Effects of polyvinyl chloride microplastic on pearl oyster (Pinctada fucata martensii)

Microplastics (MPs) have recently attracted attention as an emerging pollutant. To investigate the effects of microplastics on the pearl oyster Pinctada fucata martensii (P. f. martensii) polyvinyl chloride microplastics (PVCMPs) were used. We aimed to investigate the effect of PVC-MPs on the oxidation and reduction system by using the superoxide dismutase (SOD), malondialdehyde (MDA), reduced glutathione (GSH), and total antioxidant capacity (T-AOC); the immune system using acid phosphatase (ACP) and alkaline phosphatase (AKP); and the digestive system using amylase and protease as biomarkers. P. f. martensii were exposed to PVC-MPs at 0.15 mg/ L, 1.5 mg/L, and 15 mg/L. Exposure to PVC-MPs increased the SOD activity and MDA content in the 15 mg/L dose group in 15 d compared to the control group. When compared with the control and other groups, MDA content and GSH content in the 0.15 mg/L group were higher on day 10. The T-AOC and AKP in all treatment groups were lower than the control group throughout the experiment, except in 1.5 mg/L and 15 mg/L groups in 15 d. The ACP activity increased with time except in the 0.15 mg/L group. The amylase and protease activity had an opposite pattern with amylase activity decreasing with time except in the 1.5 mg/L group in 15 d while protease increased with time except in the 0.15 mg/L group in 15 d group. The results indicate that PVC-MPs exposure induced oxidative stress, distorted the immune system, and digestive functions of P. f. martensii. The results help to understand the effects of MPs on the physiological responses of P. f. martensii.