Miceliization and Surface Adsorption of Tetraethylammonium Perfluorooctanesulfonate in Mixed Solvents

The surface tension and cenductivity of tetracthylarnmomum perfluorooctanesulfonate (TEPFOS) solu-tions in mixed solvents were determined The criticsl micelle concentrations (cmc) and surface adsorption of TEPFOS in various solvents (Dimetbylsulfoxlde and DMSO, formamide and FA, and DMSO-H2O and FA H2O mixtures) were calculated from the above experimental date. The results show that the surface activity of TEPFOS is much higher than that of typical hydrocarbon surfactant, sodium dodecylsulfate (SDS); the melecalar interaction (in terms of colubility araneter or surface tension) of solvent is the decisive factor in sffecting the cmc of TEPFOS , in the apretic solvent DMSO, the value of entropy change during micelliza-tion of TEPFOS may beecme subsantially negative; the surfaof adsorption amount of TEPFOS is the largest in H2O, smaller in FA , and the smallest in DMSO.

Carbon Chain Length Determines Inhibitory Potency of Perfluoroalkyl Sulfonic Acids on Human Placental 3β-Hydroxysteroid Dehydrogenase 1:Screening,Structure-Activity Relationship,and In Silico Analysis

Objective This study aimed to compare 9 perfluoroalkyl sulfonic acids(PFSA)with carbon chain lengths(C4–C12)to inhibit human placental 3β-hydroxysteroid dehydrogenase 1(3β-HSD1),aromatase,and rat 3β-HSD4 activities.Methods Human and rat placental 3β-HSDs activities were determined by converting pregnenolone to progesterone and progesterone secretion in JEG-3 cells was determined using HPLC/MS–MS,and human aromatase activity was determined by radioimmunoassay.Results PFSA inhibited human 3β-HSD1 structure-dependently in the order:perfluorooctanesulfonic acid(PFOS,half-maximum inhibitory concentration,IC50:9.03±4.83μmol/L)>perfluorodecanesulfonic acid(PFDS,42.52±8.99μmol/L)>perfluoroheptanesulfonic acid(PFHpS,112.6±29.39μmol/L)>perfluorobutanesulfonic acid(PFBS)=perfluoropentanesulfonic acid(PFPS)=perfluorohexanesulfonic acid(PFHxS)=perfluorododecanesulfonic acid(PFDoS)(ineffective at 100μmol/L).6:2FTS(1H,1H,2H,2H-perfluorooctanesulfonic acid)and 8:2FTS(1H,1H,2H,2H-perfluorodecanesulfonic acid)did not inhibit human 3β-HSD1.PFOS and PFHpS are mixed inhibitors,whereas PFDS is a competitive inhibitor.Moreover,1–10μmol/L PFOS and PFDS significantly reduced progesterone biosynthesis in JEG-3 cells.Docking analysis revealed that PFSA binds to the steroid-binding site of human 3β-HSD1 in a carbon chain length-dependent manner.All 100μmol/L PFSA solutions did not affect rat 3β-HSD4 and human placental aromatase activity.Conclusion Carbon chain length determines inhibitory potency of PFSA on human placental 3β-HSD1 in a V-shaped transition at PFOS(C8),with inhibitory potency of PFOS>PFDS>PFHpS>PFBS=PFPS=PFHxS=PFDoS=6:2FTS=8:2FTS.

全氟辛烷磺酰基化合物水生生态风险和人体健康风险评价

全氟辛烷磺酰基化合物(Perfluorooctanesulfonate,PFOS)广泛用于工农业生产,PFOS可通过不同的迁移路径迁移到大气、水和土壤等环境介质中。研究表明,PFOS是一种新的持久性有机物污染物,具有毒性,可通过食物链富集。2006年PFOS被欧盟议会和部长理事会列为限制销售和使用物质。本文引用中国沿海、亚洲海域和美国部分水域的PFOS暴露浓度数据,采用商值法对PFOS的水生生态环境风险进行了评价,建立了5种因素水平的数学模型,并应用此数学模型对PFOS的人体健康风险进行了评价。结果表明我国部分地区和亚洲沿海PFOS的水生生态风险低于美国水域,亚洲沿海、我国部分地区以及美国部分城市水体中PFOS个人风险大小依次是我国部分地区<亚洲沿海<美国部分城市。

