FIBERS, FIBERS EVERYWHERE: FIRST LOOK AT MICROPLASTICS IN THE HUMAN WATER CYCLE OF SENECA LAKE, FINGER LAKES OF NEW YORK, USA

Microplastics (plastic fragments, films, and fibers < 5 mm) are ubiquitous in the environment. Beyond documenting their presence and abundance, we must understand their sources and sinks in order to remediate microplastic pollution. In this initial study, we take a holistic approach to documenting sources and potential sinks of microplastics in Seneca Lake, which is a drinking water source for several communities in the watershed. We document inputs into the lake including surface streams, treated wastewater, runoff, dry air fall, and rain. Within the lake, we quantify gradients of microplastic particle abundance and consider how particles move through the aquatic ecosystem and into the sediment. We also examine tap water derived from the lake. Samples were filtered through a 0.43 µm filter and plastic particles identified using UV fluorescence.

The majority of microplastic particles were PET fibers and very small (< 100 µm) fragments with similar fluorescence properties. This contrasts with most marine systems where fragments dominate. Microplastic particles were concentrated in the north end of the lake, reflecting prevailing wind direction, bulk current flow, and inputs from surface streams and treated waste water. Microplastic particles, particularly fibers, were twice as abundant in lake surface compared to bottom water, suggesting neutral to positive buoyancy. Microplastics were found in the digestive tracts of several species of small fish and benthic filter-feeders (Dreissena bugensis, quagga mussel). Gut passage may be an important sink of buoyant microplastics into the sediment. Streams showed little input from agricultural landscapes, significantly more (p = 0.002) from residential areas. Deposition from dry air was small but not zero. We observed significant (10,000–20,000 particles/L) deposition in rainwater with the highest amounts coming from short storms with maximum convective height of about 1000 m. We observed ~1000 particles/L of tap water from all of the buildings we sampled. No differences were observed with the age of the buildings. Secondary filtration in water bottle filling stations cut particle abundance in half.