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• ZnS-X%[N] with adjustable surface amine functional groups and Zn defects. • ZnS-X%[N] could efficiently adsorb PFAS. • The adsorbed PFAS are subsequently degraded under UV irradiation. • The regulatory mechanism of CTAB on ZnS photocatalytic performance was investigated. Perfluorinated alkylated substances (PFAS), as a category of persistent organic pollutants, have garnered extensive concern due to their resilience against environmental degradation. Herein, we developed an amine-functionalized sphalerite (ZnS) with adjustable surface amine functional groups and Zn defects (ZnS-X%[N]) by in situ coprecipitation and simple hydrothermal method in the presence of cetyltrimethylammonium bromide (CTAB). This material demonstrated efficient PFAS adsorption and subsequent photo-induced degradation under UV irradiation. The characterization results by TEM, BET, FTIR, XPS and EPR revealed that CTAB primarily influences ZnS by modulating surface amine functionalities, zinc defect density, and enhancing its photoreductive capacity. Adsorption and kinetic degradation experiments further showed that a medium CTAB concentration in ZnS-40%[N] achieves highest PFAS adsorption capacity (C max : 0.201 mol kg-1), and the corresponding decomposition rate was the fastest (k de : 1.53; k df : 1.19). This efficacy is attributed to the ZnS-40%[N]'s ideal adsorptive sites and surface shallow defects. Moreover, theoretical simulation also supports the above experimental inference. Overall, ZnS-X%[N] exhibits a synergistic effect on PFAS adsorption and degradation, showcasing its potential for environmental adaptability and practical application. [ABSTRACT FROM AUTHOR]

Fluorescent ubiquitination-based cell cycle indicator (FUCCI) embryonic stem cells (ESCs), which fluoresce green during the S-G2-M phases, generate an S-shaped curve for the accumulation of cells during normal stemness (NS) culture with leukemia-inhibitory factor (LIF). Since it was hypothesized that a culture of ESCs was heterogeneous in the cell cycle, it was expected that increased S-G2-M-phases of the cell cycle would make an S-shaped curve parallel to the accumulation curve. Unexpectedly, it was observed that the fraction of FUCCI ESCs in green decreases over time to a nadir at ∼24 h after previous feeding and then rapidly enters S-G2-M-phases after medium change. G1 delay by infrequent medium change is a mild stress, as it does not affect growth significantly when frequency is increased to 12 h. Perfluoro-octanoic acid (PFOA) and diethyl phthalate (DEP) were used as examples of members of the per- and polyfluoroalkyl substances (PFAS) and phthalate families of chemicals, respectively. Two adverse outcomes were used to compare dose- and time-dependent effects of PFOA and DEP. The first was cell accumulation assay by time-lapse confluence measurements, largely at Tfinal/T74 h. The second was by quantifying dominant toxicant stress shown by the suppression of mild stress that creates a green fed/unfed peak. In terms of speed, PFOA is 26 times faster than DEP for producing a time-dependent LOAEL dose at 100 uM (that is, 2 h for PFOA and 52 h for DEP). PFOA has 1000-fold more sensitive LOAEL doses than DEP for suppressing ESC accumulation (confluence) at day 3 and day 2. There were two means to compare the magnitude of the growth suppression of PFOA and DEP. For the suppression of the accumulation of cells measured by confluence at Tfinal/T74h, there was a 13-fold suppression at the highest dose of PFOA > the highest dose of DEP. For the suppression of entry into the cell cycle after the G1 phase by stress on day 1 and 2, there is 10-fold more suppression by PFOA than DEP. The data presented here suggest that FUCCI ESCs can assay the suppression of accumulated growth or predict the suppression of future growth by the suppression of fed/unfed green fluorescence peaks and that PFOA’s adverse effects are faster and larger and can occur at more sensitive lower doses than DEP.

