PFAS) have gained widespread commercial use across the globe in various industrial and consumer products, such as textiles, firefighting foams, and surface coating materials. Studies have shown that PFAS exhibit a strong tendency to accumulate within aquatic food webs, primarily due to their high bioaccumulation potential and resistance to degradation. Despite such concerns, their impact on marine predators like sharks remains underexplored. This study aimed to investigate the presence of 34 PFAS in the plasma (n = 315) of four small coastal sharks inhabiting the South Atlantic Bight of the United States (U.S). Among the sharks studied, bonnetheads (Sphyrna tiburo) had the highest ∑PFAS concentration (3031 ± 1674 pg g - 1 plasma, n = 103), followed by the Atlantic sharpnose shark (Rhizoprionodon terraenovae, 2407 ± 969 pg g - 1, n = 101), blacknose shark (Carcharhinus acronotus, 1713 ± 662 pg g - 1, n = 83) and finetooth shark (Carcharhinus isodon, 1431 ± 891 pg g - 1, n = 28). Despite declines in the manufacturing of perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), the long-chain (C8 - C13) perfluoroalkyl acids (PFAAs) were frequently detected, with PFOS, perfluorodecanoic acid (PFDA), and perfluorotridecanoic acid (PFTrDA) present as the most dominant PFAS. Furthermore, males exhibited significantly higher ∑PFAS concentrations than females in bonnetheads (p < 0.01), suggesting possible sex-specific PFAS accumulation or maternal offloading in some species. The results of this study underscore the urgency for more extensive biomonitoring of PFAS in aquatic/marine environments to obtain a comprehensive understanding of the impact and fate of these emerging pollutants on marine fauna.

Per/Polyfluoroalkyl Substances (PFASs) in a Marine Apex Predator (White Shark, Carcharodon carcharias) in the Northwest Atlantic Ocean

Per/polyfluoroalkyl substances (PFASs) are ubiquitous, highly persistent anthropogenic chemicals that bioaccumulate and biomagnify in aquatic food webs and are associated with adverse health effects, including liver and kidney diseases, cancers, and immunosuppression. We investigated the accumulation of PFASs in a marine apex predator, the white shark (Carcharodon carcharias). Muscle (N = 12) and blood plasma (N = 27) samples were collected from 27 sharks during 2018-2021 OCEARCH expeditions along the eastern coast of North America from Nova Scotia to Florida. Samples were analyzed for 47 (plasma) and 43 (muscle) targeted PFASs and screened for >2600 known and novel PFASs using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS). Perfluoroalkyl carboxylates with carbon chain-length C11 to C14 were frequently detected above the method reporting limits in plasma samples, along with perfluorooctanesulfonate and perfluorodecanesulfonate. Perfluoropentadecanoate was also detected in 100% of plasma samples and concentrations were estimated semiquantitatively as no analytical standard was available. Total concentrations of frequently detected PFASs in plasma ranged from 0.56 to 2.9 ng mL-1 (median of 1.4 ng mL-1). In muscle tissue, nine targeted PFASs were frequently detected, with total concentration ranging from 0.20 to 0.84 ng g-1 ww. For all frequently detected PFASs, concentrations were greater in plasma than in muscle collected from the same organism. In both matrices, perfluorotridecanoic acid was the most abundant PFAS, consistent with several other studies. PFASs with similar chain-lengths correlated significantly among the plasma samples, suggesting similar sources. Total concentrations of PFASs in plasma were significantly greater in sharks sampled off of Nova Scotia than all sharks from other locations, potentially due to differences in diet. HRMS suspect screening tentatively identified 13 additional PFASs in plasma, though identification confidence was low, as no MS/MS fragmentation was collected due to low intensities. The widespread detection of long-chain PFASs in plasma and muscle of white sharks highlights the prevalence and potential biomagnification of these compounds in marine apex predators.

The Need for Testing Isomer Profiles of Perfluoroalkyl Substances to Evaluate Treatment Processes

Many environmentally relevant poly-/perfluoroalkyl substances (PFASs) including perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) exist in different isomeric (branched and linear) forms in the natural environment. The isomeric distribution of PFASs in the environment and source waters is largely controlled by the source of contamination and varying physicochemical properties imparted by their structural differences. For example, branched isomers of PFOS are relatively more reactive and less sorptive compared to the linear analogue. As a result, the removal of branched and linear PFASs during water treatment can vary, and thus the isomeric distribution in source waters can influence the overall efficiency of the treatment process. In this paper, we highlight the need to consider the isomeric distribution of PFASs in contaminated matrices while designing appropriate remediation strategies. We additionally summarize the known occurrence and variation in the physicochemical properties of PFAS isomers influencing their detection, fate, toxicokinetics, and treatment efficiency.

Perfluoroalkyl substance pollution: detecting and visualizing emerging trends based on CiteSpace

In recent years, perfluoroalkyl substances (PFASs) have been detected in all kinds of environmental media and can harm animals and human beings. They have attracted the attention of environmental workers worldwide and have become another research hotspot in the field of environment. However, analyses of PFASs have seldom been studied systematically. Therefore, this study summarizes the available data in 6756 publications (2000-2022) using the CiteSpace software to provide insights into the specific characteristics of PFASs and consequently shows global development trends that scientists can use for establishing future research directions. As opposed to traditional review articles by experts, this study provides a new method for quantitatively visualizing information about the development of this field over the past 23 years. Results show that the countries with more research in this field are mainly the USA and China. The research on PFASs is mainly concentrated in environmental sciences and ecology. Zhanyun Wang and Robert C. Buck's research has the highest influence rate in this field, and their research group is worthy of attention. Through the analysis of hot keywords, we conclude that the research hotspots are mainly focused on PFASs' transmission media and pathways, human exposure and the mechanism of toxicity, and degradation and remediation measures. Collectively these results indicate the major themes of PFAS research are as follows: (1) transmission media and pathways, (2) human exposure and the mechanism of toxicity, (3) degradation and remediation measures. This study maps the major research domains of PFAS research; explanations and implications of the findings are discussed; and emerging trends highlighted.

