Les problèmes de pollution chimique de l'eau sont devenus une source de préoccupation importante et un enjeu prioritaire pour les industriels du nucléaire. L'objectif principal de cette thèse est d'étudier certains minéraux échangeurs ioniques utilisables pour une décontamination liquide en strontium (radioisotope toxique pour l'homme). Mais également de relier les propriétés physico-chimiques de ces matériaux avec leurs propriétés de rétention du radioisotope. Ce mémoire présente donc la synthèse de deux matériaux choisis pour leurs propriétés de sorption spécifique et quantitative du strontium : le nonatitanate de sodium et la zéolithe A. Une seconde partie du travail est dédiée à l'étude des capacités d'échange spécifique de ces matériaux vis-à-vis du strontium en présence d'autres éléments comme le sodium et le calcium. Le nonatitanate de sodium et la zéolithe A ont également été testés sur des effluents réels. Les performances d'un monolithe de zéolithe A ont été évaluées pour un procédé de traitement en colonne. Ce matériau semble prometteur pour la décontamination d'effluents car il permet de cumuler les avantages de la poudre de zéolithe A avec ceux d'un transfert de matière sans perte de charge du solide. / The problems of chemical pollution of water have become a major concern and a priority for the nuclear industry.The aim of this work is to study some ion exchangers used for the removal of strontium ions because 90Sr is one of a major pollutant in nuclear liquid wastes. This study allows linking the physical and chemical properties of these materials and their sorption properties. This work presents therefore the synthesis of two materials - sodium nonatitanate and zeolite A - selected for their specific sorption properties of strontium: A second part of this work is dedicated to the study of specific exchange capacities of these materials for the strontium in presence of other elements such as sodium and calcium. Batch experiments were performed and kinetic and ion exchange models have been applied to understand the selectivity of the materials for strontium removal. Sodium nonatitanate and zeolite A are also studied in actual effluents.Monoliths of zeolite A have been also tested in dynamic ion exchange process. This material is promising for the treatment of radioactive effluents in continuous flow because it joins the sorption properties of the zeolite powder with the advantage of a solid with a macroporous network.

A prevenção das doenças periimplantares baseia-se em procedimentos de rotina na clínica, com a remoção mecânica do biofilme associada ou não de agentes antimicrobianos locais e sistêmicos. No entanto, o controle do biofilme oral sobre a superfície de implantes é dificultado particularmente sobre as superfícies rugosas do titânio, que apesar de facilitarem a osseointegração, também favorecem a formação do biofilme. Objetivos: Objetivou-se analisar in vitro o efeito da TFD (Terapia fotodinâmica) usando curcumina como fotossensibilizador sobre o biofilme formado na superfície de discos de titânio com superfície rugosa e lisa. Material e Métodos: Biofilme mono espécie de Streptococus gordonii, colonizador inicial do biofilme dental, foi formado em superfícies lisas (usinadas) e rugosas (tratadas) de discos de titânio por 72 horas. Os discos lisos e rugosos foram então distribuídos em 3 grupos: tratados por 5 minutos com curcumina (60?M), clorexidina 0,12% como controle positivo e solução de DMSO (dimetilsufóxido), etanol e água como controle negativo (veículo da curcumina). As amostras foram divididas em 2 sub-grupos: ativado por LED azul (455-492nm) por 7 minutos e não-ativado. A atividade metabólica do biofilme foi determinada pelo método de redução do Sal tetralisol XTT e os resultados analisados estatisticamente pela análise da variância (ANOVA) seguida pelo teste de Tukey (p < 0,05). Resultados: Na ausência de luz, apenas o tratamento com clorexidina promoveu redução microbiana (controle positivo). O tratamento com curcumina ativada pela luz azul reduziu o número de bactérias viáveis no biofilme em 71% nos discos lisos e em 77% nos rugosos, não havendo diferença estatística com o controlepositivo.Conclusão: Os dados in vitro indicam que TFD associada à curcumina tem atividade sobre biofilme microbiano, sugerindo seu potencial no controle do biofilme oral sobre a superfície de titânio, e que este efeito independe da topografia da superfície. / Prevention of periimplant diseases is based on routine procedures in the clinic, with the mechanical removal of biofilm associated or not with local and systemic antimicrobial agents. However, the control of oral biofilm on the surface of implants is