Chemical fractionation and bioavailability of Fe, Mn, Pb, and Cd in soils around Meyghan Lake, Arak, Iran

The chemical fractionation and bioavailability of iron, manganese, lead, and cadmium in soils around Meyghan Lake, Arak, Iran, were studied. The samples were obtained from four sites of water entrance to the lake using a sequential extraction method. The soil sampled from the release site of wastewater of sodium sulfate plant had the lowest total heavy metal contents compared to other sites. Although the HNO3 extractable fraction was the most important phase for the four heavy metals, this fraction in salty soils was not the main fraction for Cd. The KNO3 extractable and bioavailability and contamination factor (CF) of the heavy metals were considerably high in the salt-affected soils. The NaOH extractable Fe of the non-salty soils was higher than that of the salty soils. The order of metal reactivity assessed by CF in the studied soils was observed to be Cd > Pb > Mn ≫ Fe. However, the increasing effect of salinity on promoting the metal-soluble and exchangeable form (mobility) followed the order of Cd > Mn > Pb ≫ Fe.