Laserfiche WebLink
24 January 2003 <br /> AGE-NC Project No 99-0657 <br /> IPage 4 of 7 <br /> I After water levels were measured,between 7 0 and 7 33 gallons of water(a minimum of 3 casing- <br /> water volumes per well)were purged from monitoring wells MW1 through MW4 using dedicated, <br /> disposable plastic bailers,monitoring wells MW5 through MWS were evacuated during development <br /> as described in section 2 1 5 Ground water temperature, pH and conductivity were measured at <br /> regular intervals during purging using an Oakton water analyzer Field sheets and data are included <br /> in Appendix C Purged water was stored in properly labeled DOT-approved model 17H 55-gallon <br /> drums and stored on-site <br /> I2 2 2 Collection and Analysis of Ground Water Samples <br /> Water samples were collected from each purged well using new disposable plastic bailers or a pre- <br /> cleaned inertia pump after allowing the wells to achieve a minimum 80%recovery of the pre-purge <br /> water volume Each water sample was transferred into one 1-liter amber bottle without sample <br /> preservative and into three 40-ml VOA vials containing 0 5 ml 18%hydrochloric acid as a sample <br /> Ipreservative After collection, the samples were properly labeled, placed in a chilled container and <br /> transported under chain-of-custody to CTEL, a California Department of Health Services-certified <br /> . analytical laboratory, for analysis The samples were analyzed for <br /> • - and TPH-d in accordance with EPA Method 8015M and <br /> TPH g , <br /> • BTEX, MTBE, DIPE, ETBE, TAME, TBA, 1,2-DCA and EDB in accordance with EPA <br /> Method 8260B <br /> 30. FINDINGS <br /> The soil stratigraphy, ground water elevation, flow direction, and gradient were determined from <br /> field data, the contaminant impact to soil and ground water was quantified by the laboratory <br /> analytical data <br /> I31 STRATIGRAPHY <br /> Brown to dark brown silts and very fine sands were encountered from surface grade to approximately <br /> I6 feet below surface grade (bsg) Tan to brown medium sand was generally encountered between <br /> 7 feet and approximately 15 feet bsg, inter-bedded with the sand in the areas of borings MW7 and <br /> MW8 was a thin, laterally discontinuous clay layer at approximately 13 feet to 16 feet bsg Brown <br />' silt was encountered from 15 feet bsg to approximately 20 feet bsg and again from approximately <br /> 30 feet to 40 feet bsg <br /> IAdvanced GeoEnvironmental,Inc <br />