Study of the heavy metals mobility in different soils, affecting vegetation

Human beings have been exposed to heavy metal toxins through different sources such as soil, water and plant or animal products, even direct exposure is also encountered through processes of industrialization and pots and utensils. The increasing load on environment is increasing the density of metals in soil also, which becomes fatal not only for the plants but also for the animals and human beings. Therefore, it is wise to take steps to curb the heavy metals accumulation in soil and scientific analysis of different types of soil is must to estimate the accumulation as well as mobility, which in turns affects the vegetation. Thus, the present investigation was carried out with a view to study the influence of different soil characteristics on DTPA-extractable, HCl-extractable and Tri-acid extractable heavy metals (Cd, Cr, Cu, Pb and Zn) present in sewage irrigated soils of Sheila Dhar Institute Experimental Farm, Allahabad. These soils. generally contained large amount of micronutrients. In fact, metals solubility decreased in soil as the content of CaCO3 and soil pH increased while organic matter promoted the availability of these metals by supplying complexing agents that interfered with the fixation of these metals. The availability of these metals in soil is limited by binding with humic substances as well as with clay and it finally depends on the CEC.