Sampling for Explosives Residues at Fort Greely, Alaska. Reconnaissance Visit July 2000.

摘要

Impact areas are lands used by the army for ordnance testing and training. The impact areas of Fort Greely, Alaska, are located on lands withdrawn from the public domain under the Military Lands Withdrawal Act (PL 106-65). The Army has pledged to implement a program to identify possible munitions contamination and evaluate the potential for surface water and groundwater contamination. Because of the large size (85,042 acres) of the impact areas, characterization of the contamination levels will be difficult. We have begun a multiphase sampling program at one impact area by first sampling locations that are likely to be contaminated and to identify locations that have the greatest potential to contaminate adjacent surface and groundwater. Based on a review of records at the Fort Greely Range Control and consultation with the Cold Regions Test Center (CRTC), we chose to sample the Washington Impact Area. We focused our sampling on surface soils and collected both composite (multi- increment) and discrete samples at locations of known firing events and from areas on the range that had evidence of range use. Evidence included cratering, pieces of munitions, or a designation as a firing point. Firing events included tests of 81-mm mortars, Tube-launched Optically tracked Wire-guided (TOW) missiles, 40-mm high-explosive cartridges, and Sense and Destroy Armor (SADARM). We detected explosives residue in 48% of the 107 soil samples we collected. RDX was the most frequently detected explosive (39%). Of the samples above the detection limit, median RDX concentration was only 0.021 microg/g. Low-order detonations accounted for four of the five highest RDX concentrations. TNT was the second most frequently detected explosive (21%). Median TNT concentration in samples where TNT was detected was only 0.004 microg/g. Low-order detonations produced the highest TNT concentration products of TNT were detected in about 10% of the samples.