Per- or polyfluoroalkyl substances (PFAS), a family of synthetic polyfluorinated compounds, are widely used in consumer products. Ubiquitous exposures to PFAS, in consideration of their persistence, bioaccumulation potential, and toxicities have led to concerns regarding possible harmful effects during critical periods of development in early-life and long-term consequences on health. The potential effects of PFAS depend on various factors including the type of PFAS and the timing and level of exposure. We performed a systematic review of the epidemiologic literature to assess the effects of early-life PFAS exposure on prenatal and postnatal growth, adiposity, and puberty in children and adolescents. For birth size, most studies indicated that prenatal PFAS exposure, in particular long-chain PFAS, may impair fetal growth, albeit some reports of null associations with maternal PFAS. For growth within 2 years of age, prenatal PFAS exposure showed no associations with height and either null or negative associations with weight. However, postnatal PFAS exposures were inversely related to height and weight at 2 years in a cross-sectional study. For postnatal adiposity, prenatal PFAS may mostly have negative associations with body mass index in the first 2 years of life, but positive relationships with adiposity in childhood and adolescence, although some studies showed null associations. For puberty, the evidence for associations between early-life PFAS exposure and pubertal development or sex hormone levels were limited and inconclusive. From experimental studies, plausible mechanisms through which PFAS may affect early-life growth and puberty include PFAS-induced activation of peroxisome proliferator-activated receptor, alterations of thyroid or steroid hormone synthesis and metabolism, and their weak estrogenic or anti-androgenic properties. Although the published literature suggests possible effects of PFAS exposures on early-life growth, adiposity, and puberty, current human evidence is limited in establishing PFAS-induced effects on early-life physical development. Further investigation is warranted to clarify PFAS-induced effects on growth and physical development in consideration of the critical time-window of exposure, concomitant exposure to chemical mixtures including various PFAS types, and possible non-monotonic dose-response relationship for growth and adiposity trajectories.

Per- or polyfluoroalkyl substances (PFAS), a family of synthetic polyfluorinated compounds, are widely used in consumer products. Ubiquitous exposures to PFAS, in consideration of their persistence, bioaccumulation potential, and toxicities have led to concerns regarding possible harmful effects during critical periods of development in early-life and long-term consequences on health. The potential effects of PFAS depend on various factors including the type of PFAS and the timing and level of exposure. We performed a systematic review of the epidemiologic literature to assess the effects of early-life PFAS exposure on prenatal and postnatal growth, adiposity, and puberty in children and adolescents. For birth size, most studies indicated that prenatal PFAS exposure, in particular long-chain PFAS, may impair fetal growth, albeit some reports of null associations with maternal PFAS. For growth within 2 years of age, prenatal PFAS exposure showed no associations with height and either null or negative associations with weight. However, postnatal PFAS exposures were inversely related to height and weight at 2 years in a cross-sectional study. For postnatal adiposity, prenatal PFAS may mostly have negative associations with body mass index in the first 2 years of life, but positive relationships with adiposity in childhood and adolescence, although some studies showed null associations. For puberty, the evidence for associations between early-life PFAS exposure and pubertal development or sex hormone levels were limited and inconclusive. From experimental studies, plausible mechanisms through which PFAS may affect early-life growth and puberty include PFAS-induced activation of peroxisome proliferator-activated receptor, alterations of thyroid or steroid hormone synthesis and metabolism, and their weak estrogenic or anti-androgenic properties. Although the published literature suggests possible effects of PFAS exposures on early-life growth, adiposity, and puberty, current human evidence is limited in establishing PFAS-induced effects on early-life physical development. Further investigation is warranted to clarify PFAS-induced effects on growth and physical development in consideration of the critical time-window of exposure, concomitant exposure to chemical mixtures including various PFAS types, and possible non-monotonic dose-response relationship for growth and adiposity trajectories. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFAS) represent a group of synthetic compounds widely used in industry plants due to their low grade of degradation, surfactant properties, thermic and flame resistance. These characteristics are useful for the industrial production, however they are also potentially dangerous for human health and for the environment. PFAS are persistent pollutants accumulating in waters and soil and recoverable in foods due to their release by food packaging. Humans are daily exposed to PFAS because these compounds are ubiquitous and, when assimilated, they are difficult to be eliminated, persisting for years both in humans and animals. Due to their persistence and potential danger to health, some old generation PFAS have been replaced by newly synthesized PFAS with the aim to use alternative compounds presumably safer for humans and the environment. Yet, the environmental pollution with PFAS remains a matter of concern worldwide and led to large-scale epidemiological studies both on plants’ workers and on exposed people in the general population. In this context, strong concern emerged concerning the potential adverse effects of PFAS on the thyroid gland. Thyroid hormones play a critical role in the regulation of metabolism, and thyroid function is related to cardiovascular disease, fertility, and fetal neurodevelopment. In vitro, ex vivo data, and epidemiological studies suggested that PFASs may disrupt the thyroid hormone system in humans, with possible negative repercussions on the outcome of pregnancy and fetal-child development. However, data on the thyroid disrupting effect of PFAS remain controversial, as well as their impact on human health in different ages of life. Aim of the present paper is to review recent data on the effects of old and new generation PFAS on thyroid homeostasis. To this purpose we collected information from in vitro studies, animal models, and in vivo data on exposed workers, general population, and pregnant women.

