Determination of natural and artiﬁcial radioactivity in soil at North Lebanon province O. El Samad a, * , R. Baydoun a , B. Nsouli a , T. Darwish b a Lebanese Atomic Energy Commission, Environmental Radiation Control, National Council for Scientiﬁc Research, Airport Road, P.O. Box 11-8281, Beirut 1107 2260, Lebanon b Remote Sensing Centre, National Council for Scientiﬁc Research, Beirut, Lebanon article info Article history: Received 29 November 2012 Received in revised form 28 January 2013 Accepted 17 February 2013 Available online xxx Keywords: Radioactive carte Naturally occurring radionuclide Artiﬁcial radionuclides Absorbed gamma dose rate Gamma spectrometers abstract The concentrations of natural and artiﬁcial radionuclides at 57 sampling locations along the North Province of Lebanon are reported. The samples were collected from uncultivated areas in a region not previously reported. The samples were analyzed by gamma spectrometers with High Purity Germanium detectors of 30% and 40% relative efﬁciency. The activity concentrations of primordial naturally occurring radionuclides of 238 U, 232 Th, and 40 K varied between 4e73 Bq kg 1 ,5e50 Bq kg 1 , and 57e554 Bq kg 1 respectively. The surface activity concentrations due to the presence of these radionuclides were calculated and Kriging-geostatistical method was used to plot the obtained data on the Lebanese radioactive map. The results for 238 U, 232 Th, and 40 K ranged from 0.2 kBq m 2 to 9 kBq m 2 , from 0.2 kBq m 2 to 3 kBq m 2 , and from 3 kBq m 2 to 29 kBq m 2 respectively. For the anthropogenic ra- dionuclides, the activity concentrations of 137 Cs founded in soil ranged from 2 Bq kg 1 to 113 Bq kg 1 , and the surface activity concentration from 0.1 kBq m 2 to 5 kBq m 2 . The total absorbed gamma dose rates in air from natural and artiﬁcial radionuclides in these locations were calculated. The minimum value was 6 nGy h 1 and the highest one was 135 nGy h 1 with an average of 55 nGy h 1 in which the natural terrestrial radiation contributes in 99% and the artiﬁcial radionuclides mainly 137 Cs contributes only in 1%. The total effective dose calculated varied in the range of 7 mSv y 1 and 166 mSv y 1 while the average value was 69 mSv y 1 which is below the permissible limit 1000 mSv y 1 . Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction All living organisms are continually exposed to ionizing radia- tion coming from two main sources, natural and artiﬁcial radio- nuclides. About 85% of the dose received is due to the natural radiation (Do1ha nczuk-  Sródka, 2011), which is from both cosmic and terrestrial radiation. The cosmic component originates from the reaction of cosmic radiation with the atoms of the upper at- mosphere (Khan et al., 2012); it varies with elevation above the ground (El Samad et al., 2002). The major contributors to the terrestrial radiation are the primordial radionuclides with half-lives comparable to the age of earth, mainly 238 U, 232 Th and their decay products as well as 40 K(Abu-Haija, 2012; Wang, 2008). These occur naturally in terrestrial soils and rocks and in building materials derived from them (UNSCEAR, 2000), in various concentrations according to the different geographical and geological factors (Baldik et al., 2011). Many radionuclides of artiﬁcial origin have been released to the environment by different processes. Caesium isotopes are the most important ones that may be deposited by fallout over soil and plants as they are produced anthropogenically by several types of nuclear activities including past testing of nu- clear weapons and nuclear accidents (Celik et al., 2009). Measure- ment of natural and artiﬁcial radioactivity content in soil is very important to set a baseline level and then plot the trend with time as result of any radioactive release for environmental and public protection purposes. Therefore, surveys to determine the concen- trations of radionuclides in soil have been made in many countries. The results were related to exposures using estimates of the dose rates in the air per unit concentration of radionuclide in soil (UNSCEAR, 2000). A national radiation monitoring program was established in Lebanon by the Environmental Radiation Control Department at the Lebanese Atomic Energy Commission (LAEC). Natural and artiﬁcial radioactivity measurements in soil in Mount Lebanon region (El Samad et al., 2002), water, air and the main constituents of the Lebanese diet have been evaluated (Nasreddine et al., 2008). Part of this program is the analysis of soil samples collected from uncultivated areas along the Lebanese territory, in order to set a radioactivity baseline level and consequently to * Corresponding author. Tel.: þ961 1 450811; fax: þ961 1 450810. E-mail address: osamad@cnrs.edu.lb (O. El Samad). Contents lists available at SciVerse ScienceDirect Journal of Environmental Radioactivity journal homepage: www.elsevier.com/locate/jenvrad 0265-931X/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jenvrad.2013.02.010 Journal of Environmental Radioactivity xxx (2013) 1e4 Please cite this article in press as: El Samad, O., et al., Determination of natural and artiﬁcial radioactivity in soil at North Lebanon province, Journal of Environmental Radioactivity (2013), http://dx.doi.org/10.1016/j.jenvrad.2013.02.010