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• MEMORANDUM • CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD • CENTRAL VALLEY REGION 3443 Routier Road, Suite A Phone: (916) 255-3000 • Sacramento, CA 95827-3098 CALNET: 8-494-3000 TO: Gordon L. Boggs FROM: Elizabeth A. Thayer UGT Program Coordinator Associate Engineer ��(//� DATE: 3 October 1994 SIGNATURE:�� 7/^ -+4 L/ SUBJECT: BIOREMEDIATION, 16 SOUTH CHEROKEE LANE, LODI, SAN JOAQUIN COUNTY Since our meeting on 13 May 1994, Geweke's consultant, Geological Audit Services (GeoAudit), has submitted three reports; "Bioremediation of Hydrocarbon Impacted Soil and Groundwater" on 17 June 1994, "Workplan for Completion of an Aquifer Test" on 5 July 1994, and "Quarterly Report: June 1994" on 25 July 1994. All three reports were faxed to us prior to the submittal dates. Following are summaries of and comments on the reports: I. AQUIFER TESTING WORKPLAN The Workplan proposed an aquifer test consisting of three phases. Phase I was a preliminary pumping test to determine acceptable pumping rates, maximum anticipated drawdown, and to ensure that observation wells will produce useable data. Phase II consisted of a 24-hour minimum constant-rate pumping test. Based on previous data, they selected the extraction • well EW1 for the aquifer test and monitoring wells MW7, 8, 9, and 14 as observation wells. Phase III consisted of slug tests in MW11 and MW13. Comment - The aquifer testing was conducted between 12 and 15 July 1994. The data have not yet been submitted to the Board. II. QUARTERLY REPORT Ground water samples were collected from eight monitoring wells on 21 June 1994. Wells MW1 through 5 were dry and MW13 continued to have no detectable contamination. MW6 through 11, MW14, and EW1 all continued to show various levels of contamination with up to 990 ppb TPHg in MW6 and 27 ppb benzene in MW9. TPHg and BTEX contaminant levels went up in MW6, MW7, MW9, MW10, and MW14 and went down in MW8, MWI1, and EWI. No contamination was detected in MW12 this quarter. 1,2-Dichloroethane continues to be detected in EWI, MW13, and MW14. EDB was found again in MW14. The attached map shows the locations of the wells. Comments - The upgradient monitoring well MW6 and cross gradient well MW10 continue to show contamination. The downgradient well MW12 which showed contamination last quarter was ND this quarter. III. BIOREMEDIATION REPORT • This report includes data and comments on the Bioremediation Pilot Study, a Bioremediation Proposal, a Sampling Plan, Cleanup Goals, and a Contingency Plan.