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industry practices under the supervision of Foothill Engineering A report of this work by Del-Tech <br /> Geotechnical Support Services is attached and is a part of this report The water samples were transported <br /> under ice by chain of custody to Sherwood Labs for analysis by EPA Methods 602, 5030/8015(M) and <br /> . 3510/8015(M)for BTEX,TPHg,and TPHd A water sample from each monitoring well was transported <br /> from Sherwood Labs under chain of custody to Entech Analytical Labs,Inc for analysis by EPA Method <br /> 8260B <br /> FINDINGS FROM MONITORING WELL ANALYSIS <br /> The most important change for this reporting period is the rise of three feet in the ground water elevation <br /> The direction and slope of the hydraulic gradient has also changed The direction of flow has moved from <br /> the northeast to the east The slope of the gradient has changed from S=0 0007 to S=0 004(see attached <br /> site drawing) <br /> The concentration of TPHg has reduced in all of the monitoring wells Monitoring well MW#2 has had <br /> the largest reduction in TPHg from 65700 ug/L to 34500 ug/L There has been a very small increase in <br /> benzene for monitoring wells MW#I and MW#3 (see attached data sheet) <br /> All analyses for oxygenates were non-detect for each monitoring well <br /> CONCLUSIONS <br /> The three feet rise in the water table is a significant change in the site conditions This raise in the water <br /> table may have been the result of a large irrigation well ceasing operation due to seasonal conditions A <br /> change in the direction of flow may also be a result of a change in groundwater removal by wells in the <br /> area <br /> After two quarters of sample analysis of oxygenates, all water samples have been non-detect <br /> RECOMMENDATIONS <br /> A review of groundwater receptors in the area of the site should be conducted to help determine the cause <br /> of the change in groundwater elevation There is no indication that oxygenates are present in the <br /> groundwater on this site and sample analysis by EPA Method 8260 should be suspended to conserve <br /> financial resources <br /> A soil bore and monitoring well to the full depth of the hydrocarbon contamination should be installed <br /> in the area of the of the westerly pump island This pump island is nearest to MW#1 which has the highest <br /> level of TPHg and BTEX <br /> Respectfully submitted, <br /> Foothi Engine ing <br /> E Rife b g, <br /> Attachments Water nalysis,` - - ech Report, Site Map <br /> • cc Sheldon Heckman, Connell Motor Truck Co 2 copies <br /> 2 <br />