SITE INFORMATION AND CORRESPONDENCE

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S ECOR ' Mr.James Barton January 22, 2003 Page 3 ' Groundwater monitoring has been conducted since June 1994 in accordance with RWQCB ' requirements. The current MRP consists of analyzing for TPHd and TPHg. Historically, the predominant contaminant identified has been TPHd, with non-typical TPHg and low concentrations of BTEX components typically present in well MW-3, which previously has contained free-product. Groundwater was monitored for dissolved lead and methyl tertiary butyl ether(MtBE)during the early investigation, and neither was detected. MtBE has subsequently been detected at low concentrations in wells MW-2 and MW-3. ' Regulatory Correspondence Based on the evaluation of Site parameters included with the Third Quarter 1997 Monitoring Report dated July 29, 1997, a Risk-Based Corrective Action Human Health Risk Screening Risk ' Assessment (Risk Assessment) was recommended at that time. SECOR submitted a Conceptual Site Model (CSM) with a letter dated October 27, 1997, which addressed the RWQCB's concerns that the plume is stable and extent defined. ' On February 23, 2000, Ms. Susan Gahry of SECOR spoke with Ms. Gail Wiggett who informed Ms. Gahry that she had previously verbally approved the CSM submitted to the RWQCB on October 27, 1997. On March 27, 2000, Ms. Wendy Cohen of the RWQCB advised that a Risk Assessment would not be needed to obtain Site closure, but that removal of free-product in well MW-3 was needed prior to Site closure. ' On April 28, 2000, SECOR received the draft revised MRP from the RWQCB for review and comment based on SECOR's January 28, 2000, document titled, "Fourth Quarter 1999 and Groundwater Monitoring Report and 1999 Annual Review." SECOR submitted a response to the draft revised MRP on May 18, 2000. The final revised MRP was issued on June 19, 2000, which ' required a feasibility study be conducted that would evaluate remedial options. SECOR submitted the July 10, 2000, "Feasibility Study/Remedial Options Evaluation Report" in accordance with the final revised MRP. The feasibility study recommended that free phase hydrocarbon removal from ' well MW-3 using a hydrophobic hydrocarbon absorbent sock. The RWQCB approved the feasibility study in a letter dated July 31, 2000. On September 8, 2000, a hydrophobic hydrocarbon absorbent sock was placed in well MW-3 to ' assist in the removal of free-product. The hydrocarbon absorbent sock has been successful in removing floating product in well MW-3. In accordance with the current MRP, socks will be installed and/or changed as needed based on the presence of free-product in the well. ' SECOR and Westrec met with RWQCB staff on May 15, 2002, to discuss the status of the Site and develop a revised MRP. Monitoring and Reporting Program number R5-2002-0824 was issued by the RWQCB on July 18, 2002. Under the new MRP, wells MW-3 and MW-4 are sampled on a ' quarterly basis for TPHg and TPHd, and well MW-2 is sampled annually. Annual sampling will take place during the third quarter. This report is organized as follows: '• ❑ Status report describing activities conducted during the Fourth Quarter 2002; and I:\Tower Park\QMR\2002 QMR\Q4_2002\4th QTR 2002.doc SECOR International Incorporated tSECOR Project No.0507.02926.00.0004 1/22/2003 4:30 PM