Titanium oxide nanoparticles (TiO2-NPs) are increasingly being used in many commercial products, these NPs are some of the most produced in the world. Because of this, their production can lead to their release into the environment and produce undesirable effects on human health and ecosystems. One of the main means in which these particles are released into the environment is by wastewater, ending up in the sewage sludge from treatment plants. Already was demonstrated that the sludge from wastewater treatment plants in Chihuahua, México contains TiO2-NPs, and this sludge is applied as an amendment in agricultural fields of alfalfa. This study aims at determining the tissue specific (and sub-celullar) localization of Ti, and to confirm the presence of TiO2-NPs in alfalfa leaf from plants obtained from sludge amended fields and laboratory exposed plants in hydroponic medium. This in order to evaluate food chain transfer of TiO2-NPs from agricultural soil.