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A field reconnaissance was carried out in March 1983. Members of the party included engineers and chemists from the Water Resources Division and seismologists and volcanologists from the Survey's Geologic Division. Water samples were collected from many sources, and gas and vapor samples were collected at the volcano. Instruments were installed to collect and transmit data on rainfall and seismic events directly to the Honolulu District Office via the GOES satellite. Results of this work will determine whether or not the water supply is potable and may give some indication of trends in volcanic activity.

effort to determine the areal extent of the tritium plume, the source of the tritium, and the nature of the release. One migration pathway has been identified along a buried sand-and-gravel-filled channel, and tritium is discharging through seeps to the strip-mine pond. Detailed information obtained from the test wells suggests that other pathways may also be present.

New Mexico: Unexpected Results of Streamflow and Ground-Water Investigations

Sheffield, Illinois: Ground-Water Flow and Tritium Migration From the Sheffield LowLevel Radioactive Waste Site

Sheffield, near Chicago, which was one of six commercial low-level radioactive waste disposal sites in the United States, is being studied by the Geological Survey to develop geohydrologic expertise to be included in criteria for future site selection under the Low-Level Waste Policy Act of 1980. A pebbly-sand unit underlying 67 percent of the site in Illinois extends to a strip-mine pond located about 2,000 feet northeast of the nearest waste trench. As part of a study of the hydrogeology east of the site, a number of test wells were constructed. Seventy-eight nanocuries of tritium per liter were detected in water samples from two of these wells located a few hundred feet east of the boundary of the site. (Nuclear Regulatory Commission regulations allow a maximum permissible concentration of 3,000 nanocuries of tritium per liter for release into water.)

In a cooperative investigation with the Illinois Department of Nuclear Safety, an additional 20 wells have been drilled in an

Results of investigations describing streamflow in the Pecos River, in cooperation with the Pecos River Commission, and ground-water conditions in the Albuquerque-Belen basin, in cooperation with the New Mexico Environmental Improvement Division and the city of Albuquerque, show that previous concepts associated with these hydrologic systems may need to be revised.

Studies of the Pecos River between Artesia and Carlsbad indicate that, in the last several years, base flow has not increased as much as expected after the area was cleared of phreatophytes (salt cedar). Base flow was projected to increase about 1 acre-foot per acre, but analysis of streamflow records reveal only about one-fourth that amount.

In the Albuquerque-Belen basin, reconnaissance investigations of ground water quality have detected unexpected concentrations of organic chemicals, and one municipal well has been shut down as a result of the sampling program. In addition, water-level measurements have determined that ground-water movement is in a direction away from the Rio Grande toward the eastern border of the basin, and movement of contaminants, therefore, may be in a direction opposite to that originally thought.

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the concept of isolating nuclear wastes by means of relatively independent multiple barriers to waste nuclide migration. A major requirement is to identify environments where such multiple natural barriers are believed to exist. A second major requirement is to identify and understand the critical hydrogeologic properties and processes that are involved in radionuclide migration from a repository to environments of living organisms.

The Comprehensive Nuclear Waste Policy Act of 1982 defines the timetable and responsibility of the Department of Energy in selecting the first and second repositories. As specified in the Act, the Survey program is designed to provide consultation and support to the Department of Energy to accomplish this national mission, which includes selecting the first repository site in 1987 and burial of wastes by 1998.

There are six commercial low-level waste sites in the United States. Three are closed, due wholly or in part to environmental concerns, and a fourth closure is being contested in the courts. Provisions of the Low-Level Radioactive Waste Policy Act of 1980 may result in the establishment of as many as eight new commercial sites by 1990. In addition to these commercial sites, the Department of Energy operates six major and a number of minor low-level waste disposal sites for government-generated waste.

Low-level radioactive waste can pose a threat to human health if contaminants migrate from shallow land-burial sites in concentrations exceeding accepted standards. The principal migration pathway is generally ground water. The objective of the Survey program that addresses this problem is to gain a better understanding of the geohydrologic controls on the migration of radionuclides from shallow land-burial sites. To accomplish this objective, the Geological Survey has been conducting field research studies at five commercial and three Department of Energy disposal sites. Basic research complements the field investigations. Final reports on the first phase of field studies at commercial sites were published in 1983. These and other reports on earth science aspects of low-level radioactive waste disposal will be essential information for individual States or multi-State low-level waste compacts as

Low-Level Radioactive Waste

Low-level radioactive waste is produced by hospital, research and industrial facilities, and nonfuel-related activities of nuclear-reactor operation. It is generally much less radioactive than the high-level wastes, as its characterization implies, and does not generate significant amounts of heat in its decay. Disposal in this country is by shallow land burial, although ocean dumping has occurred in the past.

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tion with earth-science information necessary to improve waste-disposal practices and to help solve existing and future ground-water contamination problems. The program uses the data bases and experiences of previous Survey work that are specifically relevant to the problem. It is closely coordinated with related programs of Radioactive-Waste Disposal, Regional Aquifer Systems Analyses projects, the Federal-State Cooperative Program, and studies of glacial deposits in the Eastern United States.

The program includes both field and laboratory investigations. Long-term research programs have been established at locations of known ground-water contamination to determine the behavior of specific contaminants in the ground-water system and to develop techniques with which to study them; these sites are near Bemidji, Minnesota, Pensacola, Florida, and Cape Cod, Massachusetts. This research is complemented by investigations of other field problems related to the reliability of predic

tive models and monitoring strategies for contamination. Geological Survey scientists have begun an appraisal of national ground-water quality to determine the magnitude and trends of the contamination problem. The appraisal is being closely coordinated with State governments.

Technical information developed within each element of the hazardous-waste program is incorporated into other elements of the program. Other Survey programs such as Regional Aquifer Systems Analyses and core research provide additional technical information and support. An early dividend of this coordination has been major support to the Department of Energy, the U.S. Nuclear Regulatory Commission, and State government agencies in the development of waste-disposal siting criteria. This comprehensive approach to solving earth science related problems of hazardous waste disposal places the U.S. Geological Survey in a position to continue contributing highly useful earth science information on this major national issue.

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