Monitored natural attenuation as a remediation tool for heavy metal contamination in soils in an abandoned gold mine area.

We report here the preliminary results of the study using monitored natural attenuation (MNA), referred to as intrinsic remediation, as an in situ treatment method in an abandoned gold mining site in Kolar Gold Fields, Karnataka. The area is called the Kolar schist belt of south India, well-known for its gold deposits which have been mined systematically for over several decades. Distribution of elements, in the form of histograms and correlation diagrams, were prepared to understand the sources of contamination in soils. Natural attenuation observed for some elements were: As (36.6%), Cr (56.6%), Co (50%), Cu (50%), Ni (53.3%), Pb (86.6%), Sr (46.6%) and Zn (50%). The outcome of this study would facilitate identification of safe waste disposal sites besides pointing out the extent of aquifer pollution and prognosis of the migration of pollutants in the plume, and finally support remedial measure. [ABSTRACT FROM AUTHOR]