Per- and polyfluoroalkyl substances (PFAS) represent a group of synthetic compounds widely used in industry plants due to their low grade of degradation, surfactant properties, thermic and flame resistance. These characteristics are useful for the industrial production, however they are also potentially dangerous for human health and for the environment. PFAS are persistent pollutants accumulating in waters and soil and recoverable in foods due to their release by food packaging. Humans are daily exposed to PFAS because these compounds are ubiquitous and, when assimilated, they are difficult to be eliminated, persisting for years both in humans and animals. Due to their persistence and potential danger to health, some old generation PFAS have been replaced by newly synthesized PFAS with the aim to use alternative compounds presumably safer for humans and the environment. Yet, the environmental pollution with PFAS remains a matter of concern worldwide and led to large-scale epidemiological studies both on plants' workers and on exposed people in the general population. In this context, strong concern emerged concerning the potential adverse effects of PFAS on the thyroid gland. Thyroid hormones play a critical role in the regulation of metabolism, and thyroid function is related to cardiovascular disease, fertility, and fetal neurodevelopment. In vitro , ex vivo data, and epidemiological studies suggested that PFASs may disrupt the thyroid hormone system in humans, with possible negative repercussions on the outcome of pregnancy and fetal-child development. However, data on the thyroid disrupting effect of PFAS remain controversial, as well as their impact on human health in different ages of life. Aim of the present paper is to review recent data on the effects of old and new generation PFAS on thyroid homeostasis. To this purpose we collected information from in vitro studies, animal models, and in vivo data on exposed workers, general population, and pregnant women. [ABSTRACT FROM AUTHOR]

A practical multi-residue method based on ultra-performance liquid chromatography/tandem mass spectrometry was developed for the simultaneous determination of 23 perfluorinated alkylated substances (PFASs) in water and suspended particles. Suspended particle samples were extracted with 1% formic acid-acetonitrile and cleaned by matrix solid phase dispersion extraction using a C18 sorbent and graphitized carbon black. Water samples were filtered through 0.7-μm glass fiber membranes and enriched utilizing weak anion exchange cartridges. The eluent was dried under a gentle stream of N2 at 45°C and suspended in 1 mL acetonitrile-5 mM ammonium acetate (1:1, vol:vol). Gradient elution for chromatographic separation utilized acetonitrile and 5 mM ammonium acetate as mobile phases on a reverse phase C18 column. The compounds were quantified using an internal standard method in multiple reaction-monitoring mode. Limits of detection and quantitation of the 23 PFAS test compounds in water samples were 0.5-10 ng L−1 and 2-20 ng L-1, respectively. Recoveries at three fortified levels of 20, 50, and 200 ng L-1 ranged from 68.5% to 118% with relative standard deviations below 9.6%. We used this method to determine PFAS levels in real water and suspended particle samples and found high sensitivity and good reproducibility. [ABSTRACT FROM AUTHOR]

