RADIOLOGICAL ASSESSMENT OF PHOSPHATE ROCKS IN SOME COUNTRIES

The phosphate rocks is used to manufacture phosphate fertilizers [1]. Radiological characterization of phosphate rocks in Turkey, Tunisia, Egypt, Morocco, Algeria and Syria were investigated using gamma ray spectrometry. The radioactivity concentration levels for 226Ra, 232Th and 40K in all phosphate rock samples ranged from 250 to 1029 Bq/kg with a mean of 535 Bq/kg, from 5 to 50 Bq/kg with a mean of 20 Bq/kg and from 117 to 186 Bq/kg with a mean of 148 Bq/kg, respectively. The radium equivalent activity (Raeq), the total air-absorbed dose rate (D) and the annual effective dose (He) rate were also calculated using for 226Ra, 232Th and 40K activity values. The calculated mean values of the Raeq, D and He for the phosphate samples were 575 Bq/kg, 266 nGy/h and 0.33 mSv, respectively. All the Raeq values of the samples except for Tunisia are higher than the recommended reference value 370 Bq/kg recommended by the Organization for Economic Co-operation and Development (OECD) [2]. Also, the computed values of He are lower than the recommended limit by the International Commission on Radiological Protection (ICRP) [3].