The Shoreline Cleanup is our best estimate of the actual pollution around Kasshabog Lake. The 2025 collection was consistent with the previous three years in both volume and composition, giving us confidence in our understanding of shoreline pollution patterns.
How does the Shoreline Cleanup compare with the microplastics in the water and sediment samples collected? There were some similarities and some differences. The proportions of the toys, containers (dark blue section), and other (light blue section) categories were relatively similar. Still, the microplastic samples contained much more fibres (purple section) and much less foam (pink section) than the Shoreline Cleanup.
Why? The primary reason is likely the site selection. The microplastic sample sites for our study were selected based on an educated guess, whereas the shoreline clean-up provides direct evidence of where larger plastic pollution accumulates. There are also environmental reasons for these differences. Different plastics have different fates in the environment. Fibres float and remain suspended more easily, while foam docks break down and accumulate in sediments or along shorelines. Different plastics also break down at different rates. Materials may be broken down into fibres and foams at a faster rate than larger, more durable items collected during the shoreline clean-up.
The shoreline cleanup and microplastic sampling results provide complementary information. The cleanup data tells us where visible plastic pollution accumulates and where we can expect it to break down into microplastics. The surface water, sediment, and beach samples show the microplastic concentrations detected at specific locations. Along with shoreline pollution data, we get a clearer picture of the pollution pathway. Our key takeaway is that local cleanup data can help improve microplastic study design by identifying source and accumulation areas. Continuing shoreline cleanups is a practical way to reduce microplastic pollution by removing larger items before they can break down.