Distribution, bioavailability and fractionation of metallic elements in allotment garden soils using the BCR sequential extraction procedure

Metal associated with urban soils are of environmental concern due to their direct and indirect effects on human health. Metallic elements in contaminated soils are absorbed by plants and undergo biomagnification in the food chain. Allotment gardens are often situated in city centers and in areas with strong anthropogenic pressure – e.g. near industrial plants and roads. The aim of this study was to identify the bioavailable forms of metals present in urban soils. The sequential extraction procedure was applied to fractionate the following metals in urban soil samples from allotment gardens in Koszalin, Poland: chromium, copper, iron, manganese, nickel, lead, cadmium, and zinc. The mobility of the metals from studied soils decreased in the order: Cd > Mn > Pb > Zn > Ni > Cr > Cu > Fe. The sum of particular metals in the bioavailability fractions BCR I-III was: Cd 77-89%, Mn 72-81%, Pb 64-80%, Zn 54-77%, Ni 31-57%, Cr 32-53%, Cu 20-50%, and Fe 12-17%.