Presence and potential trophic transfer of benzo[a]pyrene in Chironomus riparius and its predator Girardia tigrina

Purpose Planarians are increasing in relevance for ecotoxicological research. One of the advantages of using planarians as test animals is the possibility of evaluating a vast range of endpoints, encompassing neurotoxic, tumorigenic, teratogenic, or behavioural responses to stressors. Yet, the possibility of using planarians as predators in studies dealing with the trophic transfer of contaminants has not been explored. Given their epibenthic nature, planarians can be especially useful to evaluate the transfer of pollutants present in sediments, through benthic prey invertebrates. Materials and methods In this work, we exposed the Diptera Chironomus riparius larvae (prey) and Tricladida Girardia tigrina (predator) to sediments spiked with benzo[a]pyrene (B[a]P) and evaluated contaminant uptake into both species. Moreover, the dietary transfer of B[a]P-equivalents from larvae to unexposed planarians was assessed. Results Both planarians and chironomids exposed to contaminated sediments had detectable amounts of B[a]P-type compounds in their tissues, indicating that B[a]P was bioavailable to these organisms. In the dietary experiment, planarians fed on contaminated larvae, and the results suggest potential trophic transfer of B[a]P-equivalents from prey to predators. Conclusions These results indicate that planarians have the potential to be used in ecotoxicity studies using contaminated sediments, as well as in trophic transfer studies as invertebrate predators. Further studies should be focused on the consequences of such tropic transfer in predator performance.