Facilitating microplastic ingestion in aquatic models: A verified protocol for daphnia magna as a trojan horse vector

Microplastic pollution poses a significant environmental threat due to its persistence, widespread distribution, and inherent toxic potential. Despite the increasing number of publications in this field, a standardized protocol for the laboratory intake of microplastics by <i>Daphnia magna</i> has yet to be established. In this study, we introduce a verified protocol designed to facilitate the ingestion of microplastic particles (MPs) by <i>D. magna</i>, ranging in size from 5-55 µm. This protocol can be further applied to evaluate the toxicity of MPs on <i>D. magna</i>, a crucial organism model in ecotoxicology. Furthermore, this protocol can be used to assess toxicity of MPs in other aquatic species, such as fish, by using daphnids as a vehicle for ensuring the ingestion of these particles. Consequently, this protocol can be applied to study also one of the most pressing concerns regarding exposure to MPs, the transfer of MPs through different trophic levels, which has a great potential for ecotoxicological studies.•The influence of MPs concentration, duration and exposure dynamics and <i>D. magna</i> age/size in MPs intake were tested.•We have determined the optimal conditions for promoting microplastic ingestion by <i>D. magna</i>.