2. Characterization of microplastics

Plastic waste has already flooded the Earth, macromolecules that are chemically very stable show poor degradation to physical (mechanical, temperature change, etc.), chemical (pfotochemical triggered by sunlight, etc.) and biological (biochemical [enzymes], microbiological [bacteria, fungi], etc.) effects of the environment. As a result of these effects, plastic waste breaks down into smaller and smaller pieces over time and thus in the environment, it appears in the form of macro- (> 5 mm), micro- (5 mm – 100 nm) and nano-sized particles (< 100 nm) dispersed in the air (atmosphere), surface water (hydrosphere) and soil (pedosphere). Anthropogenic microplastic particles smaller than 5 mm are the new emerging persistent pollutants [17]. Plastics are highly resistant to environmental effects, normally their decomposition is extremely slow, taking decades. Fragmentation of (micro)plastic particles is mostly produced by photo-oxidation, thermal, biological or mechanical degradation [12]. Although there is no consensus on the size, the term ‘microplastics’ generally refers to pieces of plastic which are smaller than 5 mm in diameter and ‘nanoplastics’ are plastic particles with a diameter less than 100 nm [8]. There is no uniform nomenclature in the literature, comparison of studies is difficult because some studies only examine spherical microplastics while others deal with plastics with various shapes and sizes [9], therefore sampling and analytical methods are different [18]. Their harmful effects on the ecosystem have already been demonstrated in several cases, horrifying news appears every day about cases affecting marine and ocean life, mainly caused by macroplastics, but today we can only guess their effect on human health based on scientific publications, the number of which has increased significantly in recent years. The hazard can be the particle itself (chemical composition, colloidal size, shape, surface properties) or the toxic molecules bound to the surface of the particles and thus transported by them (residues of drugs and pesticides, etc.).