The Contamination of Microplastics Ingested by Freshwater Molluscs in the Mun River, Thailand

This study aims to determine the amount of microplastic contamination in freshwater molluscs consumed in the Mun River. The predominant species of freshwater molluscs included Filopaludina martensi, Mekongia sphaericula, Scabies crispate, and Corbicula moreletiana. A total of 48 samples were obtained from each species, including four distinct areas characterized by varying land uses. The mean differences in microplastics were estimated using multiple linear regression. The results showed that the average of microplastics contamination in freshwater mollousecs soft tissue was 11.19±6.89 pieces/individual. The microplastic contaminants in Scabies crispate was significantly higher than those of other species. The level of microplastic contamination in the studied mollousecs species were Scabies crispate > Corbicula moreletiana > Mekongia sphaericula > Filopaludina martensi, which Scabies crispate is more than that of the Filopaludina martensi 5.72 pieces/individual (95% CI: 4.25-7.20, p < 0.001). The average microplastic contamination in molluscs from urban areas was significantly higher than that in other areas. The studied area was urban area > confluence of Mun and Chi River area > agricultural area > natural area, which the urban area is more than that of the natural area with 18.41 pieces/individual (95% CI: 16.94-19.89, p <0.001). And the most common polymer type of microplastic was Polypropylene (PP), most common shape filaments/fiber and was blue most common color. The interpretation of this observation is that the consumption of different types of freshwater molluscs, especially bivalve and sampling sites especially in the urban area may affect microplastics exposure.