Perfluorooctane Sulfonate Concentrations Research Articles

Simulating the Fate of Perfluorooctane Sulfonate (PFOS) in Environmental Multimedia of Dalian Area

Clarifying the fate of pollutants is of great significance for their pollution control and ecological risk assessments. In the present study, a level Ⅲ fugacity model was constructed to investigate the distribution and fate of perfluorooctane sulfonate (PFOS) in environmental multimedia of Dalian. The results showed that the simulated concentrations of PFOS in atmosphere, water, soil and sediment were 5.10 pg·m-3, 22.60 ng·L-1, 2.25 μg·kg-1 and 0.34 μg·kg-1, respectively, which were consistent with the measured values. The main transfer routes of PFOS between media were from atmosphere to soil and from soil to water. Meanwhile, water and soil were identified to be main sinks of PFOS in Dalian area. The primary sources of PFOS in the area were the advection inputs in atmosphere and water, and the advection output of PFOS in atmosphere was the primary outlet from Dalian. Sensitivity analysis showed that the main parameters affecting the model output were the organic carbon partition coefficient, solubility, advection inputs in atmosphere and water, and the runoff velocity of water in soil and temperature. The results of uncertain analysis indicated that the change of the overall parameters had greatest impact on the result in water and least impact on that in sediment. This study simulated the transfer and fate of PFOS in the environmental multimedia of Dalian well, which could provide a scientific basis for its pollution control and ecological risk assessment.

Factors affecting spatial and temporal patterns in perfluoroalkyl acid (PFAA) concentrations in migratory aquatic species: a case study of an exploited crustacean.

Per- and poly-fluorinated alkyl substances (PFASs, including perfluoroakyl acids [PFAAs]) have been used in a range of applications, and are widely distributed throughout the environment including environmental media in aquatic systems. Recent literature provides multiple reports of these compounds in a range of aquatic species, but temporal and spatial variability in tissue concentrations is rarely assessed in a rigorous way. Using an important fishery species of representative biology as a case study (Eastern School Prawn, Metapenaeus macleayi), temporal (month-to-month, and year-to-year) and spatial (intra-estuarine and oceanic) variability in PFAAs concentrations was assessed alongside potential contributing factors. Perfluorooctane sulfonate (PFOS) was the dominant PFAA detected, and there was significant spatial variation in concentration driven primarily by distance to major point sources. There was also substantial variation in PFOS among months, likely driven by behavioural physiological or ecological factors. Importantly, muscle tissue concentrations were unrelated to surface water inputs of PFAAs into the estuary. A numerical model linking prawn migration data with concentrations in the estuarine nursery accurately predicted PFOS concentrations in adjacent oceanic trawling grounds. The results demonstrate the magnitude of temporal and spatial variation in PFAA concentrations, which has implications for assessing PFAA exposure risk through seafood consumption for free-ranging aquatic animals.

Bioaccumulation behavior and spatiotemporal trends of per- and polyfluoroalkyl substances in Indo-Pacific humpback dolphins from the Pearl River Estuary, China

Sixteen per- and polyfluoroalkyl substances (PFASs) were measured in liver (n = 52) and kidney (n = 18) tissues of Indo-Pacific humpback dolphins (Sousa chinensis) stranded in the Pearl River Estuary (PRE) of China between 2004 and 2016. The average concentrations of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and most of other PFASs in the liver samples were respectively greater than any records previously reported in cetaceans globally. PFOS levels in 46% of dolphin liver samples exceeded the hepatic toxicity threshold in cetaceans. For the first time, we found a U-shaped trend for the distribution pattern of perfluorinated carboxylic acids (PFCAs) between liver and kidney with increasing carbon chain lengths (C5-C16), whereas a descending trend (C4-C10) was found for perfluoroalkane sulfonic acids (PFASs), which may be explained by binding efficiencies of PFAS analogues to proteins. Dolphins with the highest levels of ∑PFASs (age-corrected) were clustered near the river outlets in Lingdingyang area, which agrees with the spatial distribution of PFASs in the environment. Significant temporal trends were observed for many PFASs. Concentrations of PFOA, perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA) and perfluoroheptanoic acid (PFHpA) all peaked in year 2011, followed by a decreasing trend, while a consistently descending trend was shown for perfluoroundecanoic acid (PFUdA) and perfluorodecane sulfonate (PFDS). Our findings contribute to the knowledge of tissue distribution and spatiotemporal trends of PFASs in the PRE dolphins, which are valuable for us to understand the PFASs exposure risk and their industrial emission in Southern China.

