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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

PFAS in recipient sediment of a military airport

Johansson Blomér, Lovisa January 2017 (has links)
Per- and polyfluoroalkyl substances, PFASs, are highly fluorinated substances where the carbon chain is fully- or partly fluorinated. A functional group is coupled at the end of the carbon chain which gives PFASs their different properties. PFASs have been used in aqueous film forming foams (AFFFs) to decrease the surface tension of water and form a film on the fuel surfaces. AFFF is one of the main sources of PFASs pollution in the environment. A previous study has shown high PFASs concentrations in surface water in Lake Vänern. This study has analysed PFASs in sediment samples. The main detected PFASs was perfluorooctane sulfonate, PFOS, with concentrations below limit of detection to 51700 pg/g wet weight (ww). The compound detected in the highest concentration in Vissbäcken was PFOS at 7290 pg/g ww, this was followed by 6:2 fluorotelomersulfonate , 6:2FTS, at 516 pg/g ww. In outlet 4 (utlopp 4), PFOS had the highest concentration at 51800 pg/g ww, followed by perfluorohexane sulfonate, PFHxS, at 1790 pg/g ww. The only detected compound in the sediment cores was PFOS with approximately 100 pg/g ww. The high concentration of PFOS might be due to extensive use with subsequent release of firefighting foam in the area and degradation of other PFAS substances into PFOS. / Per-och polyfluoroalkylsubstanser, PFASs, är en grupp högfluorerade ämnen där kolkedjan är helt eller delvis fluorerad. En funktionell grupp kopplas i slutet av kolkedjan vilket ger PFASs dess olika egenskaper. PFAS har använts i vattenhaltiga filmbildande skum (AFFF) för att minska ytspänningen av vatten och bilda en film på bränsleytan. AFFF är en av huvudkällorna för PFAS-föroreningar i miljön. En tidigare studie har visat på höga koncentrationer av PFASs i ytvatten i Vänern. I denna studie har PFASs analyserats i sedimentprover. Den huvudsakliga detekterade PFAS var perfluoroktansulfonat, PFOS, med koncentrationer under detektionsgränsen och till 51700 pg /g våtvikt. Den högst detekterade föreningen i Vissbäcken var PFOS med 7290 pg/g våtvikt, detta följdes av 6:2 fluorotelomersulfonat, 6:2 FTS, med 516 pg/g våtvikt. Den högst detekterade föreningen i utlopp 4 var PFOS med 51800 pg/g våtvikt, följt av perfluorhexansulfonat, PFHxS, med 1790 pg /g våtvikt. Den enda detekterade föreningen i sedimentpropparna var PFOS med ungefär 100 pg/g våtvikt. Förekomsten av PFOS i sediment i sjön Vänern kan bero på omfattande användning med efterföljande utsläpp av brandbekämpningsskum i området och nedbrytning av andra PFAS-substanser till PFOS.
12

Identification of Neurotoxic Targets of Diverse Chemical Classes of Dietary Neurotoxins/Neurotoxicants

Rachel M Foguth (9343949) 16 December 2020 (has links)
<p>Neurological disorders are a major public health concern due to prevalence, severity of symptoms, and impact on caregivers and economic losses. While genetic susceptibility likely has a role in most cases, exposure to toxicants can lead to neurotoxicity, including potentially developmental origins of adult disease or increased risk of disease onset. These exposures are not necessarily large, acute exposures, but could accumulate, with a chronic low-dose exposure, causing toxicity. This research focuses on the potential neurotoxicity of two classes of dietary toxins/toxicants, heterocyclic aromatic amines (HAAs) and per- and polyfluoroalkyl substances (PFAS). HAAs, such as PhIP, harmane, and harmine, are formed in charred or overcooked meat, coffee, tobacco, and other foods. PFAS are largely used in making household materials, but are found in small amounts in eggs and dairy products and largely in contaminated water. While these two classes are diverse in terms of structure, common neurotoxic targets and mechanisms often exist. Therefore, we tested the effects of these chemicals on cell viability and neurotoxicity. In the first aim, we aimed to elucidate the mechanism of toxicity of harmane and harmine, focusing on their ability to cause mitochondrial dysfunction. The second aim was to determine the effects of either harmane or PhIP on the nigrostriatal motor systems and motor function of rats and mice, respectively. The third aim determined the effects of PFAS on neurodevelopment of Northern leopard frogs, focusing on changes in neurotransmitter levels and accumulation in the brain. Harmane did not cause motor dysfunction, but potentially affected the nigro-striatal motor system in an age- or sex-dependent manner. PhIP had differential effects on dopamine levels over time and caused motor dysfunction after subchronic exposure in mice. Perfluorooctane sulfonate (PFOS) accumulated in the brains of frogs and PFAS caused changes in neurotransmitter levels that were dose- and time-dependent. Overall, this research shows that toxins/toxicants humans are exposed to over their whole lives through their diet and contaminated water can cause neurotoxicity, potentially leading to or increasing risk of disease states. </p>
13

