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Z Bioremediation Parameter Results Samples of groundwater were collected from monitoring wells MW-1 through MW-8 and were analyzed for the biodegradation indicator parameters discussed above. The results of these chemical analyses are presented in Table 2. Low concentrations of dissolved oxygen were recorded in samples collected from the center of the plume (from MW-2 and MW-3) with respect to samples collected from the other wells, which suggests aerobic biodegradation is occurring. However, the dissolved oxygen values recorded were measured during the well purging process and may be not be representative of actual conditions due agitation/oxygenation of the groundwater during well purging. Elevated concentrations of carbon dioxide were recorded in samples collected from the center of the plume with respect to samples collected from the other wells,which suggests aerobic biodegradation is occurring. Slightly lower nitrate concentrations recorded in samples collected from the center of the plume with respect to samples collected from the other wells, suggest anaerobic biodegradation may be occurring. The redox potential measured in all the samples was negative. Negative redox potential data are consistent with low levels of dissolved oxygen and increasing concentrations of carbon dioxide. The total alkalinity concentrations recorded in samples collected from the center of the plume was generally similar or slightly elevated with respect to samples collected from the other wells, which suggest biodegradation may be occurring. GEOTRACKER DATA UPLOAD The depth to water data and laboratory data associated with the July 8, 2005 sampling event were submitted electronically to the State Water Resources Control Board (SWRCB) Geotracker database (confirmation numbers 9477940201 and 9842487275, respectively). The laboratory data associated with the two domestic wells sampled on September 8, 2005, was also submitted to the Geotracker database (confirmation number 1749676883). Documentation of the data submittal is contained in Attachment 3. CONCLUSIONS AND RECOMMENDATIONS The laboratory analytical results of the groundwater samples collected on July 8, 2005, are generally consistent with recent historical results. Petroleum hydrocarbon concentrations in the groundwater samples collected from MW-1, MW-5, MW-7, and MW-8 decreased with respect to the previous sampling event. The concentrations of TPHg and ethyl benzene in the groundwater sample collected from MW-3 increased and the concentrations of benzene and MTBE decreased with respect to the previous sampling event. Petroleum hydrocarbon concentrations in the groundwater samples collected from MW-2 and MW-4 increased with respect to the previous sampling event and the concentrations of TPHg, benzene, ethyl benzene, and xylenes concentrations in the sample collected from MW-4 increased with respect to the previous sampling event. Petroleum hydrocarbons have not been detected in groundwater samples collected from MW-6 since January 2004. The results of the biointrinsic remediation parameters suggest subsurface s:\Environmental\17861\reports\3gmr2005.doc 6 ATC Associates Inc.