Cultivar-Dependent Accumulation and Translocation of Perfluorooctanesulfonate among Lettuce ( Lactuca sativa L.) Cultivars Grown on Perfluorooctanesulfonate-Contaminated Soil.

Perfluorooctanesulfonate (PFOS) is a toxic and persistent organic pollutant that can be widely detected in agricultural soils. In this study, two lettuce cultivars with low PFOS accumulation were screened out to reduce the exposure of PFOS to the human body via vegetable consumption. The screened low-PFOS cultivars may help to ensure food safety, despite planting in highly PFOS-polluted soils (1.0 mg/kg), due to their high tolerance to PFOS and 4.4-5.7 times lower shoot PFOS concentration than the high-PFOS cultivars. Protein content and protein-mediated transpiration played key roles in regulating PFOS accumulation in the lettuce cultivars tested. Lower protein content, lower stomatal conductance, and lower transpiration rate resulted in low PFOS accumulation. This study reveals the mechanism of forming low-PFOS accumulation of lettuce cultivars at physiological and biochemical levels and lays a foundation for developing a cost-effective and safe approach to grow vegetables in PFOS-polluted soils.

Dialysis Membranes Influence Perfluorochemical Concentrations and Liver Function in Patients on Hemodialysis.

Introduction: Perfluoro-octanesulfonate (PFOS) and perfluoro-octanoic acid (PFOA) are two toxic perfluorochemicals (PFCs) commonly used as surfactants. PFCs are difficult to be eliminated from the body. We investigated the influence of different dialysis membranes on the concentrations of PFCs in patients under hemodialysis. Method: We enrolled 98 patients. Of these, 58 patients used hydrophobic polysulfone (PS) dialysis membranes, and the other 40 had hydrophilic membranes made by poly-methyl methacrylate (PMMA) or cellulose triacetate (CTA). Liquid chromatography tandem mass spectrometry coupled was used with isotope dilution to quantify PFOA and PFOS. Results: The predialysis concentrations of PFOA and PFOS in patients with hydrophobic PS dialysis membranes were 0.50 and 15.77 ng/mL, respectively, lower than the concentrations of 0.81 and 22.70 ng/mL, respectively, in those who used hydrophilic membranes (such as CTA or PMMA). Older patients have higher PFOS and poorer body function, with lower Karnofsky Performance Status Scale (KPSS) scores. The demographic data of the two groups were similar. However, patients with hydrophobic PS dialysis membranes had lower predialysis aspartate transaminase (AST) (p = 0.036), lower glucose levels (p = 0.017), and better body function (nonsignificantly higher KPSS scores, p = 0.091) compared with patients who used other membranes. These differences may be associated with the effects of different membranes, because PFOA positively correlated with AST, while PFOS negatively correlated with body function. Conclusions: This is the first study comparing PFC levels in uremic patients with different dialysis membrane. PS membrane may provide better clearance of PFCs and may, therefore, be beneficial for patients.

Decomposition of perfluorooctane sulfonate (PFOS) using a hybrid process with electron beam and chemical oxidants

Among many contaminants of emerging concern, perfluorooctanesulfonate (PFOS) is widely known as one of the most difficult to decompose due to a very strong carbon-fluorine bond. Electron beam technology has been used to treat refractory compounds as a radical-based advanced oxidation process. Therefore, the aims of this study were to investigate the degradation efficiencies of PFOS with various initial concentrations and radiolytic products generated by PFOS decomposition using an electron beam, to improve the decomposition efficiency of PFOS using combined persulfate (S2O82−) and hydrogen peroxide (H2O2) with an electron beam, and to propose the radiolysis decomposition pathway of PFOS in aqueous solution. The results showed that the degradation efficiency of PFOS by the electron beam depended on the initial PFOS concentration. The addition of S2O82− with the electron beam increased the decomposition efficiency with increasing absorbed doses. The 0.1 mg/L PFOS (0.19 µM) in the presence of 5 mM S2O82− with the electron beam at a 100 kGy absorbed dose had a similar decomposition efficiency with that using only the electron beam at a 900 kGy absorbed dose. However, the addition of H2O2 was ineffective on the PFOS degradation in aqueous solution. Seven radiolytic products such as perfluorocarboxylic acids (PFCAs) were quantitatively confirmed using authentic standards among eight predicted radiolytic products. The radiolysis decomposition of PFOS can occur spontaneously in aqueous solution with the synergistic effects of eaq- and OH produced by electron beam irradiation. Therefore, the electron beam can be used as a viable process considering the decomposition efficiency and its degradation products.