Evaluation of selected parameters of Total Oxidisable Precursor Assay on per- and polyfluoroalkyl substances

Francois, Sofia January 2021 (has links)
Per- and polyfluoroalkyl substances (PFASs) are man-made fluorinated compounds that havebeen detected in humans, the environment, and wildlife. The strong C-F bonds contribute tothe high thermal stability of some PFASs and make them extremely resistant to degradationunder normal environmental conditions. The commonly studied classes of PFASs areperfluoroalkyl carboxylic acids and perfluoroalkyl sulfonic acids. Though the phase-out ofperfluorooctane sulfonic acid and perfluorooctanoic acid for some time, they were the mostfrequent compounds measured and detected in biota.In this study, the total oxidisable precursor (TOP) assay, which is a method used to indirectlymeasure and estimate PFAS precursors, was evaluated. Different parameters were studied tounderstand their effects on oxidation of precursor compounds following TOP assay method(e.g., oxidation rate, pH of the oxidation solution and different washing steps during solidphaseextraction)The results from this experiment showed that the target precursors were oxidised and part ofthe proportion of the compounds formed ranged from 37 to 100% (molar ratio). Whenperforming TOP assay, it was shown that some precursors oxidised before 0.5 h while otherprecursors were oxidised after 4 hours. However, it was still unknown what products wereformed when some precursors were oxidised e.g., 7:3 fluorotelomer carboxylic acid (7:3-FTCA) and 10:2 fluorotelomer unsaturated carboxylic acid (10:2- FTUCA) because of animbalance of precursors to degradation products (molar to molar ratio).When the washing steps for solid-phase extraction were evaluated for potential losses ofprecursors, it could be seen that the ammonium acetate and the 20% methanol in Milli-Q waterled to the loss of some precursors. These results showed precautions were needed wheninterpreting the results using TOP assay.
14

Method development and screening of extractable organofluorine (EOF) and targeted PFAS analysis in food packaging materials

Larsson, Nora January 2022 (has links)
Per- and polyfluoroalkyl substances (PFAS) have been manufactured and used in differentapplications for several decades, including food packaging materials. During the last 20 yearsthese compounds have been acknowledged as hazardous for humans and the environment, anddifferent regulations on PFAS have been established on both national and international levels.Companies started to phase-out long-chain PFAS, including both PFOA and PFOS, around 20years ago. Since PFAS are persistent, this cause concerns both for our health and theenvironment, as well as possible PFAS contamination in new products due to the recycling ofmaterials. The aim of this study was to find an effective method to extract PFAS from differentfood packaging materials; analyze the samples for their extractable organofluorine (EOF)content using combustion ion chromatography; as well as analyze targeted PFAS in the samplesusing ultra-high performance liquid chromatography tandem mass spectrometry. The findingsof this study suggest that none of the selected samples had EOF contents above the Danishindicator value of 20 mg/kg dw TOF set to determine whether PFAS has been intentionallyadded to a material, and that only two samples exceeded the limit of detection for EOF. Atakeaway bowl made out of 100% sugarcane contained the highest EOF content while the outerpackaging of a cereal box contained the second highest EOF. Both PFOA and PFOS, alongwith other long-chain PFAS were detected in a majority of the samples. The lowest total PFASconcentrations when analyzing for targeted PFAS was detected in the sugarcane take awaybowl. The highest total PFAS concentration was detected in an egg carton, followed by theouter packaging of a cereal box (same as above) and the outer box of a waffle mix. The targetedPFAS was detected in almost all samples, with PFNA and 6:2 diPAP being the most frequentlydetected PFAS. PFCAs, PFSAs, FTSAs, FOSAAs and PAPs were detected in a majority of thesamples. The highest concentrations were measured for diSAmPAP in a majority of thesamples. Mass balance calculations of the sugarcane bowl showed that the targeted PFAS onlyaccounted for 0.04% of the extractable organofluorine content. In conclusion, none of thesamples displayed EOF contents higher than the Danish indicator value, suggesting that noneof the samples were intentionally treated with PFAS. However, targeted PFAS analysis of thesesamples showed that they still contain PFAS, that could be further recycled along with therecycling of paper and board food packaging materials. Considering the persistence of PFASand that these compounds can remain in the recycling chain, with the risk of also being releasedinto the environment, it is of importance that PFAS is not introduced in any of the stages in apaper or board containers life cycle.
15