Per- and Polyfluoroalkyl Substances (PFAS) Neurotoxicity in Sentinel and Non-Traditional Laboratory Model Systems: Potential Utility in Predicting Adverse Outcomes in Human Health

Per- and polyfluoroalkyl substances (PFAS) are a class of chemicals that were widely used in manufacturing and are now present in the environment throughout the world. It is known that various PFAS are quantifiable in human in blood, but potential adverse health outcomes remain unclear. Sentinel and non-traditional model species are useful to study potential toxicity of PFAS in order to understand the relationship between environmental and human health. Here, we present a critical review of studies on the neurotoxicity of PFAS in sentinel and non-traditional laboratory model systems, including Caenorhabditis elegans (nematode), Dugesia japonica (planarian), Rana pipiens (frogs), Danio rerio and Oryzias melastigma (fish), and Ursus maritimus (polar bears). PFAS have been implicated in developmental neurotoxicity in non-traditional and traditional model systems as well as sentinel species, including effects on neurotransmitter levels, especially acetylcholine and its metabolism. However, further research on the mechanisms of toxicity needs to be conducted to determine if these chemicals are affecting organisms in a similar manner. Overall, findings tend to be similar among the various species, but bioaccumulation may vary, which needs to be taken into account in future studies by quantifying target organ concentrations of PFAS to better compare different species. Furthermore, data on the majority of PFAS is lacking in neurotoxicity testing, and additional studies are needed to corroborate findings thus far.

Occurrence and distribution of perfluoroalkyl substances in surface riverine and coastal sediments from the Beibu Gulf, south China

There is limited understanding on the occurrence of PFASs in coastal sediment, especially in less-developed coastal areas. Here, we collected surface sediment samples from the Beibu Gulf to investigate the occurrence, spatial distribution and environmental risks of 18 PFASs. The concentrations of the total PFASs (ΣPFASs) ranged from 56.2 to 586.3 pg/g dry weight (dw), with a mean value of 172.5 pg/g dw. ΣPFASs concentrations were significantly lower in riverine than in coastal sediments. Additionally, there was a decreasing trend in ΣPFASs concentrations from the west (Fangchenggang) to the east (Beihai) of the Beibu Gulf. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) were the predominant PFASs, with their concentrations in the range of 4.8-249.0 pg/g dw and not detected (n.d)-224.8 pg/g dw, respectively. On a global scale, PFOS and PFOA concentrations were at low levels in the sediment of the Beibu Gulf, and they posed negligible environmental risks.

Comparisons of tissue distributions and health risks of perfluoroalkyl acids (PFAAs) in two fish species with different trophic levels from Lake Chaohu, China

Perfluoroalkyl acids (PFAAs) are a type of persistent organic pollutants that are widely distributed in multiple environmental media and organisms and have a teratogenic effect on and toxicity to animals and humans. The residual levels of seventeen PFAAs in the tissues of two regular consumption fish species, Culter erythropterus and Aristichthys nobilis in Lake Chaohu were measured by a high-performance liquid chromatograph - mass spectrometer (HPLC-MS). The distributions of PFAAs and the effect of the lipid contents were analyzed, and the health risks of typical PFAAs were evaluated. The results showed that perfluorohexanoic acid (PFHxA) was the predominant contaminant (80.50 ± 58.31 ng/g and 19.17 ± 12.57 ng/g wet weight, ww), followed by perfluorooctanesulfonic acid (PFOS) (55.02 ± 34.82 and 14.79 ± 6.24 ng/g, ww) in both fish. The level of total PFAAs was the highest in the liver tissues of Culter erythropterus (359.87 ng/g, ww) and the lowest in the kidney tissues in A. nobilis (10.06 ng/g, ww). Due to the higher trophic level of C. erythropteru, the total PFAA concentrations were significantly higher in all tissues than those in A. nobilis. Liver muscle ratio of C. erythropteru was the highest, indicating the most accumulation in the liver. The concentrations of PFAAs in fish tissues were influenced by the lipid content, resulting in a difference between the lipid-normalized concentrations and the wet weight concentrations of the PFAAs. The non-carcinogenic risks of PFOS were higher than those of PFOA through the ingestion of C. erythropterus and A. nobilis. Both the carcinogenic and non-carcinogenic risks of C. erythropterus were greater than those of A. nobilis, and fish tissue intake could cause an increasing of risks up to 60%, indicating that long-term and large amount ingestion of carnivorous fish and related tissues with higher trophic level, such as C. erythropterus should be avoided.

Concentration, distribution and sources of perfluoroalkyl substances and organochlorine pesticides in surface sediments of the northern Bering Sea, Chukchi Sea and adjacent Arctic Ocean

Perfluoroalkyl substances (PFAS) and organochlorine pesticides (OCPs) in surface sediments were investigated from the Bering Sea, the Chukchi Sea and adjacent Arctic Ocean in 2010. Total concentrations (dry weight) of Σ₁₄PFAS in surface sediments (0.85 ± 0.22 ng g^-1) of the Bering Sea were lower than that in the Chukchi Sea and adjacent Arctic Ocean (1.27 ± 0.53 ng g^-1). Perfluoro-butanoic acid (PFBS) and perfluoro-octanoic acid (PFOA) were the dominant PFAS in these areas. The concentrations of Σ₁₅OCPs in the sediment of the Bering Sea (13.00 ± 6.17 ng g^-1) was slightly higher than that in the Chukchi and Arctic Ocean (12.05 ± 2.27 ng g^-1). The most abundant OCPs were hexachlorocyclohexane isomers (HCHs) and dichlorodiphenyltrichloroethane (DDT) and its metabolites. The composition patterns of HCHs and DDTs indicated that they were mainly derived from the early residues via river runoff. Increasing trends of PFAS, HCHs and DDTs in surface sediments from the Bering Sea to the Arctic Ocean were found, indicating oceanic transport. In summary, the concentrations of OCPs were orders of magnitude greater than the observed PFAS concentrations, and the concentrations of PFAS and OCPs in surface sediments from the Bering Sea to the Chukchi Sea and adjacent Arctic Ocean are at the low to moderate levels by comparing with other coastal and marine sediments worldwide.

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.

