TOXIDADE E TRANSFERÊNCIA TRÓFICA DO MICROPLÁSTICO POLIETILENO DE Poecilia RETICULATA PARA DANIO RERIO: EFEITO DE EXPOSIÇÃO VIA DIETA E DA CAPTAÇÃO DIRETA

Abstract

Although the toxicity of microplastics (MPs) has already been reported, their potential transfer between vertebrates of the same taxonomic group, as well as their impacts on higher trophic levels are aspects that are still little explored. Thus, from the establishment of an experimental food chain involving two species of fish, we tested the hypothesis that polyethylene MPs (PE MPs) can accumulate in animals and cause behavioral, mutagenic and cytotoxic changes at the upper trophic level. For this, we exposed Poecilia reticulata fingerlings to PE MPs (for 48 h) and then we offered them to Danio rerio adults (i.e., model system representing the upper level of the food chain) for a period of 10 days. The quantification of PE MPs in fry and in different tissues of Danio rerio revealed the accumulation of these pollutants in the two trophic levels evaluated, suggesting their absorption, adherence and translocation within the organisms. At the upper trophic level, this accumulation (also seen in D. rerio exposed directly to MPs) was associated with behavioral disorders. When confronted with a potential aquatic predator (Geophagus brasiliensis), these animals exhibited behavior suggestive of deficit of anti-predatory response (inferred by the lower cohesion of the school, less depth of the school and less distance from the potential predator). In addition, animals exposed to MPs exhibited higher rates of nuclear abnormalities and changes in the size and shape of erythrocytes and their nuclei, suggesting mutagenic and cytotoxic effects, respectively. In a broader perspective, our results demonstrate pioneeringly that microplastics are transferred via a simple food chain (involving two vertebrates), enter the organs, alter behavior and are capable of inducing mutagenicity and cytotoxicity in animals, which can have drastic ecological consequences in freshwater ecosystems.