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r f Lodi-Quarlerly Groundwater Monitoring _. Pa e 4 — .4 ` where it hydrolyzes to eth lene 1 col and bromoethanol under neutral conditions and ambient Y Y� Y g Y temperature the half-life of the reaction is 5-10 days). SRK requested further guidance and ' justification from Ms Margaret Lagorio , Senior REHS, San Joaquin County PHS/EHD, prior to the April 1992 sampling event, however no response was received by SRK from the PHS/EHD during or after the sampling event. The analytical groundwater samples were placed in a cooler containing additional frozen blue ice packets,and shipped following chain-of-custody procedures to North Creek Analytical for analysis. r 5.0 ANALYTICAL DATA V Organic analyses were performed by North Creek Analytical (California ELAP # 1267), and the .� inorganic analyses were performed by Sequoia Analytical (California Elap # 1210). It should be noted that North Creek Analytical and Sequoia Analytical are jointly owned. Copies of the analytical data and chain-of-custody are provided in Appendix C. The chain-of-custody states that d' the groundwater samples were received by the laboratory in good condition at 4°C. The chain-of- custody clearly documents that the samples were shipped from California to Washington. The chain-of-custody includes the sample location in the Project Name "Diamond Lumber-Lodi", and -MWI-LODI". The top of the chain-of-custody form clearly in the Sample Identification, "SRK states the name and address of North Creek Analytical in Bothell, Washington. The constituents of BTEX or volatile hydrocarbons were not detected in groundwater samples collected from any of the three monitoring wells. Lead concentrations were detected in each of the monitoring wells, ranging from 33 ppb in sample SRK-MWI-LODI, 260 ppb in sample SRK- ' MW2-LORI, and 93 ppb in sample SRK-MW3-LODI. ' Table 2 contains analytical groundwater data from both the November 1991 and April 1992 sampling events. As previously stated, the constituents of BTEX or volatile hydrocarbons were not detected in the April 1992 sampling event,while toluene was detected during the November 1991 sampling event in samples SRK-MW2-LODI (0.$2 ppb) and in SRK-MW3-LODI (0.63 ppb). During the November 1991 sampling event lead was only detected in sample SRK-MW1- LODI (53 ppb). Analytical data and chain-of-custody.from the April 1992 sampling event is provided in Appendix C,while laboratory data and the chain-of-custody from the November 1991 sampling event is provided in Appendix D. It should be noted that the April 1992 samples were ' received by the laboratory in good condition at 4°C. Table I contains static water level information during both sampling events. The static water ' levels were measured from the top of the 2-inch diameter PVC.casing using a Solinst Water Level Indicator. Copies of the Field Groundwater Purging/Sampling Logs from the November 1991 and April 1992 sampling events are provided in Appendix A, and copies of the Geologic Logs and ' Monitoring Well Construction Diagrams are provided in Appendix B. The static water levels in each of the three monitoring wells rose significantly since November 1991, likely due to seasonal i fluctuation. The exact amount of precipitation or groundwater infiltration is unknown, however, the elevated levels of lead may be the result of this seasonal fluctuation in the static water table. ' 325M.24.0.«IY�.24 Steffen Robertson and Kirsten