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.