A Qualitative and Quantitative Assessment of Microplastics in the Shorelines of Urban Lakes

Microplastics in lake waters are a global problem that is gaining increasing attention from researchers. However, most studies to date have focused on the water column. Much less attention has been paid to the problem of sediment pollution at the shoreline, the zone where water and land meet, and microplastics accumulate and degrade. This study assessed microplastic pollution in shoreline sediments in six urban lakes, which are exposed to varying degrees of recreational pressure. Fourier transform infrared spectroscopy (FTIR) was used in the qualitative analysis. The concentration of microplastics in the studied lakes was not high, ranging from 5.2 to 42 particles per kg dw−1. More than half of the plastics detected were filaments. Nine different types of synthetic polymers were identified in the material collected from the shorelines of the studied urban lakes. Polypropylene (PP) was the most frequently found polymer. The characteristics of the collected material allowed for the identification of potential sources of pollution, most of which can be linked to various forms of recreation. The lake most heavily used for recreation was characterized by the highest concentration of microplastics in shoreline sediments, the greatest morphological diversity, and the greatest variety of polymer types. The results of this study indicated that recreation could be a significant source of microplastic pollution and highlighted the need for sustainable recreational use of lakes.