A zebrafish-based system to study the impact of environmental factors in Inflammatory Bowel Disease (IBD)

Westling, Mikaela January 2020 (has links)
Inflammatory Bowel Disease (IBD) is a chronic disorder that affects millions of peopleworldwide. Although the etiology behind the disease is yet unknown, current theoriespropose a complex interplay between genetic susceptibility, exposure to environmentalfactors and exacerbated immune responses. While important efforts have been made to linkgenetics and environmental factors to IBD pathogenesis, a major challenge remains to assignthem a causative role. Particularly since most of the IBD-risk genetic polymorphisms arefound in non-coding regions (NCRs) with unknown regulatory activity, and for the lack ofknowledge about how environmental factors can modulate the function of these elements invivo . A main problem to address this challenge in IBD research is the lack of an appropriatemodel system in vivo that allows for high-throughput experiments with combinations ofdifferent IBD-risk factors, while keeping the in vivo context. In this work, we sought toovercome this issue by using a zebrafish reporter for a specific human IBD-risk NCR, inorder to investigate the modulation of this element by two groups of common environmentalfactors: pollutants, such as PolyFluoroAlkyl Substances (PFASs); and diet, by activation ofdietary sensors. We found that the activity of the WT-NCR in zebrafish larvae was increased in the presenceof PFAS, while the activation of the dietary sensor PPAR δ decreased the activity. These datalead us to suggest that the function of PFAS can be counteracted by PPARδ activation.Therefore, we propose zebrafish as a suitable in vivo model in which we can screen forpotentially harmful or beneficial effects of environmental factors in the activity of humannon-coding regions. / Inflammatorisk tarmsjukdom (IBD) är en kronisk störning som drabbar miljontals människorvärlden över. Även om etiologin bakom sjukdomen fortfarande är okänd, föreslår nuvarandeteorier ett komplext samspel mellan genetisk mottaglighet, exponering av miljöfaktorer ochförvärrat immunförsvar. Även om stora ansträngningar har gjorts för att koppla genetik ochmiljöfaktorer till IBD-patogenes, återstår en stor utmaning att tilldela dem en orsakande roll.Särskilt eftersom de flesta av IBD-riskgenetiska polymorfismer finns i icke-kodande regioner(NCR) med okänd reglerande aktivitet samt för bristen på kunskap om hur miljöfaktorer kanmodulera funktionen hos dessa element in vivo . Ett huvudproblem för att möta dennautmaning i IBD-forskning är avsaknaden av ett lämpligt modellsystem in vivo som möjliggörexperiment med hög kapacitet och kombinationer av olika IBD-riskfaktorer in vivo . I dettaarbete försökte vi få svar på denna fråga genom att använda en zebrafiskreporter för ettspecifikt humant IBD-risk icke-kodande område. Detta möjliggjorde att vi kunde undersökamodulering av två gemensamma miljöfaktorer: föroreningar, såsom PolyFluoroAlkyl-ämnen(PFASs); och diet, genom aktivering av dietsensorer. Vi fann att aktiviteten i WT-NCR hos zebrafisklarver ökade i närvaro av PFAS, medanaktiveringen av dietsensorn PPARδ minskade aktiviteten. Denna data leder till att vi antyderatt funktionen för PFAS kan motverkas genom PPARδ-aktivering. Därför föreslår vizebrafisk som en lämplig in vivo -modell, i vilken vi kan screena för potentiellt skadliga ellergynnsamma effekter av miljöfaktorer i mänskligt icke-kodande DNA.
16

