From the 32 papers selected and reported by Murugadoss et al. (see Table , Additional file 1) , we reviewed a selection of 21 papers that report the physicochemical properties for different ENMs. Each ENM described in the analysed papers was assigned a new ERM identifier to facilitate information extraction and later enable cross-referencing with other data resources . The RDF Schema specification was used to store information and the ENM types were set to chemical substances using the CHEBI_59999 term from the ChEBI ontology . The new identifier, label, creator information and Github page were added to the registry Turtle as in Figure (Additional file 1).