DETERMINATION OF THE RADIOACTIVITY LEVELS AND HEAVY METALS CONTENT OF THE LOCAL NATURAL ROCKS WIDELY USED AS RAW MATERIALS IN INDUSTRY

In this paper we present the results obtained by performing various high quality analyses on different types of natural rocks (calcareous, silico-aluminous, volcanic) extracted in Romania and used as raw materials in various industries such is that of building materials production. According to European and National legislations, the materials used in residential buildings constructions must be tested from the point of view of the hazard risk associated to human health. In this direction, radioactivity and heavy metals contents were determined. The measurements were performed within CPRLAB, Horia Hulubei National Institute for Physics and Nuclear Engineering(IFIN-HH). Six different types of raw materials (marl, gypsum, clay, limestone, sand and volcano tuff) from different sites and four types of residues derived from processing them (mining sterile, fly ash) were analysed. The radioactivity measurements were performed by using a high resolution HPGe gamma-ray spectrometry system. The heavy metals content was determined by using Atomic Absorption Spectroscopy (AAS). The determined activity concentrations of the natural occurring radioactive materials (NORM) embedded in the tested samples were found to be as follows: 28-217 Bq/kg for Ra-2(26), 5.7-80 Bq/kg for Th-232 (Ac-228)and 39-560 Bq/kg for K-40. The gamma index and the radium equivalent activity were also estimated. The heavy metals found in the studied samples were the following ones: Cr, Cu, Fe, Pb, Zn and Co.