Limited reproductive impairment in a passerine bird species exposed along a perfluoroalkyl acid (PFAA) pollution gradient

Although bird eggs have been used in biomonitoring studies on perfluoroalkyl acids (PFAAs), effects of environmental concentrations on reproduction remain largely unknown in wild birds. In the present study we examined the associations between the concentrations of 4 perfluoroalkyl sulfonic acids (PFSAs) and 11 perfluoroalkyl carboxylic acids (PFCAs) in the eggs of great tits (Parus major), collected along a distance gradient from a pollution source, and multiple reproductive parameters (including the start of egg laying, clutch size, hatching success, fledging success and total breeding success) along with egg shell thickness and body condition of the nestlings.The PFAA concentrations measured at the plant site were among the highest ever reported in wild bird eggs. PFAA concentrations decreased sharply with increasing distance (0–11 km) from the plant, but remained relatively elevated in the adjacent sites. PFAAs were grouped into principal components (PCs) to prevent collinearity. High concentrations of PFOS, PFDS, PFDoDA, PFTrDA and PFTeDA (grouped as PC1) were associated with a reduced hatching success of nests where at least one egg hatched, thinner egg shells and increased survival of the hatched chicks. High concentrations of PFDA (PC2) were associated with a reduced hatching success, especially in nests where no eggs hatched, an earlier start of egg laying and a reduction of total breeding success, mainly caused by the failure in hatching.Although the major manufacturer of PFAAs phased out the production of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and related products in 2002, concentrations appear to have increased since previous measurements. Surprisingly, despite the very high concentrations close to the fluorochemical plant, there was no clear evidence for reproductive impairment as the observed associations between PFAA concentrations and reproductive parameters were rather limited compared to previous studies in songbirds. These findings also suggest potential differences in sensitivity between species. CapsuleDespite the very high PFAA concentrations at the perfluorochemical hotspot, correlations with reproductive parameters were limited.

Survey design for quantifying perfluoroalkyl acid concentrations in fish, prawns and crabs to assess human health risks

Per and polyfluoroalkyl substances (PFASs) are emerging contaminants that have potential implications for human health. Perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) are perfluoroalkyl acids (PFAAs) that commonly bioaccumulate in aquatic species exposed to PFAS contaminant sources. Sampling programs aimed at measuring PFAA concentrations in free ranging aquatic animals to assess human health risk are not yet supported by any quantitative analyses to refine sampling effort required to provide a reasonable estimate of summary statistics for a species in a particular area. Here, an extensive, multi-species PFOS and PFHxS data set measured in free-ranging fish and crustaceans is employed to examine the effect of sample size on summary statistics estimated from sample data which are commonly employed in dietary exposure assessments. A unifying, cross-species model suggested that sample sizes between 20 and 40 individuals per species per location should provide a reasonable estimate of mean PFOS concentrations in free-ranging fish or crustaceans, but slightly larger sample sizes (30–50 individuals) may be required if sample medians are to be used in dietary exposure assessments. PFHxS concentrations were highly variable, so larger sample sizes should also be considered if this contaminant is of interest. The results are discussed in light of the levels of sampling effort reported in recent manuscripts, and other important considerations for designing sampling programs.

