Scholarly record

THE STUDY OF WATER POLLUTION OF THE LOWER VISTULA RIVER BY PLASTIC PARTICLES

Assoc. Prof. Dr. Hab. Eng. Piotr Zima, MSc. Eng. Pawel Wielgat, MSc. Eng. Artur Cysewski

Abstract

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 article describes the trial attempt to determine the content of plastic 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. For sampling were used plankton nets - the first with the mesh size of 0.5 mm and the inlet dimensions of 0.2x0.4 m and second with the 0.2 mm and 0.2x0.3 m. 0.5 mm nets were placed in the mainstream (velocity of approx. 1m/s) at the surface and at a depth of 0.5 m. 0.2 mm net was put at the bottom and left for sampling. After filtration of approx. 100 m3 of water, nets with samples were preserved and transported to the laboratory. The resulting catch at the surface and at a depth of 0.5 m contained plant parts and wood fragments, and the mesh placed at the bottom caught sand, wood fragments and shells. Then the samples were dried at room temperature. In order to reduce the organic matter, the dry samples were placed in a 20% solution of H2O2 and then in a 20% solution of HCl. The acquired portion of bed sediment (705g dry weight) after etching was subjected to flotation in a 40% ZnCl2 solution (solution density approx. 1.4 g/cm3). After the sand sedimentation, the solution was filtered. The samples were examined microscopically. During the investigation, some plastic particles were found plastic (size of 1-2 mm or more). While examining under a microscope at 60 times magnification were noticed single plastic fibers. The study helped to identify the presence of forms of plastic on the macroscopic and microscopic level. Various forms of plastic were found both in water and bed sediment. Due to the size of the mesh, smaller particles have not been studied.

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