The human gut microbiota plays a crucial role in human health and therefore imbalances in gut microbiota functioning can lead to the development of metabolic disorders. Short-chain fatty acids (SCFA), tricarboxylic acid (TCA) cycle metabolites, bile acids (BA) and other metabolites are the essential compounds for the metabolome. Per- and Polyfluoroalkyl substances (PFAS) are a group of chemicals that can be absorbed onto the lumen by food. Since many PFAS has shown to possess a long list of adverse effects on human health, the short term impact of PFAS on gut microbiota functioning using an in vitro model that mimics fermentation in the human colon was explored. Samples obtained from in vitro fecal fermentation were then analysed through high-performance liquid chromatography coupled to time-of-flight mass spectrometry (LC-qToF-MS) using targeted and non-targeted approaches. Fecal samples were donated by four donors which were put through a fermentation over 24 hours and treated with no PFAS mixture (control), low concentration mixture of PFAS (PFAS-L) and high concentration mixture of PFAS (PFAS-H). The PFAS mixture contained perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA). For the fermentation, samples were collected after 0, 2, 4, 6, 8 and 24 hours. The samples were spun down and the supernatant was collected. Two approaches were applied to explore the metabolism in the fermentation extracts: The first one was a “targeted SCFA and TCA cycle metabolites analysis’’ and the second one was “untargeted analysis of polar and nonpolar metabolites’’. Results show that all TCA cycle metabolites displayed different trends with the compound and little to no variation between the treatments. However, although there was no significant difference, 4 core compounds of the TCA metabolism were lower after treatment with PFAS-L or PFAS-H. For the untargeted method, 78 of 2855 compounds were identified. When comparing control samples, PFAS-H and PFAS-L, 200 features showed statistically significant differences. Most of these had higher concentrations for PFAS-treated samples. When PFAS-H was compared only with PFAS-L, 30 features were found to be statistically significant, indicating that distinct concentrations of PFAS differentially affect gut microbiota metabolism. For future identification, further analysis must be done, preferably with MS/MS, to obtain more structural information for these significant metabolites, since the masses of the fraction ions are needed to narrow down the search in databases used to obtain the identity of an ion. PFAS and the concentration seem to have an impact on the gut microbiota, the study should be done with additional donors to archive trends applicable to a whole population.

No description available.

Wastewater treatment plants (WWTP) are known spreaders of per- and polyfluoroalkyl substances (PFAS) into the environment. Luleå University of Technology is conducting a yearlong study in which PFAS concentrations in the different treatment steps are measured at Uddebo treatment plant. This report covers the first four months of the year-long study. The aims of this study are to see what happens with the PFAS concentrations in the treatment processes, if they are above regulated limits, and to see if concentrations at Uddebo are comparable toreference concentrations in Sweden. Sampled PFAS concentrations were taken once per fortnight in incoming wastewater, after primary sedimentation, after Moving Bed Biofilm Reactor (MBBR), after secondary sedimentation and after the pilot treatment plant containing granulated active carbon (GAC) filter when it was in use. Precursors in incoming wastewater and PFAS in sludge were measured in samples taken once per month. Comparing the 33 analysed PFAS in wastewater at each sampling point, 30 analysed precursors for PFAS in incoming wastewater and 30 analysed PFAS in sludge, only PFOS and PFOA wereregularly found in both wastewater and in outgoing sludge. This indicates a separation of PFAS in the different medium, with sludge having PFAS where the perfluorinated carbon chain length is grater than 6. Out of the analysed 33 PFAS in wastewater PFOA had the highest median concentration of about 7 ng/l with no significant variation between the wastewater sample points. Similarly, the median concentration of total detected 33 PFAS was around 35 ng/l with no significant variation between the wastewater sample points, indicating no significant treatment of measured PFAS during WWTP. This was also comparable to other WWTP in Sweden. PFBA, PFHxA and PFPeA precursors had the highest concentration of the measured 30 PFAS precursors, however, except for one sampling occasion, no significant deviation in precursor PFAS could be detected during the sampling period. Out of the 30 analysed PFAS in outgoing sludge, PFOS had the highest concentration of 6.8 μg/kg dry weight (dw), but no discernible pattern could be identified between sampling dates due to too few samples. PFOS was foundabove the recommended concentration for sensitive land use (3.0 μg/kg dw), but still within recommendations for less sensitive land use (20.0 μg/kg dw) in Sweden. The median concentration of 13.6 μg/kg dw measured PFAS in sludge makes it well below median Swedish concentration. However, all comparisons to other Swedish WWTPs and background concentrations in Sweden were based on a few studies with few samples, potentially increasing or decreasing the median concentration as more research is conducted.

