PROJECT HIGHLIGHT
This project will examine how infrastructures meant to control stormwater runoff — in particular “infiltration” structures, like rain gardens and permeable pavement — retain and release microplastics. The researchers will examine both design elements and factors in the surrounding catchment area, and aim to inform both the design and operation of infrastructure and the development of management strategies that effectively reduce microplastic pollution, thereby improving community health.
PROJECT SUMMARY
Stormwater best management practices (BMPs) include physical infrastructure meant to control the quantity and quality of stormwater runoff. Low Impact Development (LID) BMPs like rain gardens and permeable pavements mimic natural systems and encourage rainwater to soak into the ground rather than flow quickly into waterways.
Past studies show that more than 90% of microplastics carried into LID BMPs accumulate in the top few centimeters of their “filter layers.” Because microplastics degrade slowly, they can be later washed out of the BMP via storm events and sent into waterways. This can make it difficult to assess the true impact of BMPs on microplastic pollution. Additionally, previous work has shown how nearby land use factors such as playgrounds with plastic structures can affect the accumulation of microplastics in parks. In this project, the researchers will examine various factors that may affect the accumulation and retention of microplastics in stormwater LID BMPs.
The researchers will examine how both land use and trash management practices in the surrounding catchment impact microplastic accumulation in structural BMPs. They will also assess the impacts of various design elements, including site-specific soil conditions, the use of soil amendments, the kind of vegetation included and the size of the BMP. Finally, the researchers will determine whether high-energy stormwater flows can carry accumulated microplastics out of the soil in BMPs and further downstream — turning the structures from a sink for microplastics into a source. The results will help inform the design of future stormwater infrastructure, thereby improving the health of local communities and ecosystems.