## 2 Significance of Environmental and Food Pollution by Microplastics
Another factor is the development of technology, which enables faster acquisition of cheaper quality water and water for special purposes (e.g., water enriched with magnesium ions or iodine). There is also a growing belief among consumers that bottled water is healthier than tap water. That is why it is becoming fashionable among parents to use bottled water intended for children from the first day of their life. Availability and reliability are other determinants of bottled water purchases. The largest share of bottled water sales is represented by PET plastic packaging. The advantage of water in PET bottles is their lightness, durability,flexibility, and widespread availability. PET bottles are designed to be strong, shatter-resistant, and economically viable, making them particularly attractive to both bottled water producers and consumers. PET bottles are also highly recyclable, which increases their appeal in environmentally conscious markets [45]. Moreover, in accordance with legal regulations, this material is considered safe for contact with food. Unfortunately, consumers who choose bottled water contribute to a significant and destructive impact on the natural environment. Increased consumption of PET bottled water results in increased waste. Data from 2021 indicates that PET waste in the United States accounted for 44.7% from single-use bottles and 12% of global solid waste [46]. Plastic packaging waste poses a serious threat to the natural environment due to its very long decomposition time. This is due to the inherent stability of PET, making it highly resistant to environmental biodegradation. It is estimated that PET bottles can take up to 500 years to decompose, contributing to pollution of the terrestrial and marine environment through the accumulation of degradation products [47; 48]. In the natural environment, under the influence of atmospheric conditions, PET fragments mechanically and chemically, resulting in the formation of microplastic particles [23; 49; 50]. Degradation of plastic waste in the environment is a key process responsible for the accumulation of MP in the environment [51; 52]. The degradation rate depends on the plastic's characteristics, the degree of weathering, and the conditions of the natural environment [53]. Nanoplastics pose a serious threat because, due to their small size, they are extremely difficult to detect and monitor in the environment. Studies on the occurrence of plastic decomposition products in the natural environment have shown their presence in the air [54], soil [55; 56] and water [57; 58]. MPs contamination poses serious threats to the entire food chain. The MPs contamination pathway from bottles is presented using a modified Holdgate model (see Figure 1). The analysis of the human (target object) contamination path should start with identifying the sources of pollution and the types of harmful substances. In the case of PET bottles, harmful substances released during degradation are micro- and nanoplastic particles and chemicals (including terephthalatic acid, ethylene glycol, diethylene glycol, acetaldehyde, antimony, and bisphenol A) along with other harmful substances deposited on the surface. Figure 1: Paths of contamination from PET bottle decomposition products to the target object. The sources of these contaminants are many, depending on the stage of the packaging life cycle. These contaminants can be created at any stage of the bottle production process, starting with the production of PET granulate, preforms, and the blowing of bottles. The next source of pollution occurs when the empty bottles are filled with water and sealed with plastic caps. During storage, harmful substances migrate from the packaging into water due to direct contact. Another source of microplastic contamination in bottled water is the cap, from which particles escape into the water when unscrewed. Once used, PET bottles become a serious problem as post-consumer waste, ending up in both legal and illegal landfills, both on land and in water.