Biomonitoring microplastic pollution and polymer hazards using the Asian green mussel (Perna viridis): a baseline assessment from Santubong River, Sarawak, Malaysia

Abstract

Microplastic contamination in aquatic organisms is a growing concern due to its ubiquity and potential toxicity. Currently, data on microplastic contamination and polymer hazards in green mussels (Perna viridis) from the Santubong River, Sarawak, is unavailable. In this study, green mussels from the Santubong estuary were analyzed, revealing a 100% occurrence rate and a mean abundance of 5.51 items/individual. Fibers (54.7%) and fragments (30.9%) were dominant, with transparent (40.9%), white (26.1%), and blue (23.8%) being the most prevalent colors. Most particles (83.6%) were < 1000 µm in size. Statistical analysis showed a moderate negative correlation (r = −0.40, p < 0.05) between microplastic abundance and soft tissue weight, suggesting potential impacts on the physiological condition of the mussels. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy identified polyamide (60%), polypropylene (23.3%), and polystyrene (10%) as the primary polymers. The prevalence of polyamide is linked to local aquaculture and fishing gear, such as nylon ropes. Scanning electron microscopy (SEM) imaging confirmed extensive surface weathering, including cracks, pits, and fractures. The polymer hazard index (PHI) was calculated to be 3143.3, indicating a Level IV (high hazard) status. This study establishes a critical baseline for microplastic pollution management in P. viridis and environmental health assessments in Malaysian Borneo.