Chemical and radioactive composition of bulk deposition in Málaga (Spain) C. Dueñas a, * , M.C. Fernández a , E. Gordo a , S. Cañete a , M. Pérez b a Department of Applied Physics I, Faculty of Science, University of Málaga, 29071 Málaga, Spain b Department of Radiology and Health Physics, OPHT., and ORL Faculty of Medicine, University of Málaga, 29071 Málaga, Spain highlights < Chemistry and radioactive composition of bulk deposition. < Seasonal variations of chemistry and radioactive composition in bulk deposition. < Relationships between chemistry and radioactive composition in bulk deposition. < Factors controlling the fluxes of major ions and radionuclides in bulk deposition. article info Article history: Received 5 March 2012 Received in revised form 19 July 2012 Accepted 25 July 2012 Keywords: Bulk deposition Major ions Radionuclides Atmospheric fluxes abstract Chemical and radioactive composition of bulk deposition samples, which were collected monthly over a 5 year period (January 2007 until 31 December 2011) at a site located 30 m.a.l. in Málaga (4  28 0 8 00 W; 36  43 0 40 00 N) have been analysed. All samples were analysed for pH, major ions and gamma radionu- clides. The average pH of bulk deposition was 6.4. Cl  and SO 4 2 were the main anions, while Ca þ and Na þ were the main cations. Significant correlations were found in soil-derived species among Ca 2þ , Mg 2þ and K þ and sea-salt species between Na þ and Cl  . Other relatively good correlations were also observed between acidic anions ðSO 4 2 and NO 3  Þ and crustal-derived cations (Ca 2þ , Na þ ,K þ ). Sources of the major ions were assessed based on the enrichment factor method. The radionuclides present in all samples are 7 Be and 210 Pb and 40 K appears in 50% of the samples. Relatively poor correlations were observed between the specific activities of gamma radionuclides and the major ions. The temporal variations of major ions and radionuclides exhibit similar seasonal behaviour with low values in winter eautumn months and maximum values in springesummer months. The fluxes of major ions and gamma radionuclides have been discussed with meteorological factors controlling depositions. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Atmospheric deposition, the major removal pathway for atmo- spheric pollutants, can take place in two forms: dry and wet depositions, hence bulk deposition. Bulk compositions play an important role in scavenging soluble components from the atmo- sphere and enable the understanding of the relative contributions of different sources of atmospheric pollutants. Measurements of the chemical composition of atmospheric depositions are needed to establish depositional fluxes through the atmosphere in specific regions. These data are also very useful for validating global scale model simulations of sulphur and nitrogen compounds. The need for such information has led to an increased number of atmo- spheric deposition chemical studies in many countries around the world. Besides, the deposition of radionuclides on the ground represents an important factor in environmental radioactivity monitoring and an important input parameter in radioecological models. 7 Be and 210 Pb are highly active particles and are easily scavenged by aerosols. Both have been used as aerosol tracers in studying the vertical transport and residence time of aerosols in the troposphere based on modified versions of the general circulation model (Brost et al., 1991; Balkanski et al., 1993). Numerous appli- cations in studies of transport processes have been found in atmospheric and aquatic systems (Rehfeld and Heimann, 1995). 7 Be is produced in the upper troposphere and stratosphere as a product of the spallation of oxygen and nitrogen nuclei with energetic cosmic rays. 7 Be is removed from the atmosphere by radioactive decay (half-life 53.2 days) and by wet and dry depositions. Most of the 210 Pb in the atmosphere is formed as a decay product of 222 Rn emanating from soil .The 222 Rn flux from the soil surface is about 100 times higher than the oceanic 222 Rn flux. Little attention is paid to 40 K in airborne materials. Its origin is lithogenic and is mainly * Corresponding author. E-mail address: mcduenas@uma.es (C. Dueñas). Contents lists available at SciVerse ScienceDirect Atmospheric Environment journal homepage: www.elsevier.com/locate/atmosenv 1352-2310/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.atmosenv.2012.07.073 Atmospheric Environment 62 (2012) 1e8