## 3 Result Statements from the Analysis of the Available Literature
### Environmental Factors  
In the process of determining microplastic sorption capacity, it is important to consider environmental factors such as surrounding bacteria, pH, salinity, and dissolved organic matter (DOM). Microplastics may interact with natural organic materials and form a biomolecular corona, which leads to changes in the microplastics' surface, thereby affecting surface charge, aggregation tendency, and sorption capacity [88]. The ability of bacteria to produce extracellular polymers during biofilm formation in order to facilitate the attachment and matrix development could result in an alteration in the microplastic sorption capacity with respect to physicochemical properties per se. For example, similar metal adsorption capacities of different types of microplastics might be related to similar biofilm distributions on the microplastics, regardless of the salinity conditions of microplastic deployment sites and the biofilm formation time [89]. In addition to influencing differences in bacterial populations in terms of biofilm formation, the pH and salinity of marine waters can result in both positive and negative effects on the micro-pollutant sorption capacity of microplastics. A decrease in seawater pH in marine environments suffering from increased acidification caused by the uptake of increasing carbon dioxide from the atmosphere [90] may play the role of proton donor to the microplastic surface and the increasing cationic characteristics of microplastics. This change, in turn, can lead to the higher adsorption of anionic micro-pollutants, including lysoin and perfluorooctanesulfonic acid (PFOS), on cationic-enriched microplastics through electrostatic interactions [76,91]. pH affects the sorption capacity of trace metals, such as Cadmium (Cd), Cobalt (Co), Nickle (Ni), Lead (Pb), and Chromium (Cr), on high-density polyethylene in saltwater via increased competition, decreased chromate ion activity, as well as complexation and free ion interaction with saltwater cations [92]. Salinity is an environmental factor of considerable importance, influencing the microplastic sorption capacity in marine systems, as it can affect micro-pollutant solubility in aqueous phases and micro-pollutant partitioning in other phases [93]. The increased amount of salt dissolved in a body of water enhances the sorption capacity of microplastics to 3,3',4'-Tetrachloropiphenyl (PCB77), lubrication oil, and other micro pollutants [76,94,95,96]. Conversely, increased salinity was shown to decrease the sorption capacity of dichloroiphenyltrichloroethane (DDT) and ciprofloxacin on microplastics due to cation competition for sorption sites [74,83,97]. However, there were no observed salinity-related effects on phenanthrene (Phe), as the salt content in water did not affect the aqueous solubility and pore-filling mechanism of Phe [97]. Dissolved organic matter (DOM) is an important factor in determining microplastics' sorption capacity due to its diversity of chemical components leading to complex interactions. DOM components such as humic and fulvic acids have been reported to both increase and decrease sorption capacity in several different studies, indicating complexities of the interactions that are yet be fully described [98,99,100]. Fulvic acid negatively affected the sorption capacity of tetracycline on microplastics, as tetracycline was deemed to sorb onto DOM rather than microplastics [98]. Likewise, microplastics could adsorb fewer hydrophobic organic compounds (HOCs) due to the increasing desorption from the presence of dissolved organic matter [99]. Yet, the positive effect of the role of dissolved organic matter bridge formation in the micro-pollutant-microplastic surface complex might be a reason for the increased sorption capacity of oxytetracycline on aged microplastics [100].