ARCHIVED REPORTS_XR0002348 - Laserfiche WebLink

Home Browse Search

- 15 September 1995 AGE-NC Project No 95-0105 ' Page 2 of 7 ' After installation, a ground water sample was collected from each well Low concentrations of total petroleum hydrocarbons as gasoline (TPH-g), xylenes and ethylene dibromide(EDB)were detected in the sample from MW-3 Coliform was also detected in samples from each well No petroleum ' hydrocarbons were detected in soil or ground water samples collected from MW-1 or MW-2 Ground water at the site ranges from 8 to 10 feet below grade with a northerly flow direction 3.0. PROCEDURES ' 3 1 MONITORING WELL PURGE PROCEDURES ' On 14 February and 13 July 1995, a Solinst water level meter was used to measure the depth to ground water in each well relative to the top of the well casing The ground water elevations and hydraulic gradients were determined from these data (Table 1) For both morntonng events, each monitoring well was then purged using a three-stage down-hole pump The pump was decontaminated between each well using an Alconox solution Approximately 9 to 10 gallons of water were removed from each well(mimmum of 3 well volumes) to allow ground water to stabilize for representative sampling Ground water parameters, such as temperature, pH and conductivity were measured at 1-gallon intervals using a water analyzer, ICM model 52200 ' Stabilization data and field logs are included in Appendix A The purged water was contained in 55- gallon drums for temporary storage on-site ' 32 COLLECTION OF GROUND WATER SAMPLES ' Water samples were collected from each monitoring well using new disposable bailers The samples were transferred into 40-m1 EPA vials preserved with hydrochloric acid and 1-liter amber bottles The samples were transported in a chilled container to McCampbell Analytical, Inc (MAI) in Pacheco and ' analyzed for total petroleum hydrocarbons quantified as gasoline and diesel (TPH-g and TPH-d) and volatile organics (benzene, toluene, ethylbenzene and xylenes BTE&X) in accordance with EPA methods 8015m and 602, respectively The February 1995 sample collected from MW-3 was also analyzed for EDB in accordance with EPA method 601 ' 33 DRILLING AND SAMPLING On 22 February 1995, two soil borings drilled using a DH-55 drill rig The drill ng and two man crew were supplied by Soils Exploration Services, Inc (SES) of Benicia Dnlling was supervised by representatives of Geological Audit Services, Inc (GAS) Bonng Bl was installed north of the east