Persistent organic pollutants, such as perfluorinated alkylated substances (PFASs) and brominated flame retardants (BFRs) are widespread in the environment and most of them are bioaccumulated in wildlife and humans. The present study is the first investigation to reveal the PFAS and BFR levels of serum samples in the adult population of the Czech Republic. Altogether, 300 serum samples from blood donors in four cities were examined. In all samples 19 PFASs and 33 BFRs, including some of their metabolites, were targeted. The analyses were performed using ultra high performance liquid chromatography coupled with tandem mass spectrometry or gas chromatography with mass spectrometry (according to the type of analyte). PFASs, with the carbon chain length C6 and higher, dominated in all samples. Perfluorooctanesulfonate (PFOS; median: 2.43ng/mL), perfluorooctanoic acid (PFOA; median: 0.756ng/mL), perfluorodecanoic acid (PFDA; median: 0.145ng/mL) and perfluorohexanesulfonate (PFHxS; median: 0.184ng/mL) were detected in 100% of samples. Perfluorononanoic acid (PFNA; median: 0.325ng/mL) and perfluoroundecanoic acid (PFUdA; median: 0.058ng/mL) in 99.7% and 96.0% of samples, respectively. We observed statistically significant associations (p<0.05) between selected PFAS concentrations and the locality, gender, age of donors and education level. None of the BFRs was detected above the LOQ in more than 9% of the samples. The most frequently detected representatives of this group were congeners of polybrominated diphenyl ethers, namely BDE-47 (in 8.7%; range: 0.496-5.44ng/g lipid weight (l.w.)), BDE-99 (in 6.0%; range: 0.706-9.46ng/g l.w.), BDE-153 (in 7.3%; range: 0.736-6.44ng/g l.w.) and BDE-209 (in 7.0%; range: 13.7-2693ng/g l.w.). [ABSTRACT FROM AUTHOR]

Atlantic blue fin tuna (Thunnus thynnus) is a species of great importance for Mediterranean Sea area, from both ecological and commercial points of view. The scientific literature reports few data on the contamination of this fish by emerging organic compounds such as perfluorinated alkylated substances (PFASs) and phthalates, being the latter never been studied in tuna. This study therefore investigated the presence of the PFASs perfluorooctane sulphonate (PFOS) and perfluoroctanoic acid (PFOA) and the phthalate di-2-ethylhexyl phthalate (DEHP), also monitored by its metabolite mono-2-ethylhexyl phthalate (MEHP), to assess both the state of contamination of Atlantic bluefin tuna specimen and the risk due to the toxicity of these compounds for human consumption. While PFOA was never found, detectable levels of PFOS (0.4-1.88 ng/g), DEHP (9-14.62 ng/g) and MEHP (1.5-6.30 ng/g) were found. The results were elaborated relating the accumulation to the size and age of the individuals and showed a correlation between the levels of different pollutants investigated. [ABSTRACT FROM AUTHOR]

Perfluorooctanoic acid (PFOA) is an important and diffuse perfluorinated alkylated substance, but knowledge of the toxicological effects of this endocrine disrupter in fish is limited. Adult common carp Cyprinus carpio, L. were exposed to 200 ng/l (a concentration reported in impacted aquatic ecosystems) and 2 mg/l PFOA solutions in a flow-through system for 56 days to determine tissue accumulation and histological alterations of the primary target organs. PFOA was extracted from blood, gill, liver, muscle, kidney, gonad, and brain by an ion-pairing liquid extraction procedure and quantified using high performance liquid chromatography with electrospray ionization tandem mass spectrometry. The limit of detection (LOD) was 0.4 ng/g wet weight (ww). PFOA was not detectable in unexposed fish or in fish exposed to 200 ng/l, but was >LOD in most samples of carp exposed to 2 mg/l. Mean PFOA concentration ranged from 0.5 to 65 ng/g ww, depending on the tissue, with highest levels in the blood and liver. There were no significant differences in condition factor, hepato-somatic index, or gonado-somatic index among the fish of the three groups. Histological, histochemical, and immunohistochemical staining was performed on sections of liver and gonad. Occurrence of atretic oocytes and a paucity of spermatozoa were documented in carp treated with 2 mg/l PFOA. Exposed fish did not show gross hepatic anomalies, but there was enhancement of hepatocytes in proliferation (positive to anti-PCNA antibody) compared to controls. [ABSTRACT FROM AUTHOR]

