Microplastics in surface water and tissue of white leg shrimp, Litopenaeus vannamei, in a cultured pond in Nakhon Pathom Province, Central Thailand

The presence of microplastics in commercially important seafood species is a new issue of food safety concern. Although plastic debris has been found in the gastrointestinal tracts of several species, the prevalence of microplastics in edible shrimp tissues in Thailand has not yet been established. For the first time, the gastrointestinal tract (GT), heptapancreas (HEP), muscle (MU) and exoskeleton (EX) of farmed white leg shrimp (Litopenaeus vannamei) from commercial aquaculture facilities in Nakhon Pathom Province, Thailand, were analyzed for microplastics (MPs). The number of MP items per tissue was 27.36±2.28 in the GT, 17.42±0.90 in the HEP, 11.37±0.60 in the MU and 10.04±0.52 in the EX. MP concentrations were 137.78±16.48, 16.31±1.87, 1.69±0.13 and 4.37±0.27 items/gram (ww) in the GT, HEP, MU and EX, respectively. Microplastics ranged in size from < 100 to 200–250 μm, with fragment-shape (62.07%), fibers (37.31%) and blue (43.69%) was the most common. The most frequently found polymers in shrimp tissue organs and pond water were polyethylene terephthalate (PET), polyvinyl acetate (PVAc) and cellulose acetate butyrate (CAB). Shrimp consumption (excluding GT and EX) was calculated as 28.79 items/shrimp/person/day using Thailand's consumption of shrimp, MP abundance and shrimp consumption. The results of the study can be used as background data for future biomonitoring of microplastics in shrimp species that are significant from an ecological and commercial perspective. MP abundance in farmed L. vannamei may be related to feeding habits and the source of MPs could come from the aquaculture facilities operations.