Gestational Perfluoroalkyl Concentrations and Thyroid Hormone Levels in Faroese Pregnant Women and Neonates: A Prospective Cohort Study

Background: Exposure to perfluoroalkyl substances (PFASs) may disrupt maternal and neonatal endocrine function. Adequate thyroid hormone (TH) levels during pregnancy are essential for fetal and early childhood development.Objective: To assess the relationship between gestational PFAS exposures and maternal and cord TH levels.Methods: Data was collected from a cohort of 182 mother-child pairs from 1994-1995 in the Faroe Islands. The concentrations of 17 PFASs, including perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were measured in maternal serum. Maternal and cord serum were measured for THs such as thyroid stimulating hormone (TSH), free thyroxine (FT4), thyroxine (T4), free triiodothyronine (FT3), free triiodothyronine resin uptake (T3RU), and free T4 index (FTI). We examined relationships between PFAS concentrations and TH levels using multivariable regression models and effect measure modification in sex-stratified analyses.Results: PFAS concentrations were mostly positively associated with both maternal and fetal TSH. PFOS and PFOA had the strongest estimates; doubling PFOS and PFOA concentrations were associated with 49% (95% CI: 18, 87%) and 33% (95% CI: 11, 59%) increase in cord TSH concentrations respectively. Perfluorooctanesulfonamide (PFOSA) was negatively associated with maternal FT4 and T3RU but positively associated with cord T4 and FTI levels. In mothers carrying female fetuses, doubling PFOS concentrations was associated with a 54% (95% CI: 14, 109%) increase in maternal TSH, but not in mothers bearing male neonates (-5%; 95% CI: -27, 24%). We did not observe consistent patterns for sex-stratified associations between gestational PFAS concentrations and cord TH levels.Conclusions: Prenatal exposure to several PFASs during pregnancy, such as PFOS and PFOA, is associated with increases in infant TSH levels. PFOS may also affect maternal TSH levels depending on the fetus’s sex, the implications of which are still to be understood.

Highly selective fluorescent visual detection of perfluorooctane sulfonate via blue fluorescent carbon dots and berberine chloride hydrate.

As a kind of emerging persistent organic pollutants, perfluorooctane sulfonate (PFOS) and its salts have caused global ecosystem pollution. To develop rapid, sensitive and low-cost detection method of PFOS is of great importance. In this work, a novel sensing method has been proposed for the highly selective fluorescent visual detection of PFOS in aqueous solution based on carbon dots (CDs) and berberine chloride hydrate (BH). It was found that the fluorescence of CDs decreased apparently in the presence of berberine chloride hydrate in pH 6.09 Britton-Robinson (BR) buffer solution. When PFOS was added to the system, the fluorescence was restored slightly at 448 nm and enhanced apparently at 533 nm, but no phenomenon occurred with other perfluorinated compounds. As a consequence, an obviously distinguishable fluorescence color variation (from blue to light yellow) of solution was observed. Under the optimized experimental conditions, the enhanced fluorescence intensities at 533 nm are in proportion to the concentration of PFOS in the range of 0.22-50.0 μmol/L (R2 = 0.9919), with a detection limit of 21.7 nmol/L (3σ). The proposed approach has been successfully applied to the detection of PFOS in environmental water samples with RSD ≤ 1.1%.

Evaluation of the developmental toxicity of perfluorooctanesulfonate in the Anuran, Silurana tropicalis.

A 150-day post-metamorphosis (dpm) partial lifecycle study exposing Silurana tropicalis to <0.03 (control), 0.06, 0.13 0.25, 0.5 and 1.0mg/L perfluorooctanesulfonate (PFOS) was conducted. A subset of specimens from the control and each treatment were evaluated at metamorphic completion. A significant increase in the median metamorphosis time was observed in the 1.0mg/L PFOS treatment relative to the control. A modest increase in the occurrence, but not severity, of mild follicular hypertrophy was found in thyroid glands from organisms exposed to the 0.62 and 1.1mg/L PFOS treatments. At 150dpm, a concentration-dependent increase in whole body PFOS residues was measured ranging from 29.6 to 163.5mg/kg in the 0.05 and 1.1mg/L PFOS treatments. Decreased body weight and snout-vent length were noted in specimens exposed to 1.1mg PFOS/L at the completion of metamorphosis. Body weight was reduced in the 1.1mg/L PFOS concentration; however, snout-vent length was not affected by PFOS exposure at 150dpm. An increased proportion of phenotypic males were noted in the 0.62 and 1.1mg/L PFOS treatments. Abnormal ovary development characterized by size asymmetry, necrosis and formation of excessive fibrous connective tissue was identified in females exposed to 0.29 and 1.1mg PFOS/L. Asymmetrically misshaped testes were found at 1.1mg/L PFOS. Results suggested that PFOS is capable of interfering with S. tropicalis growth before metamorphic completion and growth and gonad development during juvenile development.

