FINAL SITE INSPECTION REPORT

156015611562156315641565156615671568156915701571157215731574157515761577157815791580158115821583158415851586158715881589159015911592159315941595concentrations are exceeded. Because there were no exceedances of background concentrations,no comparison has been completed for this SI.9.4.2 Surface Water PathwayThe surface water pathway at Boardman AFR is evaluated through sediments. The potentialreceptors for sediments are conservation area workers and wildlife. One sediment sample(NWO-030-1002) was proposed from this AOC (Figures 9-2 and 9-3). The sediment samplewas analyzed for select metals (chromium, copper, iron, lead, mercury, molybdenum, and nickel)by EPA Method 6020A. In addition, aluminum and manganese were analyzed as they may beuseful in evaluating naturally occurring concentrations of metals in soil using the method ofMyers and Thorbjornsen (2004). The sediment sample was also analyzed for explosivesincluding nitroglycerin by EPA SW-846 Method 8330A (Table 3-1).9.4.2.1 Comparison to Background DataThe detected metals concentrations in sediment are listed on Table 9-2. There were nosignificant exceedances (greater than three times maximum background concentration) of the SIbackground sediment concentrations. No explosive compounds were detected.9.4.2.2 Comparison to Human Health Screening ValuesSediment analytical results are only compared to human health screening values if backgroundconcentrations are significantly exceeded. Because there were no significant exceedances ofbackground concentrations, no comparison has been completed for this SI.9.4.2.3 Comparison to Ecological Screening ValuesSediment analytical results are only compared to ecological screening values if backgroundconcentrations are significantly exceeded. Because there were no significant exceedances ofbackground concentrations, no comparison has been completed for this SI.9.4.3 Groundwater PathwayThe TPP Memorandum indicated that groundwater was a potentially affected media, withpotential receptors located downgradient of the FUDS boundary (Shaw 2006b). No groundwaterdrinking water wells are within the AOC, but drinking water wells are located downgradient ofthe Impact Area AOC. As discussed in the TPP Memorandum, the PA/SI addressed thegroundwater pathway for the Boardman AFR; therefore, sufficient data exists to assessgroundwater. Section 2.5.3 of this SI report presents the results of the PA/SI sampling.Groundwater samples were collected within, downgradient, and cross gradient of the BoardmanAFR. A total of 25 groundwater samples were collected from the area within and surroundingthe Boardman AFR. Four of the samples were located on the Boardman AFR FUDS. Sampleswere analyzed for explosive compounds and perchlorate (see Section 2.5.3). Metals were notincluded in the PA/SI analytical suite. However, the metals associated with the munitions usedat this AOC have a low mobility, and if impacts from metals in soil were present movement toBoardman AFR Final SI Report.doc 9-3 Contract No. W912DY-04-D-0010 Delivery Order No. 003September 2007