SPRING VALLEY OU-5 - Proposed Sampling Plan Page 2 of 5 shall be located in an area containing fill. If possible, the location of the boring shall also be located in an area identified as a ground scar/stressed vegetation. The depth of the boring will be based on the cut and fill map developed for the AUES. For properties containing fill material, the boring will be conducted to 2 feet beyond fill (to a maximum of 10 feet). For properties containing only 1918 level or areas of cut, the boring will be conducted to 6 feet below ground surface (bgs). Samples will be collected from each 1-foot level and analyzed for arsenic. Samples will be collected at 1-foot intervals and analyzed for arsenic. • Samples will be collected at 1918 level. For properties containing only the 1918 level or areas of cut, the samples will be collected from 1 to 2 feet bgs. The samples will be analyzed for the following parameters: • Mustard • Mustard ABPs (Oxithiane, Dithiane, Thiodyglycol) ♦POIS 15R and 16R (CTA) Documentation indicates POIs 15R and 16R (R refers to revised boundary) were chemical persistency test areas that consisted of applying chemicals to evaluate their persistency. Chemicals that were used at POIS 15R and 16R are identified in Mark Baker's memorandum dated 27 September 1993. These chemicals documented to have been used at POIs 15R and 16R are considered the PCOCs and will be analyzed for at POIs 15R and 16R. • Surface soil (quadrant sampling) analyzed for arsenic. • Subsurface samples will be collected from one boring per property. If possible, the location of the boring shall also be located in an area identified as a ground scar/stressed vegetation. The depth of the boring will be based on the cut and fill map developed for the AUES. For properties containing fill material, the boring will be conducted to 2 feet beyond fill (to a maximum of 10 feet). For properties containing only 1918 level or areas of cut, the boring will be conducted to 6 feet below ground surface (bgs). Samples will be collected from each 1-foot level and analyzed for arsenic. Samples will be collected at 1-foot intervals and analyzed for arsenic. Samples will be collected at 1918 level. For properties containing only the 1918 level or areas of cut, the samples will be collected from 1 to 2 feet bgs. For POI 15R, these samples will be collected in the subsurface boring conducted for each property within the boundaries of the POI. For POI 16R, these samples will be collected in a subsurface boring conducted for at the center of each patch used for persistency testing as documented from aerial photography. The samples will be analyzed for the following parameters: SPRING VALLEY OU-5 - Proposed Sampling Plan Page 3 of 5 Documentation indicates POI 7 was test area used for agent persistence. Documentation indicates PO[ 13 was a circular trench used as a static test fire area. The chemicals used at POI 13 were identified in Mark Baker's memorandum dated 27 September 1993. Documentation indicates POI 39 was a static test fire area. In addition, chemicals used at unknown locations on test range were also identified in this memorandum. These chemicals documented to have been used at POI 13 and the unknown test range locations are considered the PCOCs and will be analyzed for at POIs 7, 13, and 39. • Surface soil (quadrant sampling) analyzed for arsenic, tetryl, nitroglycerin, 2,4-DNT, and 2,6DNT, and nitrobenzene. • Subsurface samples will be collected from one boring per property. If possible, the location of the boring shall also be located in an area identified as a ground scar/stressed vegetation. The depth of the boring will be based on the cut and fill map developed for the AUES. For properties containing fill material, the boring will be conducted to 2 feet beyond fill (to a maximum of 10 feet). For properties containing only 1918 level or areas of cut, the boring will be conducted to 6 feet below ground surface (bgs). Samples will be collected from each 1-foot level and analyzed for arsenic. Samples will be collected at 1-foot intervals and analyzed for arsenic. • For POIs 7 and 39, samples will be collected at 1918 level. For properties containing only the 1918 level or areas of cut, the samples will be collected from 1 to 2 feet bgs. These samples will be collected in the subsurface boring conducted for each property within the boundaries of the POI. • Trench Subsurface soil. For POI 13, four borings collected from the bottom of the trench and staggered for the inner and outer trenches similar to Sedgwick trench borings. A subsurface sample will be