## 1 Introduction
### Presence and Degradation of Plastics in the Environment  
In addition, microplastics tend to act as vectors for other contaminants, such as pathogens, organic pollutants, and heavy metals, due to their strong dispersion and diffu \begin{table}
\begin{tabular}{c c c} \hline \hline
**Type of Plastic** & **Size** & **References** \\ \hline \hline \multirow{2}{*}{Macroplastic} & \multirow{2}{*}{\(\geq\)25 mm} & [23; 26; 27; 28] \\ \cline{2-3}  & & 5-25 mm \\ \hline \multirow{4}{*}{Microplastic} & 1 \(\upmu\)m–5000 \(\upmu\)m & [21; 22; 23; 29; 30; 31; 32; 33; 34] \\ \cline{2-3}  & 0.1 \(\upmu\)m–5 mm & [19; 24; 32; 35] \\ \cline{2-3}  & 0.1 \(\upmu\)m–5000 \(\upmu\)m & [36] \\ \hline \multirow{4}{*}{Nanoplastic} & \multirow{2}{*}{\(<\)1 \(\upmu\)m} & [21; 37; 38] \\ \cline{2-3}  & 0.001 \(\upmu\)m–1 \(\upmu\)m & [22; 23; 31] \\ \cline{1-1} \cline{2-3}  & 0.001–0.1 \(\upmu\)m & [35; 36] \\ \cline{1-1} \cline{2-3}  & \(<\)0.1 \(\upmu\)m & [32; 39; 40; 41] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Plastic classification by measurement. Figure 1: The most prevalent varieties of plastic and their applications: polyethylene terephthalate (PET), high-density polyethylene (PEHD), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), and polyurethane (PU). sion mechanisms. Most ongoing research on microplastics has focused primarily on marine systems, but the contamination of land surfaces may also be important due to the observed release rate, which is approximately 20 times higher compared to the oceans [42]. The issue with plastics lies in the fact that nearly half of their production is in the form of single-use items, which are often improperly disposed of and end up polluting aquatic ecosystems [43]. Research indicates that less than 10% of industrially produced plastic is recycled, leading to its ubiquity [44]. A negative aspect of plastic in the marine environment is the economic damage to the fishing industry and tourism [45]. Plastic waste is harming and killing birds, mammals, fish, and marine reptiles through ingestion and entanglement, causing injuries and infections [46; 47]. Microplastics in the environment can result from the degradation of larger plastics by biological, photochemical, and mechanical processes [48]. Biodegradation is the action of living organisms--frequently microbes. Plastics can be degraded via biotic and abiotic pathways [49]. Biotic degradation can be subdivided into aerobic and anaerobic degradation and occurs mainly when particles are small enough to pass through microbial membranes [49; 50]. While anaerobic degradation occurs in the absence of oxygen, such as in sediments and landfills, aerobic degradation happens in the presence of oxygen. Abiotic degradation can occur through photodegradation and hydrolysis, which involve initiation, propagation, and termination steps [49]. However, when it comes to plastic polymers with a heteroatomic backbone, the degradation process is different [51]. The durability of the polymer also depends on the additives used during the treatment of the polymers. For example, the stability and durability of PE can be increased significantly by using specific additives such as UV absorbers and quenchers [52; 53]. Photodegradation refers to the action of UV rays in the degradation of the plastic matrix. Thermoxidative degradation is a slow process of oxidative degradation that occurs at moderate temperatures and breaks down plastic over time. Thermal degradation is achieved by the action of high temperatures, and hydrolysis occurs via the action of water on the plastic [53]. Due to their small size and unique shapes, which increase the surface-to-volume ratio of MP/NP, they can easily penetrate cell membranes and harm biota [54]. A particle tracking analysis revealed that polystyrene nanoplastic particles were formed after 56 days and polyethylene particles were formed after 8 weeks of exposure to artificial seawater [55].