particularly difficult on the rough surfaces of titanium, which, although facilitating osseointegration, also favors biofilm formation. Objectives: The objective of this study was to analyze in vitro the effect of PDT using curcumin as a photosensitizer on the biofilm formed on the surface of titanium discs with a rough and smooth surface. Material and Methods: Biofilm mono species of Streptococus gordonii, initial colonizer of the dental biofilm, was formed on smooth (machined) and rough (treated) surfaces of titanium discs for 72 hours. The smooth and rough discs were then divided into 3 groups: treated for 5 minutes with curcumin (60 ?M), 0.1% chlorhexidine as a positive control and DMSO, ethanol and water solution as a negative control. The samples were divided into 2 subgroups: activated by blue LED (455-492nm) for 7 minutes and non-activated. The metabolic activity of the biofilm was determined by the reduction XTT salt method and the results analyzed statistically by ANOVA followed by the Tukey\'s test (p <0.05) Results: In the absence of light, only the chlorhexidine treatment promoted microbial reduction (positive control). The blue light-activated curcumin treatment reduced the number of viable bacteria in the biofilm in 71% in the smooth discs and in 77% in the wrinkles, and there was no statistical difference with the positive control. Conclusion: In vitro data indicate that PDT associated with curcumin has activity on microbial biofilm, suggesting its potential in the control of oral biofilm on the titanium surface, and that this effect is independent of surface topography.

En réponse aux opérations futures d’assainissement des installations nucléaires, la décontamination par ablation laser de surfaces métalliques apparait comme une technique adaptée aux enjeux sanitaires et économiques actuels. L’objectif est d’ablater par un faisceau laser de façon préférentielle la surface oxydée contenant des radioéléments et de récupérer les éléments vaporisés pour pouvoir isoler la contamination radioactive en vue de son stockage. A la différence des techniques existantes comme le ponçage ou le traitement chimique par gel ou mousse, le traitement laser permet de ne pas produire de déchets secondaires et de pouvoir être effectué à distance en diminuant considérablement la dose reçue par les opérateurs. Le retour d’expérience a montré la nécessité d’optimiser le procédé en vue de limiter la contamination résiduelle. Les phénomènes responsables de cette limitation et identifiés dans la littérature sont la pénétration des contaminants dans le substrat métallique par effet thermiques induits par laser et le piégeage des radionucléides dans des défauts de surface micrométriques. Les travaux de thèse auront donc comme objectifs d’étudier et d’optimiser la décontamination de surfaces métalliques avec des couches d’oxydes contaminées de façon volumique avec un simulant de radionucléide (Eu) par ablation laser, en vue dans un second temps d’améliorer de l’efficacité de la technique au niveau des défauts surfaciques. Enfin, au-delà de la démarche expérimentale, cette thèse vise à contribuer à la compréhension de l’interaction laser/matière dans le cadre de notre étude via la simulation du chauffage de surface métallique par modélisation multi physique. / The preparation of future decommissioning of nuclear installations is currently facing economical and sanitary challenges. The metallic-surface decontamination by laser ablation is here studied as an appropriate and efficient technique, which involves ejection of surface contamination by subjecting the surface to high-energy laser pulses followed by subsequent trapping to avoid environmental dispersion. This process has many advantages such as the minimization of secondary waste, no production of effluents and the reduction of the exposition of workers by the automation of the process. Previous studies highlighted the need to optimize the process in order to limit the residual contamination. The identified reasons for this limitation are the contamination penetration into the metal bulk induced by the laser treatment and the entrapment of the radionuclides in surface defects like micro cracks. The aim of this work is the study and the cleaning optimization of metallic surfaces with an oxide layer implemented with a non-radioactive contamination (Eu). Secondly, the cleaning efficiency has been improved in case of damaged surfaces with defects such as cracks. Beyond an experimental study, The ablation of a metallic substrate with a submicrometric oxide layer is currently modeled using a numerical and multiphysics approach in order to determine the mechanism involved during the process.

