A technology assessment was initiated in March 1979 of the in-situ uranium mining technology. This report explores the impediments to development and deployment of this technology and evaluates the environmental impacts of a generic in-situ facility. The report is divided into the following sections: introduction, technology description, physical environment, institutional and socioeconomic environment, impact assessment, impediments, and conclusions. (DLC).

This report describes the results of a detailed literature review of radionuclide transport models applicable to rivers, estuaries, coastal waters, the Great Lakes, and impoundments. Some representatives sediment transport and water quality models were also reviewed to evaluate if they can be readily adapted to radionuclide transport modeling. The review showed that most available transport models were developed for dissolved radionuclide in rivers. These models include the mechanisms of advection, dispersion, and radionuclide decay. Since the models do not include sediment and radionuclide interactions, they are best suited for simulating short-term radionuclide migration where: (1) radionuclides have small distribution coefficients; (2) sediment concentrations in receiving water bodies are very low. Only 5 of the reviewed models include full sediment and radionuclide interactions: CHMSED developed by Fields; FETRA SERATRA, and TODAM developed by Onishi et al, and a model developed by Shull and Gloyna. The 5 models are applicable to cases where: (1) the distribution coefficient is large; (2) sediment concentrations are high; or (3) long-term migration and accumulation are under consideration. The report also discusses radionuclide absorption/desorption distribution ratios and addresses adsorption/desorption mechanisms and their controlling processes for 25 elements under surface water conditions. These elements are: Am, Sb, C, Ce, Cm, Co, Cr, Cs, Eu, I, Fe, Mn, Np, P, Pu, Pm, Ra, Ru, Sr, Tc, Th, 3H, U, Zn and Zr.

Municipal wastewater treatment plants treat a wide variety of materials originating in the home including detergents, personal care products, and drugs and their metabolites. Environmental risk assessments for these materials include both fate and effects assessments. The fate assessment predicts environment concentrations typically through a series of mathematical models. Depending on the availability of data, assumptions are needed to parameterize these models. To avoid the extreme conservatism resulting from use of multiple conservative assumptions for model input parameters, uncertainty analysis was used to predict distributions for the parameters of interest (i.e., surface water concentrations). Variability predicted in model output more closely resembled environmental data than results of the conventional approach. For effects data, single species acute and chronic toxicity data can be used to construct effects distributions. The risk assessment is defined by the degree of overlap of the fate and effects distributions. C12LAS disposal into surface (i.e., riverine) waters is used as a case study to demonstrate this risk assessment process. The final C12LAS risk assessment demonstrates a low risk to environmental organisms of effects due to C12LAS exposure in riverine systems in the United States.