ARCHIVED REPORTS XR0001315 - Laserfiche WebLink

Home Browse Search

•ti l\ F URS Ms Lori Duncan Page 4 San Joaquin County Environmental Health Department July 26, 2004 interval from 45 to 50 feet bgs (for MW-13D) A Monterey No 3 silica sand filter pack was installed from 51 feet bgs to 2 feet above the well screen A 12-foot bentonite annular seal was placed above the lower sand pack The upper well screen (for MW-13M) was placed from approximately 15 to 30 feet bgs The upper filter pack was placed from approximately 13 to 31 feet bgs A bentontte transition seal was placed from approximately 11 to 13 feet bgs Neat cement was used to seal the remaining annular space to the surface The surface was completed with a 12-inch flush-mounted well box, and a locking, water-tight well cap was placed on each well Well construction details are shown on the boring log in Attachment C Soil cuttings and wastewater generated during the drilling activities were placed in labeled 55-gallon US Department of Transportation (DOT)-approved steel drums pending disposal Subsurface Conditions The boring log for boring SO-3 is included in Attachment C The subsurface at the site is composed of interbedded layers of sand, silt, and clay First water was encountered at approximately 20 feet bgs in • boring SO-3 (MW-13M/D) Upon completion of drilling, the groundwater level stabilized at approximately 19 8 feet bgs in MW-13M and at approximately 20 3 feet bgs in MW-13D Monitoring Well Development, Sampling, and Surveying On May 12, 2004, Blaine Tech Services (BTS) of San Jose, California, developed MW-13M and MW- 13D by rigorously surging over the length of each respective screen interval and by purging 10 casing volumes of water from each well Well development data sheets are included in Attachment D On June 8, 2004, BTS collected groundwater samples from the newly installed groundwater monitoring wells Groundwater samples were analyzed for gasoline range organics (GRO), benzene, toluene, ethyl- benzene, and xylenes (BTEX), and fuel oxygenatesladditives and selected halogenated volatile organic compounds (HVOCs) by EPA Method 8260B Samples were non-detect for GRO, BTEX, MtBE and fuel oxygenates/additives Field and laboratory procedures are provided in Attachment G The only volatile organic compound (VOC) detected in samples was cis-1,2-dichloroethene at 28 p.g/L in MW- 13M and 12 µg/L in MW-13D Attachment E presents groundwater sampling field sheets and laboratory analytical results Tabulated analytical results are provided in Tables 1-1 through 1-4 Analytical data for the other site wells will be included in the second quarterly report for 2004 On May 19, 2004, lateral positions and top of casing elevations for the MW-13MID were surveyed by Morrow Surveying of West Sacramento, California Survey data are included as Attachment F K 1WproeessU5 BP ARCO%044931May Well 0414493 well installation report04b dm