36-Groundwater Quality in Chromite Mining Area, Sukinda Valley, Orissa

Abstract

Sukinda Valley, Jajpur district, Orissa is popularly known for huge chromite ore deposits. The open cast mining for chromium is being carried out since 1950. The extraction of chromite mostly has been carried out by open cast mining method and at few places by underground mining method. These chromite deposits are associated with ultramafic rocks of Pre-Cambrian age. The major problem associated with open cast mining is the degradation of land, aforestation, storage of extracted ore, which causes an adverse effect on environment. There is always possibility of leaching contaminants from the ore material kept in the open ground or from the wastages or degraded ore material produced during the mining processes, which may contaminate the groundwater. There is also possibility that the contaminants will add to the aquifer system from the seepage of bottom floor of the mining quarry. In order to assess the chemical quality, groundwater samples from the different part of the study area for post-monsoon (twice) period have been collected, and analyzed for various contaminants. The sample shows the metallic trace elements such as Fe (0.2 to 0.5 mg/L); Cu (0.01 to 0.2 mg/L) and Cr+6 (0.01 to 0.4 mg/L) more than the permissible limits of potable water at some places in different seasons and may cause for health hazards. The high values of TSS (12-64 mg/L) indicated the influence of mine's waste in the groundwater. Groundwater in the study area is nearly neutral to mildly alkaline (p1-1 6.1-7.6) and contains low to moderate TDS (232-507 mg/L).