Survey of the Abundance and Distribution of Nurdles and Microplastics in Long-term Monitoring Zooplankton Samples from Lake Champlain

Abstract

Microplastics are particles less than 5mm in size, characterized as fibers, fragments, beads,foams, and pellets. Microplastics arise from four main processes: environmental degradation(UV exposure, mechanical and/or biological), direct release by means of wastewatertreatment processing, unintentional loss of raw materials, and discharge of macerated wastes.Particulate polymers are identified as either lightweight (e.g., polypropylene andpolyethylene) or heavyweight (e.g., PET and PVC). Weight of the particulate dictates wherethey reside within the water column. The goal of this study was to quantify the abundanceand map the distribution of microplastics and nurdles, using long-term monitoringzooplankton samples from Lake Champlain. Microplastic sampling was conducted bysubsampling homogenized zooplankton samples (N=400) and were quantified usingextrapolation to larger sample volume. Fourier Transform Infrared Spectroscopy (FTIR) wasused to characterize nurdle polymer type as polyisoprene rubber ribbon. Nurdle distributionwas most abundant at 0-10m depth and at the southernmost end of Lake Champlain, in thevicinity of Whitehall and Ticonderoga, NY, historically associated with industry. Additionalnurdle hotspots occur in Shelburne and Missisquoi Bays located midway and at the northernreach of the lake. Microplastic abundance was greatest in the mid-section of the lake and atdepths of both 0-10m and 40-50m. Vertical particulate distribution is of greatest concern, assusceptible organisms are dispersed throughout the water column, with potential forbioaccumulation to higher tropic levels. Long-term microplastic impacts on Lake Champlaininclude intake for residential use, pathogenic and pollutant exposure during recreational use,as well as local economic impact via revenue loss associated with tourism and fisheries.