Processes Governing Chromium Contamination of Groundwater and Soil from a Chromium Waste Source

Chromium (Cr) contamination of natural resources from unregulated disposal of pretanning industrial waste, chromite ore processing residue (COPR), is a serious environmental concern, especially in developing countries. Although there have been studies on COPR characterization, the fate and transport of chromium emanating from COPR remains poorly understood. In this study, processes governing Cr contamination in groundwater and soil near known COPR disposal sites were investigated. Field sampling of groundwater, irrigated soil, and COPR was conducted near Kanpur (India) to identify the extent and forms of chromium contamination. Both dissolved and suspended fractions of groundwater were analyzed to evaluate the presence of any Cr-containing colloids. At certain locations with elevated Cr levels, the saturation state of sampled groundwater was evaluated to be near equilibrium with respect to BaCrO4(s) through speciation modeling of wet chemical data. Colloidal forms of Cr, such as BaCrO4(s) or as Cr adsorbe...