Assessment of Chromium Pollution at Baula Mines, Orissa

Abstract

This study is conducted in and around one of the chromite mines of the Nuasahi-Baula igneous complex for assessing the Cr pollution. Hexavalent chromium was found between 0.002 and 0.006 ppm in groundwater and 0.008 to 0.036 ppm in mine discharges. The total chromium ranged between 0.002 and 0.007ppm in groundwater and 0.009 to 0.042 ppm in mine discharge water. The goethite rich overburden material at chromite mines is an efficient sink for the chromate anion. Leaching experiments using a saline solution, phosphate solution and tap water showed that phosphate solution release more hexavalent chromium compared to other two solutions. These results can be useful in evaluating natural attenuation of fertilizer-derived pollutants in the agricultural land near chromite mines. From the mineralogy it was found that the laterite contains more goethite mineral compared to other minerals. The concentration of chromium is more in laterite than overburden and soil. The impacts of chromium on the environment depend on the percentage of chromium in exchangeable fraction. The study shows that percentage of chromium is less in exchangeable fraction and more in residual fraction in in the study area. So the Cr bioavailability is low and toxicity is less.