Trace metals and persistent organic pollutants contamination in batoids (Chondrichthyes: Batoidea): A systematic review

Batoids (Chondrichthyes: Batoidea; e.g. stingrays, skates, and guitarfish) comprise more than 55% of elasmobranch taxa and represent ecologically important predators in benthic and pelagic habitats. Although overexploitation and habitat degradation are the two biggest threats to batoid populations, coastal and oceanic pollution is also a pervasive potential threat. In this systematic review, we compile published scientific literature on trace metals and persistent organic pollutants (POPs) contamination in elasmobranch species of the Batoidea superorder and present contamination patterns, exposure effects, and potential human exposure risks to most reported contaminants. We found batoids to accumulate a wide range of trace metals, including mercury (Hg), arsenic (As), lead (Pb), copper (Cu), cadmium (Cd) and zinc (Zn). Accumulation of POPs is reported for chlordanes, dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyl (PCB), dieldrin, Heptachlor epoxide, hexachlorobenzene and perfluoroalkyl substances (PFAS). Hg levels in muscle tissue were significantly different among oceanic basins and habitats, consistent with previous global assessments of Hg oceanic background levels. Some batoid species presented Hg levels higher than large pelagic teleost fishes and comparable to sharks. Ecological traits such as, bottom feeding, upper trophic position and elasmobranch-specific physiology and metabolism are discussed as potential factors associated with Hg uptake and accumulation in batoids. Some species exceeded USEPA's maximum contamination safety limits in edible tissues for Hg, As and ΣPCBs. For most trace metals and POPs, there is a lack of studies focusing on contamination levels in batoids. We recommend future research increasing reporting on POPs and trace metals besides Hg in batoids to further investigate the role of Elasmobranch as a bioindicator for marine pollution.

Perfluoroalkyl acids in surface sediments of the East China Sea

The occurrence of 17 target PFAA analytes was determined in surface sediments (n = 37) of the East China Sea and potential influencing factors were examined. ΣPFAAs ranged from 0.41 ng/g dw to 3.06 ng/g dw, with perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) as the most abundant perfluorocarboxylic acid and perfluoroalkyl sulfonate, respectively. PFAAs in the sediments were strongly influenced by terrigenous input. Analysis of the relationship between dynamic influence factors and PFAA concentrations showed that the characteristics of PFAA distribution were rather complex. ΣPFAA concentrations and TOC were positively correlated (p < 0.0001). Circumfluence also influenced the whole PFAA distribution and seasonal variation. In addition, correlation analysis suggested that log K_oc values increased with increasing perfluoroalkyl chain length. Given the rapid economic development of eastern coastal cities of China, the environmental hazards of land source pollution cannot be ignored.

Occurrence and assessment of perfluoroalkyl acids (PFAAs) in commonly consumed seafood from the coastal area of Bangladesh

This study reports the first evidence of the occurrence of PFAAs in commonly consumed seafood from the coastal area of Bangladesh. Fifteen target PFAAs in 48 seafood samples (5 finfish and 2 shellfish species) were measured by HPLC-MS/MS. The ΣPFAAs in finfish and shellfish were in the range of 0.32-14.58 and 1.31-8.34 (ng/g wet weight), respectively. Perfluorooctanesulfonate (PFOS) in finfish (0.1-3.86ng/g ww), whereas perfluorooctanoic acid (PFOA) in shellfish (0.07-2.39ng/g ww) were the most abundant PFAAs. The results were comparable with other studies worldwide, particularly from China, Spain, Sweden, and USA. The majority of monitored PFAAs did not show clear seasonal variation. However, seafood from the southeast area (Cox's Bazar and Chittagong) showed relatively higher levels of PFAAs. Moreover, the dietary exposure assessment revealed that the daily intakes of PFAAs via seafood consumption were far less than the health-based guidelines, indicating low health risk for the Bangladeshi coastal residents.

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.

Blue sharks (Prionace glauca) as bioindicators of pollution and health in the Atlantic Ocean: Contamination levels and biochemical stress responses

Marine ecosystems are constantly being threatened by contaminants produced by human activities. There is an urge to better understand their impacts on marine organisms and develop reliable tools for biomonitoring studies, while also assessing their potential impacts on human health. Given their position on top of food webs, sharks are particularly susceptible to bioaccumulation, making them potential sentinel species of marine contamination. The main objective of this study was to find suitable biomarkers for future marine pollution biomonitoring studies by correlating biochemical responses with tissue contaminant body burden in blue sharks (Prionace glauca), a species heavily caught and consumed by humans, while also addressing their general health. The chemical contaminants analysed comprised different persistent organic pollutants (POPs) families from polychlorinated compounds to brominated flame retardants (BFRs) and perfluorinated compounds (PFCs) and different trace and heavy metals. Concentrations of some contaminants in sharks' tissues were found to be above the legally allowed limits for human consumption. A canonical correspondence analysis (CCA) was performed and some strong associations were found between biochemical responses and contaminants' accumulation levels. DNA damage and lipid peroxidation levels, as well as the inhibition of the antioxidant enzyme glutathione peroxidase, were the main effects and consequences of contamination. The impact of contamination on these vital macromolecules underlines the suboptimal conditions of the sampled P. glauca, which can ultimately lead to the degradation of core ecological aspects, such as swimming, feeding, and reproduction. It can be concluded that P. glauca demonstrates great potential to be used as environmental sentinel and suitable biomarker candidates were identified in this work. Moreover, this study also highlights the risks that the consumption of blue shark derived products can pose to human health, which is of upmost interest as the sampled organisms were still juveniles and already presented values above regulatory limits.

