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SITE CHARACTERIZATION OF A CHROMIUM SOURCE AREA AT THE USGS SUPPORT CENTER, ELIZABETH CITY, NC
Citation:
Paul*, C J., F A. Khan*, AND R W. Puls*. SITE CHARACTERIZATION OF A CHROMIUM SOURCE AREA AT THE USGS SUPPORT CENTER, ELIZABETH CITY, NC. Presented at Intl. Groundwater Symposium, IAHR, Berkeley, CA, 03/25-28/2002.
Description:
Chromic and sulfuric acid wastes had discharged through a hole in the concrete floor of a chrome-plating shop located within a hangar at the U.S. Coast Guard Support Center near Elizabeth City, North Carolina and infiltrated the soils and groundwater beneath the shop. Following initial site characterization conducted by the National Risk Management Research Laboratory, United States Environmental Protection Agency, in 1990 and 1991, it was hypothesized that chromium in the soils would remain immobile and would not present potential risk; therefore, initial efforts were focused on treating the diffuse chromium plume moving toward the Pasquotank River. However, a water-main break occurred in the immediate vicinity of the chrome-plating shop in 1994. The subsequent release of large amounts of water into the soils beneath the shop resulted in desorption of the soluble Cr(VI) and its redistribution throughout the underlying soils.
In an effort to re-characterize the extent of chromium contamination, soil cores were collected from 32 locations beneath the shop. The cores were cut into six-inch intervals, resulting in more than 500 discrete samples for vertical and horizontal delineation of the chromium. Selective extractions were performed in the laboratory to assess the chemical speciation and distribution of the chromium on the soils and its mobilization potential. The highest concentrations of total chromium and Cr(VI) (10,436 and 625 mg/Kg, respectively) were found in the shallow soils immediately beneath the area of the shop where chromic acid tanks had been located.
This is an abstract of a proposed presentation and does not necessarily reflect EPA policy.