Public summary of the HARMLESS Deliverable D2.3 with the findings from the HARMLESS persistency and “point of entry” bioaccumulation evaluations performed within Task 2.3 by project partners DTU, INIA and BASF. It also provides a proposal for a “HARMLESS Principles for point-of-entry bioaccumulation and persistency evaluation in a Safe and Sustainable by Design (SSbD) context” according to an assessment of the overall applicability of performed persistency tests and the HARMLESS “point of entry” approach. According to the proposed HARMLESS “point of entry” approach, materials were screened for their potential for interaction and accumulation in lower trophic level organisms (algae and daphnia), since these will act as gatekeepers for an actual biomagnification to occur. Bioaccumulation studies in fish were then used as confirmatory tests to validate the “point of entry” approach for bioaccumulation screening being proposed and the possibilities of biomagnification. Then, as nanomaterial (NM) persistency plays a key role in bioaccumulation, by determining the availability of NMs for organisms the persistency of materials to stay as NMs was evaluated using dissolution and stability monitoring studies under simulated environmental conditions. Finally, this information was used to inform the development of SbD principles and risk matrices (WP4). List of authors: Lars M. Skjolding, Fides Hensel, Aiga Mackevica, Anders Baun (DTU) Veronica Di Battista, Wendel Wohlleben (BASF) Mona Connolly, José M.Navas (INIA-CSIC)