DOI: 10.14457/tu.the.2021.84
title: Extraction and identification of microplastics in green mussels in Thailand

description: The present knowledge on the existence of microplastics (MPs) in mussels in Thailand remains meager. Therefore, this study was conducted with the aims of quantification and characterization of MPs contamination levels in aquaculture and commercial green mussels (Perna Viridis) sourced from markets in Thailand. Threemarkets namely Khlong Dan food market, Samutprakarn; Talad Thai wholesale market, Pathum Thani; and Talad Simummang market, Pathum Thani) were selected in thisstudy. Relationship between MPs in aquaculture mussels and their surrounding environment, was also investigated. Nile Red (NR) tagging was used for the enumeration of MPs. Fourier-Transform Infrared Micro-Spectroscopy (micro-FTIR) analysis was used for polymer identification.MPs were widely discovered in green mussels from all three markets with a 100% detection frequency. The average abundance of MPs in green mussels wasquantified as 7.32±8.33 items/mussel and 1.53±2.04 items/g (wet weight). Ethylene/propylene copolymer followed by low-density polyethylene (PE-LD), polypropylene (PP), and polyethylene terephthalate (PET) were found. Fragments (75.4%) were the most common morphotype, followed by fibers (24.6%). Aqua cultured green mussels were collected from Si Racha Bay, Chonburi Thailand, and Phetchaburi aquaculture demonstration farm in Thailand. Both areas were contaminated by MPs in all studied compartments. The average MPs abundance in water, mussels, and sediments in Si Racha Bay was 41.5±6.0 particles/L, 3.2±1.6 items/individual and 2.4±0.8 items/g (wet weight) and 474.6±102.6 items/kg, respectively. The average abundance of MPs in water and mussels in the Phetchaburi Aquaculture demonstration farm was 16.8±7.5 particles/L and 1.2±0.2 items/individual and 0.3±0.1 items/g (wet weight), respectively. Though there was not a significant difference between the abundance of MPs in water between two farms, MPs levels in mussels varied. This may be due to the difference in MPs loads in the two locations. High-density polyethylene (PE-HD) was the dominant morphotype in water and mussels in both places indicating the higher pollution of PE-HD in aquaculture water. In addition, PET, polyester, and ethylenepropylene copolymer were also common in surface water in both places. Farmed mussels were contaminated with PE-HD, linen, PET, polyvinyl chloride (PVC), polyester, and PP. Smaller size MPs predominated in all the water, sediments, and mussel samples analyzed in both farms. In this study, we found no correlation between the abundance of MPs levels in mussels and surrounding water and sediments. There is a significant difference between the abundance of MPs in commercial and aquaculture green mussels in Thailand. It is hard to resonate with this difference since we exactly don’t know about the source of commercial green mussels. It may be due to the spatial differences of MPs concentration in the locations where commercially sold green mussels are grown. MPs polymer types were not equally distributed across the different compartments i.e., water, mussels, and sediments. This study provides an insight into widespread MP pollution in aquaculture environments in Thailand. Moreover, green mussel presents a route for exposure of the Thai population to MPs.