Současná pandemická situace ukázala obrovské dopady rozšíření infekce na společnost, i přesto stále ještě chybí jednotný přístup k problematice infekčního odpadu. Cílem této práce je představení metodiky nakládání s infekčním odpadem v rámci regionu v kontextu situace v Česku a Evropské Unii. V teoretické části práce je uveden legislativní rámec, charakter produkce, možnosti dekontaminace a podmínky spalování infekčního odpadu. Na základě těchto poznatků je navržena metodika pro nakládání s infekčním odpadem v rámci regionu. V praktické části práce je pak metodika aplikována na konkrétní region – Královéhradecký kraj. V rámci metodiky jsou navrženy možné scénáře nakládání s infekčním odpadem a vybrány nejvhodnější z nich z pohledu zdravotních rizik, rozpočtové zátěže a dopadu na životní prostředí. Na závěr je metodika kriticky zhodnocena a srovnána s metodikami jiných studií na podobné téma.

Solvent extraction is one of the methods available for the decontamination of sensitive equipments that are contaminated with chemical warfare agents. The efficiency of extraction method have been verified on the samples, (steel or rubber) that have been contaminated with drops of mustard gas. These samples have been inserted into the extraction flow cell through which solvent (ethoxynonafluorobutane - HFE-7200) flowed. The solvent was sampled in the time intervals. These samples of solvent were analysed for the concentration of mustard gas. Process of extraction was monitored for the three operational factors (the solvent flow rate, temperature and the ultrasound power) and for three different situations (dissolution of drops of mustard gas, mustard gas desorption from the structure of the sample and dissolve drops of mustard gas with the subsequent desorption from the sample). The development of the decontamination process in time was found to consist of two stages. In the first stage the rapid dissolution of the liquid part of mustard gas in a solvent and in the second phase was such as mustard desorption from the structure of the sample and this phase was considerably slower. Extraction is to accelerate increasing the value of the flow of the solvent, the temperature and the performance of the ultrasound. These operational fac-tors have a significant impact on the thickness of the laminar layer of solvent, the solvent replacement coefficient in a cell, diffusion parameters in the process, the viscosity, the solubility of mustard gas in a solvent and the maximum achievable concentration of mustard gas in the rubber sample. The values of adjustable parameters was obtained by mathematical analysis of mathematical model. The progress of extraction under different operational conditions can be predicted by these parameters. The effect of solvents and ultrasound was experimentally verified for selected equipments of computing and communication technology. The possibility of separation of chemical warfare agents from the solvent was verified too.

Der Betrieb kerntechnischer Anlagen führt zur Kontamination von Oberflächen, das heißt der Verunreinigung mit Radionukliden, innerhalb des Containments. Die Stilllegung kerntechnischer Anlagen erfordert die Dekontamination metallischer Komponenten und Baustrukturen zur Minimierung von Masse und Volumen des radioaktiven Abfalls. Stand der Technik ist die Nutzung von chemischen und mechanischen Dekontaminationsverfahren. Die Reinigung von Oberflächen mittels gescannter Laserstrahlung ermöglicht die Bearbeitung großer Flächen bei hohen Flächenraten. Gleichzeitig ist der Laserabtrag ein kontaktloses, nahezu kräftefreies Verfahren, welches zur Minimierung oben genannter Abfälle durch Einsatz für die Dekontamination beitragen kann. In der vorliegenden Arbeit werden die Ergebnisse aus der internationalen Forschung für die Auswahl eines geeigneten Lasers aufgegriffen und auf ein praxistaugliches Lasersystem übertragen. Der ns-gepulste Nd:YAG-Laser mit einer mittleren Leistung von 150 W wird für den Einsatz im kerntechnischen Umfeld durch den Einschluss der Reaktionszone angepasst und so die Rekontamination durch mobilisierte Radionuklide verhindert. Die Nutzung kurzgepulster