Is Tin Tailing Sand the Source of a High Natural Gamma Background in Na Mom Districts, Songkhla Province, Southern Thailand?

This study aims at quantitatively analysis of the activity concentration of the naturally occurring radionuclides in samples collected from the abandoned tin mining areas in Na Mom district of Songkhla province of Southern Thailand. The main objective is to assess whether the tin tailing sand from abandoned tin mines used for house construction in the district could affect the gamma dose rate exposed to public in the area or not. In this study the gamma-ray ground survey was performed using a portable NaI(Tl) Gamma spectrometer to determine the absorbed dose rate in the study area. The 22 sand samples were collected from house construction sites and tin tailing sites in Na Mom district and from clean sand quarries in Hatyai districts, Songkhla province. Totally 34 soil samples were also collected from Na Mom district. All collected samples were analyzed using a high resolution HPGe gamma-ray spectrometer. Results show the external gamma dose rate in Na Mom district ranged 39-235 nGy/h and is averaged at 103 nGy/h. Results clearly showed that the specific activities of the Naturally Occurring Radionuclides in tin tailing sand samples collected from Na Mom district are 2-6 times higher than those collected from the clean sand quarries in Hat Yai district. However, radium equivalent activities and the radiation hazard indices of the measured samples used to assess the radiation hazards arising due to the use of these tin tailing sands in constructing of dwelling were within the safety limits recommended by the UNSCEAR. (author)