Analysis of the presence of perfluoroalkyl substances in water, sediment and biota of the Jucar River (E Spain). Sources, partitioning and relationships with water physical characteristics

The presence, sources and partitioning of 21 perfluoroalkyl substances (PFASs: C4-C14, C16, C18 carboxylate, C4, C6-C10 sulfonates and C8 sulfonamide) were assessed in water, sediment, and biota of the Jucar River basin (E Spain). Considering the three matrices, perfluoropentanoate (PFPeA) and perfluorooctane sulfonate (PFOS) were the most frequent compounds, being remarkable the high occurrence of short-chain PFASs (C≤8), which are intended to replace the long-chain ones in several industrial and commercial applications. In general, all samples were contaminated with at least one PFAS, with the exception of three fish samples. Mean concentrations detected in sediments (0.22-11.5ng g(-1)) and biota (0.63-274µgkg(-1)) samples were higher than those measured in water (0.04-83.1ngL(-1)), which might suggest (bio) accumulation. The occurrence of PFAS is related to urban and industrial discharges (Cuenca city in the upper part of basin, and car's factory, and effluents of the sewage treatment plant (STP) of Alzira, in the lower part). Increasing pollution gradients were found. On the other hand, higher contamination levels were observed after regulation dams of the catchment pointing out their importance in the re-distribution of these contaminants. None of the hazard quotients (HQ) calculated indicate potential risk for the different tropic levels considered (algae, Daphnia sp. and fish). PFAS concentrations found in this study can be considered in acceptable levels if compared to existing Regulatory Legislation and, consequently, they do not pose an immediate human health risk.

Annual dynamics of perfluorinated compounds in sediment: A case study in the Morava River in Zlín district, Czech Republic

Two groups of perfluorined compounds (PFCs), i.e. perfluoroalkyl sulfonates (PFASs) and perfluoroalkyl carboxylates (PFCAs) were analysed during a period of 1 year in monthly collected riverbed sediment samples from five sampling sites in an industrial region in Morava River catchment in Czech Republic. Levels of PFCs determined in sediment samples were up to 6.8 μg kg(-1) of dry weight. Among PFCs analysed, mainly short-chain PFASs (C6 to C8) including PFOS were found in sediment samples and their levels were similar to those found in comparable river basins in other parts of Europe. Concentrations of PFCs were correlated with organic carbon content and their variations were mainly correlated by high flow events on Morava River and its tributaries. The changes in PFC concentrations were induced by displacing of PFCs containing particles to the river sediment during these elevated flow events.

Perfluoroalkyl acid (PFAA) levels and profiles in breast milk, maternal and cord serum of French women and their newborns

One major concern regarding perfluoroalkyl acids (PFAAs) is their potential role in onset of health troubles consecutive to early exposure during the perinatal period. In the present work, the internal exposure levels of 18 targeted PFAAs were determined in ca. 100 mother-newborn pairs recruited in France between 2010 and 2013. In serum, the cumulated concentrations of the 7 most frequently detected compounds were 5.70ng/mL and 2.83ng/mL (median values) in maternal and cord serum, respectively. Perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexylesulfonic acid (PFHxS) and perfluorononanoic acid (PFNA) contributed to around 90% of the total PFAAs contamination, with concentration levels and contamination profiles in accordance with other published work in Europe. Levels measured in breast milk were far lower (20 to 150 fold) than those determined in serum. Associations between the different monitored substances as well as between levels determined in the different investigated biological matrices mostly do not appear statistically significant. The estimated materno-foetal transfer would be thus substance-dependant, mainly driven by the physico-chemical properties of the different PFAAs (nature of polar group and length of alkylated side chain). We conclude that trans-placental passage and breastfeeding are both significant routes of human exposure to PFAAs.

Spatial distribution and partition of perfluoroalkyl acids (PFAAs) in rivers of the Pearl River Delta, southern China

This study investigated the occurrence of perfluoroalkyl acids (PFAAs) in surface water from 67 sampling sites along rivers of the Pearl River Delta in southern China. Sixteen PFAAs, including perfluoroalkyl carboxylic acids (PFCAs, C5-14, C16 and C18) and perfluoroalkyl sulfonic acids (PFSAs, C4, C6, C8 and C10) were determined by high performance liquid chromatography-negative electrospray ionization-tandem mass spectrometry (HPLC/ESI-MS/MS). Total PFAA concentrations (∑ PFAAs) in the surface water ranged from 1.53 to 33.5 ng·L(-1) with an average of 7.58 ng·L(-1). Perfluorobutane sulfonic acid (PFBS), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS) were the three most abundant PFAAs and on average accounted for 28%, 16% and 10% of ∑ PFAAs, respectively. Higher concentrations of ∑ PFAAs were found in the samples collected from Jiangmen section of Xijiang River, Dongguan section of Dongjiang River and the Pearl River flowing the cities which had very well-developed manufacturing industries. PCA model was employed to quantitatively calculate the contributions of extracted sources. Factor 1 (72.48% of the total variance) had high loading for perfluorohexanoic acid (PFHxA), perfluoropentanoic acid (PFPeA), PFBS and PFOS. For factor 2 (10.93% of the total variance), perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUdA) got high loading. The sorption of PFCAs on suspended particulate matter (SPM) increased by approximately 0.1 log units for each additional CF2 moiety and that on sediment was approximately 0.8 log units lower than the SPM logKd values. In addition, the differences in the partition coefficients were influenced by the structure discrepancy of absorbents and influx of fresh river water. These data are essential for modeling the transport and environmental fate of PFAAs.

Spatial distribution of perfluoroalkyl acids in surface sediments of the German Bight, North Sea

Perfluoroalkyl acids (PFAAs) have been determined in the environment globally. However, studies on the occurrence of PFAAs in marine sediment remain limited. In this study, 16 PFAAs are investigated in surface sediments from the German Bight, which provided a good overview of the spatial distribution. The concentrations of ΣPFAAs ranged from 0.056 to 7.4 ng/g dry weight. The highest concentration was found at the estuary of the River Ems, which might be the result of local discharge source. Perfluorooctane sulfonic acid (PFOS) was the dominant compound, and the enrichment of PFOS in sediment might be strongly related to the compound structure itself. The geographical condition of the German Bight influenced the movement of water and sediment, resulting in complex distribution. Following normalization according to total organic carbon (TOC) content, PFAA distributions showed a different picture. Significant linear relationships were found between total PFAA concentrations and TOC (R2=0.50, p<0.01). Compared with a previous study conducted in the same area, a declining trend was presented for the concentrations of PFOS and perfluorooctanoic acid (PFOA). Compound structure, geographical condition, and organic carbon in the sediment influence the distribution of PFAAs in the German Bight. Environmental risk assessment indicated that the risk from PFOA is negligible, whereas PFOS in marine sediment may present a risk for benthic organisms in the German Bight.