Poly- and perfluoroalkyl substances (PFAS) are a class of bioaccumulative toxicants used in numerous industrial and commercial products. Perfluorooctanesulfonic acid (PFOS) alters pancreatic organogenesis during development, and perfluorohexanesulfonic acid (PFHxS) has been suggested as a replacement for PFOS due to its shorter carbon chain, but they are often found together in surfactants, such as legacy aqueous film-forming foam. This study investigates how developmental exposures to a PFAS mixture (PFHxS + PFOS) impact the developing exocrine pancreas. Zebrafish embryos (Tg(ptf1a:GFP)) were exposed to 0.01% DMSO, or 8, 16, 32 μM PFHxS alone, 16 μM PFOS alone, and 8, 16, and 32 μM PFHxS plus 16 μM PFOS. Embryos underwent refreshing exposures (3 hours post fertilization (hpf) - 96 hpf) or static exposures (3, 24, 48, or 72 hpf - 96 hpf) and then live imaging to quantify the truncated exocrine pancreas phenotype that occurred, and at what point in development it became apparent. PFAS mixtures significantly impacted growth parameters and exocrine pancreas length. The truncated pancreas phenotype was seen most often in the 16 μM PFHxS + 16 μM PFOS treatment group, so this concentration was used for subsequent experiments. Time lapse imaging (58 - 72 hpf, 80 - 96 hpf) and cellular proliferation assays (3 - 96 hpf) were used to ascertain the cause of the truncated phenotype as an issue of cellular migration or proliferation within the pancreas. Cell migration and proliferation were decreased in response to toxicant exposure. This study offers insights to how developmental exposures to toxicants may impact the pancreas.

Per- and polyfluoroalkyl substances (PFAS) are known for their persistence as well as their hydrophobic and lipophobic nature. Widespread use has led to increasing prevalence of PFAS in the environment. Due to PFAS:s extensive spread and adverse health effects, remediation of PFAS-contaminated areas has increased in recent years, resulting in an increased demand for disposal of contaminated soil. To dispose waste at landfills in Sweden, certain criteria need to be met. However, for PFAS there are no specific guidelines and landfills therefore decide their own acceptance criteria. This can lead to varying requirements, potentially causing environmentally hazardous practices. The aim of this study was to survey the requirements applied by landfills, as well as investigate how different assessment bases affect the evaluation of PFAS-contaminated soil. The study was conducted both as a questionnaire sent to 80 landfills in Sweden, and as an analysis of test results from samples of PFAS- contaminated soil. The findings reveal varying information requirements, with common criteria including soil origin, presence of contaminants and analysis of PFAS when soil is suspected of contamination. Landfills also typically required documentation about the contaminated site, sampling plan and leachate tests when accepting PFAS-contaminated soil. Additionally, this study demonstrates that the evaluation of PFAS-contaminated soil can depend on the assessment basis used. The assessment based on toxic equivalents, may alter the risk valuation in comparison to those based on measured concentrations. To include commonly occurring PFAS, the analysis should include a minimum of PFAS11.

