ARCHIVED REPORTS_XR0005852 - Laserfiche WebLink

Home Browse Search

I 11 ' Site Background Information: Ripon Farm Service Page 5 of.7 detected at maximum concentrations in samples collected from well VW-1 of 720 µg/l and 800 µg/l, respectively. Low concentrations (less then 3 µg/1) or lack of detectable BTEX ' compounds have been encountered in ground water samples from wells MW-1 and MW-3 through MW-8. • DIPE has been detected in ground water samples from wells MW-3, MW-4 and MW-8 at concentrations as high as 17 µg/l. TBA has been detected in samples from wells MW-1, MW-2, MW-3, MW-4, MW-8 and soil vapor wells VW-1 and VW-2 at concentrations.as high as 120 µg/l, respectively. MTBE has been detected in samples from wells MW-1 and MW-3 at concentrations as high as 6.7 µg11.ETBE and TAME have not been detected in any of the wells sampled. TPH-d concentrations exceeded TPH-g concentrations in the samples containing both analytes. ' Impacted soil was present below the ground water table at the time remediation began, due to historically lower ground water elevations at the site during which time a portion of the unauthorized hydrocarbon release occurred. The former UST area was impacted by diesel fuel compounds, but ' also is impacted by significant concentrations of gasoline fuel compounds. The volume of soil addressed by the remediation system was estimated to be 645 cubic meters based ,. on the limited lateral extent of the vadose zone contamination and a depth to ground water of 20 . feet bsg. The generalized mass of vadose-adsorbed TPH-g was approximately 65.2 lbs or 29.58 kg and generalized mass of adsorbed TPH-d was approximately 77.16 lbs or 35 kg. 1 ' The total volume of impacted soil addressed by the remediation system was estimated to be 1,240 ' cubic meters,from the base of the former UST excavation to the depth of 30 feet bsg.The total mass of adsorbed TPH-g was approximately 123.5 lbs or 56.8 kg and mass of total adsorbed TPH-d was approximately 150 lbs or 68.2 kg. ' Hydrocarbon-impacted ground water in the former UST area has higher average TPH-g:TPH-d rations(0.702- 1.852)indicating a greater contribution to ground water of TPH-gin the former UST ' area. 1 SOIL AND GROUND WATER REMEDIATION On 25, 26 and 27 April 2000, four air=sparge (IAS)pilot borings and eleven soil vapor extraction ' (SVE)pilot borings were advanced at the site.Borings IAS 1 through IAS4 were completed as two- inch diameter air sparging wells,drilled to a total depth of 25 feet bsg with a 5-foot screen interval. Two vertical zones of remediation wells were installed as follows: borings VW-3A, VW-8 and ' VW-9A were completed as vapor extraction wells, drilled to a total depth of approximately 13 feet bsg and completed with a 5-foot screen intervals; borings VW-3B,VW-4, VW-5, VW-6, VW-7, ' Advanced GeoEnviron mental,Inc. 1 .