Academic literature on the topic 'Non-intentionally added substances (NIAS)'

Les plastiques sont une composante essentielle de la société moderne, mais leur utilisation généralisée soulève des préoccupations concernant la contamination environnementale et les risques pour la santé humaine. Alors que de nombreuses recherches se sont concentrées sur la formation et la dégradation des microplastiques, peu d'attention a été accordée à la migration des additifs plastiques dans les systèmes biologiques. Cette thèse étudie la préparation et la caractérisation des microplastiques de polyéthylène contenant des additifs industriels, leur impact sur les propriétés physico-chimiques du polymère et leur migration potentielle dans la peau humaine. Une méthodologie a été développée pour produire des microplastiques de polyéthylène avec une teneur en additifs et une distribution granulométrique contrôlées, se rapprochant étroitement de ceux trouvés dans les conditions environnementales. La caractérisation a révélé une hétérogénéité significative dans la forme et la taille des particules, les rendant plus représentatives de la pollution plastique réelle. L'étude a également exploré l'influence des additifs sur la cristallinité du polymère, son comportement mécanique et la formation de substances non intentionnellement ajoutées (NIAS), mettant en évidence leurs transformations potentielles au fil du temps. Un axe clé de cette recherche a été l'évaluation de la migration des additifs dans la peau humaine à l'aide d'expériences in vitro avec des Сellules de Diffusion de Franz. Tous les additifs testés ont montré une migration dans l'épiderme, certains pénétrant plus profondément dans le derme. Cependant, aucun additif n'a été détecté dans le liquide récepteur, ce qui suggère soit une migration transdermique limitée dans la période expérimentale, soit des concentrations inférieures au seuil de détection. L'étude a également révélé des variations spécifiques aux donneurs en matière de perméabilité, soulignant l'influence des propriétés individuelles de la peau sur la migration des additifs. Ces résultats contribuent à une meilleure compréhension des interactions entre les additifs plastiques et la peau humaine, mettant en évidence la nécessité de recherches supplémentaires sur les risques liés à l'exposition à long terme. Les perspectives futures incluent l'évaluation de la migration dans différentes matrices polymères, l'amélioration des méthodologies de détection et l'analyse de l'impact des conditions d'exposition réelles. De plus, les organismes de réglementation devraient réévaluer la liste des additifs autorisés dans les plastiques destinés aux consommateurs, en tenant compte de leur potentiel d'absorption cutanée. Ce travail apporte des connaissances précieuses pour le développement de matériaux polymères plus sûrs et plus durables, tout en alimentant les discussions réglementaires sur la sécurité des plastiques<br>Plastics are an essential part of modern society, yet their widespread use raises concerns regarding environmental contamination and human health risks. While much research has focused on microplastic formation and degradation, limited attention has been given to the migration of plastic additives into biological systems. This thesis investigates the preparation and characterization of polyethylene microplastics containing industrially relevant additives, their impact on the physicochemical properties of the polymer, and their potential migration into human skin. A methodology was developed to produce polyethylene microplastics with controlled additive content and particle size distribution, closely resembling those found in environmental conditions. Characterization revealed significant heterogeneity in particle shape and size, making them more representative of real-world plastic pollution. The study further explored the influence of additives on polymer crystallinity, mechanical behaviour, and the formation of non-intentionally added substances (NIAS), highlighting their potential transformations over time. A key focus of this research was the assessment of additive migration into human skin using in vitro Franz diffusion cell experiments. All tested additives exhibited migration into the epidermis, with some penetrating deeper into the dermis. However, no additives were detected in the receptor liquid, suggesting either limited transdermal migration within the experimental timeframe or concentrations below the detection threshold. The study also revealed donor-specific variations in permeability, underscoring the influence of individual skin properties on additive migration. These findings contribute to understanding the interactions between plastic additives and human skin, emphasizing the need for further research on long-term exposure risks. Future perspectives include evaluating migration in different polymer matrices, refining detection methodologies, and assessing the impact of real-life exposure conditions. Additionally, regulatory bodies should re-evaluate the list of approved additives in consumer plastics, considering their potential for dermal absorption. This work provides valuable insights for developing safer, more sustainable polymer materials while informing regulatory discussions on plastic safety

O Polietileno Tereftalato (PET) é o principal polímero para a produção de garrafas de água e refrigerantes, sendo cada vez mais importante, no contexto global, o combate ao desperdício e descarte através da reciclagem deste importante recurso. Neste trabalho, seis resinas processo mecânicos aprovados pela EFSA foram avaliadas. As propriedades de cor, viscosidade intrínseca, temperatura de fusão, concentração de benzeno, limoneno, oligómeros e substâncias não intencionalmente adicionadas (NIAS) foram avaliadas. No que toca à determinação das concentrações de Benzeno, Limoneno e Oligómeros, foram encontrados valores superiores comparativamente ao reportado em bibliografia. As concentrações obtidas foram de 30 – 410 μg kg-1 PET para o benzeno, 20 – 66 μg kg-1 PET para o limoneno; 52 – 78 mg kg-1 PET para o dímero e 999 – 1394 mg kg-1 PET para o trímero. A concentração de NIAS detetada nas resinas conduz a um nível de exposição estimado (considerando uma garrafa de 8,5 g e 0,3 L) inferior ao correspondente à Classe 3 de Cramer da abordagem TTC para o limite de risco toxicológico. A análise estatística dos dados pelo modelo paramétrico univariado agrupou as amostras em 3 sub-grupos de homogeneidade: o primeiro grupo compreende as amostras IN, NO e F, o segundo as amostras F, FBL e BA e o terceiro a amostra MO. A análise por componentes independentes (ICA) confirmou alguns dos resultados deste teste. Foi possível verificar a similaridade das amostras MO e BA pelos conteúdos em nonanal, F e FBL pelo etilhexilacetato, dodecano e o difenil éter e as amostras FBL e IN pelo farneceno. A amostra NO foi a única que não apresentou correlação com as restantes.<br>Polyethylene terephthalate (PET) is the most important polymer for the production of bottles for water and soft drinks, being increasingly important globally to reduce waste by recycling this material. In this work, six PET resins from different mechanical recycling processes, with positive opinions from EFSA, were evaluated for the properties: color, intrinsic viscosity, melting temperature and for the concentration of benzene, limonene, oligomers, and non-intentionally added substances (NIAS). Regarding the determination of Benzene, Limonene, and Oligomers, the samples in study have higher concentration values than those found in the literature. The obtained concentrations are 30 – 410 μg kg-1 PET for benzene, 20 – 66 μg kg-1 PET, for limonene and 52 – 78 mg kg-1 PET for PET dimer and 999 – 1394 mg kg-1 PET for trimer. The unknowns and NIAS concentration detected in the resins, yield and estimated exposure levels (considering a bottle of 8,5 g and 0,3 L) lower than that corresponding to the Cramer Class 3 of TTC approach for toxicology risk. The statistical analysis by univariate approach grouped the samples into 3 subsets: one group including the samples IN, NO, and F, the second group including the samples F, FBL, and BA, and NO as the only sample in the third group. The ICA approach confirmed some results from the univariate model: it was found out that MO and BA correlate by nonanal, F and FBL by the ethylhexylacetate, dodecane and diphenyl ether, and FBL and IN by farnesene. NO showed no correlation with the remaining.