## 3 Result Statements from the Analysis of the Available Literature
### Environmental Factors
Microplastics: The Potential for Microplastic-Sorbed Micropollutant Bioaccumulation in Aquatic Organisms  
The term bioaccumulation refers to the net result of processes by which organisms uptake substances both directly from the abiotic environment (e.g., air, water, and soil or sediment) as well as indirectly from dietary sources and then transform and ultimately eliminate them [101]. In this framework, substances can be various micro-pollutants adsorbed on microplastics that act as their delivery vehicle to organisms. Once microplastics have entered the organism, we describe five possible scenarios of interaction between micro-pollutants and microplastics in terms of sorption and desorption related to micro-pollutant bioaccumulation in organisms [77; 102]. The first scenario assumes that the sorption ability under aquatic conditions and the desorption ability under the gut conditions of organisms are high. This possibility could allow microplastics to act as a vehicle with the ability to transfer micro-pollutants in the organism. The presence of microplastics with high sorption and desorption abilities could enhance the bioaccumulation of venlafaxine in the hepatic tissue of Oriental weatherfish, _Misgumus anguillicaudatus_[103]. Moreover, the rapid desorption of organic micro-pollutants under gut conditions could increase the bioaccumulation of phenanthrene, DDT, perfluorooctanoic acid (PFOA), and di-2-ethylhexyl phthalate (DEHP) [104]. The second scenario assumes a high sorption ability in aquatic environments and a low desorption ability in the body of organisms that could lead to low bioaccumulation. However, the high sorption of micro-pollutants on microplastics may nevertheless adversely affect the health of organisms. For example, mussels exposed to relatively high concentrations of fluoranthene sorbed on polyethylene showed low bioaccumulation levels but an increase in tissue alterations and antioxidant biomarker levels [105]. In the third scenario, the occurrence of low sorption ability in the environment coupled with high desorption ability in the body could also lead to low bioaccumulation. For example, despite the low PE adsorption capacity and subsequent lower concentrations of polybrominated diphenyl ethers (PBDEs) and bifenthrin on PE, these chemicals bioaccumulate in amphipods and midge _Chironomus pepperi_, respectively. This contradiction is explained by PBDEs and bifenthrin having low sorption on polyethylene in aqueous phases but the ability to be almost completely desorbed from PE microplastics inside the organisms, therefore allowing for significant bioaccumulation [106; 107]. The fourth scenario assumes that the sorption and desorption abilities are low in both the environment and organism (digestive tract) conditions. This combination is likely to result in low bioaccumulation, as illustrated by the studies of the exposure of fluoranthene-sorbed microplastic in mussels (_Mytilus_ spp.) [105]. The fifth scenario considers the high sorption and low desorption abilities of microplastics, but only inside an organism (internally). Such a variant could assist in the depruation or removal of micro-pollutants from the affected organism. High sorption could trap and remove micro-pollutants via excretion, leading to the lower bioaccumulation of micro-pollutants. Such processes were observed when contaminated polychlorinated biphenyls (PCBs) in feed were adsorbed to and transferred by virgin polyethylene in simulated gut conditions [108]. Therefore, it is highly likely that a range of potential bioaccumulation outcomes can be attributed to the physicochemical properties of microplastics (such as sorption and desorption abilities), the environmental conditions, the exposed organism characteristics, and the position of an organism in a food chain [97; 109; 110; 111] (Figure 2).