###### Abstract  
The widespread use of polyethylene terephthalalate (PET) in bottled water packaging remains significant and is expected to increase further in the coming years. This trend raises concerns due to the generation of large amounts of waste. The degradation of PET leads to the release of low-molecular-weight substances and microplastic particles, which contaminate food products and the environment. This work highlights the significance of microplastic pollution, summarizes the mechanisms of PET degradation, and discusses methods for microplastic detection. A key section of the paper explores potential degradation management strategies, focusing on their applications and existing limitations. The study underscores the need for coordinated action among the scientific community, industry, and policymakers to mitigate this pressing environmental challenge. waste management; sustainable development; polyethylene terephthalalate; PET bottle; microplastic +
Footnote †: journal: Applied sciences  
0000-0001-5000-0000]J.J.W.W. Exposure to microplastics can be considered a risk factor for cardiovascular disease [3]; MPs exhibit proinflammatory activity [4; 5], may cause endocrine disruption and infertility problems [6], and lead to other adverse effects. The presence of microplastics may hinder efforts towards sustainability, particularly in waste management and renewable energy generation. For example, MPs can negatively affect the anaerobic digestion of organic matter during kitchen waste treatment [7; 8]. This example demonstrates the far-reaching consequences of MPs, not only from the perspective of human health but also in the context of developing technologies essential for sustainable development. The growing popularity of convenience foods, which are primarily sold in disposable containers, has contributed to the steady increase in global packaging production year over year. In 2024 alone, the value of the polyethylene terephthalate (PET) bottle market amounted to USD 45.50 billion and is forecast to grow to USD 60.30 billion by 2033 [9]. In addition, the amount of plastic waste in 2024 was 220 million tons (an increase of over 7% compared to 2021) of which over 6 billion PET bottles were recycled [10]. The growth of PET packaging production may appear inconsistent with the UN sustainable development goals and EU environmental policy. However, in the Single-Use Plastic (SUP) Directive [11] and the Packaging and Packaging Waste Regulation (PPWR) [12], there is no limit to the production volume of PET packaging, but there are guidelines on the amount of recycled PET used in the production of new bottles. In this way, the growth of the market value may result from the development of the recycled PET segment, which is in line with the principles of closed circulation. Considering the above fact and the detrimental environmental impact of increasing bottled water consumption in PET containers, the UN and the EU require PET packaging manufacturers to operate in compliance with sustainable development principles, emphasizing, among other approaches, the circular economy [11; 13]. PET bottle producers are working to align their production with sustainability requirements. In 2021, Danone's Aquas brand became the first in the mineral water sector to use 100% recycled PET (rPET) [14] and Coca-Cola switched to rPET bottles in the Netherlands and Norway [15]. Other initiatives include the introduction of a deposit return system in Europe [16; 17], which helps increase PET recycling rates, and the use of \"super-cleaning\" technology for rPET [18], ensuring food safety standards are met. These actions, along with Environmental, Social, and Governance reporting and fiscal policies, support a more sustainable circular economy. The increasing focus on sustainability also draws attention to the material itself--its origins, structure, and inherent properties. Polyethylene terephthalate is a polymer that is part of the polyester group.