PhD: Studying the influence of some soil properties on the contents of heavy metals in tobacco produced in the Republic of Macedonia

Biljana Jordanoska Shishkoska
Institute of Chemistry, Faculty of Natural Sciences and Mathematics, Ss. Cyril and Methodius University, Skopje, Macedonia
May, 2014


Tobacco is one of the most important agricultural products in the Republic of Macedonia. Elemental composition of tobacco and soil from different agricultural areas was studied for monitoring purposes. The main purpose was to determine the intensity of accumulation of various elements in tobacco plants and to determine possible relationships of certain chemical and physical properties of soil (pH, clay, cation exchange capacity - CEC, organic matters - OM and total organic carbon - TOC) that affect that accumulation. The study was conducted on 150 locations from three well known tobacco regions in Macedonia (Pelagonia, Southeastern region and Vardar Valley). Total (HF digestion), pseudo-total (aqua regia extraction) and DTPA (diethylenetriaminepentaacetic acid) extractable content of eighteen elements (Ag, Al, Ba, Ca, Cr, Cu, Li, Fe, K, Mg, Mn, Na, Ni, Pb, P, V, Sr, and Zn) from soil samples and their total content in plant material was analyzed by atomic emission spectrometry with inductively coupled plasma (ICP-AES). The results suggested the general effectiveness of total digestion for determination of most of the elements. Element accumulation is mostly in the tobacco leaves. Only Cu, Zn and P had higher concentration in tobacco seeds, Na in root and K in stem in comparison to other tobacco organs. Higher concentrations of metals were determined in tobacco leaves grown in soils with increased content of the corresponding metal. Element content in tobacco leaves generally show weak correlation with DTPA extractable elements, soil properties and total element content from the soil. Strong correlations were observed only within soil properties and within tobacco organs. All analyzed elements in soil samples correlated poorly with soil properties and had high inter-element correlation. Despite intensive tobacco production, the content of most of the heavy metals in soil was at levels which are typical of agricultural and low anthropogenic pressured areas.