The purpose of this project is to quantify microplastic loads at single sites on selected beaches at a continental scale to better understand microplastic distribution. A collaborative effort with the National Park Service and NOAA Marine Debris Program provided the opportunity to sample a wide geographic distribution of coastal beaches to quantify microplastic loads in a snapshot of time. Beaches can capture microplastics from both open water bodies (oceans or lakes) and riverine systems. Additionally, beaches are dynamic systems, with constant movement of sand and other particles like shells, glass, and plastic.
While the type of manmade material found was not determined, the techniques employed maximize the separation of microplastics from sand, so we assumed that mostly plastic was captured during this process as heavier materials, even if small, would have been separated from plastics. Given the ubiquitous nature of the microplastics concern, sampling beaches using a standard protocol provides an opportunity to compare relative amounts of microplastics across a wide geographic region. The overall approach of a one-time sampling at multiple sites across a broad geographic area allows us to determine how widespread and variable microplastic
pollution is and to begin to make inferences about sources and sinks. Data produced from this study should be used to gain a better understanding of where microplastics are located in the environment and an idea of the range of loads found along US coasts. However, NPS units should not use this single study to make strong inferences about the immediate risk of microplastics to wildlife and human health at their sites.