FRAN GJOKA1, ROLF-ALEXANDER DUERING2, JAN SIEMENS2, ENKELEDA SHKURTA3
|
1 Agricultural University of Tirana, Kodër Kamëz 1029, Tiranë, Albania Abstract Soil contamination by heavy metals is a direct threat to the environment and human health. A DAAD-supported research project in 2016 produced the first comprehensive database in Albania for nine heavy metals such as Cd, Cr, Cu, Ni, Pb, Zn, As, Co and Hg in topsoil with a total of 278 soil samples collected from the main soil types, parent materials of soil formation and current land use categories. This unique database provides a national overview of soil metal concentrations. After testing the database for its suitability for determining the background values, the latter were calculated for six metals as the antilog of the median of the ln-transformed metal concentration (on aqua regia basis). Background values for agricultural soils were as follows (mg/kg): Cd 0.24, Cr 131.63, Cu 41.26, Ni 287.15, Pb 19.11, Zn 81.80. These values for Ni, Cr and Cu were higher than the international guidelines used for comparison, with the exception of the EU Directive 86/278/EEC for Cr and Cu. The study indicated that a small number of soil samples had higher heavy metal concentrations than these background values, suggesting contamination from anthropogenic sources. The obtained background values can be used to complete the picture of metal concentrations in European agricultural soils. They can also be used as reference values for Albanian environmental legislation. The study should continue to complete the existing database and to determine the maximum allowable and intervention values for heavy metal concentrations in agricultural and other soils. Keywords: Heavy metal, background concentration, land use, natural log transformation, soil parent material |