collected from the bottom of the trench in these borings. • These subsurface samples at POIs 7, 39, and 13 will be collected and analyzed for the following parameters: Documentation indicates POI 38 was a test area where shells were fired. The chemicals used at POI 38 were identified in Mark Baker's memorandum dated 27 September 1993. The chemicals documented to have been used at POI 38 are considered the PCOCs and will be analyzed for at POI 38. • Surface soil (quadrant sampling) analyzed for arsenic, tetryl, nitroglycerin, 2,4-DNT, and 2,6DNT, and nitrobenzene. • Subsurface samples will be collected from one boring per property. If possible, the location of the http://www.nab.usace.army.mil/projects/WashingtonDC/springvalley/SSP/finalSSP.htm 8/31/01 SPRING VALLEY OU-5 - Proposed Sampling Plan Page 4 of 5 boring shall also be located in an area identified as a ground scar/stressed vegetation. The depth of the boring will be based on the cut and fill map developed for the American University Experiment Station (AUES). For properties containing fill material, the boring will be conducted to 2 feet beyond fill (to a maximum of 10 feet). For properties containing only 1918 level or areas of cut, the boring will be conducted to 6 feet below ground surface (bgs). Samples will be collected from each 1-foot level and analyzed for arsenic. Samples will be collected at 1-foot intervals and analyzed for arsenic. • Samples will be collected at 1918 level. For properties containing only the 1918 level or areas of cut, the samples will be collected from 1 to 2 feet bgs. The samples will be analyzed for the following parameters: Spring Valley Formerly Used Defense Site 3.) What levels of arsenic were found in the initial stages of the investigation? What levels are being found now? During the original investigation in Spring Valley, conducted from 1993 to 1995, the Corps' soil sampling efforts primarily focused on chemical warfare agents, explosives, and their breakdown products. Because arsenic is so ubiquitous, the decision made at the time was to concentrate our efforts on more specific chemical indicators that could be more confidently linked with chemical warfare materiel. Although we did take a limited number of samples for arsenic, none of these sample results was outside the range of what would be considered "background" for this area (3 to 18 parts per million). Of the 260 soil samples collected by the Corps, 136 were "split" with the Environmental Protection Agency (EPA), allowing them to sample for other contaminants. EPA analyzed each of these split samples for a different suite of contaminants, which included arsenic. They also collected a limited number of independent samples. Most of EPA's sampling results indicated arsenic levels below 17 parts per million, which would generally be considered to be within background levels. Higher levels were detected in a few isolated samples, with the highest being 241 parts per million. However, environmental risk assessments conducted on these results did not indicate a need for further evaluation. Starting in 1999, in concert with the Corps' new investigation of the burial pit at 4801 Glenbrook Road, EPA collected additional soil samples in the vicinity of the burial pit. One of these samples detected elevated levels of arsenic, and as a result the Corps conducted more extensive sampling at the 4801, 4825, and 4835 Glenbrook Road properties. These results ranged as high as 1,040 parts per million near the burial pit. The risk assessment for these sample results indicated a need for a response action, which is now underway. As a result of the findings on the Glenbrook Road properties, in 2000 the Corps expanded its arsenic sampling to include private residences in the vicinity of the Glenbrook Road properties, as well as the southern half of the American University campus. This round of sampling found arsenic concentrations ranging from non-detect to 101 parts per million, and indicated that ten properties required additional sampling and evaluation. The Corps is currently conducting a risk assessment at these properties. On May 31, 2001, the Corps began its current effort to sample every property within the Spring Valley formerly used defense site. This includes approximately 1,200 residential properties and 400 non-residential lots. The Corps has results for approximately 550 of these properties as of August 27, 2001, and approximately 12% of these properties have results above our screening threshold of 12.6 parts per million, indicating additional evaluation is recommended. |