SITE INFORMATION AND CORRESPONDENCE_FILE 3

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0 0 Frontier Transportation, Incorporated Page 2 of 3 425 Larch Road March 20, 2014 Tracy, California 95376 • Collection of groundwater samples each month from the pump discharge line of each extraction well for analysis of total petroleum hydrocarbons as gasoline (TPH-g) and volatile organic compounds (VOCs), including fuel oxygenates, by a laboratory licensed by the State of California Department of Health Services; and • Monitoring and sampling of groundwater from wells at the site using the low-flow/micro- purge method. The EHD approves the work plan to install the groundwater pumping remediation system as proposed in the work plan, and collection of groundwater each month from the two extraction wells for chemical analysis. To clarify, groundwater samples will be analyzed for TPH-g, and VOCs that include: benzene, toluene, ethylbenzene and total xylenes (BTEX); MTBE, ethyl tertiary-butyl ether (ETBE), di-isopropyl ether (DIPE), tertiary-amyl methyl ether (TAME) and tertiary-butyl alcohol (TBA). Please submit an EHD Well and Boring Permit Application form, Master File Record form, and the appropriate fees. The permit fee for the installation of each extraction well is $125, along with a $375 Inspection Activity fee per parcel, bringing the total installation fee to install two extraction wells to $625.00. The EHD approves the low-flow/micro-purge method to collect groundwater samples. Notify the EHD of the pending sampling event at least two weeks prior to the scheduled event so that an inspector can be present. The EHD approves the destruction of the dual-phase extraction and monitoring wells listed above in the first bullet. As first mentioned by letter dated 18 July 2013, please submit a scope of work proposal that details the conditions and construction of the wells and the methods and materials to be used to destroy them. To be issued a well destruction permit, the proposal must address the concerns of the EHD and the San Joaquin County Well Standards requirements, such as: • Wells that have laboratory data from the last sampling event that demonstrate the presence of any contaminants of concern remaining in groundwater are to be destroyed by removing all the contents of the well [well casing (except steel conductor casing), screen, filter pack, grout sealant]; the cleared borehole is then to be sealed with neat cement from the bottom upward to the depth of three to five feet bsg. • Wells with unknown construction and/or located in an area of known or suspected contamination are to be destroyed by removing all the contents of the well [well casing (except steel conductor casing), screen, filter pack, grout sealant]; the cleared borehole o is then to be sealed with neat cement from the bottom upward to the depth of three to five feet below grade. • Wells that have laboratory data from the last groundwater sampling event that report { non-detectable concentrations of contaminants of concern and with acceptable € laboratory detection limits, and are not in areas of known or suspected soil contamination, may be destroyed by pressure grouting from the bottom upward, while leaving the well casing in place. The top three feet or more of the well shall be drilled out with an auger that is at least one foot larger in diameter than the auger originally