Laser führt zum Abtrag durch Schmelzen und Verdampfen auf metallischen Oberflächen, wobei eine maximale Schmelztiefe von 1,8 μm ermittelt wird. Durch Analysen an Querschliffen mittels Auflichtmikroskopie und Rasterelektronenmikroskopie kann die Gefügeänderung der metallischen Substrate unterhalb dieser Tiefe bei Pulsfolgefrequenzen von 12 kHz ausgeschlossen werden. Der Abtrag von Dekontaminationsanstrichen erfolgt ab einer Fluenz von 1,8 J/cm² bei hohen Abtragraten um 1,1 μm/(J cm²) im Vergleich zu sehr geringen Abtragraten um 0,006 μm/(J cm²) von ferritischem Stahl. Der vollständige Abtrag von Beschichtungen ist somit äußerst selektiv, was zur Abfallminimierung beiträgt. Der Dekontaminationseffekt wird in vergleichenden Untersuchungen zwischen stabilen und radioaktiven Isotopen geprüft. Für beide Verunreinigungen werden Präparationsroutinen zur reproduzierbaren Herstellung kontaminierter Proben entwickelt. Die Aktivität der radioaktiven Proben wird durch den Laserabtrag um mehr als 97 % reduziert, was auf die sehr gute Eignung des Laserverfahrens für die Dekontamination hinweist.:1 Einleitung 2 Kontamination in kerntechnischen Anlagen 3 Grundlagen der laserbasierten Dekontamination 4 Untersuchungen zur laserbasierten Dekontamination 5 Experimentelle Ergebnisse 6 Zusammenfassung und Ausblick / The operation of nuclear sites results in contamination of surfaces within their containment. Decommissioning of nuclear sites requires decontamination of metal surfaces and building structures to minimize the mass and volume of radioactive waste products. State of the art decontamination technologies are based on chemical and mechanical approaches, which achieve high decontamination factors, but result in the generation of chemical and secondary radioactive waste. Cleaning of surfaces by scanned laser beams renders the processing of large surfaces at high surface rates possible. Laser cleaning is simultaneously free of contact and restoring forces and could lead to the further reduction of radioactive waste from decommissioning of nuclear sites. The results of international state of science are summarized and applied for the choice of a laser, which is able to comply with the demands for application in decontamination tasks. Within this thesis a ns-pulsed Nd:YAG-laser with a mean power of 150 W is modified for the utilization in nuclear sites by enclosing the process zone around the ablation area to omit the spread of the mobilized radionuclides. Laser/substrate-interaction results in metal removal via melting and vaporization and a maximum melt depth of 1,8 μm is detected. No further changes within the grain structure of metal substrates are found by the analysis of cross-sections using microscopy and scanning electron microscopy when pulse frequencies of 12 kHz are applied. The removal of decontamination paint is achieved for fluences above 1,8 J/cm² at high removal rates of 1,1 μm/(J cm²), compared to the very low removal rate for ferritic steel of 0,006 μm/(J cm²). Complete and selective removal of the paints can thus be realized, which contributes to the waste minimization in decontamination projects. Laser-based decontamination is exercised for stable as well as radioactive isotopes in comparative experiments. For this purpose, sample preparation methods are developed to provide replicable contaminated surfaces. The activity of radioactive samples is reduced to less than 3 % of the starting value by laser-based decontamination, which is proof of the very good suitability of the process for the application in nuclear decommissioning.:1 Einleitung 2 Kontamination in kerntechnischen Anlagen 3 Grundlagen der laserbasierten Dekontamination 4 Untersuchungen zur laserbasierten Dekontamination 5 Experimentelle Ergebnisse 6 Zusammenfassung und Ausblick