PFAS (per- and polyfluoroalkyl substances) are a large group of substances that are used in a large variety of products because of their unique water and dirt repellent properties. The substances are extremely persistent and can spread over large distances in groundwater, surface water, and in the air, which makes them an environmental and a health concern. A significant pathway of PFAS into the environment is through wastewater, where the usage of consumer products containing PFAS contribute to the emissions. The project was performed by analysing data of PFAS concentrations in wastewater and sludge sampled continuously during 2022 at Uddebo wastewater treatment plant (WWTP) in Luleå municipality. The aim was to evaluate the composition of PFAS compounds and their concentrations in wastewater and sludge and compare with other municipalities, to analyse how PFAS concentrations change during the existing wastewater treatment process, and to suggest strategies for future treatment of PFAS in wastewater.  No significant change of the PFAS content in wastewater could be observed throughout the treatment process in Uddebo WWTP. Evaluation of the PFAS composition showed that PFOS was the most abundant substance in both water and sludge. Over the year some variations in the total PFAS concentration could be seen, which coincided with increased water flow during the snowmelt period and an operational disturbance at the treatment plant. The variations of the total PFAS concentrations in wastewater over the year were mainly caused by PFBA, PFOS and 6:2 FTS. Analysis of total oxidizable precursors in the wastewater showed that substances that can transform into more persistent PFAS are present in the incoming water to the plant to a large extent. The pilot plant designed for treatment of pharmaceuticals, including ozonation and a granular activated carbon filter, did not result in any separation of PFAS from the water. An assessment of the contribution of PFAS from landfill leachate showed that it constitutes a significant share of the total PFAS content in wastewater. Compared with the content of PFAS in other Swedish WWTPs the total concentrations in wastewater at Uddebo WWTP was among the highest of five compared municipalities, while Luleå had the lowest PFAS concentrations in sludge among two compared municipalities.  The comparison between municipalities was limited by large differences in sampling frequency and performed analyses between the municipalities. Standardised analyses, additional background information, and more detailed statistical analyses are necessary to be able to make this type of comparison more informative. The occurrence of PFOS, which have been globally banned since 2009, shows that restrictions of the usage of PFAS must be combined with treatment of contaminated media to reduce the concentrations of PFAS in the environment. Development of PFAS degradation techniques is vital to remove PFAS from circulation. The difficulties of treating large amounts of water with low concentrations motivates investigations concerning if treatment of smaller water flows with higher PFAS concentrations is a better alternative than implementing treatment of the total amount of water that reaches the WWTP.

Per- and polyfluoroalkyl substances (PFAS) are a rising topic in the field of contaminated sites around the world, with destruction of these being an area in dire need of innovation. Previous experiments of destructive character have been proven efficient using boron doped diamond electrodes (BDD) in small scale electrochemical cells. Further need for experimentation on actual site conditions is needed to further evaluate the use of this method, as well as research on alternative electrode materials to reduce the cost of remediation.  In this study, four cells containing contaminated soil were used: one with BDD electrodes, one with iron electrodes and two control cells. The iron electrodes were used to investigate if a less costly electrode material could achieve any degree of PFAS degradation. For the experiment a soil from a previous firefighting training site where firefighting foam containing high amounts of PFAS (620                     g/kg soil concentration) was used. During the first phase of the experiment a constant flow of deionized water was added to the cells containing the soil, and porewater was sampled at the in- and outflow along with the soil porewater, on a weekly basis, to evaluate the distribution of PFAS to provide information about possible degradation taking place. The extent of degradation was not quantified. However, due to differences in the molecular composition of the analysed PFAS a trend where short-chain PFAS increase throughout the experiment in the BDD cell indicated that short-chain PFAS were generated, which is an expected by-product in electrochemical oxidation of PFAS. No short-chain PFAS generation was seen in the iron electrode cell, nor was there a high amount present in the control cell leachate.  Further, leaching of PFAS was more efficient in the control cells, while PFAS in the BDD and iron electrode cell were retained or leaching was slowed down, most likely due to the electrode interaction with PFAS in porewater.Additionally a second phase where water flow through was halted and the cells were run in a batch mode was conducted to see PFAS degradation in stagnant conditions over time. In the stagnant cell in the second phase, only low PFAS concentrations in porewater were recorded while no degradation was established.  Further, fluoride analysis recorded F- concentrations in the range of    M, where the limit of detection was   M, which limited the confirmation of PFAS mineralisation in soil.  From this study insight of the difficulties with soil treatment of PFAS using electrokinetic method was highlighted, with sampling being a key factor in the accuracy of the result. For a more accurate establishment of the degradation experiments in a closed cell, with more extensive sampling throughout the entire column would be necessary. This is needed to generate a clearer picture of changes in PFAS concentration in the soil from the presumed degradation, coupled with a mass balance to provide the fate of PFAS in this type of setup.