A perfluorinated alkylated substances (PFAS) biomonitoring study was conducted in European eel ( Anguilla anguilla ) in Italy for the first time. Perfluorooctanesulfonate (PFOS) and perfluorooctanoic acid (PFOA) concentrations were assessed in the organs of 35 wild eels from two locations, the highly impacted Po River and the Comacchio Lagoon along the north-western Adriatic coast. PFAS were extracted by ion-pairing liquid extraction procedure and measured using high performance liquid chromatography with electrospray ionization tandem mass spectrometry. There were no significant differences in mean PFAS concentrations ( p > 0.05) between samples from the two sites. PFOS and PFOA were detectable (>0.4 ng g −1 wet weight, w.w) in 73% and 31% of the total samples, respectively. PFOS concentrations ranged from <0.4 to 6.28 ng g −1 w.w and PFOA from <0.4 to 92.77 ng g −1 w.w. The highest PFAS levels were observed in blood and the lowest in muscle. Histology showed macrophage aggregates and hepatocytic vacuolation in some liver samples. No tissue anomalies were seen in the gonads, suggesting no reproductive impairment. The PFAS contamination levels observed were comparable to, or lower than, those reported in fish in other European countries, seeming to indicate that PFAS pollution of the study area is not remarkable. [ABSTRACT FROM AUTHOR]

Profiles of seven compounds of perfluoro-alkyl substances (PFASs) were compared among three species of top predators from the Danish North Sea: the white-beaked dolphin ( Lagenorhynchus albirostris), the harbor porpoise ( Phocoena phocoena), and the harbor seal ( Phoca vitulina). The seals had higher total burdens (757.8 ng g ww) than the dolphins (439.9 ng g ww) and the porpoises (355.8 ng g ww), probably a reflection of feeding closer to the shore and thus contamination sources. The most striking difference among the species was the relative contribution of perfluorooctanesulfonamide (PFOSA) to the profiles; the seals (0.1 %) had much lower levels than porpoises (8.3 %) and dolphins (26.0 %). In combination with the values obtained from the literature, this result indicates that Carnivora species including Pinnipedia have a much higher capacity of transforming PFOSA to perfluorooctane sulfonic acid (PFOS) than cetacean species. Another notable difference among the species was that the two smaller species (seals and porpoises) with supposedly higher metabolic rates had lower concentrations of the perfluorinated carboxylic acids, which are generally more easily excreted than perfluorinated sulfonamides. Species-specific characteristics should be recognized when PFAS contamination in marine mammals is investigated, for example, several previous studies of PFASs in cetaceans have not quantified PFOSA. [ABSTRACT FROM AUTHOR]

Abstract: A previously developed and validated methodology based on liquid chromatography coupled to high resolution mass spectrometry was used for determine the concentration levels of 14 perfluoroalkylated substances (PFASs) in a set of 48 breast milk samples collected from French women in the frame of the ELFE pilot study. In accordance with other similar studies conducted at european and international levels, PFOS, PFOA, and PFHxS were detected and quantified in most of the analyzed samples (90%, 98% and 100%, respectively), and appeared as major contributors to the total PFAS exposure (38%, 37%, 25%, respectively), whereas the other targeted PFAS were very rarely, if not, found at the limits of detection of the method. Also in agreement with other published data, the concentration levels measured for the detected substances varied from <0.05 to 0.33μg/L for PFOS (median=0.079), from <0.05 to 0.22μg/L for PFOA (median=0.075), and from 0.04 to 0.07μg/L for PFHxS (median=0.050). On the basis of this relatively limited data set, no statistically significant relation was observed between these exposure levels and developmental outcomes, in particular the weight at birth. Similarly, no relation was observed between the measured PFAS levels and various socio-demographical parameters including the consumption of seafood, alcohol, smoking, or socio-economical level. These results suggest a need for further research and better knowledge regarding the sources, pharmacokinetics, and factors of exposure for other substances belonging to this class of emerging contaminants. [Copyright &y& Elsevier]