PERFLUOROOCTANESULFONIC ACID CATALYZED FRIEDEL-CRAFTS ALKYLATION WITH OLEFINS IN GAS-LIQUID PHASE

Solid superacid perfluorooctanesulfonic acid(POSA)catalyzed Friedel-Crafts alkylation of aromatic hydrocarbons with olefins in gas-liquid phase.The alkylations gave good yields with simple operation and easy work up.The amount of the catalyst used in the reactions was small and could be reused.The optimum temperature of the reactions and the effect of the amount of the catalyst used in the reactions are also discussed.

Effects of perfluoroalkyl and polyfluoroalkyl substances(PFAS)on soil structure and function

Soils are impacted globally by several anthropogenic factors,including chemical pollutants.Among those,perfluoroalkyl and polyfluoroalkyl substances(PFAS)are of concern due to their high environmental persistence,and as they might affect soil structure and function.However,data on impacts of PFAS on soil structure and microbially-driven processes are currently lacking.This study explored the effects of perfluorooctanesulfonic acid(PFOS),perfluorooctanoic acid(PFOA)and perfluorobutanesulfonic acid(PFBS)at environmental-relevant concentrations on soil health,using a 6-week microcosm experiment.PFAS(even at 0.5 ng g-1 for PFBS)significantly increased litter decomposition,associated with positive effects on-glucosidase activities.This effect increased with PFAS concentrations.Soil pH was significantly increased,likely as a direct consequence of increased litter decomposition affected by PFAS.Soil respiration was significantly inhibited by PFAS in week 3,while this effect was more variable in week 6.Water-stable aggregates were negatively affected by PFOS,possibly related to microbial shifts.PFAS affected soil bacterial and fungal abundance,but not microbial and certain enzyme activities.Our work highlights the potential effects of PFAS on soil health,and we argue that this substance class could be a factor of environmental change of potentially broad relevance in terrestrial ecosystem functioning.

Tissue distribution of perfluoroalkyl acids and health status in wild Mozambique tilapia(Oreochromis mossambicus) from Loskop Dam, Mpumalanga, South Africa

This study examined concentrations of 15 perfluoroalkyl acids（PFAAs） in tissues from male Mozambique tilapia（Oreochromis mossambicus） collected at Loskop Dam, Mpumalanga,South Africa in 2014 and 2016. Nine of the 15 PFAAs were detected frequently and were included in statistical analysis and included two of the most commonly known PFAAs,perfluorooctanesulfonic acid（PFOS）（median, 41.6 ng/g） and perfluorooctanoic acid（PFOA）（median, 0.0825 ng/g）. Of the tissues measured, plasma（2016 and 2014 median, 22.2 ng/g）contained the highest PFAA burden followed by（in descending order）： liver（median,11.6 ng/g）, kidney（median, 9.04 ng/g）, spleen（median, 5.92 ng/g）, adipose（median, 2.54 ng/g）, and muscle（median, 1.11 ng/g）. Loskop Dam tilapia have been affected by an inflammatory disease of the adipose tissue known as pansteatitis, so this study also aimed to investigate relationships between PFAA tissue concentrations and incidence of pansteatitis or fish health status. Results revealed that healthy tilapia exhibited an overall higher（p-value 〈 0.05） PFAA burden than pansteatitis-affected tilapia across all tissues.Further analysis showed that organs previously noted in the literature to contain the highest PFAA concentrations, such as kidney, liver, and plasma, were the organs driving the difference in PFAA burden between the two tilapia groups. Care must be taken in the interpretations we draw from not only the results of our study, but also other PFAA measurements made on populations（human and wildlife alike） under differing health status.