GEOCHEMISTRY AND FLOW STRUCTURE OF CONTAMINATED SUBSURFACE WATERS IN FISSURED BEDROCK OF THE LAKE KARACHAI AREA, SOUTHERN URALS, RUSSIA

摘要

Hydrogeochemical investigations of natural and contaminated subsurface waters were carried out in 1992-1994 at the area of surface storage of liquid radioactive waste (RAW) of the Radiochemical plant of the Amalgamated Industrial (AI) "Mayak". The water-bearing horizon in fissured volcanogenic rocks was penetrated by uncased observation wells that allowed the use of hydrogeochemical logging. The hardware for the logging includes the hydrogeochemical probe, eight channels of which constantly measure T, P, electric conductivity (E), pH, Eh, concentrations of dissolved oxygen (O{sub}2), Na, and NO{sup}3 in the wells. This technique allowed us to simulate the natural hydrogeochemical setting in the RAW storage area, to delineate anomalies of contaminated waters of different origin, to evaluate the role of radiolitic processes in the formation of chemical compositions of technogenic solutions, to study the chemical composition and physico-chemical properties of sodium nitrate brines, associated with RAW storage, and to propose a conceptual model for the flow structure of the contaminated subsurface waters.