Nehir kaynaklı mikroplastik tasınımı ve birikim alanlarının mekansal analizi: Melen Havzası orneği

With the increased occurrence of microplastics in natural environments, it became significantly important to define the sources, sinks and factors affecting the transport of microplastics in natural ecosystems to integrate mitigation strategies. It is known that freshwater systems are a major source of microplastics in oceanic environments and microplastics due to their physical properties, have hazardous potential to natural habitat. In this thesis study, it is aimed to understand the transport mechanisms of microplastics in river environments and to define the factors resulting the spatial and temporal differences of microplastic accumulation in basin level. For this purpose, Melen Basin, being an important water supply and being prone to having high plastic waste occurrence due to human activities in the area, is chosen as a case study. To represent the horizontal transport of microplastics, hydrological and hydraulic models are created using HEC-HMS and HEC-RAS. Then, using Goldsim software, advection-dispersion equation is adapted to understand the behavior of particle transport in an open surface flow. The land use characteristics, physical parameters of the watershed and microplastics sampled are evaluated to determine the parameters affecting retention. As a result of this study, significance of hydrological, environmental and land cover characteristics to microplastics retention is discovered. The conclusion of the study suggests that temporal and spatial variations in hydraulic parameters significantly influence the transport velocity of microplastics, and land use parameters in the watershed area are possible determinants in identifying accumulation areas of microplastics.