FROM SOURCE TO TAP: MICROPLASTICS IN A SUB-WATERSHED OF THE HUDSON RIVER ESTUARY

Oceans are a major sink for microplastics, with plastic accounting for the majority of total marine pollution. The Hudson River contributes ~ 300 million microplastic fibers to the Atlantic Ocean per day, and some samples in the lower Hudson have been found to have over 6,000 pieces of microplastics. Plastic pollution enters the Hudson River via stormwater runoff, wind, and atmospheric deposition, treated wastewater discharge and stormwater. Troy, NY is the uppermost town of the Hudson River estuary, 153 miles north of New York Harbor. Tap waters from Troy, NY show an abundance of microplastic fibers in the water, with an average of 156 microplastic particles/L suggesting that water treatment is not removing microplastics. Most wastewater treatment plants in NY are not equipped to filter out small particles, so microplastics in household waters are ultimately making their way into the Hudson River via outflow and combined sewer overflow.

The Tomhannock Reservoir in Pittstown, NY is the drinking water source for Troy, NY. Three streams supply water to the reservoir and developed land in each is < 10% area. In the summer of 2023, water sample were collected from 3 the tributaries, reservoir, and taps throughout Troy. Both grab samples and net sampling methodologies were deployed at different flow conditions to assess methodological differences as well as spatial variation. All samples contained microplastics and concentrations varied considerably from location-to-location and over the summer. On June 14^th, Otter Creek had 668 microplastic particles identified in 1 L, whereas on July 26^th, only 12 microplastic particles were identified. Significant variation was observed between samples of different volumes; concentrations ranged from 153 particles/L to 668 particles/L for 5 L and 1 L volumes respectively. For both dates, there was no precipitation in the previous 24 hours, however velocity was greater on July 26^th. This work demonstrates the highly variable nature of microplastic pollution in a small watershed of the Hudson River estuary. Further work is ongoing to identify plastic polymers in surface and drinking waters, and to test effectiveness of microplastic removal from tap waters using commercially available filters.