Occurrence of perfluorinated alkyl substances in sediment from estuarine and coastal areas of the East China Sea

Perfluorinated alkyl substances (PFAS) have drawn much attention due to their environmental persistence, ubiquitous existence, and bioaccumulation potential. The occurrence and spatial variation of PFAS were investigated through collection of riverine and marine sediments from estuarine and coastal areas of the East China Sea. Among them, perfluorooctanesulfonic acid (PFOS), perfluoroheptanoic acid (PFHpA), and perfluorooctanoic acid (PFOA) were the three predominant PFAS with the highest detection frequencies in the sediment. PFOS up to 32.4 ng g(-1) dw and ∑PFAS up to 34.8 ng g(-1) dw were detected. Compared to other studies, high levels of PFOS were found in sediments from the East China Sea. PFHpA was also detected at higher frequency and concentration than those of other studies, which suggests point sources in this area. Concentrations of PFAS in riverine sediments were much higher than in marine sediments. Analysis of spatial variations presented overall decreasing trends of PFAS from inshore to offshore areas.

Effects of pH on photochemical decomposition of perfluorooctanoic acid in different atmospheres by 185nm vacuum ultraviolet

Perfluorooctanoic acid (PFOA), a persistent organic pollutant, receives increasing concerns due to its worldwide occurrence and resistance to most conventional treatment processes. The photochemical decomposition by 185nm vacuum ultraviolet (VUV) is one of the efficient methods for PFOA decomposition. The effects of pH on PFOA decomposition in nitrogen atmosphere or oxygen atmosphere were investigated. At its original pH (4.5) of PFOA aqueous solution, PFOA decomposed efficiently both in nitrogen and in oxygen atmosphere. However, when the pH increased to 12.0, PFOA decomposition was greatly inhibited in oxygen atmosphere, while it was greatly accelerated in nitrogen atmosphere with a very short half-life time (9min). Furthermore, fluorine atoms originally contained in PFOA molecules were almost completely transformed into fluoride ions. Two decomposition pathways have been proposed to explain the PFOA decomposition under different conditions. In acidic and neutral solutions, PFOA predominantly decomposes via the direct photolysis in both atmospheres; while in the alkaline solution and in the absence of oxygen, the decomposition of PFOA is mainly induced by hydrated electrons.

Size and age-concentration relationships for perfluoroalkyl substances in stingray livers from eastern Australia

While the literature has reported a widespread occurrence of perfluoroalkyl substances (PFASs) in marine biota, very limited studies have been dedicated to the southern hemisphere. Hepatic concentrations of nine PFAAs were analysed in 49 stranded stingrays from eastern Australia using liquid chromatograph coupled with tandem mass spectrometry and relationships with biological parameters (i.e. body size, age and sex) were investigated. Perfluorooctanesulfonate (PFOS) and perfluorooctanoate (PFOA) were the predominant compounds quantified, with hepatic concentrations varying from 2 to 117 and from 0.2 to 19 ng·g(-1) w.w., respectively. A negative correlation between the concentration of PFASs in the livers of 32 blue-spotted stingrays and the body size/age was found. This relationship was independent of the animal's sex. We postulate that the dependence on body size is related to differing uptake kinetics of the chemicals, after the sting rays were exposed to an increased level of the contaminants in their environment. Such a pollution event could be related to a severe flood event that occurred at this location a few months before the samples' collection. Our results indicate that the influence of the body size/age should be taken into account when estimating bioaccumulation parameters from environmental measurements or exposure levels of biota to PFASs.

Perfluoroalkyl substances in the blood of wild rats and mice from 47 prefectures in Japan: use of samples from nationwide specimen bank

Numerous studies have reported on the global distribution, persistence, fate, and toxicity of perfluoroalkyl and polyfluoroalkyl substances (PFASs). However, studies on PFASs in terrestrial mammals are scarce. Rats can be good sentinels of human exposure to toxicants because of their habitat, which is in close proximity to humans. Furthermore, exposure data measured for rats can be directly applied for risk assessment because many toxicological studies use rodent models. In this study, a nationwide survey of PFASs in the blood of wild rats as well as surface water samples collected from rats' habitats from 47 prefectures in Japan was conducted. In addition to known PFASs, combustion ion chromatography technique was used for analysis of total fluorine concentrations in the blood of rats. In total, 216 blood samples representing three species of wild rats (house rat, Norway rats, and field mice) were analyzed for 23 PFASs. Perfluorooctanesulfonate (PFOS; concentration range <0.05-148 ng/mL), perfluorooctane sulfonamide (PFOSA; <0.1-157), perfluorododecanoate (<0.05-5.8), perfluoroundecanoate (PFUnDA; <0.05-51), perfluorodecanoate (PFDA; <0.05-9.7), perfluorononanoate (PFNA; <0.05-249), and perfluorooctanoate (PFOA) (<0.05-60) were detected >80 % of the blood samples. Concentrations of several PFASs in rat blood were similar to those reported for humans. PFSAs (mainly PFOS) accounted for 45 % of total PFASs, whereas perfluoroalkyl carboxylates (PFCAs), especially PFUnDA and PFNA, accounted for 20 and 10 % of total PFASs, respectively. In water samples, PFCAs were the predominant compounds with PFOA and PFNA found in >90 % of the samples. There were strong correlations (p < 0.001 to p < 0.05) between human population density and levels of PFOS, PFNA, PFOA, and PFOSA in wild rat blood.

Perfluorinated compounds in sediment samples from the wastewater canal of Pančevo (Serbia) industrial area

Perfluoroalkyl sulfonates (PFSAs) and perfluoroalkyl carboxylates (PFCAs) were analyzed in sediment samples from the wastewater canal draining the industrial complex of Pančevo, Serbia (oil refinery, petrochemical plant, and fertilizer factory). The canal is directly connected to Europe's second largest river, the Danube, which drains its water into the Black Sea. Perfluorooctane sulfonate (PFOS) up to 5.7ngg(-1) dry weight (dw) and total Perfluorinated compounds (PFCs) up to 6.3ngg(-1) dw were detected. Compared to other reports, high levels of PFOS were found, even though PFCs are not used in the industrial production associated with this canal. The PFOS concentration in water was recalculated using the adsorption coefficient, KOC from literature. Using the average output of wastewater from the canal, a mass load of 1.38kg PFOS per year discharged in the Danube River has been calculated, which undoubtedly points to the contribution to global persistent organic pollution of surface waters originating from this industrial place.

