Ingested microplastics: a comparative analysis of contaminated shellfish from two sites in the Makassar Strait

Marine plastic debris, particularly microplastics (MPs), is an urgent and significant threat to the global marine environment. The emergence of MPs in the marine environment and their potential presence in human-consumed seafood necessitates immediate investigation. In light of this, a study was conducted on the occurrence of MPs in shellfish collected from two locations in Makassar Strait with distinct oceanographic conditions. Three commonly consumed shellfish species (Perna viridis, Meretrix meretrix, and Mactra chinensis) were collected by fishermen and examined for microplastic contamination, with a total sample size of 170 individuals. Microplastics were extracted from the soft tissue of the bivalves using the alkaline digestion method. The results revealed a significantly higher number of microplastics ingested by P. viridis and M. chinensis in samples collected from the Sanrobengi Islands (14.64 MPs/individual and 2.29 MPs/individual, respectively), compared to the P. viridis and M. meretrix from Mandalle coastal area (0.70 MPs/individual and 1.00 MPs/individual, respectively). The predominant microplastic form detected was blue microfibres. A prevalence of MP contamination between 58 and 100% and the results of Fourier Transform Infrared Spectroscopy (FTIR) analysis indicated that polystyrene was the dominant polymer present, threatening the welfare of the bivalve mollusks and posing potential health risks to seafood consumers. The results emphasize the urgent need for pollution control measures such as reducing plastic waste discharges and improving waste management systems. In addition, a comprehensive study focusing on the long-term ecological and health effects of microplastic pollution is necessary to guide future policy interventions.