La séparation magnétique est utilisée dans le domaine de la purification de l’eau. Des nanoparticules magnétiques fonctionnalisées ou nues sont en charge de capter un polluant ciblé puis sont enlevées de l’eau par l’application d’un champ magnétique. Nous avons montré que l’utilisation d’un ferrofluide aqueux classique constitué de nanoparticules d’oxyde de fer recouvertes par une double couche de surfactant d’acide oléique permet une adsorption efficace des cations métalliques (ion nickel Ni2+) puis leur enlèvement en utilisant des microparticules magnétiques. Nous avons montré que des interactions magnétiques suffisamment fortes entre les nanoparticules induisent une transition de phase colloïdale. Il existe trois régimes de captage qui dépendent de deux paramètres, le premier paramètre est lié à l’intensité du champ magnétique et le second est la concentration en nanoparticules. En présence de l’écoulement de la suspension des nanoparticules, le captage des nanoparticules est toujours régi par la concentration en nanoparticules et également par le nombre de Mason. Nous avons mené une expérience de captage des nanoparticules par un milieu poreux. L’efficacité de filtration est liée à la compétition entre les forces hydrodynamiques et magnétiques ainsi que de la séparation de phase au sein de la suspension. Les théories développées lors de ce travail sont en accord raisonnable avec les résultats expérimentaux et montrent l’augmentation de l’efficacité de captage des nanoparticules avec l’augmentation de l’intensité du champ magnétique et de la concentration en nanoparticules ainsi que la diminution de l’efficacité de captage avec l’augmentation du nombre de Mason. / Magnetic separation is used in the domain of water purification. In these systems, functionalized or bare magnetic nanoparticles are used to capture a target pollutant then they are extracted from water by an applied magnetic field. We have shown that a classical aqueous ferrofluid composed by iron oxide nanoparticles covered with an oleic acid double layer allows efficient adsorption of metallic cations (nickel ion Ni2+) followed by nanoparticle extraction with the help of magnetic microparticles. We have shown that strong enough magnetic interactions between nanoparticles can induce a colloidal phase transition. There exists three capture regimes which depend on two parameters, the first one is related to the magnetic field intensity and the second is the nanoparticle concentration. In the presence of the flow of nanoparticle suspension, the nanoparticle capture is always governed by the nanoparticle concentration and also by Mason number. We have carried out an experiment on nanoparticle capture in a porous medium. The filtration efficiency is related to the competition between the hydrodynamic and magnetic forces, as well as to the phase separation in the suspension bulk. The theories developed in the frames of this work show a reasonable agreement with the experimental results. They predict an increase of the capture efficiency with an increase of the magnetic field intensity and the nanoparticle concentration as well as a decrease of the capture efficiency with the growth of the Mason number.

Transmissive spongiform encephalopathies, also called prion disorders, are fatal neurodegenerative diseases affecting mammals. In patients, the pathological prion protein (PrPTSE ) accumulates in CNS and causes death. Prions possess high binding affinity to surfaces. Moreover, they are highly resistant to conventional sterilization procedures which rise the risk of nosocomial transmission from patients in subclinical stage of prion disease through medical tools. In the thesis, we evaluate the efficiency of photodynamic inactivation (PDI) for prion decontamination. The PDI is induced by photoactivation of phthalocyanine (Pc) derivates AlPcOH(SO3)2, SiPc(OH)2(SO3)1-3 or ZnPc(SO3)1-3. Pc exposed to light generate reactive oxygen species, mainly singlet oxygen (O2(1 ∆g)). Production of O2(1 ∆g) in aqueous solution was confirmed by iodide method, quenching by NaN3 and oxidative degradation of uric acid. The photoactivation of Pc in infectious brain homogenate led to elimination of PrPres signal (= proteinase K-resistant PrPTSE fragment) below the detection limit of western blot by using nanomolar AlPcOH(SO3)2 concentration. The complete elimination of PrPres signal was accompanied with total protein concentration decrease by a maximum of 20% in brain homogenate No signs of protein fragmentation or...

