EVALUATION OF REMEDIATION ABILITY OF PONGAMIA PINNATA (L.) PIERRE UNDER HEXAVALENT CHROMIUM STRESS SOIL CONDITIONS

Abstract

The increase in demands for industrial and mining products alters the conventional ecosystemapproach and attainment of sustainable development. Production of industrial products,processing of metals and protection of environment are intimately connected with one another andmake a challenge for sustainable growth and development of human-beings. In the industrial andmining environment, the release of heavy metals like hexavalent chromium [Cr(VI)] in solid,liquid or gaseous states influence the soil health of the region. Its concentration exceeding thethreshold limits is highly toxic and expresses in the form of manifold health problems. The healthof crop plants and animal husbandry are not spared from its toxic effects. The Cr (VI) is a highlytoxic, mobile, inter-convertible form of chemical element mostly used in industrial applications forits tensile strength and anti-corrosion ability. The soil pollution due to high Cr(VI) load is anegative attribute of mining and industrial developmental activities. Restoration of soil quality inthese mining and industrial areas is highly essential for sustainable development and healthyliving. Confinement of this toxic element in the closed biological system is a move towardsreducing its load in the soil profile. In the present approach Pongamia pinnata (L.) Pierre isexperimented as a renewable closed biological system for improving the soil health of Cr(VI) richmining and industrial sites. In this experimental set up the assessment of Cr(VI) content in selectedparts of this experimental plant species and the rhizospheric soil of their growth was performedusing the standard methodologies of APHA (1998). The positive aspect of this approach is thesurvival of this species under high soil Cr(VI) concentration and differential accumulation of thistoxic element in this biotic system. The targeted plant species was able to accumulateapproximately 50 % of the soil Cr(VI) within a period of 135 days from the initiation of treatment.The order of accumulation of Cr(VI) was found to be root > leaf > stem. Compared to thelimitations of physical, chemical and microbiological techniques, this process is sustainable in thelong run, cheaper and has least negative interference with other components of the environment.Further work in this area has the possibility to improve the efficiency of Cr(VI) intake by thisliving system.