Per- och polyfluorerade alkylsubstanser, PFAS, är syntetiska kemikalier som är bioackumulerande, persistenta och toxiska för människor. Dessa ämnen har använts i produkter som textiler, brandsläckarskum, teflon och livsmedelsförpackningar sedan 1930-talet. Avfallsdeponier har länge förvarat olika typer av avfall som innehåller PFAS. Lakvatten från avfallsdeponier är idag en av de största källorna till läckage av PFAS i grundvatten och närliggande vattenkällor. Lakvattnet från Koviks deponi behandlas i en sekventiell biologisk reaktor innan det släpps ut till Östersjön, vilket resulterar i att 83,5 % av utgående vatten består av korta PFAS-kolkedjor, medan resterande 16,5 % av långa kolkedjor. En granskning av historiska data samlad under två år visar att ingen minskning av PFAS över tid erhållits i Koviks lakvatten med den nuvarande behandlingsmetoden, vilket indikerar att den biologiska reningen inte är tillräcklig för att effektivt rena PFAS från lakvatten. För att minska PFAS-utsläpp från lakvatten är PreZeros mål att implementera en metod som effektivt kan separera PFAS med korta kolkedjor från lakvattnet. En jämförelsestudie har utförts av konventionella reningsteknikerna som aktivt kol, skumfraktionering och membrantekniker, inklusive en patenterad teknik kallad Selpaxt, utvecklad av Chromafora. Selpaxt-tekniken från Chromafora, som kombinerar både kemisk och fysisk retention av PFAS med ett ultrafilter, uppvisar en initial avskiljningsgrad på 95%. Denna avskiljningsgrad sjunker dock till 88% efter fem dagars användning. Den minskade avskiljningsgraden beror på återanvändningen av kemikalier i processen. Detta innebär att avskiljningsgraden kan optimeras baserat på ekonomiska överväganden. Tekniken anses lämplig för lakvattnet på Kovik och kan anpassas efter specifika reningskrav. För effektiv avläsning av PFAS i lakvatten från Koviks deponi rekommenderas Chromaforas Selpaxt-teknik. Denna rekommendation baseras på analysresultat från Chromaforas pilotanläggning, i jämförelse med andra reningstekniker och utvärdering av tidigare insamlade data från Kovik. Efter en femdagars rening med Chromaforas teknik visade mätningar att koncentrationen av PFAS minskade från 9583 ng/l till 758 ng/l, vilket motsvarar ett genomsnittligt värde på 92%. Selpaxt-tekniken visar på att vara särskilt fördelaktig för vatten med hög total halt av fasta ämnen och selektiv för korta PFAS-kolkedjor. / Per- and polyfluoroalkyl substances, PFAS, are synthetic chemicals that are bioaccumulative, persistent, and toxic to humans. These substances have been used in products such as textiles, firefighting foam, teflon, and food packaging since the 1930s. Landfills have long stored various types of waste containing PFAS. Leachate from landfills is today one of the largest sources of PFAS leakage into groundwater and nearby water sources. The leachate from Kovik's landfill is treated in a sequential biological reactor before it is released into the Baltic Sea, resulting in 83.5% of the outgoing water consisting of short PFAS carbon chains, while the remaining 16.5% consists of long carbon chains. A review of historical data collected over two years shows that no significant reduction of PFAS over time has been achieved in Kovik's leachate with the current treatment method, indicating that biological treatment is insufficient to effectively clean PFAS from leachate. To reduce PFAS emissions from leachate, PreZero's goal is to implement a method that can effectively separate PFAS with short carbon chains from the leachate. A comparative study has been carried out of conventional purification techniques such as activated carbon, foam fractionation, and membrane techniques, including a patented technique called Selpaxt, developed by Chromafora. Chromafora's Selpaxt technique, which combines both chemical and physical retention of PFAS with an ultrafilter, exhibits an initial separation rate of 95%. However, this separation rate drops to 88% after five days of use. The decreased separation rate is due to the reuse of chemicals in the process. This means that the separation rate can be optimized based on economic considerations. The technique is considered suitable for the leachate at Kovik and can be adjusted according to specific purification requirements. For effective removal of PFAS in leachate from Kovik, Chromafora's Selpaxt technique is recommended. This recommendation is based on analysis results from Chromafora's pilot facility, comparisons with other purification techniques, and an evaluation of previously collected data from Kovik. After a five-day treatment using Chromafora's method, readings showed a drop in PFAS concentration from 9583 ng/l to 758 ng/l, which corresponds to an average value of 92%. The Selpaxt method proves especially beneficial for water with a high total solid content and shows selectivity for short PFAS carbon chains.