Perfluorooctanoate and Perfluorooctanesulfonate plasma concentrations and survival after prostate and bladder cancer in a population-based study

Background: Perfluorooctanoate (PFOA) and perfluorooctanesulfonate (PFOS) are synthetically produced chemicals, which have been linked to cancer in animal studies, whereas the evidence in humans is merely suggestive. We investigated the association between PFOA and PFOS concentrations in plasma samples and mortality in two survivor cohorts of prostate and bladder cancer patients. Methods: We included 688 prostate and 307 bladder cancer cases diagnosed between baseline (1993–97) and July 1, 2006 in the Danish Diet, Cancer and Health cohort. PFOA and PFOS concentrations in plasma samples taken at baseline were measured using high-pressure liquid chromatography. We used Cox proportional hazards models to estimate mortality rate ratios. Results: Between diagnosis and February 1, 2016, 356 prostate and 149 bladder cancer cases died. We found no association between PFOA or PFOS concentrations and survival among prostate cancer cases. This was regardless of prognostic factors. For bladder cancer cases, there was an inverse association between PFOA and PFOS and subsequent mortality. Associations were similar for both overall and bladder cancer-specific mortality. Conclusions: The results of the present study does not suggest an association between PFOA or PFOS concentrations and survival among prostate cancer patients. In contrast, they may be inversely associated with both overall and bladder cancer–specific mortality in bladder cancer patients. However, this finding requires replication in further studies before firm conclusions can be drawn.

Occurrence and spatial distribution of perfluorinated compounds in groundwater receiving reclaimed water through river bank infiltration

Perfluorinated compounds (PFCs) in groundwater are of widespread concern due to their potential toxicity to human health and ecological systems. PFCs in rivers can infiltrate into groundwater through riverbank infiltration, potentially endangering the safety of drinking water and causing a deterioration in the groundwater environment. This study investigated the occurrence of PFCs in rivers and riverside groundwater from 2014 to 2017 in a city in north China. PFCs were detected in most of the groundwater samples, ranging from not detected to 64.8 ng L−1. The predominant PFCs in both river and groundwater samples were perfluorooctane sulfonate, perfluorooctanoic acid, perfluorobutane sulfonate and perfluorobutanoic acid. The PFC concentrations and major compounds were consistent in both the river and riverside groundwater samples at each site, suggesting that the adjacent river was the source of the PFCs in the riverside groundwater. The spatial distribution of the PFCs in the riverside groundwater was affected by the hydraulic connection between the groundwater and the river, the lithology of the aquifer and the properties of the compounds. The results indicated that PFCs were attenuated during riverbank infiltration and the ability of different riverbank lithologies to remove PFCs was in the order sandy clay > fine sand > sandy gravel. Perfluorooctane sulfonate concentrations decreased sharply with increasing distances from river, whereas perfluorooctanoic acid, perfluorobutane sulfonate and perfluorobutanoic acid could by transported for greater distances in riverside groundwater. This study provides valuable information on PFCs in riverside groundwater affected by riverbank infiltration.

Prenatal concentrations of perfluoroalkyl substances and bone health in British girls at age 17.

PFAS are used to make protective coatings on common household products. Prenatal exposures have been associated with developmental outcomes in offspring. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), we investigated the association between prenatal concentrations of PFAS and bone health in girls at 17years of age and whether body composition can explain any associations. We measured concentrations of perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), and perfluorononanoic acid (PFNA) in maternal serum samples collected during pregnancy. We obtained bone health outcomes in the girls, such as bone mineral density, bone mineral content, bone area, and area-adjusted bone mineral content from whole-body dual-energy X-ray absorptiometry (DXA) scans. We used multivariable linear regression to explore associations between each PFAS and each bone health outcome with adjustment for important confounders such as girls' age at clinic visit, maternal education, and gestational age at sample collection. We also controlled for girls' height and lean mass to explore the role body composition had on observed associations. Prenatal PFOS, PFOA, PFHxS, and PFNA concentrations were associated with inverse effects on bone size and mass after adjusting for important confounders. Conversely, PFNA was positively associated with area-adjusted bone mineral content. However, most significant associations attenuated after additional controlling for height and lean mass. Prenatal concentrations of some PFAS may be associated with reduced bone mass and size in adolescent girls, although it is not clear whether these associations are driven by body size.

