Developing Clean Methodology for Microfiber Analysis in Freshwater Macroinvertebrates & Total Suspended Solids

Although modern society turns to plastics (synthetic polymers) for their durability and versatility, plastic’s resistance to natural degradation poses a great ecological threat. Microplastics (diameter < 5mm) are the result of both the physical breakdown and the intentional production of smaller plastic materials. Microfibers (MFs), a type of microplastic that comes from synthetic materials like clothes and carpet, are of growing concern because of their abundance in consumer products and persistence in the ecosystem. Recent studies have reported the detection of these materials in surface water. While our earlier studies in the Salt Creek (Valparaiso, IN) confirm the presence of MFs, this project focused on refining methodology for more accurately quantifying MFs from macroinvertebrate and water samples. Clean laboratory methodology is necessary in order to determine their presence in the environment since MFs are ubiquitous. Several procedural methods were implemented to minimize MF contamination in the lab and field. Once blank samples showed minimal contamination (< 3 MFs/sample), macroinvertebrates and total suspended solids (TSS) water samples from sites along the creek were collected and examined. Macroinvertebrates were preserved using a freeze-dryer, and digested with the Fenton reaction. Water samples were filtered using standard TSS protocol with nylon filter paper. The collected solid material was processed again using the Fenton reaction. All samples were then analyzed for MFs under a stereomicroscope. Using these cleaner methodologies, MFs were still found in local creek samples. Further sampling will be performed with the established protocol to determine the extent of MF contamination.