Effects of nanoplastics on zebrafish embryo-larval stages: A case study with polystyrene (PS) and polymethylmethacrylate (PMMA) particles

Plastic production has been rising consistently in the last 30 years and with it, the presence of plastic particles in the environment. A decrease in size often increases the bioavailability and reactivity of the particles. In this study the impact of polystyrene (PS; 22 nm) and polymethylmethacrylate (PMMA; 32 nm) nanoparticles on zebrafish embryo-larval stages was assessed by studying mortality, hatching, morphological features, and biochemical endpoints (associated with neurotransmission, antioxidant status and oxidative damage, and energy metabolism) after 96 h exposure, and swimming behavior after 120 h exposure. Organisms exposed to PMMA nanoparticles exhibited higher mortality and pericardial edema than those exposed to PS nanoparticles but displayed less effects on swimming behavior. Biochemical endpoints were altered to a higher degree in organisms exposed to PS nanoparticles (acetylcholinesterase, glutathione S-transferase and catalase activities) but higher peroxidative damage was found after exposure to lower concentrations of PMMA nanoparticles. Both types of nanoparticles affected energy metabolism with higher levels of glycogen found in animals exposed to PS nanoparticles. The use of integrated biomarker response index confirmed that PS nanoparticles had a higher impact on biochemical endpoints of zebrafish.

Automated summary

Plastic production and the presence of plastic particles in the environment have been increasing in the past 30 years. This study found that polymethylmethacrylate (PMMA) nanoparticles had a greater impact on zebrafish, resulting in higher mortality and pericardial edema compared to polystyrene (PS) nanoparticles, although they had less effect on swimming behavior. PS nanoparticles significantly altered biochemical endpoints, while PMMA nanoparticles caused greater peroxidative damage even at lower concentrations. The integrated biomarker response index confirmed that PS nanoparticles had a greater impact on zebrafish biochemistry.