Detection of potential plastic accumulations using spectral signature and remote sensing indices

The increasing level of plastic and microplastic pollution is a major environmental problem. The popular traditional method used to sample and analyse plastic and microplastic accumulations has several limitations, including lack of high spatial and temporal coverage. In this study, we aimed to identify and differentiate floating materials, including plastics and microplastics, in Galway Bay, Ireland, using Sentinel-2 satellite data. This analysis was done using visual inspection, spectral signatures of floating materials, and remote sensing indices. However, in-situ data were not available to confirm the presence of the floating materials. Still, the results from this study show that high-resolution satellite images, such as Sentinel-2 data, have a high potential to effectively identify and monitor floating materials in the water environment. This study identified areas most likely to contain plastic pollution by using spectral signatures and remote sensing indices, demonstrating the potential of these techniques to detect plastics, particularly in locations with high accumulation of plastic debris. However, it will be difficult to observe microplastics on Sentinel-2 images with 10 m resolution or other satellite data because of the small size of microplastics, less than 5 mm, unless they form dense patches and unrealistic concentration levels. Furthermore, cloud cover is another major limitation in the application and effectiveness of using satellite images for detecting floating materials.