eDNA Adsorption onto Microplastics: Impacts of Water Chemistry and Polymer Physiochemical Properties

• DOI: 10.1021/acs.est.3c10825
• Publication Date: 2024-04-16T12:21:34Z
• Authors: Nicolas D. Müller; Anish Kirtane; Roman B. Schefer; Denise M. Mitrano
• Keywords: Water chemistry

Adsorption of biomacromolecules onto polymer surfaces, including microplastics (MPs), occurs in multiple environmental compartments, forming an ecocorona. Environmental DNA (eDNA), genetic material shed from organisms, can adsorb MPs which potentially either (1) promote long-range transport antibiotic resistant genes or (2) serve to gain insights into the pathways and origins by analyzing sequences on MPs. However, little is known about capacity eDNA factors that influence sorption, such as water chemistries. Here we investigated adsorption extracellular linear a variety model MP fragments composed three most environmentally prevalent polymers (polyethylene, polyethylene terephthalate, polystyrene) their pristine photochemically weathered states. Batch experiments chemistries were complemented with nonlinear modeling quantify rate extent sorption. Ionic strength was shown strongly impact reducing inhibiting electrostatic repulsion. Polyethylene terephthalate exhibited highest when normalizing for specific surface area, likely due presence ester groups. Kinetics showed fast (majority adsorbed under 30 min) before eventually reaching equilibrium after 1–2 h. Overall, demonstrated quickly binds MPs, pseudo-first- -second-order models describing kinetics Freundlich isotherms accurately. These sorption show there potential act vectors interest, especially considering particle-bound typically persists longer environment than dissolved DNA.