42-4 Identifying the Influence of Watershed Development and Precipitation on Anthropogenic Fiber Pollution in Freshwater: A Natural Experiment of Three Finger Lakes in Western New York, USA

Abstract:

Microplastics, defined as anthropogenic polymer particles < 5mm in size, are pervasive in freshwater lakes. This raises concerns for the services lakes provide to ecosystems and communities within their watersheds. Microplastic fibers, alongside manufactured natural fibers, make up the majority of freshwater contamination. These anthropogenic fibers are easy to identify and offer a useful proxy for total microplastic contamination. In this study, we compare three Finger Lakes to assess the influence of watershed development and precipitation by quantifying levels of anthropogenic fiber contamination. Seneca, Hemlock, and Canadice lakes vary in their watershed characteristics, and have different possible sources controlling their anthropogenic fiber abundances. Seneca lake has the most developed watershed, receiving treated wastewater, primary runoff from urban areas, and various human activities. Hemlock and Canadice lakes have forested watersheds and undeveloped shorelines, do not receive treated wastewater, and host limited recreational use. From 2023-2026 water samples were collected from the surface and bottom of each lake’s water column, these samples were then filtered and anthropogenic fibers were identified and quantified. Statistical comparison of the anthropogenic fiber levels in each lake revealed no statistically significant difference (Kruskal Wallis: H = 0.135, p = 0.94). Seneca lake’s median fiber count was 19.4 ± 20 fibers/L, 20 ± 18 fibers/L in Hemlock, and 20 ± 20.5 fibers/L in Canadice. These results show that treated wastewater and watershed development do not positively influence anthropogenic fiber levels in Seneca Lake. In contrast, we found a strong, positive correlation between rainfall and anthropogenic fiber contamination (Pearson’s Correlation: t = 8.86, p < 0.0001). This implies that, in the humid climate of the Finger Lakes region, the atmosphere is the most influential source of a lake’s fiber concentration, rather than the make up of an individual watershed.

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