Sorption of okadaic acid lipophilic toxin onto plastics in seawater

Abstract

The present study tested under laboratorial conditions the sorption of okadaic acid (OA), a lipophilic toxin produced by marine phytoplankton, onto 6-mm plastic circular fragments. Fragments (4 g L-1) of polyethylene terephthalate (PET), polypropylene (PP), expanded polystyrene (EPS) and non-expanded polystyrene (PS) were exposed for 96 h to seawater spiked with 10 ng mL(-1) of OA. Results of the experiments showed a broad percentage of OA removed from the water by plastics after 48 h of exposure: 30 +/- 5.1% (PET), 37 +/- 9.5% (PP), 62 +/- 7.1% (EPS) and 83 +/- 1.9% (PS). Sorption appears to be highly influenced by polymer’s characteristics, such as polarity and degree of crystallinity. Further studies are needed to clarify the effect of the contact area on sorption by expanded plastics. These results point to the plausible interaction of OA and plastics in coastal waters.