Analysis and risk assessment of natural radioactivity elements in coal wastes from Medan industrial area

The Analysis of Natural Radioactivity content in coal wastes from Medan Industrial Area has been carried out by using Gamma Spectrometer with HP-Germanium detector. Coal wastes was collected from a pile of wastes in a plant which used two different origin of coal was Palembang and Kalimantan areas. The aim of this study to determine the content of activity concentration of natural radioactivity elements and to assess risk exposure to human and environment. The results of quantitative analysis of the activity concentration of natural radioactive elements from Palembang coal wastes of U-238, Th-232 and K-40 were 3640.60±593.70; 112.78±13.14 and 155.82±32.18 Bq/kg, respectively. Whereas for Kalimantan coal wastes the concentration of U-238, Th-232 and K-40 were obtained 1778.77±79.29; 52.00±2.27 and 160.10±5.92 Bq/kg, respectively. Risk assesment of the exposure to radiation gamma of the wastes to human and enviroment in the vicinity of area, was calculated as risk indeces. The average radium equivalent (Raeq) was of 2760.4168 Bq/kg, the average of absorbed dose rate (D) was of 1275.0414 nGy/h, gamma index (γ_i) was of 64.3468 and the average of annual effective dose was of 10.9022 mSv. All indeces were above average world values and therefore its suggested to suspend the use of the coal and the wastes. This was the preliminary study to measure the activity concentration of natural radioactivity in the study area. (paper)