SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

Mr. Robert Garcia • - 2 - • 31 December 2004 downgradient plume because the concentration of TPHd in MW-19 has increased from 190 ug/1 when the well was first sampled to 1,100 ug/l in the third quarter sample. Leprino needs to show that the TPHd plume is stable or decreasing in concentration. Therefore, Leprino needs to propose a monitoring plan that will show that natural degradation of the plume is occurring by monitoring natural attenuation parameters and TPHd in all wells that are not within the capture zone of ,the groundwater extraction and treatment system. If the concentration of TPHd continues to increase in M,W-19, additional downgradient wells will be required. In the SAMR and in previous submittals, Leprino requests changes to the groundwater monitoring plan, hi our letter of 29 January 2004, Regional Board staff responded to this request by stating that additional remedial measures were proposed by Leprino in their 22 September 2003 Proposed Remediation System Enhancements and Recommended Modifications to Monitoring and Reporting Program (Proposal), and that we would consider changes to the monitoring and reporting program when those enhancements were implemented. Leprino needs to determine the steps they intend to take to bring this project to closure and submit a final cleanup plan that addresses both the source area and the downgradient plume. When the cleanup plan is implemented,we will evaluate changes to the monitoring and reporting program. By 7 March 2005,please submit a final cleanup plan. The cleanup plan should be written in general accordance with Items To Be Included In A Cleanup Plan, which is attached for your convenience. If you have any questions, you may contact me at(916)464-4677 or at gdjuth@waterboards.ca.gov. GERALD J. DJUTH,P:K, C.E.G. Associate Engineering Geologist Attachment cc: Ms. Lori Duncan, San Joaquin County Environmental Health Services, Stockton Mr. Brendan Shine, HSI GeoTrans, Westminster, Colorado