Leaching and bioavailability of selected perfluoroalkyl acids (PFAAs) from soil contaminated by firefighting activities

Historical usage of aqueous film-forming foam (AFFF) at firefighting training grounds (FTGs) is a potential source of perfluoroalkyl acids (PFAAs) to the surrounding environment. In this study the leaching of PFAAs from field contaminated soil and their uptake into biota was investigated. Soil was sampled from FTGs at two airports and the total as well as the leachable concentration of 12 PFAAs was determined. A greenhouse study was carried out to investigate the uptake of PFAAs from soils into earthworms (Eisenia fetida) and wheat grass (Elymus scaber). Perfluorooctane sulfonate (PFOS) and perfluorohexane sulfonate (PFHxS) were the most dominant PFAAs in all soils samples, with concentrations of PFOS reaching 13,400 ng/g. Leachable concentrations of PFOS and PFHxS reached up to 550 μg/L and 22 μg/L, respectively. In earthworms concentrations of PFOS reached 65,100 ng/g after a 28-day exposure period, while in wheat grass the highest concentration was measured for uptake of PFHxS (2,800 ng/g) after a 10-week growth-period. Bioaccumulation factors (BAFs) for earthworms ranged from 0.1 for perfluorohexanoic acid (PFHxA) to 23 for perfluorododecanoic acid (PFDoA) and initially showed a decreasing trend with increasing perfluoroalkyl chain length, followed by an increase with increasing perfluoroalkyl chain length for perfluoroalkyl carboxylic acids (PFCAs). In wheat grass the highest BAF was found for perfluorobutanoic acid (BAF = 70), while the lowest was observed for perfluorononanoic acid (BAF = 0.06). BAFs in wheat grass decreased with increasing perfluoroalkyl chain length for both PFCAs and perfluoroalkyl sulfonic acids (PFSAs). The results show that PFAAs readily leach from impacted soils and are bioaccumulated into earthworms and plants in an analyte dependent way. This shows considerable potential for PFAAs to move away from the original source either by leaching or uptake into ecological receptors, which may be a potential entry route into the terrestrial foodweb.

Comprehension and perceptions of study participants upon receiving perfluoroalkyl substance exposure biomarker results.

Measurement of environmental biomarkers in biomedia is increasingly used as a method of exposure characterization in human population studies. Reporting the results of biomarker measurements back to study participants has been controversial, including questions of ethics and whether the study participants would want to receive and would understand the results. Recently we mailed individual measurements of two serum biomarkers, perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) to participants in three exposure studies of persons living in the Ohio River Valley, of whom 60 were parents of children who had been sampled. Many had serum concentrations of PFOA above the US population 95th percentile value. Reporting forms used in the three studies were somewhat different (either tables or charts for comparison to US population values) and varied in complexity. With all reports, we included information about concentrations of PFOA and PFOS in the general population, and a survey designed to ascertain the opinions of the study participants about the information they received. Approximately 33% (273/821) returned the survey, and of those, 96% reported that they were pleased that we had sent them the report. Most (86%) responded that the results were easy to understand and the enclosed fact sheet was helpful in answering questions (87%). Regarding the amount of information, most felt that we provided the "right amount" (78%) but some "too much" (7%) and some "too little" (15%). The majority (53%) were surprised at their serum concentrations. Of those with serum values > 13.0 ng/mL, 74% responded that they thought their serum concentration was "high", but only 22% of those with serum concentrations ≤5.6 responded that their concentration was "low". Surprisingly, many talked to no one about their levels; those who did were most likely to discuss the report with family members. Reporting back individual environmental biomarker results is generally well received by study participants, and those with high concentrations perceived them to be high. Questions remain as to why study participants did not discuss their results with others.

