AUTHOR=Duester Lars, Burkhardt Michael, Gutleb Arno C., Kaegi Ralf, Macken Ailbhe, Meermann Björn, von der Kammer Frank TITLE=Toward a comprehensive and realistic risk evaluation of engineered nanomaterials in the urban water system JOURNAL=Frontiers in Chemistry VOLUME=2 YEAR=2014 URL=https://www.frontiersin.org/articles/10.3389/fchem.2014.00039 DOI=10.3389/fchem.2014.00039 ISSN=2296-2646 ABSTRACT=The European COoperation in Science and Technology (COST) Action ES1205 on the transfer of Engineered Nano materials from wastewater Treatment and stormwatEr to Rivers (ENTER) aims to create and to maintain a trans European network among scientists. This perspective article delivers a brief overview on the status quo at the beginning of the project by addressing the following aspects on engineered nano materials (ENMs) in the urban systems: (1) ENMs that need to be considered on a European level; (2) uncertainties on production-volume estimations; (3) fate of selected ENMs during waste water transport and treatment; (4) analytical strategies for ENM analysis; (5) ecotoxicity of ENMs, and (6) future needs. These six step stones deliver the derivation of the position of the ES1205 network at the beginning of the projects runtime, by defining six fundamental aspects that should be considered in future discussions on risk evaluation of ENMs in urban water systems.