Déterminants des concentrations sériques de substances per- et polyfluoroalkyliques (PFAS) chez les enfants canadiens

Al Kassem, Hala 05 1900 (has links)
Les déterminants de l’exposition aux substances per- et polyfluoroalkyliques (PFAS) chez les enfants sont mal connus. Cette étude visait à analyser les concentrations sériques de 9 PFAS chez 204 enfants participant à l’étude MIREC-Endo ; évaluer les associations entre ces concentrations et celles dans le sérum maternel (grossesse) et le lait maternel ; évaluer les déterminants des concentrations. Nous avons effectué des statistiques descriptives des concentrations et évalué leurs associations à l’aide de corrélations de Pearson et de tests de comparaisons de moyennes. Des analyses de régression ont été faites pour quantifier l’influence de l’allaitement sur les concentrations sériques. Les moyennes géométriques de PFOS, PFOA, PFHxS, PFNA et PFDA (détectés dans >67% des échantillons) étaient de 1,37 ; 1,21 ; 0,55 ; 0,42 et 0,13 µg/L, respectivement. Les concentrations sériques de certains PFAS étaient corrélées avec les concentrations sériques maternelles (r=0,315 [PFOS], 0,314 [PFOA], 0,328 [PFHxS]) et les concentrations dans le lait (r=0,273 [PFOA], 0,509 [PFHxS], 0,237 [PFNA]). Les concentrations sériques de certains PFAS chez les enfants étaient négativement associées avec l’âge maternel à l’accouchement (PFOS, PFHxS, PFDA), le tabagisme durant la grossesse (PFNA, PFDA), l’emploi de la mère (PFOS), alors qu’elles étaient positivement associées avec le niveau d’éducation maternel (PFNA) et le revenu familial (PFOA). Nous avons observé une augmentation de 2,8% (PFOS) et 1,85% (PFOA) dans les concentrations sériques par mois d’allaitement exclusif. En conclusion, les concentrations sériques de certains PFAS chez les enfants étaient associées aux expositions périnatales, à l’âge de la mère, au revenu familial et à la durée d’allaitement. / The determinants of exposure to per- and polyfluoroalkyl substances (PFAS) in children are unclear. The objectives of this study were to analyze serum concentrations of 9 PFAS in 204 children aged 7.5 to 11.8 years participating in the MIREC-Endo study, to assess associations between these concentrations and those in maternal serum (during pregnancy) and breast milk; and to evaluate the determinants of these concentrations. We performed descriptive statistics of the concentrations and assessed their associations using Pearson correlations and comparison tests. Regression analyses were performed to quantify the influence of breastfeeding on serum concentrations. The geometric means of PFOS, PFOA, PFHxS, PFNA, and PFDA (detected in >67% of samples) were 1.37, 1.21, 0.55, 0.42, and 0.13 µg/L, respectively. Serum concentrations of selected PFASs were correlated with maternal serum concentrations (r=0.315 [PFOS], 0.314 [PFOA], 0.328 [PFHxS]) and milk concentrations (r=0.273 [PFOA], 0.509 [PFHxS], 0.237 [PFNA]). Serum concentrations of children PFAS were negatively associated with maternal age at delivery (PFOS, PFHxS, PFDA), smoking during pregnancy (PFNA, PFDA), maternal employment (PFOS), whereas they were positively associated with maternal education level (PFNA) and family income (PFOA). We observed an increase of 2.8% (PFOS) and 1.85% (PFOA) in serum concentrations per month of exclusive breastfeeding. In conclusion, serum concentrations of selected PFAS in children were associated with perinatal exposures, maternal age, family income, and duration of breastfeeding.
17

