In view of the possible need for disposal of low-level radioactive waste in Delaware under the Nuclear Waste Policy Act of 1982, the Delaware Geological Survey has prepared this report to assist the citizens of our State in understanding this complex subject. Emphasis here is on geologic and hydrologic aspects of disposal. Health, social, and economic factors are outside the scope of this report and are not discussed. However, they are very important integral parts of the safe disposal of low-level radioactive waste, and must be considered when selecting suitable disposal sites.
In the United States more than 3.5 billion tons of solid waste are generated annually. Of this, more than 2 billion tons are agricultural waste, such as manure and crop waste. Almost 300 million tons are generated by commercial and industrial activities and municipalities, and another 1.1 billion tons are attributed to various mining operations (Vaughan, 1969). Increasing amounts of solid waste have had detrimental effects on environmental quality. It has become necessary to reprocess and reuse some, and to provide safe and environmentally acceptable ways of disposing of the remaining waste in properly constructed landfills. Pollution brought about by improperly constructed landfills may be very severe. For example, the contaminants generated by the waste at the old, abandoned Army Creek Landfill, New Castle County, Delaware, were so widespread that the situation received national attention. General and sincere concern expressed by many citizens of our State has prompted the Delaware Geological Survey to prepare this report. The report explains the functioning of a landfill, problems improperly constructed landfills may cause, and the geologic and hydrologic aspects that have to be considered in selecting a suitable disposal site for solid waste. The report does not contain discussions of other important factors, such as social impact, transportation, and specific health hazards, that must also be considered.
This report was prepared to provide a simple but comprehensive overview of programs and concepts of highly radioactive waste disposal. This report is not based on original research, but was prepared from data and information reported in voluminous publications of the U.S. Department of Energy, the Nuclear Regulatory Commission, the U.S. Environmental Protection Agency, and the U.S. Geological Survey.
OFR5 Removal of Metallic Contaminants from Industrial Waste Waters by the Use of Greensands, A Preliminary Report
The Delaware Geological Survey, in cooperation with the U. S. Bureau of Mines, has investigated glauconite-bearing greensand deposits in Delaware for several years. The purpose of this effort is to find possible practical uses for this potentially important mineral resource. This report briefly describes the preliminary results of one phase of the study: application of greensands to the purification of industrial waste waters.
Inspection of water analyses on file at the Delaware Geological Survey revealed that 25 percent of the shallow wells yield water with nitrate concentrations approaching or in excess of the Delaware State Board of Health and U. S. Public Health Service limit of 45 parts per million (ppm). Nitrate concentrations greater than 45 ppm seem to be detrimental to the health of infants during their first few months of life; adults drinking the same water are not affected but breast-fed infants of mothers drinking such water may become ill. The illness ("blue baby sickness" or methemoglobinemia) results from the conversion of nitrate to nitrite by nitrite-forming bacteria in the upper part of the digestive tract of some infants and the further conversion of hemoglobin to methemoglobin which is incapable of transporting oxygen; the result is oxygen starvation. Little is known about the low level effect of undetected methemoglobinemia on infants.
Distilled water spiked with heavy metal cations was passed at a rate of 2-4 ml/min through a filter composed of greensand containing about 80 percent glauconite. The capability of the greensand to trap metal cations is increased by prolonging the contact time between the leachate and the greensand. Flushing the charged greensand filter with water does not cause significant release of cations back into solution, suggesting that polluted greensand might be disposed in landfills without adding pollutants to either ground or surface water in the vicinity.
OFR35 Estimate of Nitrate Flux to Rehoboth and Indian River Bays, Delaware, through Direct Discharge of Ground Water
Agricultural fertilizer application, animal (poultry) waste, and wastewater disposal practices of the past 40 years have resulted in widespread nitrate contamination of ground water in coastal Sussex County, Delaware. Discharge of contaminated ground water to Rehoboth and Indian River bays is suspected of being a significant contributor to elevated nutrient concentrations in these surface water bodies, resulting in excessive phytoplankton growth and other related problems.
OFR30 Evaluation of Remote Sensing and Surface Geophysical Methods for Locating Underground Storage Tanks
Delaware Code, Title 7, Chapter 74, Section 7415 states in part: "The Delaware Geological Survey shall investigate the feasibility of utilizing aerial photographs and other new advanced techniques for locating abandoned tanks." In response to this charge, the Delaware Geological Survey has completed a survey of currently available remote sensing and geophysical tools to determine which methods may be utilized to locate underground storage tanks. Limited preliminary field testing has been performed.
This poster shows three different map views of the water table as well as information about how the maps were made, how the depth to water table changes with seasons and climate, and how the water table affects use and disposal of water. The map views are of depth to the water table, water-table elevation (similar to topography), and water-table gradient (related to water flow velocity).
The increasing population of the State of Delaware is placing severe strains on the quality of ground water in the water-table aquifer by disposing of septic-tank effluent in the soil. At the same time the water resources of this aquifer are being used in greater amounts. The permeable water-table aquifer, containing reserves of 331 million gallons per day, is very vulnerable to contamination by objectionable or toxic fluids and dissolved substances placed on or in the soil.
Forty-eight samples of Delaware clays were collected and tested jointly by the Delaware Geological Survey and the U. S. Bureau of Mines. Clays potentially useful for face brick are common. The nonmarine Cretaceous Potomac Formation is a potential economic clay at virtually all locations sampled. Some Miocene and Pleistocene clays are also possibilities for brick clays. Other Potomac clays are potential sources for glazed tile, sewer pipe, refractory brick, and stoneware. Coastal marsh clays, frequently containing much organic debris, are potential source material for lightweight aggregate used in lightweight, strong concrete products. Lightweight aggregate has the potential for augmenting dwindling reserves of crushed stone and gravel aggregate.