Year
1989
Abstract
An 88,000-m2 industrial waste storage site is located within the metropolitan area in the midwest. The land surrounding the site is used heavily for transportation, recreation, and industrial activities. Concern for groundwater contamination underneath the existing storage site has been a major issue for many years.The site was operated between 1946 and 1966 to store waste residues and scrap materials during uranium processing operations. In 1984, the U.S. government proposed to use the storage site for long-term management of radioactive materials. To evaluate the effectiveness of each remedial action alternative, analysis of radionuclide transport in the existing groundwater system is undertaken.A three-dimensional solute transport model is used to predict radionuclide migration in the groundwater system. Transport mechanisms included in formulating the governing equation are: advection, hydrodynamic dispersion, chemical sorption, and radioactive transformation. The model calculates groundwater concentrations over a time period of 10,000 years for two major critical radionuclides (radium-226 and uranium- 238) in the wastes that could pose a threat to the public health. The model simulations indicate that the spatial distributions of the radionuclide concentrations are limited to only the areas beneath the bottom of the waste. The predicted maximum radium-226 and uranium-238 concentrations in the nearby off-site well water are 0.3 and 4.5 pCi/L, respectively. The consequent health risks from ingestion of contaminated groundwater for nearby individuals are also evaluated.