Carpathian Journal of Earth and Environmental Sciences

In this study, the surface soil samples collected from irrigated soils of Bregu i Matit Plain were analysed for mobile forms of heavy metals in order to evaluate the risk of soil pollution with metals. The NH₄EDTA extractable As, Cr and Ni and NH₄NO₃ extractable Cr, Cu, Ni and As increased significantly in the irrigated soils as compared to non-irrigated soil. The higher metal proportions extracted with EDTA are found for Cd (33.6%), Cu (11.34%), Pb (11%) and Ni (1.37%), and for Cd (0.70%) and Cu (0.28%) extracted with NH₄NO₃. The order of metal extractability in EDTA was: Cd>Cu>Pb>Ni>Zn>As>Cr indicating that Cd and Pb are associated with organic matter more than Cu and Ni, and in NH₄NO₃ was: Cd>Cu>Pb> Ni>As>Zn>Cr which corresponds to the sequence of metal mobility. Only the Pb was proportional to the total content in aqua regia. The mobility of Cd, Cu, Ni, Pb and Zn is controlled by pH. Although there is no actual harmful pollution of soils with heavy metals, a potential risk of soil pollution with Cd, Cu and Pb exists, because their mobility and bioavailability can be increased due to soil acidification.