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Soil and Groundwater Investigation Report and Second Quarter 2005 Monitoring and Sampling,US Can-Welty Road October 2005 chloride(PVC)well screen within the hollow drive rods and then the rods were partially withdrawn(2 to 4 feet) from the borehole exposing the well screen for sample collection. Grab groundwater samples from borings SB-13, SB-14, and SB-17 were collected from the temporary well screen using disposable bailers. Laboratory-provided bottles were filled directly from the bailers. Immediately on collection,the groundwater samples were labeled and placed in an ice-cooled chest pending analysis. 5. RESULTS 5.1 SOIL SAMPLE ANALYSES All selected soil samples were submitted for chemical analyses to Lancaster Laboratories(Lancaster) in Lancaster,Pennsylvania(California State-certified laboratory#2116)under SAIC chain-of-custody protocol. Selected soil samples were analyzed for BTEX and methyl tertiary butyl ether(MTBE)by EPA Method 8021B, TPHc by EPA Method 8015B Modified, TPHg by N CA LUFT gasoline method, and polynuclear aromatic hydrocarbons(PAHs)by EPA Method 8270C with selective ion monitoring(SIM). 5.1.1 Soil Sample Analytical Results BTEX,MTBE, and TPHg were not reported at or above the laboratory detection limit in any of the soil samples analyzed from borings SB-13, SB-14, and SB-15. However, ethylbenzene and total xylenes were reported at very low levels in a soil sample collected from boring SB-17 at 42 feet bgs (ethylbenzene, 0.2 mg/kg;total xylenes, 2.9 mg/kg). TPHg was also detected in that sample at a concentration of 510 mg/kg. TPHc were detected in several soil samples analyzed from borings SB-14 and SB-17, ranging in concentrations from 17 to 6,700 mg/kg. The highest TPHc concentration(6,700 mg/kg)was detected in boring SB-17 at 42 feet bgs. Low concentrations of PAHs were reported in all soil borings. The soil sample collected from SB-17, at 42 feet bgs, contained the highest PAH concentration detected, which was phenanthrene at a concentration of 3.2 mg/kg. To define the vertical extent of petroleum-affected soil off site, SAIC collected one soil sample from boring SB-15 at 47 feet bgs. TPHc, TPHg,BTEX, or MTBE were not detected in this soil sample. Soil sample chemical analytical results are presented in Table 1 and Table 2. Soil concentrations are presented on Figure 3. 5.2 GRAB GROUNDWATER SAMPLE ANALYSES Three grab groundwater samples were collected from soil borings SB-13, SB-14, and SB-17, submitted for chemical analyses to Lancaster under SAIC chain-of-custody protocol, and analyzed for BTEX and MTBE by EPA Method 8260; TPHd in the range of C10-C25 with and without silica-gel cleanup, and TPHg by EPA Method 8015B Modified; and PAHs by EPA Method 8270 C SIM. For silica-gel cleanup an aliquot of the sample extract for TPHd analysis was passed through a 10-gram column of silica gel and re-analyzed for TPHd by EPA Method 8015 Modified. 5.2.1 Grab Groundwater Sample Analytical Results BTEX or MTBE were not detected in any of the grab groundwater samples analyzed with the exception of 0.6µg/L of benzene detected in groundwater sample from S13-17. TPHg concentrations were not detected in two (SB-13, S13-14)of the three groundwater samples analyzed. However, TPHg was detected in groundwater sample SB-17 at a concentration of 480 µg/L. TPHd was detected in all groundwater samples analyzed ranging in concentrations between 200 gg/L(SB-14)and 150,000 gg/L (SB-17). Following a silica gel-cleanup preparation, all samples with TPHd detections still contained concentrations of TPHd ranging from 460 gg/L to 390,000 µg/L. PAHs were detected in low concentration in all the groundwater samples. Grab groundwater chemical analytical results are summarized in Tables 3 and 4. Concentration maps presenting dissolved-petroleum constituents in groundwater are presented on Figure 4. Total petroleum hydrocarbon distribution in soil and groundwater AEM 6 From Science to Solutions-