Characterization of microplastics in sediments and surface waters of Turkish lakes

Abstract

This study examined microplastic (MP) pollution in the sediments and surface waters of seven distinct lakes in Turkey, aiming to assess the status and characteristics of MP contamination. Hydrogen peroxide was introduced to eliminate organic matter present in the samples. MPs were separated and filtered using methods based on differences in density using ZnCl₂ (d: 1.65 g cm⁻³) solution. Microplastics were subjected to Nile red staining observed using a fluorescent microscope, and subsequently, the types of polymers were identified through ATR-FTIR analysis. MP concentrations varied among lakes (p < 0.05), with Borçka Dam Lake (0.69 ± 0.65 MP L⁻¹) exhibiting the highest levels in water, while Karagöl (Şavşat) Lake (344 ± 188 MP kg⁻¹) showed the highest sediment contamination. Five distinct types of polymers were identified, with polyethylene and fragments being predominant in water, while polypropylene and fibers were more prevalent in sediment. The fibers predominantly measured less than 500 μm in length, whereas the fragments exhibited a more uniform distribution. The results indicate that microplastic pollution is prevalent in lake ecosystems, with human activities such as tourism, fishing, and urban waste discharge which have been identified as significant contributors. This study underscores the pervasive presence of microplastic pollution in protected areas and stresses the necessity for robust mitigation strategies to tackle the impacts of tourism on freshwater ecosystems. Additional investigations will elaborate on the precise origins, transport mechanisms, and ecological consequences of MPs, facilitating the formulation of efficient response strategies.