Microplastics contents in natural and maricultured shellfish from Pasir Putih Estuary in Johor, Malaysia

Abstract

Microplastics (MPs) are plastic debris diameters ranging from 1 µm to 5 mm. The prevalence of MPs in green mussels and their environment is now being questioned as to whether aquaculture practices or human environmental activities cause them. Hence, this study focuses on looking into the prevalence of microplastics (MPs) in natural environments and mariculture mussels (P.veridis) which comprise physical characteristics to compare microplastics (levels, type, size and colour) uptake based on the mood of living from Pasir Putih estuary in Johor, Malaysia. Specimens of P.veridis were obtained from two sampling stations in the Pasir Putih estuary. Soft tissues were removed and digested with a 10% KOH solution and the density of microplastics was isolated using 1.2 g/cm3 NaCl solution respectively. Microplastics were visually inspected using a stereo microscope and my-solution premium (IMT Cam3) software at magnifications ranging from 40x to 45x. The ATR-FTIR spectroscopy was then utilised to verify the presence of microplastics. In cultured P.veridis samples, microplastic abundance ranged from 0 to 6.67 Mp particles/individual with average values of 2.23 ± 1.04 MPs particles/individual and 0.4 ± 0.24 for each gram of soft tissue. Meanwhile, the microplastic found in wild P.veridis averages 1.29 ± 1.19 Mp particles/individual and 0.44± 0.34 Mp particles/gram. The shapes of microplastics found in the tissue of the green mussel are high in fragments. Most polymers in fragments found in the natural and wild mussels were standard plastic used in plastic products such as polyethylene (PE) and polypropylene (PP). In comparing microplastic abundance in wild and farmed mussels, cultured mussel was the most contaminated with microplastics. However, a statistical test revealed no significant differences in the microplastic concentration between farmed and wild green mussels (T-test, confidence level of 5%, P value <0.05). The presence of MPs in mussels has an impact on health and provides a pathway for human exposure.