SITE INFORMATION AND CORRESPONDENCE FILE 2

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Messrs Larson and Trommer F June 14, 2010 April and May 2010 Draft Five-Year Review Page 2 of 4 Recommendation Various Sites the field work has been completed the analytical results are reportedly favorable, although the report of findings and the analytical report have not been received. The EHD anticipates moving forward with site closure upon receipt of those materials if found to be favorable. 639 W. Clay Street, Stockton, CA; Claim Number 8542: The CUF has recommended that future efforts on this site be focused on active remediation to achieve WQOs in a timely manner. The EHD concurs with this recommendation, and following installation of the recently approved monitoring wells and borings, will turn the focus toward active remediation. 308 N. Grant Street, Stockton, CA; Claim Number 1028: The CUF recommended that groundwater remediation by insitu air sparging (IAS) be implemented in conjunction with the ongoing remediation of impacted soil by soil vapor extraction (SVE). An IAS pilot test was recently conducted and reported to the EHD as effective; however there were some ambiguities as to how the data was collected, and therefore the EHD is not certain that the reported results and conclusions truly show IAS as effective. The EHD has sought resolution of the issues of concern and will approve implementation of the method if the issues are favorably resolved (see the EHD letter dated April 16, 2010). The EHD agrees that active groundwater remediation is necessary and will move the site toward addressing impacted groundwater as rapidly as possible. 308 S. EI Dorado Street, Stockton, CA; Claim Number 10841: The CUF concurred with the EHD directive to conduct an ozone injection bench-scale test; our agencies are in agreement. 139 S. Center Street, Stockton, CA; Claim Number 5820: The CUF repeated the recommendation that the EHD issue a directive to the RP to assess remedial technologies and implement active remediation to achieve WQOs in a timely manner. The EHD recently commented on a feasibility study submitted for the site that concluded that groundwater extraction (GWE), dual-phase extraction, referred to as 'two phase extraction (TPE) in the report, and ozone injection technologies would not be cost effective based on previous field tests. The current consultant recommended collecting data to evaluate monitored natural attenuation (MNA), which of course would not accelerate achieving WQOs. The EHD commented by letter dated May 6, 2010, noting what the EHD considers to be test design problems and missing information, and requesting that certain information be provided to the EHD and that the data and conclusions from the tests be reevaluated. 3250 W. Hammer Lane, Stockton, CA; Claim Number 15783: The CUF recommended that the site be referred to the Central Valley Regional Water Quality Control Board (CVRWQCB) for enforcement and that the approved remediation plan be implemented without delay. The EHD met recently with the RP and his consultants, and they agreed to submit a work plan to pilot test ozone injection. As the RP appears to be ready to comply with the EHD directives, the EHD will defer referring the site to the CVRWQCB for the present. We are in agreement that the site should be put into remediation as rapidly as possible. 15 E. Grant Line Road, Tracy, CA; Claim Number 17179: The CUF recommendation noted that the EHD had directed the RP to conduct a soil vapor survey to evaluate the risk posed by vapor intrusion, and stated the CUF belief that the survey was unnecessary and was not appropriate to conduct at an active service station, and the CUF recommended site closure consideration. The EHD agrees that the site is ready for closure consideration, but remains concerned over the vapor intrusion evaluation submitted for the site that does not appear to be April and May 2010 Annual 5-year Reviews Vickie's Sites.doc