ARCHIVED REPORTS XR0006329 - Laserfiche WebLink

Home Browse Search

INTRODUCTION This update, STATUS UPDATE 38, presents data from March 29, through April 26 , 1995 and includes the sewer discharge update, Quarterly Ground Water Monitoring and results of venting MW8 The permit to dump treated ground water to the sewer has been renewed Presently we are batch dumping the treated water from the "ConVault" whenever -it is full . The water for treatment is collected from the vapor recovery condensate dropouts and produced from the sampling and monitoring of the monitor wells by Lawrence Tank Testing (LTT) pumping service LOCATION The station is located at 6425 Pacific Avenue at the intersection of Douglas Road, Stockton, in San Joaquin County, California The site lies in Section 21, T2N; R6E, MDB&M at approximately 12 feet above mean sea level (MSL) (see Figures 1, 2 , 3) . The parcel is # 31 and can be located in Assessor' s Book 97 on page 41 (97-041--31) . On October 2 , 1992 , a licensed surveyor with Nolte & Assoc surveyed all monitoring well locations and top of casing elevations to a known datum, ie City of Stockton Bench Mark Number 12 , elevation 11 . 741 above mean sea level GROUND WATER MONITORING Depth to ground water measurments and water samples were obtained from all monitor wells on April 12, 1995 The vapor extraction was on at the time, therefore corrections to the measurements were necessary to compensate for reducing the atmospheric pressure at the well head. Figure 4 , represents the measurements obtained on April 14 , 1995 Ground water gradient shows a relatively flat mound beneath the site with depressions at vapor extraction wells (VEW) MW3 and MW10 . Discharge is occuring away from the site to the southwest towards MW9, and the east southeast towards MW5, MW11, and MW12 Currently MW6 represents the upgradient direction, north of the site GROUND WATER QUARTERLY„SAMPLING Ground water samples were collected on March 15 , 1995 see Table 1 These samples were collected by a WEGE Geo-technician and "Chain of Custody" delivered on ice to State certified testing laboratory, AMERICAN ENVIRONMENTAL NETWORK, INC. DHS #1172, for chemical analyses These samples were analyzed for TPH and BTEX concentrations using EPA Methods 8015/5030 and 602 respectively Since diesel has never shown up in the sample results, the samples obtained on 11/27/90 and later were analyzed using EPA methods 5030 and 602 for Total Fuel Hydrocarbons and BTEX The next quarterly sampling will occur in June, 1995 PAGE 1 R603 UPDATE-38 5/04/95