The lack of biodegradability of PFAS, or per- and polyfluoroalkyl substances, is due to the presence of many strong carbon-fluorine bonds. Two common PFAS that are found in the environment are perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). This work first studied an innovative pathway for PFAS removal through the adsorption of PFOA and PFOS (pre-concentrating the contaminants) by nanoscale zero-valent iron/reduced graphene oxide (rGO-nZVI) and their subsequent degradation via photocatalysis under UVC light. The GO that was later reduced in nanohybrid production was made utilizing a modified Hummer’s method. The rGO-nZVI nanohybrid was prepared for the first time via thermal reduction at high temperatures. Additionally, the nanohybrid was prepared using the wet chemistry method for comparison. LC/MS/MS analysis was conducted to determine the adsorption efficiencies for PFOA and PFOS using the nanohybrids and their successive removal under UVC light. Chlorinated hydrocarbons are another group of contaminants of concern that should be removed from the subsurface due to their harmful effects. In this study, a more complex mixture of the contaminants including PFAS and chlorinated hydrocarbons was investigated, which is usually found in the superfund and other contaminated sites. Considering the effectiveness of nZVI to remove chlorinated hydrocarbons from the subsurface, engineered nZVI coupled with rGO was utilized to enhance the removal efficiency of the mixture of contaminants, i.e., PFAS comingled with chlorinated hydrocarbons. The synthesized rGO-nZVI nanoparticle showed high adsorption efficiencies for both PFOA and PFOS, i.e., removal of 55.3%, 98.2%, and >99.9% of PFOA of 10, 1, and 0.1 mg/L, and 94.9%, 97.6%, and 85.0% of PFOS of 10, 1, and 0.1 mg/L, respectively, in 3 h. Later degradation of pre-concentrated PFAS under UVC light was also achieved. Using extracted rGO-nZVI, 55.1%, 77.6% of preconcentrated PFOS was degraded starting from 10, and 1 mg/L of initial concentrations before adsorption in the photoreactor at the end of 24 h. In comparison, 68.5% and 47.2% of PFOS and PFOA (starting from 1 mg/L each) was degraded, respectively, using rGO-nZVI directly under UVC light after 24 h. Moreover, it was found that rGO-nZVI had high adsorption capacity of 69.4% and 68.7% respectively for TCE and PFOA in a mixture of these contaminants. Under UVC irradiation, the preconcentrated mixture of TCE and PFOA were both degraded to below the detection limit in 21 h. It was also found that PFOA concentration dropped by 64.3% at 5 h and by 88.7% at 24 h by fresh rGO-nZVI in presence of 10 mg/L TCE. Short-chained PFCAs like PFHpA and PFHxA were found as the intermediates for PFOA degradation using rGO-nZVI under UVC light. Also, under UVC irradiation of a mixture of TCE and PFOA, TCE degradation was supported by the formation of intermediates during the reaction. Because of its composition, photocatalytic activity, large surface area, magnetic properties, and environmental friendliness, the thermal reduced rGO-nZVI particle demonstrated its potential to successfully remove PFAS and comingled chlorinated hydrocarbon from pre-concentration followed by degradation under UVC light. The nanohybrid is promising to be used to repair PFAS-contaminated water bodies.