Occurrence of Per- and Polyfluoroalkyl Substances (PFAS) in Private Water Supplies in Southwest Virginia

Hohweiler, Kathleen A. 24 May 2023 (has links)
Per- and polyfluoroalkyl substances (PFAS) are a class of man-made contaminants of increasing human health concern due to their resistance to degradation, widespread occurrence in the environment, bioaccumulation in human and animal organ tissue, and potential negative health impacts. Drinking water is suspected to be a primary source of human PFAS exposure, so the US Environmental Protection Agency (US EPA) has set interim and final health advisories for several PFAS species that are applicable to municipal water supplies. However, private drinking water supplies may be uniquely vulnerable to PFAS contamination, as these systems are not subject to EPA regulation and often include limited treatment prior to use for drinking or cooking. The goal of this study was to determine the incidence of PFAS contamination in private drinking water supplies in two counties in Southwest Virginia (Floyd and Roanoke), and to examine the potential for reliance on citizen-science based strategies for sample collection in subsequent broader sampling efforts. Samples for inorganic ions, bacteria, and PFAS analysis were collected on separate occasions by homeowners and experts at the home drinking water point of use (POU) in 10 Roanoke and 10 Floyd County homes for comparison. Experts also collected an outside tap PFAS sample. At least one PFAS compound was detected in 76% of POU samples collected (n=60), with an average total PFAS concentration of 23.5 parts per trillion (ppt). PFOA and PFOS, which are currently included in EPA health advisories, were detected in 13% and 22% of POU samples, respectively. Of the 31 PFAS species targeted, 15 were detected in at least one sample. On average, a single POU sample contained approximately 3 PFAS, and one sample contained as many as 8 different species, indicating that exposure to PFAS in complex mixtures is worth noting. Although there were significant differences in total PFAS concentrations between expert and homeowner collected samples (Wilcoxon, alpha = 0.05), it is unclear whether this difference was due to contamination by the collector or the water usage and time of day of sampling (i.e. morning, afternoon). It is worth noting that there was no significant difference in the number of PFAS species in the samples collected by homeowners and experts. Given the considerable variation in PFAS detections between homes, future studies reliant on homeowner collection of samples appears possible given proper training and instruction to collect at the same time of day (i.e. first thing in the morning). / Master of Science / Per- and polyfluoroalkyl substances (PFAS) belong to a large family of manmade compounds that are commonly used in a variety of household and consumer products due to their unique water and stain resistant properties. PFAS compounds are not easily broken down in the environment and have been detected globally in air, soil, and water samples. In addition to their environmental detections, PFAS are slow to be removed from the body after ingestion and known to cause negative health effects in concentrations less than one part per trillion. Drinking water is considered to a main source of PFAS consumption for humans; as such, the US Environmental Protection Agency (US EPA) has set strict, but not legally binding, interim and final health advisories (HA) for four types of PFAS. However, these health advisories only apply to public water services and do not cover private drinking water systems, such as wells or springs, which are the full responsibility of the well owner. Private drinking water system users often do not treat their water before drinking which may make these systems uniquely vulnerable to PFAS contamination. This study focused on 20 total homes, 10 in Roanoke County and 10 in Floyd County to see if PFAS was present and to determine whether or not homeowners would be able to collect their own samples for PFAS analysis at home as accurately as researchers or experts with proper instructions. Homeowners and experts collected drinking water samples inside at a point of use (POU), usually at a kitchen faucet, and outside of the home, usually from a tap. PFAS were present in 76% (n=60) of POU samples, with an average combined concentration of 23.5 parts per trillion (ppt). The two most well studied PFAS, PFOA and PFOS were detected in 13% and 22% of POU samples, respectively. It was also common to detect at least 3 PFAS in a single sample. Although there were differences in total average concentrations of PFAS in samples collected by homeowners and experts, variation could be caused by several factors indicating that with proper training and instruction it is likely future studies could still rely on homeowners to collect samples for PFAS analysis.
18

