Microplastics – a new threat for the aquatic environment? (review)

Summary

Plastic debris components with a size from microns to meters are found in the pelagic and benthic zones of all the seas and oceans. Fine plastic fractions get to the municipal wastewater treatment facilities and water treatment plants with water and wastewater after pretreatment. By microplastics particles with a size less than 5 mm are implied. By origin they are classified as primary and secondary. Microplastic materials that are a part of industrial products are classified as primary; the secondary microplastics are formed as a result of bigger microplastics fragmentation. In municipal wastewater secondary microplastics prevail in the form of fibers; their concentration can reach 100 particles/l. Incomplete removal of microplastics at the treatment facilities is considered an accepted fact. Effluent discharge results in the rivers becoming the main source of these pollutants entering seas and oceans. The growth trend of sea water pollution with microplastics is considered absolute. Besides, the tendency of their reduction in size is noted. Microplastics are characterized by bioaccessibility for the wide range of marine biota. In animal organisms microplastics can cause physical damages or become sources of toxic impact as a result of monomers and different additives used in the production of plastics migrating from their structure. High sorption activity of microplastics in the sea water is also noted; it results in the concentration of resistant organic substances in them sixfold exceeding the concentration in sea water. High probability of bioaccumulation and trophic transfer of a whole number of toxic substances adsorbed by microplastics exists.

Key words

treatment facilities , toxicological effect , aquatic environment , primary and secondary microplastics , sorption activity