## 4 Interactions of MPs and Other Pollutants  
MP particles come into contact with various organic and inorganic pollutants during the production process (chemical additives), during release into the environment (mostly from landfills and wastewater) and in the environment itself (water, soil, air, sediment and biota) [36,47]. Several thousand synthetic chemicals with potentially toxic effects and a tendency to migrate into the environment are used to produce plastics [48,49]. Additives are added to plastic materials to improve their functional properties (PACs): plasticizers, flame retardants, heat stabilizers, lubricants, pigments, antistatic agents, antioxidants, dyes, pigments, biocides, fillers, etc. [50,51,52]. The most prominent chemicals added to plastic products are formaldehyde (carcinogen), bisphenol A (endocrine disruptor), phthalates [48,53] and heavy metals (cadmium, zinc and lead) [48,54]. About 4% of MP mass is made up of additives [49]. Polyvinyl chloride (PVC) plastic contains the largest amount of additives and is the main source of heavy metal contamination from plastic waste in the oceans [54]. In addition, it is often considered the most dangerous plastic due to the high content of chlorides and additives and the formation of dioxins during the production process and burning [55]. Additives are not chemically bound to the plastic material, but they diffuse into its' interior down a thermodynamic concentration gradient and later leachate into the environment, where they potentially become biologically available [41,56]. The lifetime of plastic materials such as textiles, furniture, household appliances and electronic devices is several decades, whereby PACs are continuously released into the environment by direct evaporation or abrasion of the surface layer. The emission of PACs depends on their physicochemical properties, characteristics of plastic products and environmental conditions (temperature and UV light) [56]. The European Chemicals Agency (ECHA) proposed the restriction of additives added to plastics in 2019; therefore, some countries limited the amount of additives in plastic products that come into contact with food but still not in other plastic materials (e.g., building materials and rubber) [57]. MPs have the potential to bind, accumulate and release organic and inorganic chemicals. This ability can contribute to the reduction of the concentration of organic pollutants in the environment [36], while at the same time, it represents a serious problem for the environment and human health. Acting as a vector that transports the pollutants in the environment, MPs contribute to the imbalance between environmental compartments and represent an entry route for pollutants into living organisms [36,48,58]. Interactions of MPs with various pollutants that are present in the environment from various anthropogenic sources were investigated, such as heavy metals (iron, aluminum, manganese, lead, copper, silver, zinc and cadmium), pharmaceuticals and hydrophobic organic pollutants (HOCs) or persistent organic pollutants resistant to degradation by biochemical and photolytic processes (POPs): polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyl (PCB),dioxins, polybrominated diphenyl ethers (PBDE), organochlorine pesticides (DDT and HCH), herbicides and their metabolites, etc. [36; 41; 48; 49; 58]. According to some studies, MPs react most easily with pharmaceuticals, heavy metals and pesticides [58]. Interactions of MPs with organic and inorganic pollutants depend on its physico-chemical and structural characteristics, such as the type of material, chemical composition, surface structure, size, shape, density, concentration, aging, surface-to-volume ratio of particles and hydrophobic properties of MPs and pollutants [47; 48; 58; 59]. Different types of polymers have different surface structures and thus a different affinity for pollutants.