FINAL SITE INSPECTION REPORT

15251526152715281529153015311532153315341535153615371538153915401541154215431544154515461547154815491550155115521553155415551556155715581559Access to the Impact Area is restricted by locked gates and fences. Access is controlled by TheNature Conservancy.The MEC risk for the Impact Area AOC is low. This assessment is based on: No MEC has been reported at this AOC; No observed accumulations of MD during the SI. However, an employee of The NatureConservancy stated that he has observed MD at the AOC; Munitions assumed to have been used at the Impact Area contain no sensitive explosivecomponents; Access to area is only through locked gates.9.4 Munitions Constituents EvaluationPotential MC at the Impact Area includes metals associated with steel, sheet metal, paint, andother components of munitions metals (chromium, copper, iron, lead, molybdenum, and nickel)from bomb bodies. Black powder was the explosive most likely used; however, other explosiveswere possibly used. Perchlorate was not identified as a potential MC at the Impact Area.Nonetheless, discussion of perchlorate analytical results from groundwater samples collectedduring the PA/SI is included in the following evaluation for completeness.9.4.1 Terrestrial PathwayTerrestrial receptors may be exposed to MC because soil may have been directly affected by thecorrosion of metals from the bomb bodies or explosives used. One surface soil sample (NWO-030-0012) was proposed and collected from the Impact Area. The samples were analyzed forselect metals (chromium, copper, iron, lead, mercury, molybdenum, and nickel) by EPA Method6020A. In addition, samples were analyzed for aluminum and manganese for potential use inevaluating naturally occurring concentrations of metals in soil using the method of Myers andThorbjornsen (2004). The two samples from the Demolition Area were also analyzed forexplosives including nitroglycerin by EPA SW-846 Method 8330A (Table 3-1). The samplelocation and results are shown on Figures 9-2 and 9-3).9.4.1.1 Comparison to Background DataDetected metals were compared to background soil concentrations (Table 9-1). There were noexceedances of background soil concentrations.9.4.1.2 Comparison to Human Health Screening ValuesSoil analytical results are only compared to human health screening values if backgroundconcentrations are exceeded. Because there were no exceedances of background concentrations,no comparison has been completed for this SI.9.4.1.3 Comparison to Ecological Screening ValuesSoil analytical results are only compared to ecological screening values if backgroundBoardman AFR Final SI Report.doc 9-2 Contract No. W912DY-04-D-0010 Delivery Order No. 003September 2007