I Rosersberg har Trafikverket byggt en ny trafikplats under 2011-2013. Projektet stötte på komplikationer som ledde till att arbetet försenades främst på grund av förekomsten av arsenik i jord, berg samt grundvattnet. Dessa förseningar ledde till att projektet försenades med ca nio och en halv månad till en merkostnad på över 30 miljoner kronor till följd av över 200 (ÄTA). Detta projekt behandlar grundämnet arsenik i byggfasen och hur en hantering av ämnet bör gå till. Genom instudering av arbetsmaterial från projektet samt intervjuer med personer som varit inblandade har undersökningar gjorts och en sammanställning av dessa återfinns i rapporten.  I rapporten har jag arbetat med att sammanfatta metoderna som Trafikverket arbetat med och hur projektet fortlöpt. Jag har även arbetat med att ta fram alternativa metoder för hantering och sanering av arsenik för grundvatten, jord- och bergmassor. Problemlösning som jag sökt svar på är: • Hur man stabiliserar arsenik och sedan hindrar det från att sprida sig från en nivå till en annan. • Hur man kan sanera och hantera arsenik när det förekommer i produktionsskedet, med en rimlig lösning. • Hur man återanvänder sanerade massorna. • Hur utförandet av sanering kan göras på kortare tid och med mindre kostnader. Dag- och grundvatten samlades i dammar som därefter pumpades ut till vägdiken för att därefter luftas genom självfall till Verkaån. Jordprover gjordes genom XRF och laborationsanalyser som därefter klassificerades till KM och MKM. Dessa massor kunde därefter deponeras eller återanvändas om massorna var rena. Sprängsten från ramp 118 och borrkax laktestades och därifrån gjordes en riskbedömning för spridning av arsenik. Sprängmassor som inte överskred naturvårdsverkets riktlinjer kunde användas i berglager och förstärkningslager i vägkonstruktionen. Framtagning av alternativa lösningar till sanering för grund- och ytvatten, jord- och bergmassor har gjorts. Genom reaktiv barriär/filterteknik kan yt- samt grundvatten renas effektivt. Jordmassor kan genom jordtvätt renas på plats vid bygganläggningen, denna metod kan rena upp till 20 ton/timme. Denna metod är effektiv då jordmassorna inte är alltför stora. Ur kostnadsperspektiv är denna metod inte alltför dyr då transportkostnader inte finns. Berg kan genom inneslutning deponeras i marken. Då tätning är korrekt omsluten bör inte den hydrauliska konduktiviteten överstiga 5*10^-10 m/s. Jag anser att dessa metoder är lämpliga i fall där arsenik förekommer i stora mängder. / The Transport administration in Rosersberg had built a new interchange in 2011-2013. The project faced a lot of complications that led mainly to the delay of the work because of the presence of arsenic in soil, rock and groundwater. The result of these complications was that, the project was delayed for about nine and half months, with additional cost of over 30 million as a result of over 200 (ÄTA). This project deals with arsenic substance in the construction phase, and how the handling of the substance should be done. By studying the construction documents about the project, interviews with those involved, studies have been made with a summary of these can be found in the report. In this report I have worked to summarize the methods that the Transport Administration worked with, and how the project progressed. I have also worked to develop alternative methods for the management and remediation of arsenic in groundwater, soil and rock masses. Problems solving as I sought to answer are: How to stabilize arsenic and then prevents its spreading from one level to another. How to handle the error when it occurs in the production period, with a reasonable solution. How to reuse the decontaminated masses. How the execution can be done within a shorter period of time and with less costs. Surface and groundwater collected in ponds, then pumped out to the road ditches and then go down to Verkaån. Soil samples are made by XRF and lab analyzes are subsequently classified to KM and MKM. These masses then can be disposed of, or reused if they are clean. There was a risk of the spread of arsenic from blasted rocks of the ramp 118 and borrkax leaching tests. Bursting lots that did not exceed EPA’s guidelines could be used in rock layers and reinforcement layers in road construction. I have presented alternative solutions for the remediation of groundwater, soil and rock masses. By the reactive barrier/filter technology the surface and groundwater may be cleaned efficiently. Soil masses can be treated by soilwashing on the construction site. This method can clean up to 20 tons per hour. This method is effective when the soil masses are not too large. In terms of cost, this method is not too expensive when transportation is not available. Rock can be deposited by containment in the ground. When the seal is properly enclosed, the hydraulic conductivity should not be greater than 5*10^-10 m/s. I believe that these methods are suitable in cases where arsenic is present in large amounts.

