ORIGINAL ARTICLE Natural radionuclide concentrations in thermal springs of east Algeria Hadda Kebir 1,2 • Ahmed Boucenna 2 Received: 9 January 2016 / Accepted: 24 December 2016 Ó Springer-Verlag Berlin Heidelberg 2016 Abstract The variation of the natural radionuclide con- centrations depends on the chemical composition of each site. In this work, two thermal springs in the east of Algeria have been chosen to assess the activity concentration of natural radionuclide, mainly the three natural radioactive series 238 U, 235 U and 232 Th, and 40 K. The high-resolution gamma ray spectroscopy was used to determine these concentrations. In these water samples, 235 U, 234 Th, 210 Pb, 226 Ra radionuclides are less than the minimum detectable activity. The activity of 238 U is dominant. The 238 U activity was determined by taking the mean activity of two separate photo-peaks of daughter nuclides 214 Pb at 351.92 (37.2%) keV and 214 Bi at 609.31 (45%) keV. The measured activity concentrations of 238 U in water samples obtained from the concentrations of 214 Bi and 214 Pb ranged from 0.56 ± 0.20 to 1.13 ± 0.20 Bq/L. The annual effec- tive dose value due to the ingestion of the measured radionuclide 238 U in 1 L of water, for an adult, ranged from 9.20 to 18.56 lSv. Keywords Gamma spectroscopy Á Activity concentrations Á Water sample Á Thermal springs Á Annual effective dose Introduction The average 238 U content in the earth’s crust has been estimated to be 2.7 mg/kg, and concentrations may be as high as 120 mg/kg in phosphate rocks (Singh et al. 1996), while the average 232 Th content of the earth’s crust is about 9.6 mg/kg (Firestone et al. 1996). Enhanced levels of uranium, thorium and their daughter products might be present in groundwater that is rich in natural radioactivity. The earth’s crust of Algeria is covered by sedimentary phosphate rocks that make the water aquifer sources, which arise from snow and rain precipitation, during winter. These sources are rich in 238 U and its daughters. These may be found dissolved or suspended in water. The geology of the area indicates that it is covered by a sedimentary sequence with some interruption of sand- stone that contains iron uranium. The upper part of the sequence consists of phosphoric beds and limestone that contain 238 U minerals. Northern Algeria is located at the plate boundary between Eurasia and Africa, and it is one of the most seismically active regions of the Mediterranean (Buforn et al. 1995; Stich et al. 2003, 2006). The tectonic evolution of this region results from the convergence between the European and African plates (Argus et al. 1989), marked by the Miocene (*15 Ma) cessation of subduction of the Tethyan Ocean across the west-Mediterranean subduction zone (Faccenna et al. 2004) and the birth of an Alpine-type orogen which bounds Northern Africa (Auzende et al. 1973), namely the Rif and Tell-Atlas mountains. Today, this area undergoes slow-rate contractional deformation distributed over a relatively wide area (Frizon de Lamotte et al. 2000; Serpelloni et al. 2007). The convergence rate of Eurasia and Africa is about 5 mm/year at the longitude of Algiers and increases up to 8 mm/year near Tunisia (Calais & Hadda Kebir haddakebir@yahoo.fr Ahmed Boucenna aboucenna@yahoo.com 1 Present Address: Physics Department, Faculty of Sciences, Mohamed El-Bachir El Ibrahimi Bordj Bouarreridj University, 34000 BBA, Algeria 2 DAC Laboratory, Physics Department, Faculty of Sciences, Ferhat Abbas Setif-1 University, 19000 Setif, Algeria 123 Environ Earth Sci (2017) 76:52 DOI 10.1007/s12665-016-6373-z