The results of a research in progress at the Istituto di Fisica Generale Applicata--University of Milan--on natural and anthropogenic elements' determination in mosses as biological indicators are shown. The analytical technique was the energy dispersive X-ray fluorescence (EDXRF) spectrometry. The chosen areas for a preliminary pollution mapping were Italian Central Alps (Valmalenco and Valtellina) and the hills around Como (pre-Alps); in addition, a group of mosses was from Monza Park, near Milan.