Chronic Microplastic Exposure and Cadmium Accumulation in Blue Crabs

Aquatic ecosystems are severely threatened by the presence of a multitude of pollutants. In seas and oceans, the amount of plastics continues to increase and there is great concern about toxic element accumulation. Specifically, cadmium (Cd), a toxic metal, is highly relevant to public health safety due to its ability to accumulate in the internal tissues of crustaceans; likewise, microplastics (MPs) are emerging as pollutants capable of causing alterations in marine organisms. The aim of this study was thus to evaluate the accumulation and distribution of Cd in the tissue of blue crabs (Callinectes sapidus) chronically exposed to MPs (25 μg L^-1). In total, 24 crabs were exposed in water for 118 days to 2 types of MPs (virgin and oxidised). During the final 21 days of the experiment, the crabs were fed with tuna liver, a viscera in which Cd accumulates (mean of 7.262 µg g^-1). The presence of MPs caused no changes in Cd concentrations in either the haemolymph or tissues (hepatopancreas, gills, and muscles) of the crabs, although for oxidised MPs, there was a positive correlation between Cd concentrations in the hepatopancreas and muscles, a relevant finding for food safety.