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.

Determination and partitioning behavior of perfluoroalkyl carboxylic acids and perfluorooctanesulfonate in water and sediment from Dianchi Lake, China

Perfluorinated compounds (PFCs) have received much attention on their distribution in various matrices including water bodies, precipitations, sediment and biota in different areas globally, however, little attention has been paid to their occurrence and distribution in urban lakes. In this study, water and sediment samples collected from 26 sites in Dianchi Lake, a plateau urban lake in the southwestern part of China were analyzed via high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for ten analytes involving nine perfluoroalkyl carboxylic acids (PFOAs) and perfluorooctanesulfonate (PFOS). Total levels of PFCs were 30.98 ± 32.19 ng L(-1) in water and 0.95 ± 0.63 ng g(-1) in sediment. In water samples PFOA was the dominant PFC contaminant, with concentrations ranging from 3.41 to 35.44 ng L(-1), while in sediments PFOS was the main PFC contaminant at levels from 0.07-0.83 ng g(-1) dry weight. Field-based sediment water distribution coefficients (K(D)) were calculated and corrected for organic carbon content (K(oc)), which reduced variability among samples. The log K(oc) ranged from 2.54 to 3.57 for C8-C12 perfluorinated carboxylic acids, increasing by 0.1-0.4 log units with each additional CF2 moiety. The log K(oc) of PFOS was 3.35 ± 0.32. Magnitudes and trends in log K(D) or log K(oc) appeared to agree well with previously published laboratory data. Results showed that different PFC composition profiles were observed for samples from the lake water and sediments, indicating the presence of dissimilar characteristics of the PFCs compounds, which is important for PFC fate modeling and risk assessment.

Perfluorinated compounds in surface waters from Northern China: comparison to level of industrialization

Inclusion of Perfluorooctane Sulfonate (PFOS) in the Stockholm Convention because of its exemptions, has resulted in increased annual production of PFOS-containing chemicals in China to accommodate domestic and overseas demands. Accordingly, concern about environmental contamination with perfluorinated compounds (PFCs), such as PFOS, has arisen. However, little information is available on the status and trends in the distribution, sources or risk of PFCs in aquatic environments of China. In the present study, forty two surface water samples collected from five regions with different levels of industrialization were monitored for concentrations of PFCs by use of solid phase extraction and LC/MS/MS. Mean concentrations (maximum concentration) of PFOA and PFOS, which were the dominant PFCs, were 1.2 (2.3) and 0.16 (0.52)ng/l for Guanting, 1.2 (1.8) and 0.32 (1.1)ng/l for Hohhot, 2.7 (15) and 0.93 (5.7)ng/l for Shanxi, 6.8 (12) and 2.6 (11)ng/l for Tianjin, 27 (82) and 4.7 (31)ng/l for Liaoning, respectively. The greatest concentrations of PFCs (121 ng/l), PFOA (82 ng/l) and PFOS (31 ng/l) were observed in Liaoning, which might originate from tributaries of the Liaohe River, the most polluted watershed in Northeast China. While, concentrations of PFCs in the Guanting and Hohhot regions were 3 to 20 fold less than those from Tianjin and Liaoning. This result is consistent with little contribution of PFCs being released from agricultural and non-industrial activities. The magnitudes of mass flow for PFOA and PFOS in decreasing order were: Guanting<Hohhot<Tianjin<Liaoning<Shanxi and Guanting<Hohhot<Shanxi<Tianjin<Liaoning. The larger mass flows of PFOS were accompanied by relatively larger magnitudes of PFOA. Concentrations of both PFOA and PFOS in waters from all regions were less than suggested allowable concentrations. However, the relatively greater concentrations of PFCs in Tianjin and Liaoning suggest that further studies characterizing their sources and potential risk to both humans and wildlife are needed.

Occurrence of perfluorinated compounds in water and sediment of L'Albufera Natural Park (València, Spain)

PURPOSE

Perfluorinated compounds (PFCs) are widely distributed from industrialized to remote locations throughout the world. This study demonstrates the spatial distributions of PFCs in water and sediments from the L'Albufera Natural Park (Valencia, Spain).

METHODS

Grab water and sediment samples were collected. PFCs were extracted from sediments with acidified acetonitrile by ultrasonication and cleaned up by solid-phase extraction (SPE) and from water by SPE. Determination was carried out by liquid chromatography-tandem mass spectrometry.

RESULTS

In 100% of the samples (both water and sediments), perfluorooctane sulfonate (PFOS) and perfluoroctanoic acid (PFOA) were the predominant PFCs. Among the 12 sampling sites, PFOS concentrations in sediments ranged from 0.10 to 4.80 ng/g dry weight and in water from 0.94 to 58.1 ng/L. PFOA concentrations in sediment were from 0.004 to 1.24 ng/g and in water from 0.99 to 120 ng/L. Other perfluorocarboxylic acids (C5, C6, C7, C9, and C10) and perfluorosulfonates (C4 and C10) were also identified in several locations. The sum of all 10 compounds (ΣPFCs) concentration range from 0.99 to 120 ng/L in water and from 0.25 to 17.4 ng/g in sediments. Sediment-water distribution coefficients (log K (D)) were in the range 2.31-4.51 and positively correlated with perfluoroalkyl chain length.

CONCLUSIONS

PFC concentrations in water and sediment were both less than those able to cause acute toxicity; low but detectable PFCs pollution in the L'Albufera Natural Park in Valencia was demonstrated. These compounds are bioaccumulative; thus, the risk associated with these exposures requires a deeper evaluation of long-term chronic toxicity.

Occurrence of perfluorinated organic acids in the North and Baltic Seas. Part 2: distribution in sediments

PURPOSE

The distribution of polar perfluorinated compounds (PFCs) in sea water of the North and Baltic Seas has been described in part 1 of this study. In part 2, their occurrence in sediments is described in order to further investigate their distribution routes and possible sinks.

