A Survey of Microplastic Pollution from Wastewater Treatment Plant Effluent Within the Lake Champlain Basin

Abstract

Microplastics are an emerging and ubiquitous pollutant. Recent studies suggest that consumer care products and laundering of synthetic garments are major sources of microplastics. Most current wastewater treatment plant (WWTP) technologies are limited in their ability to remove particulate <5mm in size and pose a threat to aquatic organisms. Since 2013, we have been surveying WWTP post-treatment effluent samples with the city of Plattsburgh, NY (N = 61), in 2016 we brought online St Albans, VT (N = 64), Ticonderoga, NY (N = 42), and Burlington, VT (N = 21), and in 2017 Vergennes, VT (N = 20). Post-treatment effluent samples derive from 24 hour plant sampling events and were processed using wet peroxide oxidation methods. All samples were characterized based on the type of microplastic (e.g., fragment, fiber, pellet, film, foam), size, and color, as well as polymer type using Fourier Transform Infrared Spectroscopy (FTIR). Plant-specific characterization revealed fibers were the most common microplastic in Vergennes (55%) and Ticonderoga (39%), as compared to foam (52%) in St. Albans, fragments (43%) in Plattsburgh, and similar proportions of fragment and films (31%) in Burlington. Estimated output of microplastic particles per day were: Plattsburgh (n = 14,972), St. Albans (n = 28,620), Burlington (n = 19,806), Ticonderoga (n = 10,544), and Vergennes (n = 576). Additionally, polymer type varied by plant and included HDPE, PVA, and styrene. Differences likely reflect plant characteristics, for example Plattsburgh and Burlington serve a similar sized population and have a similar capacity, the difference in particle abundances may be due to varied infrastructure updates. In addition, St. Albans and Vergennes have tertiary treatment; however dates of recent upgrades vary. Microplastic pollution is a concern when we account for plant 24 flow rate and lakewide distribution. Microplastics have the potential to adsorb harmful chemicals residing in the water and pose risk to aquatic organisms and human health. By documenting wastewater treatment plants as a source of microplastics, we can share these findings with plant operators, lake stewards, government officials, and work towards solutions both up and downstream.