Risk assessment of non-intentionally added substances in polyester yarn made from recycled polyethylene terephthalate (PET)

Abstract: Polyester is a synthetic material made from polyethylene terephthalate (PET), which is synthesised from fossil raw materials. Many clothing manufacturers are using polyester in their clothing, which, from an environmental perspective, creates a non-sustainable cycle. However, manufacturing can be made more sustainable by using recycled PET bottles as the raw material for polyester yarn. A clothing company that has taken a stand against materials made from fossil fibres and instead invests in only selling clothes made from sustainable materials is the Swedish children's clothing brand Polarn o. Pyret. Being able to use polyester made from PET bottles is important for Polarn o. Pyret to ensure the use of sustainable fibres in their clothing. In the past, the recycled polyester was used in combination with polyester from virgin fibre, but now the goal is instead to switch completely to the recycled polyester. However, the increased quantity of recycled polyester can involve new risks. The need to map potential contaminants is important because Polarn o. Pyret makes clothes for children, which entails strict requirements on the chemical content of the clothes. The purpose of this work is to get an overview of which contaminants that can accumulate in the polyester fibre and thus pose a risk when using recycled polyester made from PET bottles. The goal is to be able to shed light on these contaminants and write a proposal for a risk assessment guide that can establish a foundation for how Polarn o. Pyret should be able to act when using recycled polyester. The work was carried out through an extensive literature study, where research articles and review articles published on scientific databases were the main source of information. Focus was on the risk of non-intentionally added substances that can be traced from recycled PET bottles. The risk assessment was done in consideration of the regulations that is established within the European Union (EU), using the EU chemicals regulation REACH and the European Chemicals Agency (ECHA) database.  After the mapping of NIAS in r-PET, the literature showed 42 potential contaminants to be present. These substances originated from the degradation of PET or the degradation of additives, and impurities from the recycling process and post-consumption use. Adhesives, labels, and caps are a contributing factor to the formation of NIAS originating from the recycling process. Since PVC was found to be the most common plastic that could contaminate PET via recycling, the additives used in PVC could also migrate to PET and create impurities. The most common phthalate found in this study was DEHP, which was the main plasticiser in PVC.  15 substances of the NIAS found in the literature was CMR substances, which means that they either were, or were suspected to be, carcinogenic, mutagenic and/or toxic to reproduction. Among these were substances such as benzene, antimony, cadmium, lead, acetaldehyde, and formaldehyde. Certain substances found through the literature were classified to be endocrine disruptors. These NIAS were p-nonylphenol, the organophosphite TNPP, the phthalates DEHP, DBP, BBP and, DIBP, nickel and BPA. Some of the NIAS found were under assessment of being classified as persistent, bioaccumulativ and toxic (PBT). The PBT substances found were the organophosphite compound Irgafos 168 and the UV-stabilisers Tinuvin P, UV-234 and UV- 328. The risk assessment showed 20 contaminants that may cause irritation to the skin/eyes and/or throat and 24 contaminants which may be toxic to the aquatic life.  This risk assessment showed that the recycling process of PET bottles is not completely safe, because potential contaminants could be transferred into the polyester yarn, and then carried over into children's garment and pose health risks to children.