<p dir="ltr">The frequency and intensity of wildfires occurring at the wildland-urban interface is increasing, and public drinking water systems operating in these communities are at risk. Widespread volatile organic compound (VOC) and semi-VOC (SVOC) contaminations have been detected in water distribution systems, often at concentrations above regulatory limits. Uncertainty about the source and fate of these contaminants has hindered recovery efforts. It is hypothesized that one source of the contaminants is the thermal degradation of plastic components within water distribution systems. Plastics are commonly used for water conveyance due to their low cost and ease of installation. However, plastics are vulnerable to thermal degradation, and have been shown to release VOC/SVOCs into the air when thermally degraded. Further, certain plastics such as polyethylene, are vulnerable to organic compound permeation, which could result in the contamination of otherwise undamaged components. This dissertation is comprised of four studies aimed at evaluating if plastic components within water distribution systems may be a source of contamination post-wildfire.</p><p dir="ltr">First, the aqueous leaching from commercial drinking water pipes was evaluated following thermal degradation in air. In this work, eleven plastic drinking water pipes were exposed to elevated temperatures (200°C to 400°C), and subsequently submerged in water or in <i>n</i>-hexane to observe the extent of VOC leaching. Results indicated that thermally damaged drinking water pipes can be sources of VOC leaching, with ten of the eleven materials leaching benzene, a carcinogen, into water. As exposure temperature increased, there was an increase in VOC leaching from the polyethylene plastics. Conversely, in the vinyl plastics the significant mass loss associated with high exposure temperature was inversely proportional to the amount of leaching that was observed.</p><p dir="ltr">The second study determined how the direct contact of water during plastic thermal degradation impacts the formation and aqueous leaching. Experiments were carried out using a continuously stirred tank reactor (CSTR) to expose plastics to a range of temperature (100°C to 300°C) in the presence of water. Five polyethylene materials were tested, including three cross-linked polyethylene (PEX) pipes, one high-density polyethylene pipe (HDPE), and one HDPE resin. Following degradation, clean water was pumped through the reactor to evaluate the efficacy of flushing to remove contaminants from thermally damaged plastics. Again, material type and exposure temperature impacted the leaching profile. Flushing removed contaminants from the thermally damaged plastics, however the removal rate varied based on chemical properties. Exhumed materials from wildfire impacted water systems were extracted in water to assess similarities and leached up to twelve different compounds, seven of which were also detected in laboratory experiments.</p><p dir="ltr">The third study investigated the impact of polyethylene formulation on aqueous leaching following thermal degradation to further understand the underlaying phenomenon causing the formation and leaching of contaminants. The impact of resin density, antioxidant type (Irganox 1010^® or Irgafos 168^®), antioxidant dose (0 to 10 wt. %), and impact of carbon black (0 or 2 wt. %) was investigated by compounding 12 different composites and thermally degrading them in the CSTR reactor described previously. Results found that all variables tested impacted the observed leaching. The addition of antioxidants decreased the observed leaching of polyethylene degradation products but increased the leaching of a variety of antioxidant degradation products. Carbon black was found to interact with the antioxidants during compounding, leading their consumption, and as a result decreased their effectiveness in protecting the polymer chain.</p><p dir="ltr">Lastly, the susceptibility of plastic water supply connectors such as ice-maker lines, faucet connectors, and washing machines hoses was assessed. The vulnerability of rigid plastic materials within water systems has been well studied, however, water supply connectors tend to be made of flexible plastics such as plasticized PVC and low-density polyethylene, and limited data exists on the susceptibility of these materials to contamination. In this study, seven connectors were exposed to hydrocarbon contaminated water, and subsequently decontaminated by water flushing. Following an initial 24 h contamination period, water samples were collected at three consecutive periods of 72 h. Results found that all materials sorbed more than 90% hydrocarbon contaminants. All materials released contaminants into the water during decontamination, at times above health-based limits. The majority of sorbed mass remained in the plastics at the end of the decontamination periods.</p>