Manufactured nanomaterials (MNMs) altered by the treatments in waste water treatment plants (WWTPs) may pose a risk for the environment. Via transfer of post-WWTP MNMs in food webs and bioaccumulation this may lead ultimately to risks also for human health. The assessment of chronic toxicological endpoints and of the bioaccumulation potential is hence an important part of the substance evaluation and requires test systems suitable for MNMs. Furthermore, such studies need to be carried out not only on pristine MNMs, but also on NPs processed by WWTP to allow for a realistic hazard and risk assessment. To evaluate existing impact of MNMs in aquatic ecosystems there is a need for fast detection methods. These methods developed and refined in FENOMENO will help to develop a more efficient system to monitor the impairment of ecological functionality by post- WWTP MNMs. If available, this will allow the validation of the risk assessment that is indispensable to understand the impact of end-of-life MNMs on the environment and to ensure a safe use of MNMs.