Hydrogeologic and water-quality data from well clusters near the wastewater-treatment plant, U.S. Marine Corps Air Station, Cherry Point, North Carolina

Abstract

Hydrogeologic and groundwater quality data were collected near the wastewater-treatment plant and associated polishing lagoons at the Marine Corps Air Station, Cherry Point, North Carolina, in 1988. Between March and May 1988, two observation wells were installed upgradient and six wells were installed downgradient of the polishing lagoons and sampled for organic and inorganic U.S. Environmental Protection Agency priority pollutants. Placement of the well screens allowed sampling from both the upper and lower parts of the surficial aquifer. Natural gamma-ray geophysical logs were run in the four deepest wells. Lithologic logs were prepared from split-spoon samples collected during the drilling operations. Laboratory hydraulic conductivity tests were conducted on samples of fine-grained material recovered from the two confining units that separate the surficial aquifer and the drinking-water supply aquifer; values ranged from 0.011 to 0.014 foot per day (4xlO~6 to 5xlO~6 centimeters per second). Static water levels were recorded on April 25, 1988. Relatively low concentrations of purgeable organic compounds (up to 2.2 micrograms per liter for dichlorodifluoromethane), acid and base/neutral extractable compounds (up to 58 micrograms per liter for bis(2-ethylhexyl) phthalate), or pesticides (up to 0.03 micrograms per liter for diazinon and methyl parathion) were detected in water samples collected from all of the wells. Trace metals were detected in concentrations above minimum detectable limits in all of the wells and were found to be higher in water samples collected from the downgradient wells (up to 320 micrograms per liter for zinc) than in water samples from the upgradient wells.

Application of geophysical methods to the delineation of paleochannels and missing confining units above the Castle Hayne aquifer at U.S. Marine Corps Air Station, Cherry Point, North Carolina

“…They recognized that the confining units between the surficial, Yorktown, and Castle Hayne aquifers are thin and(or) discontinuous beneath the southern part of the Air Station and that contamination of supply wells in this area was probably related to downward movement of contaminants from the surficial aquifer through' more permeable sediments above the Castle Hayne aquifer. Murray and Daniel (1990) present hydrogeologic and water-quality data collected from four well clusters within the area of the wastewatertreatment plant and adjacent polishing lagoons. The data include lithologic descriptions, geophysical logs, water levels, laboratory tests for hydraulic conductivity, grain-size analysis, and results of waterquality analyses.…”

Hydrogeology and simulation of ground-water flow at U.S. Marine Corps Air Station, Cherry Point, North Carolina, 1987-90

“…Emphasis is on the western half of the Air Station where the greatest number of water-supply wells and historical wastedisposal and spill sites are located. Murray and Daniel (1990) present hydrogeologic and water-quality data collected within the area of the waste water-treatment plant and adjacent polishing lagoons. The data, collected from four well clusters, include lithologic descriptions, geophysical logs, water levels, laboratory tests for hydraulic conductivity, grainsize analysis, and results of water-quality analyses.…”

“…The paleochannel could coincide with a known waste disposal or spill site in the southwestern part of the Air Station (Murray and Daniel, 1990). At present, the direction of ground-water flow, based on hydraulic-head data, is upward in the paleochannel area (Murray and Keoughan, 1990).…”

“…The U.S. Geological Survey has cooperated with the Cherry Point Marine Corps Air Station since 1985 in an investigation to evaluate ground-water resources at the Air Station. Lloyd and Daniel (1988), Murray and Daniel (1990), and Murray and Keoughan (1990) describe the quality of ground-water being pumped from the Air Station wells that tap the Castle Hayne aquifer and the potential for contamination of the aquifer by hazardous and toxic chemicals that are present at various surface disposal sites.…”