METHODS

Sediments were extracted with methanol and PFCs with chain lengths of C(4) to C(10) analysed by liquid chromatography coupled with tandem mass spectrometry.

RESULTS

Using the developed procedure, PFCs could be determined in sediments from all 15 stations which had been sampled. In most samples from the German Bight and western Baltic Sea, perfluorooctane sulphonate had the highest concentrations (0.02 to 2.4 μg/kg dry weight), followed by perfluorooctanoate at 0.06 to 1.6 μg/kg dry weight. Levels of the other PFCs were five to ten times lower. Concentrations of PFCs were similar to those of classical chlorinated hydrocarbons. The spatial distribution is strongly influenced by sediment parameters (e.g. total organic carbon (TOC)). By normalisation to TOC, regional differences were identified between the North and Baltic Sea samples. Sediment/water enrichment ratios estimated from field concentrations showed clear dependences on carbon chain length and chemical structure. Time trends of PFCs, investigated by analysing a sediment core (Skagerrak), differed clearly from those of "classical" pollutants.

CONCLUSION

Because of the strong influence of sediment parameters and the relatively low enrichment of PFCs in sediments, this matrix is less suited for investigating spatial distributions. Sediments should be used mainly for monitoring temporal trends, preferably using sediment cores.

Levels, temporal trends, and tissue distribution of perfluorinated surfactants in freshwater fish from Asian countries

Perfluorinated surfactants (PFSs) in Asian freshwater fish species were analyzed to investigate tissue distribution, temporal trends, extent of pollution, and level of PFS exposure through food intake. Freshwater fish species, namely carp, snakehead, and catfish, were collected in Japan, Vietnam, India, Malaysia, and Thailand, and 10 PFSs, including perfluorooctanesulfonate (PFOS) and perfluorooctanoate, were analyzed by liquid chromatography-tandem mass spectrometry. PFSs in carp in Tokyo were more concentrated in kidneys (Σ10 PFSs = 257 ± 95 ng/g wet weight [ww]) and livers (119 ± 36 ng/g ww) than in ovaries (43 ± 2 ng/g ww) and muscles (24 ± 17 ng/g ww). Concentrations of PFOS and its precursor, perfluorooctane sulfonamide, in livers of carp and in waters in Tokyo showed a dramatic decrease during the last decade, probably because of 3 M's phasing-out of the manufacture of perfluorooctanesulfonyl-fluoride-based products in 2000. In contrast, continuing contamination by long-chain perfluorocarboxylates (PFCAs) with ≥ 9 fluorinated carbons was seen in multiple media, suggesting that these compounds continue to be emitted. PFS concentrations in freshwater fish species in tropical Asian countries were generally lower than those in developed countries, such as Japan, e.g., for PFOS in muscle, Vietnam < 0.05-0.3 ng/g ww; India < 0.05-0.2 ng/g ww; Malaysia < 0.05-0.2 ng/g ww; Thailand < 0.05 ng/g ww; and Japan (Tokyo) = 5.1-22 ng/g ww. Daily intake of short-chain PFCAs with ≤ 8 fluorinated carbons from freshwater fish species in Japan was approximately one order of magnitude lower than that from drinking water, whereas daily intake of PFOS and long-chain PFCAs with ≥ 9 fluorinated carbons from freshwater fish species was comparable with or greater than that from drinking water. Because the risk posed by exposure to these compounds through intake of fish species is a matter of concern, we recommend the continued monitoring of PFS levels in Asian developing countries.

Monitoring of perfluorinated compounds in aquatic biota: an updated review

The goal of this article is to summarize new biological monitoring information on perfluorinated compounds (PFCs) in aquatic ecosystems (post-2005) as a followup to our critical review published in 2006. A wider range of geographical locations (e.g., South America, Russia, Antarctica) and habitats (e.g., high-mountain lakes, deep-ocean, and offshore waters) have been investigated in recent years enabling a better understanding of the global distribution of PFCs in aquatic organisms. High concentrations of PFCs continue to be detected in invertebrates, fish, reptiles, and marine mammals worldwide. Perfluorooctane sulfonate (PFOS) is still the predominant PFC detected (mean concentrations up to 1900 ng/g ww) in addition to important concentrations of long-chain perfluoroalkyl carboxylates (PFCAs; sum PFCAs up to 400 ng/g ww). More studies have evaluated the bioaccumulation and biomagnification of these compounds in both freshwater and marine food webs. Several reports have indicated a decrease in PFOS levels over time in contrast to PFCA concentrations that have tended to increase in tissues of aquatic organisms at many locations. The detection of precursor metabolites and isomers has become more frequently reported in environmental assessments yielding important information on the sources and distribution of these contaminants. The integration of environmental/ecological characteristics (e.g., latitude/longitude, salinity, and/or trophic status at sampling locations) and biological variables (e.g., age, gender, life cycle, migration, diet composition, growth rate, food chain length, metabolism, and elimination) are essential elements in order to adequately study the environmental fate and distribution of PFCs and should be more frequently considered in study design.

Spatially detailed survey on pollution by multiple perfluorinated compounds in the Tokyo Bay basin of Japan

Pollution from 35 perfluorinated compounds (PFCs) in the water of the Tokyo Bay basin was examined. The water in the basin contained relatively high levels of perfluorononanoate (PFNA), perfluorooctanoate (PFOA), and perfluorooctane sulfonate (PFOS) compared to the other PFCs, which were present at concentrations of 20.1 ng/L, 6.7 ng/L, and 5.8 ng/L, respectively. In contrast, the concentrations of their precursors and degradation products were an order of magnitude lower. Sewage treatment plant (STP) effluent in the area also contained high levels of PFNA compared with the river water samples (Mann-Whitney U-test, p<0.0002). From a spatial aspect, increases in PFC pollution levels correlated with increased urbanization in the study area suggested that there are nonpoint source contributors to the PFC pollution in this area. Branched isomers of the PFCs were also quantified. Samples that contained high concentrations of perfluoroalkyl carboxylates (PFCA) showed lower proportions of its branched isomer. This indicates that the branched isomers are more prominent in the area with lower PFC pollution. This analysis was beneficial for estimating the individual contributions of different PFCA production processes. This survey provided new information on the sources, spatial distribution, and behavioral characteristics of PFC pollutants in this area.