Abstract: The present study documents development and validation of a novel approach for determination of 23 perfluorinated alkylated substances (PFASs) in food of animal origin represented by milk and fish. The list of target analytes comprises four classes of PFASs, both ionic and non-ionic: 11 perfluorocarboxylic acids (PFCAs), 4 perfluorosulphonic acids (PFSAs), 5 perfluorosulphonamides (FOSAs) and 3 perfluorophosphonic acids (PFPAs). Fast sample preparation procedure is based on an extraction of target analytes with acetonitrile (MeCN) and their transfer (supported by inorganic salts and acidification) into the organic phase. Removing of matrix co-extracts by a simple dispersive solid phase extraction (SPE) employing ENVI-Carb and C18 sorbents is followed by an efficient sample pre-concentration performed by acetonitrile evaporation and subsequent dilution of residue in a small volume of methanol (matrix equivalent in the final extracts was 16 and 8gmL−1, for milk and fish respectively). Using modern instrumentation consisting of ultra-high performance liquid chromatography (UHPLC) hyphenated with a tandem mass spectrometer (MS/MS), limits of quantification (LOQs) as low as 0.001–0.006μgkg−1 for milk and 0.002–0.013μgkg−1 for fish can be achieved. Under these conditions, a wide spectrum of PFASs, including minor representatives, can be determined which enables collecting data required for human exposure studies. The pilot study employing the new method for examination of milk and canned fish samples was realized. Whereas in majority of canned fish products a wide spectrum of PFCAs, perfluorooctanesulphonic acid (PFOS) and perfluoro-1-octanesulphonamide (PFOSA) was detected, only in a few milk samples very low concentrations (LOQ levels) of PFOS and perfluorooctansulphonic acid (PFDS) were found. [Copyright &y& Elsevier]

Abstract: Polybrominated diphenyl ethers (PBDEs), perfluorinated alkylated substances (PFAS), and metals were monitored in tile drainage and groundwater following liquid (LMB) and dewatered municipal biosolid (DMB) applications to silty-clay loam agricultural field plots. LMB was applied (93,500Lha−1) in late fall 2005 via surface spreading on un-tilled soil (SSLMB), and a one-pass aerator-based pre-tillage prior to surface spreading (AerWay SSD) (A). The DMB was applied (8Mgdwha−1) in early summer 2006 on the same plots by injecting DMB beneath the soil surface (DI), and surface spreading on un-tilled soil (SSDMB). Key PBDE congeners (BDE-47, -99, -100, -153, -154, -183, -209) comprising 97% of total PBDE in LMB, had maximum tile effluent concentrations ranging from 6 to 320ngL−1 during application-induced tile flow. SSLMB application-induced tile mass loads for these PBDE congeners were significantly higher than those for control (C) plots (no LMB) (p <0.05), but not A plots (p >0.05). PBDE mass loss via tile (0–2h post-application) as a percent of mass applied was ~0.04–0.1% and ~0.8–1.7% for A and SSLMB, respectively. Total PBDE loading to soil via LMB and DMB application was 0.0018 and 0.02kg total PBDE ha−1 yr−1, respectively. Total PBDE concentration in soil (0–0.2m) after both applications was 115ngg−1 dw, (sampled 599days and 340 days post LMB and DMB applications respectively). Of all the PFAS compounds, only PFOS (max concentration=17ngL−1) and PFOA (12ngL−1) were found above detectable limits in tile drainage from the application plots. Mass loads of metals in tile for the LMB application-induced tile hydrograph event, and post-application concentrations of metals in groundwater, showed significant (p <0.05) land application treatment effects (SSLMB >A>C for tile and SSLMB and A>C for groundwater for most results). Following DMB application, no significant differences in metal mass loads in tile were found between SSDMB and DI treatments (PBDE/PFAS were not measured). But for many metals (Cu, Se, Cd, Mo, Hg and Pb) both SSDMB and DI loads were significantly higher than those from C, but only during <100days post DMB application. Clearly, pre-tilling the soil (e.g., A) prior to surface application of LMB will reduce application-based PBDE and metal contamination to tile drainage and shallow groundwater. Directly injecting DMB in soil does not significantly increase metal loading to tile drains relative to SSDMB, thus, DI should be considered a DMB land application option. [Copyright &y& Elsevier]

