Most plastics produced worldwide end up in the marine environment, leading to potential pollution problems. Physico-chemical and biological processes degrade plastics into fine particles, known as microplastics (MPs) and nanoplastics (NPs). Several research studies have been carried out on the MPs impacts on organisms, but very few studies have been investigated on their ingestion and depuration dynamics using labelled particles. This project highlights the preparation of 14C-radiolabeled polystyrene microparticles and the study of their effect, bioaccumulation and biodistribution using autoradiography in Atlantic scallops (Placopecten magellanicus) of socio-economic interest in Eastern Canada.
This study presents the bioaccumulation kinetics of 1.3 ± 0.2 μm MPS-14CPS and their potential impact on the energetic condition of exposed individuals. MPS-14CPS and non-radiolabeled MPs (MPS-PS) were synthesized to obtain the desired size for organism contamination. The exposure period was then carried out over 3 months, feeding the organisms with a mixture of microalgae and MPS-14CPS at concentrations similar to those found in the marine environment. During the 3-month depuration period, the organisms were fed microalgae, enabling us to assess the rate of MPs depuration by the organisms.
The results show that MPs are ingested in the digestive system, particularly in the hepatopancreas, intestine, and anus. Thus, little bioaccumulation of MPs was observed during the exposure period. Moreover, the organisms were able to eliminate the microparticles rapidly, 5 days after the last exposure. Our results indicate that polystyrene PMs are not bioaccumulated in the other organs of the scallop, including the muscle, which is the edible part. Finally, the microparticles had no effect on the energy status of the scallops, with no variation in glycogen reserves or lipid profiles observed.