GSA Connects 2022 meeting in Denver, Colorado

Paper No. 196-12
Presentation Time: 2:00 PM-6:00 PM

NURDLES: IMPACT OF PRIMARY MICROPLASTIC SOURCES ON THEIR PRESENCE IN GREAT LAKES BEACH SEDIMENT


SIMPSON, Mathew and PICHTEL, John, Department of Environment, Geology, and Natural Resources, Ball State University, Muncie, IN 47306

Nurdles, i.e., preproduction microplastics, are an emerging contaminant in aquatic environments. Improper management of nurdles at land-based facilities and offshore spills are responsible for an estimated 230,000 tons entering the world's oceans annually. A recent study found that Great Lakes coastal sediments contain an average of 19.1 nurdles/m2. Microplastics are highly mobile once released to aquatic environments, and migrate on the water surface, in the sub-surface, and in sediment. Polymers that have circulated in the environment for extended periods will display physical and chemical weathering that can be detected with light microscopy and Fourier-transform infrared spectroscopy (FTIR). Preliminary work using FTIR on nurdles collected along the shores of Lake Michigan found that they lack characteristic regions consistent with oxidation (weathering), i.e., between 1650 – 1750 cm-1. The polymers in the Great Lake study and preliminary Lake Michigan data show little physical or chemical weathering, indicating limited environmental exposure. The objectives of this study are to: (1) review all potential sources (e.g., railroads, manufacturers, major ports, port facilities, known spills, landfills) for the presence of nurdles in the Great Lakes watershed within 10 km of shore; (2) assess if proximity to a known source increases the presence of nurdles detected in the environment; (3) evaluate if proximity to multiple sources increases the presence of nurdles; and (4) determine if proximity of sources to each other increases the presence of nurdles in the environment. Multidimensional Scaling will be used to construct a visual representation of the complex relationships between sources and contamination, ordinating possible source types to the presences/absence of nurdles in beach sediment where proximity will indicate similarity.