SITE INFORMATION AND CORRESPONDENCE_FILE 2

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Ken Gillies September 17, 2014 Gillies Trucking Page 2 of 3 3931 Newton Road The EHD discussed closure of your site with a representative of the Central Valley Regional Water Quality Control Board (CVRWQCB) on 10 September 2014. The CVRWQCB representative questioned whether the dissolved cadmium and zinc encountered in the groundwater samples collected from GT-16A and GT-31 were background concentrations or related to a possible unauthorized release from the former waste oil UST; it was also questioned whether or not the plume of dissolved TPHd was delineated in each defined aquifer and vertically. The EHD plotted the most recent data for each well by aquifer and determined that the plume is adequately delineated in each aquifer and vertically. To resolve the cadmium/zinc issue, the CVRWQCB recommended either collecting additional groundwater samples from several wells to determine if the dissolved metals are background constituents or of limited areal distribution around the former waste oil UST, or collecting a soil sample under the former UST location and testing directly for a release from the former UST. The CCS&NFAR included the work plan (WP) for destroying the monitoring and remediation wells installed on your site as part of the corrective actions taken to address the unauthorized release(s) from your former UST system. It was proposed in the WP to destroy all wells by over-drilling (removing all well contents) and grouting to near surface grade with neat cement with the exception of wells GT-18A, GT-18B, GT-19, GT-30, and GT-31 which were proposed for destruction by pressure grouting. As all wells that are located in an area of known or suspected contamination must be destroyed by removal of all the well contents, the EHD cannot approve destruction of monitoring wells GT-18A and GT-18B by pressure grouting because the wells contained impacted groundwater when last sampled in January 2011, however monitoring wells GT-19, GT-30 and GT-31 are approved for destruction by pressure grouting as proposed. The EHD examined the soil and groundwater data for all the wells on your site and will also approve destruction of monitoring wells GT-12A, GT-13A, and GT-13B by pressure grouting. The EHD noted several wells with favorable soil data, but that contained low concentrations of TPHd when last sampled in January 2011; over the last three and a half years, natural attenuation may have reduced the dissolved TPHd sufficiently for a number of the wells to qualify for destruction by pressure grouting, thereby saving considerable expense. The wells so identified are GT-6, GT-14A, GT-14B, GT-16A, GT-16B, GT-17A, GT-17B, GT-18A, GT-18B, GT-20 and GT-32. If current groundwater analytical data is obtained, the EHD will approve the destruction of each well found to have cleaned up by pressure grouting. In summary, six wells are approved for destruction by pressure grouting as is, and additionally, as many as 11 more wells will be approved for destruction by pressure grouting if favorable current groundwater data is obtained. The EHD recommends sampling the groundwater in the latter group of wells listed above and analyzing all for TPHd, and at the same time collecting groundwater samples from GT-6, GT-14A, GT-18A, GT-16A, GT-20 and GT-31 for analysis for dissolved cadmium and zinc to resolve the lingering question on the waste oil UST issue. By letter dated 10 April 2014, the EHD informed you that the LTCP requires that a 60-day public notification process be conducted to allow the local property owners and occupants, and other interested parties opportunity to have their concerns regarding the pending case closure addressed before the case is actually closed. A list of agencies and persons to be notified and a sample letter was provided in the April 10 letter. Please submit a draft case closure consideration notice by Closure Request Response Letter 0914