River inflow of microplastics and their distribution in sea areas on the example of the southern Baltic Sea

Since the beginning of widespread use of plastic its consumption and production has been constantly increasing. As a result of human activity part of waste ends up in our environment and is deposited in each of the elements of the biosphere. These impurities can be in the form of large elements, small particles fragmented to macroscopic level (pellets, facial scrub grains) and the microparticles visible under a microscope. Particularly harmful for the environment are microplastic particles, which can be deposited in living organisms. Impurities get into surface waters, and then through rivers into the seas and oceans, as the final reservoir. Currently greater attention is paid to rivers. In rivers plastic can undergo further fragmentation and be transported along with water and bed sediment. The research describes an attempt to determine the plastic content in the water of the lower Vistula, the largest river flowing into the Baltic Sea. The material extraction for the research was done in the Tczew gauge profile (Km 33+080). During this process the hydrometric measurements and the velocity distribution and flow rate using ADCP device was completed. The primary objective of the study was to analyse the dynamics of riverine transport of microplastics. On the basis of analyses of samples taken from various points in the Vistula River cross-section at the Tczew profile 12 times a year, the size of the inflow of microplastics discharged by the river to the Baltic Sea waters was determined, which is of fundamental importance for the formation of the state of the marine environment. The data obtained were used to feed the MIKE 3D hydrodynamic model for predicting polymer transport in marine areas. The samples were examined microscopically. The work is the result of the research project DS-O 3.1/2019 funded by the Ministry of Science and Higher Education Also see: https://micro2024.sciencesconf.org/559385/document