FINAL SITE INSPECTION REPORT

9139149159169179189199209219229239249259269279289299309319324.4.3.1 Comparison to BackgroundComparison of metals analytical results from well 008 to the local background (well 120)from 2005, indicates that the iron concentration from well 008 of 50 g/L exceeded the threetimes background criteria of less than 10 g/L. This indicates that a significant exceedance ofbackground has occurred. Note that PGE does not monitor for molybdenum and nickel and noevaluation of these two analytes of concern can be completed.During the PA/SI, groundwater samples were collected in the vicinity of Target No. 1 (wells 008and 120) and analyzed for explosives and perchlorate. No explosive compounds were detected.Perchlorate was detected in the local upgradient well 120 at a concentration of 3.56 g/L. Thisconcentration is far lower than the DoD action level of 24 g/L. Perchlorate was not detected inthe downgradient well 008.4.4.3.2 Comparison to Human Health Screening ValuesComparison to human health screening levels is only completed for those analytes thatsignificantly exceed the background concentration. Iron was the only metal to be significantlydetected (greater than three times background) above background at a concentration of 50 g/L.This concentration is below the human health screening value of 11,000 g/L.4.4.4 Air PathwayAir is considered to be a potential pathway due to inhalation of MC in from blowing dust. Thepotential inhalation of soil particles is included in the development of health-based screeningvalues for soil.Boardman AFR Final SI Report.doc 4-5 Contract No. W912DY-04-D-0010 Delivery Order No. 003September 2007