Microplastic contamination represents a widespread pollutant in the marine environment. Despite concerns regarding ingestion and its associated risk linked to food safety, few studies have assessed the abundance and characteristics of microplastics in commercially important species. The present study evaluated the presence of ingested microplastics in the gastrointestinal tract of a decapod crustacean, Nephrops norvegicus, collected from five known prawn grounds around Ireland. The efficiency of three digesting solutions (KOH, HNO3, and KOH+Tween20) at different incubation temperatures (40ºC, 50ºC, and 60ºC), spiked with six different plastic polymers suggest that a KOH 10% solution incubated at 40ºC for a 48h period is the most efficient digestion of biological material, with no significant damaging effect on all tested polymers. Of the 150 prawns examined, c. 69% had ingested microplastics with an average of 1.75±2.01 particles per individual. A total of 262 particles were isolated, and predominantly categorized as fibres (98 %) with a common size class of 1-2 mm. A subset was identified as poly-vinyl chloride, polyamide, and polyethylene using FTIR Spectroscopy. No significant spatial pattern was recorded, however, samples from the North Irish Sea recorded the highest occurrence of microplastics in the population (c. 83%). Positive correlation was found between the abundance of microplastics and condition factor (carapace length and weight) of the prawn. Strategic monitoring and quality assessment is needed to explore the potential for microplastic exposure from the consumption of seafood, with this study showing that consumption of N. norvegicus in Ireland is estimated to range from 15 to 4471 particles per year.
Keywords: Biomonitoring, seafood, contamination, food safety, FTIR