In situ measurement of perfluoroalkyl substances in aquatic systems using diffusive gradients in thin-films technique

To better understand the environmental impact of ubiquitous perfluoroalkyl substances (PFASs) in waters, reliable and robust measurement techniques are needed. As one of the most widely used passive sampling approaches, diffusive gradients in thin-films (DGT) is not only easy to handle but also provides time-weighted analyte concentrations. Based on DGT with XAD18 as a binding agent, we developed a new methodology to measure two frequently detected PFASs in surface waters and wastewaters, i.e. perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Their diffusion coefficients in the diffusive gel, measured using an independent diffusion cell, were 4.37 × 10−6 and 5.08 × 10−6 cm2 s−1 at 25 °C, respectively. DGT had a high capacity for PFOA and PFOS at 196 and 246 μg per gel disk, suggesting the DGT sampler was suitable for deployment of several weeks. Time-integrated concentrations of PFOA and PFOS in a natural lake and river, and a municipal wastewater treatment plant effluent using DGT samplers deployed in situ for 12–33 d were comparable to those measured by a solid-phase extraction method coupled with high-frequency grab sampling. This study demonstrates that DGT is an effective tool for in situ monitoring of PFASs in natural waters and wastewaters.

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

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

Perfluorooctanesulfonate (PFOS) Induces Apoptosis Signaling and Proteolysis in Human Lymphocytes through ROS Mediated Mitochondrial Dysfunction and Lysosomal Membrane Labialization.

Perfluorinated compounds (PFCs) such as perfluorooctanesulfonate (PFOS) are stable chemicals that accumulate in biological matrix. Toxicity of these compounds including immunotoxicity has been demonstrated in experimental models and wildlife. Although limited number of studies examined the effects of PFOS on human lymphocytes but so far no research has investigated the complete mechanisms of PFOS cytotoxicity toward human lymphocytes. The main goal of this investigation was to find out the mechanisms underlying the cytotoxic effect of PFOS toward human lymphocytes using accelerated cytotoxicity mechanisms screening (ACMS) technique. Human lymphocytes were isolated from blood of healthy donors using Ficoll-paquePLUS standard method. Cell viability was determined following 12 h of incubation of human lymphocytes with 100-500 µM PFOS. Our results showed that IC50 concentration (163.5 µM) of PFOS reduced viability of human lymphocytes approximately 50% via increased ROS formation, lipid peroxidation, glutathione depletion and damage to cell sub organelles such as mitochondria and lysosomes. Besides, in this study we demonstrated involvement of cellular proteolysis and activation of caspase-3 in PFOS induced lymphocyte cytotoxicity. We finally concluded that at environmentally related concentration, PFOS can induce toxic effect toward human lymphocytes through induction of oxidative stress and damage to cell sub organelles.

Ecological risk assessment of perfluooroctane sulfonate to aquatic fauna from a bayou adjacent to former fire training areas at a US Air Force installation.

Per- and polyfluoroalkyl substances (PFASs) continue to receive significant attention, with particular concern for PFASs such as perfluorooctane sulfonate (PFOS), which was a constituent of aqueous film-forming foam used widely as a fire suppressant for aircraft since the 1970s. We were interested in the potential for risk to ecological receptors inhabiting Cooper Bayou, which is adjacent to 2 former fire-training areas at Barksdale Air Force Base (LA, USA). Previous research showed higher PFOS concentrations in surface water and biota from Cooper Bayou compared to reference sites. To estimate risk, we compared surface water concentrations from multiple sites within Cooper Bayou with several PFOS chronic toxicity benchmarks for freshwater aquatic organisms (∼0.4-5.1 μg PFOS/L) and showed probability of exceedances from 0.04 to 0.5, suggesting a potential for adverse effects in the most contaminated habitats. A tissue-residue assessment similarly showed some exceedance of benchmarks but with a lower probability (maximum = 0.17). Both fire-training areas have been inactive for more than a decade, so exposures (and, thus, risks) are expected to decline. Several uncertainties limit confidence in our risk estimates including highly dynamic surface water concentrations and limited chronic toxicity data for relevant species. Also, we have little data concerning organisms higher in the food chain which may receive higher lifetime exposures given the potential for PFOS to bioaccumulate and the longevity of many of these organisms. Overall, the present study suggests that PFOS can occur at concentrations that may cause adverse effects to ecological receptors, although additional, focused research is needed to reduce uncertainties. Environ Toxicol Chem 2018;37:2198-2209. © 2018 SETAC.