Perfluorooctane sulfonate toxicity, isomer-specific accumulation, and maternal transfer in zebrafish (Danio rerio) and rainbow trout (Oncorhynchus mykiss)

Perfluorooctane sulfonate (PFOS; C(8)F(17)SO(3) (-)) bioaccumulation and toxicity have been demonstrated in both aquatic and terrestrial organisms. The majority of investigations have examined total PFOS concentrations in wildlife and in toxicity testing, but isomer-specific monitoring studies are less common, and no laboratory-based study of PFOS isomer accumulation in fish has been reported. The present study examined accumulation and maternal transfer of PFOS isomers in zebrafish and tissue-specific accumulation of PFOS isomers in trout parr. A median lethal dose (LC50) of 22.2 and 2.5 mg/L was calculated for adult zebrafish and trout parr, respectively. A two-week PFOS exposure resulted in tissue-specific PFOS accumulation in trout, with maximum concentrations identified in the liver tissue (>50 microg/g). Prior exposure to PFOS as alevin did not affect the accumulation of PFOS in tissues later in life. In both species, accumulation of branched PFOS isomers generally occurred to a lesser extent than linear PFOS, which may explain the relative deficiency of branched PFOS isomers in some aquatic species in the field. Analysis of exposed trout tissues indicated that isomer discrimination may occur at the level of elimination or uptake and elimination processes in the kidney or gill, respectively. When zebrafish underwent a reproductive cycle in the presence of PFOS, approximately 10% (wt) of the adult PFOS body burden was transferred to the developing embryos, resulting in a higher total PFOS concentration in eggs (116 +/- 13.3 microg/g) than in the parent fish (72.1 +/- 7.6 microg/g). The isomer profile in eggs was not significantly different from that of adults, suggesting that the maternal transfer of branched and linear PFOS isomers in fish is largely nonisomer specific.

High levels of perfluorochemicals in Taiwan's wastewater treatment plants and downstream rivers pose great risk to local aquatic ecosystems

We studied perfluorochemicals (PFCs) in the influents and effluents of two municipal wastewater treatment plants (MWWTPs) and in the effluents of an industrial wastewater treatment plant (IWWTP). The impact of IWWTP effluents on the receiving rivers (the Nanmen and Keya Rivers) was evaluated by measuring PFC levels in the surface waters of both rivers and the sediments of the Nanmen River. Perfluorooctane sulfonate (PFOS) (293 ng L(-1)) and perfluorohexanoic acid (406 ng L(-1)) were identified as the compounds present in greatest concentrations in the influents and effluents of both MWWTPs, which are largely influenced by domestic sources. High concentrations of PFCs (up to 1,0000 ng L(-1)) were found in IWWTP effluents and receiving rivers, with more perfluoroalkyl sulfonates (PFASs) found than perfluoroalkylcarboxylic acids (PFCAs). This study confirms the IWWTP as the point source of the persistent contamination of the Nanmen and Keya Rivers. Sediments of the Nanmen River were also impacted by IWWTP discharges, with high concentrations of PFOS (up to 9,0000 ng kg(-1)). PFCAs with longer carbon chains exhibited preferred partitioning onto the sediments. The occurrence of higher PFC concentrations in Taiwan's aquatic media compared to other countries stresses the necessity for PFC risk management. Accordingly, a preliminary risk assessment was performed using the predicted no-effect concentration (PNEC) and indicative maximum permissible concentration (iMPC). The likelihood of ecological risk due to PFOS was plausible at a risk quotient of 1.21, as calculated using iMPC. Given our findings of high environmental PFC concentrations, rapid and meaningful steps should be taken to reduce entry of PFCs into Taiwan's aquatic environment.

Isomer profiling of perfluorinated substances as a tool for source tracking: a review of early findings and future applications

The two major manufacturing techniques for perfluorochemicals can be distinguished based on the isomeric profile of their products. ECF (major use from 1950s to 2002) results in a product containing both linear and branched isomers, while telomerization (major use from 2002 to present) typically yields an isomerically pure, linear product. Among the most important question today, which has implication for future regulation of these chemicals, is to what extent human and environmental exposure is from historical products (i.e., ECF) versus currently manufactured fluorochemicals (i.e., telomer). Perfluoroalkyl-chain branching can also affect the physical and chemical properties of these chemicals, which may influence their environmental transport and degradation, partitioning, bioaccumulation, pharmacokinetics, and toxicity. Unless perfluorinated substances are considered as individual isomers, much of this information will be overlooked or missed altogether, which could potentially lead to inaccuracies in human and environmental risk assessments. In this review, we have highlighted novel findings, current knowledge gaps, and areas for improvement based on early experiments on the disposition of PFA and PFA-precursor isomers in the environment. We have also emphasized the wealth of information that can potentially be gleaned from future work in this area, which renders routine adoption of isomer-specific methodologies an attractive and logical next step in the progression of fluorochemicals analysis. However, despite vast improvements in recent years, a fast and comprehensive method capable of separating all major PFA and PFA-precursor isomers, while removing interferences is still required before these methods becomes routine in most labs. Purified and characterized standards of PFOA and PFOS that have isomer profiles consistent with those of historically produced (i.e., 3M) PFOS and PFOA are also required. The limited data available on PFA isomer profiles that exist in the environment and the biological properties of each isomer suggest that examination of isomer profiles may yield clues on the source of PFA contamination to human and the environment. For example, contributions from historical versus current PFOA emissions can be quantified by examining the isomer profile in abiotic samples . Similarly, residual PFOS/PFOA in pre-2002 consumer products may be distinguished from directly emitted PFOS/PFOA by the existence of slight difference in isomer profile. PFOS signatures may also have the potential to distinguish between indirect exposure (via precursors) versus direct exposure (via the sulfonate), based on findings of isomer-specific and/or enantiospecific biotransformation in vitro. Isomer-specific monitoring extended to longer-chain PFAs may also be informative in determining current and historical exposure sources. Finally, given the recent increase of production of PFOSF-based chemicals, following their 2002 phase out, the ability of using isomer profiles to distinguish between historical and currently produced PFOS may also be possible.