Microplastic contamination in the sediment of the Johor Strait Estuary, Malaysia

Abstract

The issue of microplastics has garnered significant attention in light of their potential environmental hazards and possible health effects on higher trophic organisms and humans. However, the available information is restricted and knowledge about the interaction between microplastics in aquatic sediments and the microplastic-related impacts of aquaculture activities, and this area has not yet been adequately researched. This research looks at the occurrence and properties of microplastics in the bed sediment from Perna veridis aquaculture activity areas, in the Strait of Johor, Malaysia. Bed sediments were collected in replicates from five sampling sites using a box corer (Wildco). The extracted organic matter was digested with 30% hydrogen peroxide (H2O2) before being separated using NaCl and ZnCl solutions. The inspection of plastic debris was conducted via a Stereomicroscope (HSZ-600) at magnifications ranging from 40x to 45x and considered according to morphology, size, and colour. Microplastic polymers were validated using Attenuated Total Reflection Fourier Transferred Infra-Red (ATR-FTIR) spectroscopy. The sediment samples exhibited a varying range of microplastic abundance, with values ranging from 29 to 60 particles/kg.d.w. Microplastics within the size range of 101-500μm (63%) predominated in all samples collected, with fragments (79%) and fibres (18%) being the main morphologies of MPs found. The dominant particles found in the sediment were polypropylene (PP) and polyamide. The findings suggest that aquaculture practises may have an impact on the presence of microplastics (MPs) in bottom sediment, as these locations are well-known aquaculture areas for Perna veridis.