Enhanced desorption of fluoxetine from polyethylene terephthalate microplastics in gastric fluid and sea water

Abstract There are concerns that microplastics act as a vector of pharmaceuticals in the aquatic environment. Most studies have focussed on pharmaceutical adsorption and not investigated desorption various matrices enter. Therefore we studied antidepressant drug fluoxetine from polyethylene terephthalate (PET) river water, sea simulated gastric intestinal fluids. We found most occurred rapidly, within few hours exposure. Fluoxetine fitted well to Freundlich isotherm with r 2 values ranging 0.97 0.99. Desorption decreased following order: fluid at 20 °C 37 °C; water then °C. The little difference gastrointestinal fluids suggests similar exposure risk cold- warm-blooded organisms PET microplastic ingestion. Total sequential incubation h 4 mimic digestion was 37% 41% Interestingly, higher 18–23% compared 4–11%. Under worst-case scenario, more than 44 mg kg −1 body weight d or 52 respectively, need be consumed exceed mammalian acceptable daily intake for fluoxetine. Further needed ingestion bioavailability adsorbed range exposed organisms.