ARCHIVED REPORTS_REPORT SUMMARIZING INSTALL OF MONITORING WELLS MW4,MW5,MW7,MW8 & SOIL BORING RDM1 & 4TH QTR 2013 GROUNDWATER SAMPLING

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1 Ms.Angela Lee Huntbrook Holdings,LLC February 12, 2014 Page 12 Based on the depths that petroleum hydrocarbons are encountered onsite, it appears the former UST(s) were most likely the source of the contamination and not the former fuel island. Since the petroleum hydrocarbon impacts to soil extend right up to the property lines at the intersection of East Main Street and South Golden Gate Avenue, in order to fully assess the lateral extent of petroleum hydrocarbons in soil would require encroachment into the public right-of-way. These are both very busy streets and a signalized intersection that most likely has numerous critical subsurface utilities. It's RDM's opinion that based on experience the soil impact probably does not extend more than 30 feet into the public right-of-way and is at depths deeper than would typically be encountered by construction workers. The risk of performing subsurface exploration in the public right-of-way is not worth the additional soil data that would be obtained. Due to the residual hydrocarbon impacted soil (secondary source) remaining onsite in the northeast corner of the property, RDM recommends continuing with conducting the soil vapor extraction and air sparging remedial pilot testing that was proposed in its Workplan, but revising the locations of the two proposed soil vapor extraction wells. Since the property owner has decided not to demolish the former station building and upon further review of the soil data,proposed soil vapor extraction well SVE-IA/B will now be installed near monitoring well MW-3 and the former UST (Figure 2), and soil vapor extraction well SVE-2A/B will now be installed immediately adjacent to the west wall of the former station building between soil borings SB-2 and SB-4(Figure 2). Since we were unable to advance CPT boring CPT-I to the necessary depth to collect depth discrete groundwater samples using both a 20 and 25-ton CPT rig, RDM recommends mobilizing a resonant sonic (sonic) drill rig to the site to accomplish the task. Since this will be beyond RDM's approved scope of work and budget, a new budget for this task will need to be approved through the OSCF in order for RDM to proceed. RDM will also seek approval of the OSCF funding for the remedial pilot testing previously disapproved by the OSCF/USTCF staff. • RDM recommends continued semi-annual groundwater monitoring during the first and third quarters; the next sampling event is scheduled for March 2014 and all seven of the wells will be sampled. A site conceptual model(SCM)and corrective action plan(CAP)will be prepared following the completion of the remedial pilot testing. All At this time, RDM also recommends holding off on the installation of monitoring well MW-5 until at least two more semiannual sampling events are completed so a trend can be evaluated and potential offsite sources of TCE/PCE can be further investigated, if necessary. S Future Work Based on the data available to date and future proposed remedial activities, RDM proposes the following 2014 schedule for the site: • March 2014 - perform the first quarter 2014 semiannual groundwater monitoring event (all seven monitoring wells). Also collect groundwater samples from three wells (upgradient, source area and downgradient)and analyze for monitored natural attenuation parameters; • March-April 2014 - install the two previously proposed soil vapor extraction nested wells and one air sparge well, and advance deep boring to approximately 100 fbgs using a sonic drill rig and collect depth discrete groundwater samples; 0 By April 30,2014- submit First Half 2014 semiannual groundwater monitoring report;