Microplastics (MPs) in freshwater are an emerging pollution threat deriving from personal care products, textile laundering, marine debris, as well as mechanical and photodegredation of macroplastics. Most current wastewater treatment plant (WWTP) technologies are unable to capture and remove MPs, defined as <5mm in size. As a result MPs are subject to trophic transfer within aquatic organisms. Since 2015, we have processed WWTP post-treatment effluent samples from the city of Plattsburgh, NY (N = 59), St Albans, VT (N = 29), Ticonderoga, NY (N = 23), and Burlington, VT (N = 9), representative plants in the Lake Champlain Basin. All samples underwent wet peroxide oxidation digesting to isolate particulate, size-separation, characterization based on MP type (e.g., fragment, fiber, pellet, film, foam), and Fourier Transform Infrared Spectroscopy (FTIR) to determine polymer type. Given the abundance of MPs in the lake, we surveyed digest tracts of (n = 506) lake organisms, specifically invertebrates (n = 301), 15 species of fish (n = 190), and Phalacrocorax auritus (double-crested cormorants) (n = 15).
Results/Conclusions
The most common MP type varied by WWTP and was dominated by fibers in Plattsburgh (42%) and Ticonderoga (39%), versus foams and fragments in St. Albans (44%) and Burlington (57%), respectively. Estimated MP emission/ day was: Plattsburgh (n = 14,105), St. Albans (n = 30,268), Burlington (n = 16,843), and Ticonderoga (n = 7,841), differences reflecting plant characteristics, population served, infrastructure updates, and tertiary treatment. Fibers were the were the most common (80.1%) MPs in all organisms, followed by fragments (9.64%), films (6.36%), foams (3.01%), and pellets (<1%). In fish, bowfin (Amia calva) contained the greatest mean MPs (n = 29.67), followed by lake trout (Salvelinus hamaycush) (n = 21.42), and northern pike (Esox lucius) (n = 20.1). In invertebrates, Hydropsyche, a filter-feeder, contained the greatest mean MP’s (n = 3). We noted trophic transfer in Lake Champlain organisms, as invertebrates, fish, and double-crested cormorants contained on average 0.36, 6.08, and 22.93 MPs, respectively. FTIR analysis revealed MP fibers were predominantly polyester [PET] (14.5%), cellulose (11.1%), alpha-cellulose (11.0%), and rayon (8.5%). These MPs have the potential to adsorb and desorb harmful chemicals (e.g., heavy metals, bisphenol, phthalate) and pose risk to aquatic organisms and human health.