Abstract: Perfluorinated alkylated substances (PFAS) are of global interest due to their occurrence and persistency in the environment. This study includes surface waters and sediments for the analysis of eleven PFAS. The PFAS studied can be grouped in perfluoroalkyl carboxylates (PFCAs), perfluoroalkyl sulfonates (PFS) and perfluoroalkyl sulfonamides (PFSA). The two most important compounds are perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS). These two substances showed the most significant values for surface water samples with maximum concentrations of 21ngl−1 for PFOA and 37ngl−1 for PFOS. Sediment samples from seven Austrian lakes and the river Danube were studied. Whereas PFSA and PFS were not detected in any sediment sample PFCAs were detected in most of the lake samples in concentrations up to 1.7μgkg−1 dry wt. PFOA, perfluorohexanoic acid (PFHxA) and perfluoroheptanoic acid (PFHpA) were detected in all Danube river sediment samples in concentrations varying from 0.1 up to 5.1μgkg−1 dry wt. For the various sampling points the proportional mass flows deriving from wastewater discharges were calculated. Whereas only up to 10% of the average flow is discharged wastewater up to more than 50% of the PFAS mass flows in the rivers can be attributed to wastewater discharges. Besides wastewater different other pathways as emissions from point sources, further degradation of precursor products, runoff from contaminated sites or surface runoff as well as dry and wet deposition have to be considered as relevant sources for PFAS contamination in surface waters. [Copyright &y& Elsevier]

Fluorescent ubiquitination-based cell cycle indicator (FUCCI) embryonic stem cells (ESCs), which fluoresce green during the S-G2-M phases, generate an S-shaped curve for the accumulation of cells during normal stemness (NS) culture with leukemia-inhibitory factor (LIF). Since it was hypothesized that a culture of ESCs was heterogeneous in the cell cycle, it was expected that increased S-G2-M-phases of the cell cycle would make an S-shaped curve parallel to the accumulation curve. Unexpectedly, it was observed that the fraction of FUCCI ESCs in green decreases over time to a nadir at ∼24 h after previous feeding and then rapidly enters S-G2-M-phases after medium change. G1 delay by infrequent medium change is a mild stress, as it does not affect growth significantly when frequency is increased to 12 h. Perfluoro-octanoic acid (PFOA) and diethyl phthalate (DEP) were used as examples of members of the per- and polyfluoroalkyl substances (PFAS) and phthalate families of chemicals, respectively. Two adverse outcomes were used to compare dose- and time-dependent effects of PFOA and DEP. The first was cell accumulation assay by time-lapse confluence measurements, largely at Tfinal/T74 h. The second was by quantifying dominant toxicant stress shown by the suppression of mild stress that creates a green fed/unfed peak. In terms of speed, PFOA is 26 times faster than DEP for producing a time-dependent LOAEL dose at 100 uM (that is, 2 h for PFOA and 52 h for DEP). PFOA has 1000-fold more sensitive LOAEL doses than DEP for suppressing ESC accumulation (confluence) at day 3 and day 2. There were two means to compare the magnitude of the growth suppression of PFOA and DEP. For the suppression of the accumulation of cells measured by confluence at Tfinal/T74h, there was a 13-fold suppression at the highest dose of PFOA > the highest dose of DEP. For the suppression of entry into the cell cycle after the G1 phase by stress on day 1 and 2, there is 10-fold more suppression by PFOA than DEP. The data presented here suggest that FUCCI ESCs can assay the suppression of accumulated growth or predict the suppression of future growth by the suppression of fed/unfed green fluorescence peaks and that PFOA's adverse effects are faster and larger and can occur at more sensitive lower doses than DEP., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Abdulhasan, Ruden, You, Harris, Ruden, Awonuga, Alvero, Puscheck and Rappolee.)