The Mobility of Some Nutrient Metal ions as Affected by Heavy Metals in Presence of Added Soil Organic Matter in an Illitic Soil

Author(s): N. Nazar Khan

The mobility of some nutrient metals such as Fe, Zn, Mn and Cu have been investigated in an illitic fine sandy loam soil as affected by some toxic heavy metals (Pb, Cd, Cr, and Ni) in the presence of added organic matters using soil thin layer chromatography (Soil TLC). The soil organic matter (SOM) and humic acid (HA) fraction was extracted from the sample soil by standard methods and purified. The heavy metals like Pb, Cd, Cr, and Ni were added to the soil in the form of their SOM and HA complexes to study their effects on the mobility of nutrient metal ions in the soil. The mobility of nutrient metals was found to follow the order as Mn > Zn > Cu > Fe. The presence of SOM and its fraction as HA significantly increases the mobility of all the nutrient metal ions in soil. An addition of the heavy metal-SOM and heavy metal-HA complexes in soil further increases the mobility of all the metals except in the case of Cd, which decreases the mobility of all the nutrients. The results so obtained have been explained on the basis of metal ion interactions with soil colloids and their physico-chemical properties in the soil solutions.

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