Microplastic–Tebuconazole Interactions Under Ocean Acidification: Role of Material Type and Salinity

The escalating global plastic pollution has led to the widespread presence of microplastics in marine environments, posing a significant risk by adsorbing organic pollutants such as tebuconazole (TEB). Ocean acidification, a consequence of increased carbon dioxide (CO 2 ) emissions, is also altering the marine environment. This study investigates the adsorption behavior of TEB on various microplastic materials under conditions of seawater acidification, a critical environmental stressor. It was found that the adsorption capacity of TEB varies among different microplastics, with degradable microplastics Poly(butylene adipate-co-terephthalate) (PBAT) and Poly(butylene succinate) (PBS) exhibiting higher adsorption capacity due to the presence of oxygen-containing functional groups. The sorption capacity followed the order of PBAT ≈ PBS > Polyamide (PA) > Polyvinyl Chloride (PVC) > Polystyrene (PS) > Polyethylene (PE). The influence of salinity on adsorption was pronounced, with increased salt concentrations enhancing adsorption on certain microplastics (PA, PBAT, and PBS), likely due to the salting-out effect and charge neutralization. Acidification significantly affected the adsorption on nondegradable microplastics by altering the degree of TEB dissociation and microplastic surface potential, showing up to 15–30% higher capacity when exposed to CO 2 - or HCl-acidified environments, while degradable microplastics and PA showed minimal pH sensitivity, suggesting hydrogen bonding as the conduct adsorption mechanism, which makes them less affected by changes in pH. These findings provide insights into how microplastic properties and environmental changes affect the distribution and behavior of organic pollutants in marine settings, emphasizing the ecological risks linked to microplastic pollution and ocean acidification.