145-8 Avenues of Litter Transport: Mismanaged Waste Distribution and Composition across Suburban Roadsides, Storm Drains, and Streams

Session: Dynamics of Natural and Built Environments (Posters)

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The accumulation of human-manufactured waste is affecting our environment and water quality.  As part of an ongoing study of sources and movement of mismanaged waste in the Lake Macatawa Watershed around Holland Michigan, we compared litter captured in storm drain traps to roadside litter and floating litter in streams.  We deployed eight under-grate litter traps in storm drains in a mix of sites near commercial and industrial establishments and schools.  These traps were deployed between August 2–4, 2024 and June 24, 2025.  We captured floating waste between June 28, 2024 and July 1, 2025 using a Trash Trout Jr. floating litter cage in a large creek, and supplemented this with floating litter booms that spanned three small streams from June 19 through July 17, 2025.  Collections of roadside litter served as presumptive starting material, allowing us to compare how litter characteristics change as items move from the roadside into storm drains and streams.

Storm drains captured mainly naturally-occurring organic matter (>99% by dry mass).  Human-sourced mismanaged waste in the storm drain traps was mainly plastic (54.9% of recovered items), mostly in the form of hard plastic fragments, and cigarettes (23.3%).  Expanded plastic foam comprised an additional 6.8% of storm drain litter.  This mix of materials is comparable to compositions of local roadside litter collected over the last 3 years, where roadside mismanaged waste averaged 49.8% plastics and 9.8% plastic foam.  In general, items in storm drain traps were more fragmentary than was roadside litter, but similar in their overall range of compositions.  In contrast, plastic foam was the most common item in stream and creek floating waste, totaling 92.5% of all collected litter.  This in part reflects the limitation of our in-stream equipment to collecting only floating waste, but may also indicate degradation of some types of waste, such as bags, wrappers, and other flexible plastics that might be expected to float but are not well represented in collected stream litter.

A single drain along a road without sidewalks in a shopping center produced 40% of all storm drain items.  Traffic density and the proximity to parking lots, newly opened packaging, and sources of food in disposable containers are all potential factors that should be examined as contributing to the abundance of mismanaged waste entering storm drains.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-6288

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