Distribution of Cd, Cu, Ni, Pb and Zn in Particle Size Fraction in Polluted and Unpolluted Soils in Bulgaria

P. SHEGUNOVA and I. ATANASSOV

Agricultural University, Department of Soil Science, BG-4000 Plovdiv, Bulgaria

Abstract

SHEGUNOVA, P. and I. ATANASSOV, 2000. Distribution of Cd, Cu, Ni, Pb and Zn in particle size fraction in polluted and unpolluted soils in Bulgaria. Bulg. J. Agric. Sci., 6: 183-194

An investigation was conducted to evaluate the distribution of Cd, Cu, Ni, Pb and Zn in whole soil samples and in particle size fractions 2-0.2, 0.2-0.02, 0.02-0.002 and <0.002 mm. Five soil profiles were studied: an Orthic Luvisol (profile P1), an Eutric and a Calcic Fluvisols (profiles P2 and P3) - all situated in vicinity of Cu-Zn-Pb smelters and two Cambisols (profiles P4 and P5) situated in unpolluted or background areas. The results show, that the heavy metals tend to accumulate in the surface soil horizons both in soils, situated in polluted and background areas. There is a tendency for concentration of these elements in clay fraction (particles less than 0.002mm). On the other hand, the contents of the investigated elements in sand fraction (particles 2-0.2 mm) separated from soil horizons are closed or equal to the contents of these metals in parent rocks. The particles with size 2-0.2 mm carry the fingerprint of the geogenic basic content of above discussed elements and this can be used for description of the geogenic/background values independently whether the soils are situated in polluted or unpolluted territories.

Key words: Cd, Cu, Ni, Pb, Zn, background content, soil pollution, sand fraction, clay fraction