SITE INFORMATION AND CORRESPONDENCE

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-> MEMORANDUM CALIFORNIA REGIONAL TER QUALITY CONTROL BOARD u CENTRAL VALLEY REGION 3443 Rouder Road,Suke A Phone:(M)255-3000 Sacramento CA 95827-3098 - a'i CALNET:8494-3000 To: Gordon L. Boggs From: Elizabeth A Thayer UST Program M er Associate Engineer DATE: 29 January 1997 SIGNATURE: &r Subject: FORMER BEA ONSTATION, 900 SOUTH CHEROKEE LANE, LODI, SAN JOAQUIN CO A TRC meeting was held 6 January 1997, to discuss no further action at this site. SITE HISTORY Beginning in the 1940's the site was a fuel service and/or bulk fuel station owned by a succession of companies, including Tokay Oil, Douglas, Kayo, and Conoco. Conoco conducted the site investigation from 1985 until 1990,when Ultramar purchased the property. In 1994,the property was purchased by Texaco,the current owner. However, Ultramar retained responsibility for investigation and remediation. See Site Location Map, Figure A. Soil at the site consists of multiple and complex interbedded layers of sandy silt, silty sand,gravelly sand, clayey sand, sand, sandy clay, silty clay, clayey silt, silt, clay, and silty sand with gravel,with a hard pan layer at a depth of 10 feet. (See Cross Sections, Figures B and C.) Depth to water has varied between approximately 55 feet and 69 feet. Direction of groundwater flow is generally southerly. The closest municipal well is 2600 feet southwest of the site and is screened between 170 and 440 feet bsg. The closest private water supply well is 5300 feet east of the site and is screened between 52 and 72 feet bsg. SUMMARY OF SITE ACTIVITY(See Site and Excavation Maps, Figures D and E) 1985 - Wells, MW-1 through MW-14,were drilled;MW-2 through MW-7 were intended to be vapor extraction wells,were drilled to a maximum depth of 30 feet, and for the most part have been dry - MW-1 was redrilled and resealed 1987 - Five borings and wells MW-15 through MW-20 were drilled - MW-8 was redrilled and resealed and MW-1 was redrilled and resealed for the second time - MW-11, MW-12, MW-13, and MW-14 were destroyed 1988 - Four borings and MW-21 through MW-25 were drilled 1989 - Groundwater recovery well, RW-1, was installed - An aquifer test was conducted - Began free product removal from MW-8, MW-10, and MW-17 1990 - A soil vapor survey was conducted using, eight temporary vacuum probes, P-1 through P-8. - A vapor extraction test was conducted, using P-1 through P-5 and MW-3, MW-8, and MW-10.