The Marine Corps Air Station is located in the Coastal Plain province of North Carolina. Four freshwater aquifers of sand and limestone underlie the area to a depth of about 500 feet. Saline water occurs below this depth. The aquifers are separated by three confining units that are thin and discontinuous in the southern part. Water supply is obtained from 195- to 330 feet wells in the Castle Hayne aquifer. Many wells are near landfills that have received hazardous wastes. Groundwater withdrawals have reduced hydraulic heads in the Castle Hayne some 20 feet around active production wells, creating potential for downward movement of contaminated water from the surface and for upward movement of saline water that occurs at depth. Chemical analyses of water from the Castle Hayne aquifer indicate median concentrations of iron and manganese are 0.78 and 0.08 milligrams per liter, respectively, and lead and (or) nickel exceed drinking water standards in three wells. Chloride increased from 10 to more than 40 milligrams per liter in the deepest operating well over a 45-year period. Benzene concentrations range from 0.5 to 1.9 milligrams per liter in the southern part of the Air Station but were below the 5 milligrams per liter maximum contaminant level for drinking water. Fatty acids were found in concentrations as much as 28 micrograms per liter in water from wells in an area centered around the intersection of Roosevelt Boulevard and Slocum Road. Resampling is needed to verify all constituents that indicate contamination.
