A Survey of Microplastics in Wastewater Treatment Plant Effluent in the Lake Champlain Basin
Microplastic pollution researchers are beginning to quantify, characterize, and collaborate on finding solutions to this emerging pollution problem. Recent studies have documented consumer care products and laundering of synthetic garments as major sources of microplastics. Most current wastewater treatment plant (WWTP) technologies are unable to capture and remove particulate <5 mm in>size; thus, bioaccumulation over time poses a threat to aquatic organisms. In 2015, we began surveying WWTP post-treatment effluent samples from the city of Plattsburgh, NY (n = 31) and in 2016, added 3 other plants in the Lake Champlain watershed, specifically St Albans, VT (n = 8), Ticonderoga, NY (n = 4), and Burlington, VT (n = 1). Twenty-four–hour post-treatment effluent samples were collected and digested using wet peroxide oxidation methods. All samples were characterized based on microplastic type (e.g., fragment, fiber, pellet, film, foam) and color. Across all sites, the majority of microplastics were characterized as fragments, followed by fibers, with the exception of St Albans, which was dominated by fibers. The fragment:fiber ratio was 51:23 at Plattsburgh, 61:18 at St Albans, 44:40 at Ticonderoga, and 69:18 at Burlington. Pellets and films were characterized at all sites as 1–12% of total particulates; whereas foam comprised 3–11% of total particulates and was absent in Ticonderoga. Over the course of this collection period, high flow rates yielded more pellets and low flow rates more films. When accounting for the number of samples processed, average particles per 24-hour sampling event are 21, 29, 49, and 117 for Plattsburgh, St. Albans, Ticonderoga, and Burlington, respectively. Plattsburgh and Burlington serve a similar-sized population and have a similar capacity, the difference in particle abundances may be due to differences in infrastructure updates (2013 at Plattsburgh and 1994 at Burlington). St. Albans and Ticonderoga serve similar population sizes; however, St. Albans has tertiary treatment, which may account for the lower average particulates per sample (29 at St. Albans and 49 at Ticonderoga). By documenting wastewater treatment plants as a source of microplastics, we can share these findings with wastewater treatment plant operators, lake stewards, government officials, and work towards solutions both up and downstream.