Impacts of nanoplastics on Artemia franciscana larvae: effects on growth and proteins responses

The accumulation of plastic litter on beaches and open oceans have been identified as one of the major threats in marine ecosystems worldwide. Laboratory experiments have proved that the formation of nano-sized plastics during the plastic degradation may reach marine ecosystem, considered as the most in danger. While the impact of macro- and microplastics on the marine organisms is worldwide well documented, the least known and characterized fraction of marine litter, due to its difficult sampling and analytical identification, is probably nanoplastics. Polystyrene nanoparticles (PS NPs), widely studied for drug delivery in human studies, were recently recommended as nanoplastics model in ecotoxicological studies. In present study the impact of 50 nm cationic amino polystyrene (PS-NH2) was evaluated on the brine shrimp Artemia franciscana. Nanoparticles properties such as dimension, dispersion and surface charge were characterized using Dynamic Light Scattering (DLS) in two different environmental media, milli Q water (mQW) and natural sea water (NSW). Acute toxicity tests were performed on A. franciscana exposed to different suspensions of PS-NH2 (0.1, 1 and 10 μg/mL) in NSW for 48 hours. Growth rate and several biomarkers involved in important physiological processes, such as biotransformation of xenobiotics (carboxylesterase, glutathione-S-transferase), neuronal transmission (cholinesterase) general stress (Heat Shock Protein) and oxidative stress (catalase) were evaluated