Modeling of heavy metal contamination within an irrigated area

Leaching of exposed rocks associated with the Madneuli complex ore deposit and direct discharge of mine waters to nearby watercourses are attributed to the heavy metal contamination of ground and surface water. Human-health issues may exist for two reasons. First, contaminated surface water, such as the Kazretula, Poladauri and Mashavera Rivers, is diverted to agricultural fields through a network of irrigation channels. Second, the Bolnisi Kvemo and Bolnisi villages derive their water supply from wells drilled into alluvial deposits of the Poladauri River. Field and laboratory investigations were carried out to understand the water quality of this area. Geophysical prospecting by electrical and seismic methods was used in the Poladauri valley to establish the intensity and direction of ground water flow. The results of sampling and analysis of surface and ground water, soil, and vegetables were used to assess the extent and character of metal contamination. Using the GIS-technology, thematic maps were used to create 3-dimensional models to visualize the geological-hydrogeological and geochemical structure of the region and identify likely pathways of contamination. Geochemical and transport modeling indicates that the present-day maximum contaminant levels will eventually reach the total investigation area posing health risks to the local population.