Fluorescence signatures of dissolved organic matter leached from microplastics: Polymers and additives.
Despite the numerous studies that have investigated the occurrence and the fate of plastic particles in the environment, only a limited effort has been devoted towards exploring the characteristics of the dissolved organic matter (DOM) leached from microplastics. In this study, using excitation emission matrix-parallel factor analysis (EEM-PARAFAC), we explored the fluorescence signatures of plastic-derived DOM from commonly used plastic materials, which included two polymers (PVC and PS), two additives (DEHP and BPA), and two commercial plastics. The exposure of the selected plastics to UV light facilitated the leaching of DOM measured in terms of dissolved organic carbon and fluorescence intensity. Four fluorescent components were identified, which included three protein/phenol-like components (C1, C3, and C4) and one humic-like component (C2). The C1 and the C4 were highly correlated with the amounts of the DOM leached from DEHP and BPA, respectively, under both leaching conditions, while both the C2 and the C4 presented good correlations with the DOM leached from the polymers under UV light. The C4 may serve as a good fluorescence signature for the DOM leached from BPA or BPA-containing plastics. This study highlights the overlooked issue of plastic-derived DOM leaching into the aquatic environment through optical characterization.