Caption title. At head of title: Project summary. Distributed to depository libraries in microfiche. "July 1987." Includes bibliographical references (page 5). "EPA/600-S8-87-013."

About 11 percent of all hazardous wastes are disposed of by Injection wells Into deep subsurface environments. Some 250 of these Class I wells are in the United States, and their record of performance is good. Provisions of the Resource Conservation and Recovery Act (RCRA) require that by 1988 the Environmental Protection Agency (EPA) must show that the disposal of specified wastes is safe to human health and the environment, or discontinue the practice of deep- well injection of hazardous wastes. These provisions necessitate knowing the long-term fate of these wastes in the injection zones. A survey of the literature shows that some information is available on nearly all potential chemical and biological transformation processes of hazardous wastes. The literature survey also indicates that additional research is needed in all areas of abiotic and biotic waste interactions. before definitive explanations can be given on the long-term fate of hazardous wastes. Usually, the first experimental test is the fluid-fluid test of the waste's compatibility with the formation fluids. However, research shows that this simple test is not always adequate for determining the interaction of injected wastes with the subsurface environment Among the many factors affecting the ultimate fate of injected wastes are the pH-Eh of the waste and reservoir fluids, brine concentration of the waste fluids, clay type and amount In the reservoir, presence or absence of iron oxides, presence or absence of organic complexing agents, molecular characteristics of organic materials, and the anaerobic or aerobic nature of the environment Since all of these factors are interrelated, any mixing of different types of hazardous wastes in the reservoir further complicates the situation, making it difficult to predict exactly the action or fate of wastes after their injection. Only limited relevant research has been conducted to date, and the results are insufficient to adequately address this problem. The National Institute for Petroleum and Energy Research staff conducted research in partial fulfillment of Contract Number DW89931947-01-0 under the sponsorship of the U.S. Environmental Protection Agency. The report covers the contract period from May 1, 1986, to December 15, 1986, and the work was completed as of December 15, 1986.