Tracking and quantifying the level of translocation of ingested microplastics into the tissues of fish is key to estimating MP impacts on fish physiology, performance and possible implications for consumers, including humans. Controlled studies on the passage and destination of MPs within higher marine organisms are few.
In this study, established methods were applied to quantify translocation of ingested microplastic (MP) into blood, intestine, gill, liver and fillet of juvenile European seabass, Dicentrarchus labrax. European seabass consumed fluorescent MP (1-5μm) particles for 16 weeks in a controlled feeding experiment before organs/tissues were collected and analyzed for quantitative MP contamination.
The average abundance of MPs differed significantly between tissues and was highest in blood samples (54.6 ± 46.3 MPs/g), the intestinal tract (26.8 ± 18.7 MPs/g) and gills (9.8 ± 9.4 MPs/g). In contrast, lower average MP amounts were found in liver with 0.6 ± 1.5 MPs/g and in fillet samples with 0.4 ± 0.3 MPs/g. A clear trend of MP size distribution was observed within the examined tissues. The highest relative abundance of 1 µm of MP was found in intestine, 2 µm in blood and gill, 4 and 5 µm in liver and fillet samples, respectively.