干旱区生态环境知识资源中心

All over the world people are using different hard rocks as ornamental building stones. Information regarding the activity concentration rates for such rocks is very scarce, despite their environmental hazards. Therefore, samples of one of the most spectacular dotted granite were collected from Mueilha area located in the South Eastern Desert, Egypt. The activity concentrations were measured using high-purity germanium detector, and the inductively coupled plasma mass spectroscopy together with the atomic emission spectroscopy techniques were used for the chemical analyses of the samples. Furthermore, the rare earth elements (REEs) of the studied rocks were determined to study the expected economic benefits. It was found that the average concentration values of the radioisotopes (U-238, Ra-226, Th-232 and K-40) were above the worldwide average in building materials. Distinct variations between the calculated radiological hazards and the corresponding reference values were observed, where some indices had values greater than the world average, e.g. internal hazard index (H (in)), annual gonadal dose equivalent (AGDE) and the excess lifetime cancer risk (ELCR), while some others had values lower than the world average, e.g. radium equivalent activity index (Ra-eq), the gamma representative level index (I (gamma)) external hazards index (H (ex)) and the indoor absorbed dose rate (ADR). These variations indicate to the difficulty of using these rocks as a bulk building material.