Toxicological effects of polystyrene nanoplastics on marine organisms

Nanoplastic (NP) is an emerging contaminant in recent years, and it has been detected in water and even in polar ice. Further verification of the toxic potential of NPs in marine organisms is needed so that the ecological threat can be minimized. This study investigated the effects of 0.1, 0.2, 0.5, and 1.0μg (g shrimp)−1 of polystyrene nanoplastics (PS-NPs) on immune and oxidative response in Litopenaeus vannamei (L. vannamei) and the survival rate was recorded everyday. After 7 days, the immune and antioxidant parameters were analyzed, and histopathology and accumulation of PS-NPs were observed. The results indicated that the survival rate of shrimp receiving > 0.5μg (g shrimp)−1 PS-NPs was remarkably decreased than that of the control. The immune response results indicated that phagocytic activity (PA) receiving different concentrations of PS-NPs was remarkably decreased than the control. Respiratory burst activity (RB) receiving different concentrations of PS-NPs was remarkably increased than the control. However, superoxide dismutase activity (SOD) receiving > 0.2μg (g shrimp)−1 of PS-NPs was remarkably decreased than the control. The oxidative response results indicated that SOD activity receiving different concentrations of PS-NPs was remarkably decreased than that of the control. The catalase (CAT) activity, SOD mRNA expression, and malondialdehyde (MDA) content receiving different concentrations PS-NPs was remarkably increased than that of the control. In addition, CAT mRNA expression receiving > 0.2μg (g shrimp)−1 of PS-NPs was remarkably increased than the control. The histopathology shows that different concentrations of PS-NPs cause muscle, hepatopancreas, midgut gland, and gill damage. These results indicate that PS-NPs cause toxicity to L. vannamei by immune disruption, increased oxidative stress, and histopathology damage.