Syftet med den här studien var att undersöka skummet som bildas på ytan i flockningskammare för kemisk fällning vid dricksvattenberedning i Kommunalförbundet Norrvattens ytvattenverk Görvälnverket. Skummet som bildas sprayas sönder med vatten och följer med vidare i reningsprocessen. För Norrvatten är det intressant att veta om det finns PFAS eller andra miljögifter i skummet för att en eventuell avskiljning av skummet skulle kunna vara aktuellt. Målet var att svara på följande frågor: 1. Under vilka förutsättningar bildas skum i flockningskammare för kemisk fällning på Görvälnverket? 2.Vad skulle det betyda för vattenkvaliteten om skummet avskiljs? 3.Vilka möjligheter finns det för Görvälnverket att avskilja skummet?  Poly- och perfluorerade alkylsubstanser (PFAS) uppdagas på flera ställen i samhället och t ex i dricksvatten hittas förhöjda halter. Det har observerats att PFAS orsakar skada på både djur och människors hälsa. PFAS har en hydrofil (vattenlöslig) och en hydrofob (olöslig i vatten) ände. De egenskaperna gör att de kan agera som ett ytaktivt ämne och förekomma i naturligt eller processrelaterat skum och kan också därför avskiljas med hjälp av t ex skumfraktionering.  Det genomfördes två provtagningar vid olika tillfällen för att mäta halten av PFAS11 och totalt organiskt kol (TOC) i skummet. Två enkäter skickades ut, en till skiftingenjörer på Görvälnverket och den andra till vattenverk i Sverige. En flödesmätning av sprayvattnet utfördes samt en analys av mätdata från Görvälnverket.  Resultatet bekräftade halter av PFAS11 i skummet, 2600 ng/l vid första provtagningstillfället och vid andra 3200 ng/l. TOC-halten vid andra tillfället var 180 mg/l TOC. Enkätsvaren påvisade att det skummar mest på våren i Görvälnverket och att andra ytvattenverk också har skumbildning i flockningskammare. Under ett år går det åt nästan 22 miljoner liter vatten för att spraya sönder skummet som istället skulle kunna distribueras. Dataanalys visade att det finns ett samband mellan TOC och konduktivitet.  Slutsatsen är att avskiljning av skummet skulle ge en förbättrad vattenkvalitet då flotation inte är i bruk. Ett förslag på en sugfunktion presenteras som en möjlig avskiljningsmetod. Vidare undersökning för under vilka förutsättningar det bildas skum behöver utföras. / The aim of this study was to investigate the foam formed on the surface of a flocculation chamber for chemical precipitation, which is a step in the preparation of drinking water in the Norrvatten local federation's surface water plant Görvälnverket. The foam that is formed is removed by spraying with water and hence the material in the foam follows the treatment process. Norrvatten are interested to know whether PFAS or other environmental toxins are present in the foam so that a possible removal of the foam could be considered. The objective was to answer the following questions: 1. Under what conditions is foam formed in flocculation chambers for chemical precipitation at Görvälnverket? 2.What would be the impact on water quality if the foam was removed? 3. What are the possibilities for Görvälnverket to remove the foam?  Poly- and perfluoroalkyl substances (PFAS) are found in many places in society and examples of elevated levels include drinking water. PFAS has been observed to cause harm to both animal and human health. PFAS have a hydrophilic (water-soluble) and a hydrophobic (water-insoluble) end. These properties allow them to act as surfactants and to be present in natural or process-related foam and can therefore also be separated by e.g. foam fractionation.  Two samples were taken at different times to measure the PFAS11 and total organic carbon (TOC) content of the foam. Two surveys were sent out, one to engineers at Görvälnverket and other to waterworks in Sweden. A flow measurement of the spray water was carried out as well as an analysis of the measurement data from Görvälnverket.  The result confirmed levels of PFAS11 in the foam, 2600 ng/l at the first sampling point and 3200 ng/l at the second. The TOC content at the second occasion was 180 mg/l TOC. The survey responses showed that foaming is most common in spring at Görvälnverket and that other surface water plants also have foaming in flocculation chambers. In a year, almost 22 million litres of water are used to spray the foam, which could be distributed instead. Data analysis showed that there is a correlation between TOC and conductivity.  It is concluded that removal of the foam would improve the water quality when the flotation step is not in use. A proposal for a suction feature is presented as a possible removal method. Further investigations on under what conditions foaming is formed needs to be carried out.