SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

Mr. Robert Garcia • • 29 January 2004 Leprino Foods, Inc. 3 4. We concur that it is necessary to assure that polluted groundwater will not reach potential receptors and that human health is protected. LFC needs to conduct a well survey to identify all operating wells within a 0.5-mile arc downgradient and sidegradient of the source area. 5. The most appropriate remediation strategy can only be determined after defining the size and mobility of the TPHd plume. The existing GWETS is appropriate as an interim measure to control the source area, but because of the length of time since the original spill, it is probable that a downgradient plume has migrated off the LFC site. LFC must define this plume with downgradient monitoring wells. Only after the plume is defined and documented through monitoring can remedial measures,whether pump and treat, oxygen injection, monitored natural attenuation or other measures,be evaluated in a feasibility study. 6. We concur with a trial cessation of pumping from RW-4A. After turning off the pump, the cone of depression from extraction well EW-2 should be monitored for a minimum of four quarters to confirm that there are no adverse effects of eliminating pumping from RW-4A before determining whether this well can be abandoned. 7. Regarding changes to the monitoring and reporting program, MRP No.R5-2003-0808 was revised last year and LFC was sent a draft of this MRP. LFC had comments at that time, which we incorporated. It is likely that the MRP will need to be revised in the near future, after the plume is defined and when oxygen injection or another remedial measure is implemented. Therefore, we will consider LFC's requests at that time. In a letter dated 7 November 2003, Regional Board staff approved a work plan to define the downgradient extent of the TPHd plume emanating from LFC, and the investigation report was due 5 January 2004. That report is now past due. In your email dated 5 January 2004, you stated that you have not yet received access to off-site locations but did not provide an updated schedule or steps you would take to complete the necessary work. Please submit the names and addresses of all involved parties, along with details of your attempts to contact them, and Regional Board staff will contact them. By 17 February 2004, submit a revised schedule for the downgradient well installation, submittal of an investigation report, and submittal of a well survey of all active wells 0.5 miles downgradient and sidegradient to the source area. We concur with turning off the pump in extraction well RW-4A; all other monitoring shall continue under the terms of MRP No. R5-2003-0808. If you have any questions, you may contact me at (916) 464-4677 or at djuthg@rb5s.swrcb.ca.gov. GERALD J. DJUTH,P.E., C.E.G. Associate Engineering Geologist cc: Ms. Lori Duncan, San Joaquin County Environmental Health Services, Stockton Mr. Brendan Shine,HSI GeoTrans, Westminster, Colorado