Effects of pH and Cation Composition on Sorption of Per- and Polyfluoroalkyl Substances (PFASs) to Soil Particles / Effekter av pH och katjonsammansättning på sorption av per- och polyfluoral- kylsubstanser (PFAS:er) till jordpartiklar

Ullberg, Malin January 2015 (has links)
Per- and polyfluoroalkyl substances (PFASs) have drawn great attention recently, due to their environmental persistence, potential toxicity and global distribution. PFAS is a large family of substances, characterized by a perflourinated carbon chain and a functional group. All PFASs are synthetic and have been widely used since the 1950s due to their unique properties of being both hydrophobic and oleophobic, making them useful for many industries. To be able to predict the fate of PFASs in the environment and to obtain detailed understanding of the transport processes, their partitioning behavior between soil particles and water depending on a range of parameters must be investigated. The aims of this study was to investigate the effects of pH, cation composition, functional group and perfluorocarbon chain length on sorption of PFASs to soil particles, by batch sorption experiment in laboratory scale. The laboratory-scale experiments were combined with modelling of the net charge to evaluate if net charge is a good predictor for sorption of PFASs to soil particles. 14 PFASs of varying length and functional groups were studied (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS and FOSA). The effect on sorption of Na+, Ca2+ (two different concentrations) and Al3+ were investigated at pH-range 3-6. Modelling of net charge was carried out in the geochemical model Visual MINTEQ. The soil had 45% organic carbon content. The adsorption of PFASs was strongly correlated with perfluorocarbon chain length, showing a stronger adsorption to particles with increasing perfluorocarbon chain length (i.e. more hydrophobic). The relation between sorption (represented by the distribution coefficient log Kd) and perfluorocarbon chain length was linear for all PFSAs and C3 to C10 PFCAs. The PFSAs (sulfonate functional group) sorbed stronger to soil particles than the PFCAs (carboxylic functional group), and FOSA (sulfonamide functional group) sorbed the strongest. For most PFCAs, (C5-C13) there was a trend of decreasing log Kd (i.e. decreased sorption) with increasing pH, due to pH-dependent changes of the soil particle surfaces. For short and intermediate perfluorocarbon chain length PFCAs (C5-C8) and for PFHxS among the PFSAs, cations had a clear effect on sorption. Aluminium ions (trivalent, Al(NO3)3) had the largest effect, followed by calcium (divalent, Ca(NO3)2) where higher concentration resulted in stronger sorption. Sodium (univalent, NaNO3) had the least influence on sorption. The net charge modelled with Visual MINTEQ takes into account many parameters (including pH) that affect the surface charge and sorption of PFASs to soil particles. When comparing log Kd for the different PFASs with pH and net negative charge, net charge was a better predictor of sorption of PFASs to soil particles than solution pH alone. / Per- och polyfluoroalkylsubstanser (PFAS:er) har dragit stor uppmärksamhet till sig på senare tid, på grund av deras persistenta egenskaper, potentiella toxicitet och globala utbredning. PFAS är en stor grupp ämnen, kännetecknad av en perflourinerad kolkedja och en funktionell grupp. Alla PFAS är syntetiska och har använts i stor utsträckning sedan 1950-talet på grund av deras unika egenskaper av att vara både vatten- och fettavstötande, vilket gör dem användbara för många industriella tillämpningar. För att kunna förutsäga var dessa föroreningars hamnar i miljön och få mer detaljerad förstående för transportprocesserna, måste deras fördelningbeteende mellan jordpartiklar och vattenundersökas för en rad olika parametrar. Syftet med denna studie var att undersöka effekterna av förändrat pH, katjonsammansättning, funktionell grupp och perfluorkolkedjelängd på sorption av PFAS:er till jordpartiklar. Detta gjordes med sorptionsexperiment i laboratorieskala. Laboratorieexperimentet kompletterades med modellering av nettoladdning, för att se huruvida detta väl kunde förklara sorptionen till jordpartiklar. 14 PFAS:er av varierande längd och med tre olika funktionella grupper studerades (PFBA, PFPeA, PFHxA, PFHpA, PFOA, PFNA, PFDA, PFUnDA, PFDoDA, PFTeDA, PFBS, PFHxS, PFOS och FOSA). Effekten på sorption av Na+, Ca2+ (två olika koncentrationer) och Al3+ undersöktes vid pH-intervallet 3-6. Modellering av nettoladdning utfördes i den geokemiska modellen Visual MINTEQ. Jorden som användes hade en halt av organiskt kol på 45%. Adsorptionen av PFAS:er var starkt positivt korrelerad med kedjelängden på de perfluorinerade kolkedjan. Ju längre kolkedja (dvs. mer hydrofob), desto starkare adsorption till partiklar. Relationen mellan sorptionen (här uttryckt som partitioneringskofficienten log Kd) och kedjelängd var linjär för alla PFSA och för C3 till C10 för PFCA. PFSA (sulfonat) adsorberade starkare än PFCA (karboxyl), och FOSA (sulfonamid) adsorberades starkast. För de flesta PFCA, (C5-C13) fanns en allmän trend där log Kd (dvs. sorption) minskade med ökande pH, på grund av pH-beroende förändringar på jordpartiklarna. För korta och medellånga PFCA (C5-C8) och för PFHxS hade katjonsammansättningen en tydlig effekt på sorptionen. Aluminiumjoner (trevärd, Al(NO3)3) hade den största effekten, följt av kalcium (tvåvärd, Ca(NO3)2) där den högre koncentrationen resulterade i starkare sorption. Natrium (envärd, NaNO3) hade minst påverkan på sorptionen till jordpartiklar. Visual MINTEQ tar hänsyn till många parametrar (inklusive pH), när nettoladdningen på jordpartiklarnas yta räknas ut. När log Kd för olika PFAS:er jämfördes med endera pH eller negativ nettoladdning, drogs slutsatsen att nettoladdning korrelerade bättre med sorption än pH.
19

