Quantifying and Analyzing Synthetic Microfiber Pollution in Great Lakes Sediment near Cladophora Mats

Microfiber pollution is ubiquitous in aquatic environments. Synthetic microfibers, a major class of microplastics, such as polyester, rayon, acrylic, and nylon, are present in clothing and other textile items, and are now viewed as contaminants of emerging concern. Routine laundering of synthetic fabrics has contributed to massive microfiber contamination in surface waters. In addition to its presence in water and sediment, previous microfiber research by our group showed that Great Lakes Cladophora, a common macroalgae, entangles and adsorbs microfibers in much greater amounts. This research aims to assess the role of the lake sediment below and near Cladophora mats in the fate of these microplastics. To determine if this sediment traps synthetic microfibers, research was conducted with sediment samples collected by the United States Geological Survey (USGS). Samples were cleaned using a ZnCl2 solution for density separation, which suspends most microfibers from the heavier sediment. All samples were then subjected to an advanced oxidation technique, which generates hydroxyl radicals that decompose most natural organic materials, including natural fibers. Microscopic analysis was implemented to quantify synthetic microfibers. The early analyses indicate that the lake sediment does not have entanglement or adsorbent properties. Due to the ubiquitousness of microfibers, method blanks were implemented to determine the amount of microfiber contamination introduced in the lab and suggest some work is still needed to reduce external contamination. A range of 0 to 12 microfibers (Av = 7) have been found in the samples per average dry weight of 32.152 g.