Kaitlyn Suchomel, “Size Fractionation and Characterization of Microplastic-Derived Dissolved Organic Matter Using Ultrafiltration and Spectroscopic Techniques”
Mentor: Laodong Guo, Freshwater Sciences, Freshwater Sciences (School of)
Poster #81
Microplastics contribute to the pool of dissolved organic matter (DOM) in aquatic environments, influencing biogeochemical cycling and contaminant transport. Microplastics are a ubiquitous pollutant that when exposed, induces a variety of toxic effects causing major environmental concerns. This study investigates the molecular size distribution and optical properties of size-fractionated DOM released from microplastics using ultrafiltration equipped with membranes with 1 and 10 kDa cut-offs. Chromophoric dissolved organic matter (CDOM) was characterized using UV-visible and fluorescence spectroscopy coupled with excitation-emission matrix (EEM) – parallel factor (PARAFAC) analysis. Specific UV absorbance at 254 nm (SUVA254) was used to assess DOM aromaticity, while the spectral slope (S275−295) provided insights into CDOM molecular weight. Fluorescence EEM-derived indices, including humification index (HIX) and biological index (BIX), were applied to evaluate DOM sources and transformation processes. Following optical characterization, changes in molecular size and zeta potential of DOM were analyzed to assess colloidal stability and charge properties. The relationship between molecular size, charge behavior, and molecular composition was explored to better understand the reactivity, aggregation potential and transport of microplastic-derived DOM in aquatic systems. By linking size fractionation with molecular charge properties, this study provides a comprehensive understanding of the size and chemical heterogeneity of microplastic-derived DOM. The findings offer insights into the environmental behavior of DOM and its role in pollutant transport and water quality dynamics in aquatic ecosystems.