Toxicity Studies Of Per- and Polyfluoroalkyl Substances (PFAS)

Shittu, Adenike Rofiyat 02 September 2021 (has links)
No description available.
20

PFAS-föroreningar i råvatten. : En studie uppströms Borgs vattenverk / PFAS contamination in raw water. : An upstream study of Borg's water treatment plant

Hansen, Lovisa January 2021 (has links)
Poly- och perfluorerade alkylsubstanser (PFAS) är syntetiskt tillverkade kemikalier som omfattar cirka 4700 individuella ämnen. PFAS har använts sedan 1950-talet i ett antal applikationer som brandsläckningsskum, impregneringsmedel samt textilier, på grund av sina unika egenskaper att vara både vattenlöslig (hydrofila) och vattenavstötande (hydrofoba). Dessa egenskaper gör att göra att PFAS kan transporteras långa vägar. Dessutom är ämnets kol-fluorbindning en av det starkaste kemiska bindningar som gör dem mycket stabila och därför svårnedbrytbara i miljön. Många PFAS misstänkts vara skadliga och kan ansamlas i både djur och människor. Ett antal PFAS har visat sig ge negativa effekter på reproduktion, immunsystem, sköldkörtelhormoner och levern vid djurförsök. Vissa tas lättare upp av kroppen men det är oklart vilken påverkan exakt alla 4700 PFAS-ämnen har. Dessa potentiellt skadliga föroreningar upptäcks på flera ställen i Sverige och har redan resulterat i allvarliga problem för dricksvattenförsörjningen. Dagens reningsmetoder avlägsnar inte PFAS och i kombination med toxiska egenskaper och hög bioackumuleringspotential kan det bli farligt för både människor och miljö. Därför regleras summan av 11 PFAS-ämnen (summa-11) med en åtgärdsgräns på 90 ng/L för vattenverk i Sverige. Vissa vattenverk har tvingats sättas ur bruk på grund av för höga PFAS-koncentrationer i producerat dricksvatten. Kunskapen om källor till PFAS är fortfarande låg men utredning av flera potentiella källor pågår.  I detta arbete har ett antal PFAS-ämnen analyserats uppströms Glan, den sjö i Norrköping kommun som försörjer över 90 % av invånarna med dricksvatten. Syftet är att kartlägga och karaktärisera PFAS i Norrköpings råvattentäkt Glan med tillflöden för att få en ökad förståelse för potentiell påverkan på dricksvattenproduktion. Kartläggningen skedde genom provtagningar uppströms Borgs råvattenintag. Det samlades också in data från andra aktörer längre uppströms i vattensystemet längs Motala Ström, Stångån samt även i Glan. Provtagning skedde också vid Bråvalla som är ett sedan tidigare välkänt förorenat område i direkt anslutning till Glan. All data analyserades sedan med ett Kruskal-Wallis test. Studien visar 1) av 21 analyserade PFAS-ämnen detekterades PFHxS, PFOS, PFPeA, PFHxA, PFHpA, PFOA och PFBA i flest provpunkter 2) Både PFOS och PFOA hade högst koncentration i Motala ström av de tillflöden till Glan som undersökts 3) PFBA, visade högst koncentration i andra tillflöden än Motala Ström, Hällestaån, Ysundaviken, till Glan med okänd källa 4) Av alla inflöden till Glan uppmättes högst halter av summa-11 i Motala ström som också utgör det största tillflödet till Glan 5) Våtmarken vid Bråvalla är en potentiell PFAS-källa till Glan då koncentrationen i dessa provpunkter är mycket höga i jämförelse med övriga provpunkter. Däremot indikerar inte resultaten på att Bråvalla är en källa i dagsläget men kan bidra till framtida