Sorption of pharmaceuticals on the surface of microplastics.

The presence of both pollutants: microplastics and pharmaceutical residues in various environmental compartments is an issue of increasing concern. Available literature data indicates that microplastics can affect the environmental distribution and transport of e.g. persistent organic pollutants (POPs) through sorption interactions, concentrating them at a given point and thus influencing the environmental risks represented by the sorbent and sorbate pair. Therefore, their potential to change the fate of other contaminants in the environment, such as pharmaceuticals, is worth investigating. The aim of this study was to evaluate the sorption capacity of nine pharmaceuticals, commonly used in human and veterinary medicine, which constitute known ubiquitous water pollutants: enrofloxacin (ENR), ciprofloxacin (CIP), norfloxacin (NOR), 5-fluorouracil (5-FU), methotrexate (MET), flubendazole (FLU), fenbendazole (FEN), propranolol (PRO) and nadolol (NAD), on the surface of the most often identified microscopic plastic particles in the aquatic environment, i.e. polypropylene (PP), low density polyethylene (LD-PE), high density polyethylene (HD-PE) and polyvinyl chloride (PVC). The obtained results suggest a complex nature of sorption, including both hydrophobic and electrostatic interactions. However, since the ionic strength of the medium was found to be a significant factor influencing the sorption potential, minute interactions are observed in conditions common for the natural environment.