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Mr.M. Scott Mansholt—CEMC Fourth Quarter 2005 Groundwater Monitoring and Sampling Report and 2005 Annual Summary January 5,2006 US Can-Welty Road,Vernalis,California Page 5 of 7 SAMPLING Following DTW measurements, groundwater samples were collected from wells MW-3 through MW-5 and WFSMW-1 on October 19,2005. Wells MW-3 through MW-4 were not purged due to the low volume of water in the well casing. Wells MW-5 and WFSMW-1 were purged of approximately four casing volumes using either a 2-inch disposable polyethylene bailer or a low- flow submersible pump. In these wells,pH, specific conductance, dissolved oxygen,turbidity, and temperature water-quality parameters were recorded. After water-quality parameters stabilized(i.e., a minimum of three consecutive readings with values within 10 percent for each parameter), groundwater samples were collected. No samples were collected from MW-1 and MW-2 due to the presence of SPO in these wells. Field data sheets are included as Attachment A. GROUNDWATER ANALYTICAL RESULTS Groundwater samples were collected on October 19,2005. All samples were collected using a bailer or by a low-flow submersible pump using new polyethylene tubing through which groundwater was extracted. Laboratory-provided bottleware was used to preserve the samples. The bottles were labeled, sealed, and placed immediately into an ice-cooled chest for delivery to Lancaster Laboratories, Inc. (Lancaster),under SAIC chain-of-custody protocol. Lancaster is a California State-certified laboratory(ELAP#2116). The samples were analyzed for the following: • TPHd: C10—C25 using Environmental Protection Agency(EPA)Method 8015M and TPHd with silica-gel preparation for samples with detectable concentrations of TPHd using EPA Method 8015M; • TPHg: C6—Clo,using EPA Method 8015M; • BTEX using EPA Method 8260B; and • PAHs using EPA Method 8270C SIM. SPO was present in MW-1,and a petroleum odor was detected in MW-2;therefore,no samples were collected from these wells. No TPHd, TPHg,BTEX were detected in the groundwater samples, except 2,500 and 240 gg/L TPHd in wells MW-3 and WFSMW-1,respectively. No PAHs were detected in the groundwater samples from MW-4 and MW-5. Four PAHs were detected in groundwater sample from well MW-3 at concentrations just above detection limits. Fluorene was detected in WFSMW-1 at the detection limit. The groundwater analytical results are presented in Tables 2 and 3. A petroleum hydrocarbon distribution map is presented as Figure 4. A copy of the laboratory analytical report is presented as Attachment B. ABSORBENT(OLEOPHILIC) SOCK REPLACEMENT An oleophilic sock has been installed in well MW-1 due to the presence of SPO in the well and an oleophilic sock was placed in MW-2 due to the petroleum odor detected from the well. The oleophilic sock in MW-1 has been monitored and replaced as necessary on a quarterly basis. During the fourth quarter 2005,the oleophilic sock from MW-1 was weighed but not replaced, and approximately 10 ounces(0.07 gallon) of SPO had been absorbed. A summary of SPO thickness measurements is included in Table 1. QUALITY ASSURANCE/QUALITY CONTROL (QA/QC) All field procedures were conducted in accordance with SAIC's Quality Assurance and Quality Control Sample Collection, Handling, and Analysis procedures. No sample was received by the