Bodrum ve Güllük plajlarında (Muğla, GB Türkiye) seçilen yerlerin mikroplastik i̇çerikleri ve sediment sınıflandırması

The use of plastics has increased in the last 60 years. The excessive use of these plastics has caused great environmental and water pollution due to industrial activities, thus producing macro and micro-sized plastics depending on their purpose. The amount of plastic recorded in 2015 was 322 million tons. According to researchers, between 5 and 13 Mt of plastic waste entered the ocean in 2010. The gradual breakdown of large plastic into smaller sizes creates microplastics (MPs). Plastics from 5 mm to 1 mm are considered microplastics (MP). The instantaneous accumulation of microplastics in water bodies including oceans, seas, lakes, rivers, and sediments has become a global challenge. This has attracted great interest of scientists to study and address the negative impact on humans and aquatic animals in the future. Most of the studies on microplastics have focused mostly on the ocean. To date, very little work has been done on microplastics in the sediment. Therefore, the issue of understanding and separating microplastics from the sediment has remained complex. The main aim of this study is to focus on the identification and systematic separation of microplastics from coastal sediments. For this purpose, sampling was carried out depending on the size and length of the beach. For wider beaches such as Boğaziçi and Güllük , the samples were collected on both shoreline and backshore at each 50-100m stretch at every point. A total number of 24 samples were collected from all locations. From the results of sieve analyses conducted, the skewness, sorting, kurtosis and average grain sizes of the sediment sediments were defined. The sediment was classified as gravel (G), sandy gravel (sG), slightly gravely sand (g)S and gravelly sand (gS) according to the Folk classification of sediment. Microplastics were separated using different methodologies such as hand picking, Distilled water separation, and NaCl solution separation method. A total number of 1446 MPs were determined in the overall mass of 7200g of sediments in the study areas. Fourier Transform Infrared Spectroscopy FTIR analyses were carried out on various MPs to identify the type of polymers. The results pointed out a clear identification of different polymers including polyethylene (PE), polyvinyl acetate (PVAC), Polytetrafluoroethylene (PTFE) and glass fibers containing Si-OH – bending band and SiOSi – tensile band in the various study areas. Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy EDS and X-Ray Diffractometry (XRD) analyses were also carried out to identify the morphology, mineralization and sediment characteristics concerning microplastics. Our findings show that hydrophilic minerals have a high capacity to retain more microplastics. We also observed that as the proportion of coarse-grained sediments increases, the rate of microplastics retained in them is relatively low. In Bodrum Peninsula, Güllük Formation (Lower Triassic schist-calcschist), Pazardağı Formation (Middle Triassic-Jurassic marble), Karadağ Formation, and Kışladağ Formation (Middle Jurassic-Cretaceous cherty limestones), as well as Bodrum Formation (Upper Cretaceous metaclastics and metacarbonates) which are unconformably overlain by Miocene classics, Miocene volcanic with Quaternary deposits, was mapped using the digitized geological map prepared by Mineral Research and Exploration Institute of Turkey (MTA).