No abstract

Forest fires are annual problem during the dry season and become a biggest threat to forest resources in Indonesia. The forest fires release into the atmosphere large quantities of particulate matter and volatilized substances. The present study investigates effects of forest fire on air quality in the case of a radiological event of ashes from forest fires emissions in Riau province during an intense forest fire season that occurred in 2015. Atmospheric aerosol samples were collected from May to December, 2015 using a large volume TSP (total suspended particles) sampler. Concentrations of radionuclides in airborne particulate matter were measured by using gamma spectrometry. It was shown that the activity concentrations of 226 Ra, 232 Th and 40 K ranged from 0.026 to 0.114 mBq/m 3 , 0.005 to 0.011 mBq/m 3 and 0.99 to 5.64 mBq/m 3 , respectively. The activity concentrations of 137 Cs in air was found lower than the minimum detectable activity of the gamma counting systems (

No abstract

Natural radionuclides 226 Ra, 232 Th and 40 K in soil are the primary component of the background exposure sources of the population. Study of the external exposure due to gamma-ray radiation of natural radionuclides is important because this may contribute significantly to the total annual individual dose. The purpose of this study is to investigate the natural radionuclides in soils collected from Tual and Kei islands and assess the radiological hazard due to natural radionuclides contents in soil. The soil samples were analyzed for natural radionuclides 226 Ra, 232 Th and 40 K using gamma ray spectrometry. Radiological hazard parameters were estimated from the activity concentration of these radionuclides in order to assess health implication of exposure of the general public. The activity concentrations of 226 Ra, 232 Th and 40 K in soil samples varied from 7.50 Bq kg-1 to 6326 Bq kg-1 , 0.99 Bq kg-1 to 157 Bq kg-1 , 2.97 kg-1 to 98.91 Bq kg-1 with the average value of 2162 Bq kg-1 ; 69.68 Bq kg-1 and 30.74 Bq kg-1 , respectively. The absorbed dose rates due to the presence of 226 Ra, 232 Th and 40 K, in soil samples in the studied area vary between the range of 4.88 nGy h-1 and 3018.80 nGy h-1 with the average value of 1042 nGy h-1. The corresponding outdoor annual effective doses ranged between 0.01 mSv y-1 and 3.70 mSv y-1 with the average value of 1.28 mSv y-1. Radium equivalent activities are calculated to be in the range of 10.42 Bq kg-1-6553.03 Bq kg-1 with the average value of 2264 Bq kg-1. The external and internal hazard indexes vary from 0.03 to 17.71 with the average value of 6.12 and 0.05 to 34.81 with the average value of 11.96, respectively. All calculated average radiological hazard indices were higher than the limits recommended for individual members of the public.