Nanoparticle–EPS interaction was for the first time studied by EEM–PARAFAC technique.
Three independent organic components were identified from all EEM spectra of EPS matrix.
Binding potential was related to EPS fractions, organic components and nanoparticle types.
The transportations of nano-CuO and nano-Fe3O4 would be controlled by LB– and TB–EPS, respectively.
Toxicity of nanoparticles would be changed in eutrophic waters due to the presence of EPS.