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• <br />SANAOAQUIN <br />q <br />w d <br />COUNTY <br />Greatness grows here. <br />ai <br />Waning im YOU <br />September 18, 2018 <br />Mr. Howard Hold, P.G. <br />Senior Engineering Geologist <br />Central Valley Regional Water Quality Control Board <br />11020 Sun Center Drive #200 <br />Rancho Cordova, California 95670-6114 <br />• Department of Public Works <br />Kris Balaji, Director of Public Works <br />Fritz Buchman, Deputy DirectorlDevelopmeni <br />Michael Selling, Deputy Director/Engineering <br />Jim Stone, Deputy DirectorlOperations <br />Kristi Rhea, Manager of Strategic Initiatives <br />SUBJECT: WORK PLAN FOR THE DETECTION OF FLUID AT LYSIMETER LZ -4 - <br />FOOTHILL SANITARY LANDFILL <br />Dear Mr. Hold: <br />During the routine 2018 2nd Semiannual Monitoring event for the Foothill Sanitary Landfill <br />(FSL), water was extracted from suction lysimeter LZ -4 (see attached map). The analysis of <br />this water by EPA Method 8260 indicated that several volatile organic compounds (VOCs) were <br />present. Based in this initial detection of VOCs at LZ -4, the County submitted a letter report to <br />the Regional Water Quality Control Board (Board) on August 10, 2018. <br />The letter report presented the following information: <br />• The extraction of water from any of the suction lysimeters at FSL is very unusual <br />• Because only a limited amount of water could be extracted from the lysimeter pair at the <br />LZ -4 location, it is apparent that soil in which the lysimeters lie is not saturated <br />• A comparison of lysimeter water to leachate indicated that the source of the water <br />extracted at LZ -4 is not landfill leachate, as follows: <br />o LZ -4: <br />■ pH — 8.12 <br />■ Specific conductivity 934.7 standard units <br />■ Temperature 23.1 C <br />o Leachate at FSL: <br />■ pH -6.75 to 6.86 <br />■ Specific conductivity 4,822 to 4,237 standard units <br />■ Temperature 31.8 to 28.4 C <br />The letter report proposed to confirm these initial detections of VOCs with a verification <br />sampling event be conducted at LZ -4 by September 10, 2018. On September 6, 2018 a <br />verification sampling event was conducted. The field sheets are attached. A small amount of <br />water (fluid) was again extracted from the LZ -4 lysimeter pair. <br />The primary suction lysimeter produced approximately 250 milliliters (ML) of fluid, which was <br />sufficient to collect a sample for VOC analysis. The secondary suction lysimeter produced only <br />approximately 30 ML of fluid, which was insufficient to collect a sample for analysis. During <br />application of suction, fluid in the tubing gurgled and was expelled out of the sample tubing of <br />the secondary suction lysimeter. Because a sustained flow of fluid was not achieved from the <br />1810 East Hazelton Avenue I Stockton, California 95205 1 T 209 468 3000 I F 209 468 2999 <br />