Presence and abundance of microplastics in edible freshwater mussel (

Abstract

The abundance and identification of microplastics were investigated for the first time in the gills and soft tissues of freshwater mussels (Batissa violacea) harvested from five rivers in Fiji. Microplastics were found in 100% of the mussels sampled from all the rivers. The average site concentration varied from 2.78 ± 0.40 to 6.84 ± 0.89 microplastics per gram of dry weight. The overall average concentration was 5.93 ± 0.39 microplastics per mussel. This is concerning because these mussels, commonly known as kai, are an important source of protein and income for many people. Microplastic concentration in mussels was significantly dependent on sampled location but evenly distributed among tissues. The dominant size of microplastics was <0.4 mm, representing 52 and 50% of all microplastic in gills and soft tissue respectively. Fourier transform infrared spectroscopy in attenuated total reflectance (FTIR–ATR) was used for polymer identification of the isolated microplastics. Nylon was the most dominant type of polymer followed by polyolefins. Freshwater mussels in Fiji are an important component of the artisanal fishery, the diet of local communities and an emerging export commodity. These results showed that freshwater mussels are ingesting microplastics in their natural environment and, thus, they represent a potential health problem for human consumption.