komplikationer för Borgs råvattentäkt pga. klimatförändringar. / Per- and polyfluoroalkyl substances (PFAS) are synthetically manufactured chemicals comprising about 4700 individual substances. PFAS has been used since the 1950s in a number of applications such as firefighting foam, impregnating agents and textiles, due to its unique properties of being both water-soluble (hydrophilic) and water-repellent (hydrophobic). These properties allow PFAS to be transported long distances. In addition, the substance's carbon-fluorine bond is one of the strongest chemical bonds that makes them very stable and therefore difficult to degrade in the environment. Many PFASs are suspected to be harmful and can accumulate in both animals and humans. A number of PFASs have been shown to have adverse effects on reproduction, immune systems, thyroid hormones and the liver in animal experiments. Some are more easily absorbed by the body, but it is unclear what effect exactly all 4700 PFAS substances have. These potentially harmful pollutants are discovered in several places in Sweden and have already resulted in serious problems for the drinking water supply. Today's purification methods do not remove PFAS and in combination with toxic properties and high bioaccumulation potential, it can be dangerous for both humans and the environment. Therefore, the sum of 11 PFAS substances (summa-11) is regulated with a limit value of 90 ng/L for waterworks in Sweden. Some waterworks have been forced out of service due to too high PFAS concentrations in produced drinking water. Knowledge of sources for PFAS is still low, but investigation of several potential sources is ongoing. In this study, a number of PFAS substances have been analyzed upstream of Glan, the lake in Norrköping municipality that supplies more than 90% of the inhabitants with drinking water. The aim is to map and characterize PFAS in Norrköping's water catchment Glan with inflows to gain an increased understanding of the potential impact on drinking water production. The mapping took place through sampling upstream of Borg's raw water intake. Data were also collected from other actors further upstream in the water system along Motala Ström, Stångån and also in Glan. Sampling also took place at Bråvalla, which is a previously well-known polluted area in direct connection to Glan. All data were then analyzed with a Kruskal-Wallis test. The study shows 1) of 22 analyzed PFAS substances, PFHxS, PFOS, PFPeA, PFHxA, PFHpA, PFOA and PFBA were detected in most test points 2) Both PFOS and PFOA had the highest concentration in Motala stream of all the inflows examined to Glan 3) PFBA showed the highest concentration in inflows other than Motala stream, Hällestaån, Ysundaviken, to Glan with unknown source 4) Of all inflows to Glan, the highest levels of summa-11 were measured in Motala stream which also constitutes the largest inflow to Glan 5) The wetland at Bråvalla is a potential PFAS source of Glan as the concentration in these test points is very high compared to other test points. However, the results do not indicate that Bråvalla is a source at present, but may contribute to future complications for Borg's raw water source due to climate change.

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