1. DETERMINATION OF Fe, Mn AND Pb IN TREE-RINGS AND BARK OF LINDEN (Tilia platyphyllos Scop.) FROM LOCATIONS ZEMUN AND OBRENOVAC I. Novović 1, D. M. Marković 1, D. Vilotić 2, Lj. Ignjatović 3 and V. Srećković 1 1 Institute of Physics, P.O.Box 57, Pregrevica 118, Belgrade, Serbia 2 Faculty of Forestry, University of Belgrade, Kneza Viseslava 1, Belgrade, Serbia 3 Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, Belgrade, Serbia Abstract -The U-shaped DC arc with aerosol supply was applied for the determination of Fe, Mn and Pb in Tilia platyphyllos Scop. tree- rings and bark from the locations Zemun and Obrenovac. The mean concentrations of Mn and Pb in bark in Tilia platyphyllos Scop. are higher than corresponding concentrations in tree-rings.Introduction -Heavy metals are present in the atmosphere in ever increasing levels as a result of anthropogenic and natural emissions. They are long-term contaminants with the ability to accumulate in soils and plants and have no natural way to be removed. Increasing urbanization results in the production of a wide range of different pollutants that can have an adverse effect on the surrounding environment. The primary sources of anthropogenic emission of most trace metals are the combustion of fossil fuels and automobile exhaust emission in certain areas and they now exceed or equal their natural emission [1]. Dendroanalysis, the method of analyzing tree-rings for trace metal pollution is based on the assumption that element concentrations in the tree represent element availability in the environment in which the tree was grown [2]. The presence of distinct annual rings in the wood of trees growing in temperate climates gives them a unique potential as indicators of pollution histories and numerous studies have delt with the use of tree-rings as historical monitors of heavy metal pollution [2, 3, 4, 5]. Tree-bark, has been found to be useful bioindicator for monitoring airborne pollution [6, 7]. Considering the increasingly stricter demands for environmental control, the development of very sensitive methods for the detection of trace elements in natural samples and complex matrices is of great significance. The spectrochemical method applied in the study is a simple method for determination of low concentrations.Experimental The experimental operational conditions of our spectrochemical method are presented in Table I. TableI. Experim. operating conditions of our spectrochemical method In this study, Fe, Mn and Pb concentrations were measured in annual tree rings in linden growing in Obrenovac. Tree-ring and bark samples were collected in March 2007 from location Zemun and Obrenovac. The first measuring site was in urban area 10 km NW from the center of Belgrade, the second one was in Obrenovac 42 km upstream from the Belgrade. Each Tilia platyphyllos Scop., core was divided into 3 year segments. Tree- ring samples (3 year segments) were placed in pre-washed (15% H 2 SO 4 ) 50mL borosilicate glass tubes dried at 70 o C for 48h and weighed. Samples were suspended in 10 mL of 70% HNO 3 at 80 o C for 24h. The cold solution was filtered through acid washed (10% HNO 3 ) Whatman No.42 filter paper and diluted to 50 mL with bidistilled water [8]. A series of reference solutions (Fe, Mn and Pb) were prepared in the range from 5 to 5000 ng/mL, by appropriate dilution of the stock solution (1mg/mL, Merck). Each solution contained 0.5% potassium chlorate as a spectroscopic buffer. Results and discussion The mean concentrations of Fe, Mn and Pb in Tilia platyphyllos Scop. in tree-rings and bark from the locations Zemun and Obrenovac are shown in Table II. Table II. The mean concentrations of Fe, Mn and Pb in Tilia platyphyllos Scop. in tree-rings and bark from the locations Zemun and Obrenovac between 1971 and 2006 and bark. In Table III. are shown differences and ratios in the mean Fe, Mn and Pb concentrations in tree-rings and bark in Tilia platyphyllos Scop. from the locations Zemun and Obrenovac. Table III. Differences and ratios in the mean Fe, Mn and Pb concentrations in tree- rings and bark in Tilia platyphyllos Scop. from the locations Zemun and Obrenovac between 1971 and 2006 and bark. -In almost all cases the average values concentrations of Fe, Mn and Pb in bark were higher than in tree-rings except in case of Fe from the location Zemun. The heist ratio of C bark /C tree -rings is for Pb from the location Zemun. The results presented in this paper indicate that the value ratio for Pb from Zemun was 15.53 and from Obrenovac 7.71.Conclusions -In this study Fe, Mn and Pb contents in Tilia platyphyllos Scop. tree- rings and bark from the locations Zemun and Obrenovac were compared. The mean concentrations of Mn and Pb in Tilia platyphyllos Scop. bark are higher than corresponding concent. in tree-rings. References 1. O. Odukoya, T.A. Arowolo, O. Bamgbose, Environ. Internat., 2000, 26, 11-16. 2. K.L. Padilla, K.A. Anderson, Chemosphere, 2002, 49, 575-585. 3. A. Jonsson, M.Eklund, K. Håkansson, J. Envir. Qual., 1997, 26, 1638-1643. 4. B.E. Cutter, R.P. Guyette, J. Environ. Qual., 1993, 22, 611-619. 5. G.Liu, Y. Zhang, Y. Qi, L. Zheng, Y. Chen, Z. Peng, Environ. Monit. Assess., 2007, 133, 99-103. 6. H. Schulz, P. Popp, G. Huhn, H.J. Stark, G. Schurmann, Science Total Environ., 1999, 232, 49-58. 7. L. Harju, K.E. Saarela, J., Rajander, J.O. Lill, A. Lindroos, S.J. Heselius, Nuclear Instrum.Methods B, 2002, 189, 163-167. 8. M. Orlandi, M. Pelfini, M. Pavan, M. Santilli, M. P. Colombini, Microchem. J., 2002, 73, 237-244. Institute of Physics, Laboratory for Plasma Chemistry