ARCHIVED REPORTS_XR0005466 - Laserfiche WebLink

Home Browse Search

' December 2003 and the suspect 0 58 mg/Itr in March 2004, they have again decreased Contamination levels in this well were 0 1 during this quarterly ' sampling (December 17, 2005) In an effort to establish a "clean line" further out from the source, CPT bonngs were carried out in November 2003 followed by a second round and later a third On May 28, 2004, nine new holes were pushed using a CPT rig to ground water to ' sample outlying groundwater to determine if the new sampling points were beyond the underground hydrocarbon plume Results vaned between <0 062 mg/Itr and 0 150 mg/ltr at the westernmost point 55 FT north of MW 3 On .tune ' 29, 2005, ten new holes were pushed using a CPT rig to ground water to sample outlying groundwater to determine if the new sampling points were beyond the underground hydrocarbon plume Results varied between 0 060 mg/Itr and 0 140 ' mg/Itr at the easternmost point (HP 25) 350 FT east northeast of MW 6 The 0 140 mg/Itr finding in HP25 does not fit the 0 050-0 100 mg/Itr range of the other 28 hydropunch samples ' The potential of any threat to neighboring wells drove a well survey of surrounding wells Department of Water Resources information is presented in ' this report for those wells down gradient and within 2,000 FT from the WOS site's source assumed to be near MW No 1 ' • Groundwater contamination between 50 to 55 FT bgs exists off the site A ND defining the leading edge was not found Excepting HP 25, noted above, most recent HP borings located further out from the source were less than 0 100 mg/Itr The original underground storage tanks (USTs) suspected source has been removed The closest operating offsite down gradient well is at least 600 FT away Residual shallow soil contamination, possibly contributing to the ground water contamination has been identified and removal of a portion not covered by structures may be anticipated ' Removal of shallow contaminated soil was proposed in the 12 August 2004 work plan for Fall 2004 However, upon discussion with your agency WOS agreed to further characterization in the field north of the site CPT and Hydropunch ' methodology were employed in an attempt to define the plume's leading edge and characterize any threat posed to neighboring property shallow domestic 1 wells Trenching, by WOS, in the area between MW No 2 (east fence line and the concrete block wall secondary containment area between MVVs No 1 and No 6 in November 2004 revealed soil contamination The findings were discussed and attached in an earlier ( December 2004) quarterly report report and its ATTACHMENT 8, FIELD INVESTIGATION SHALLOW SOIL, 22 November 2004 ' Access to the contaminated soil area is important to WOS for continued operations at the Acampo facility ' A summary of all ground water sampling events is included Reference ATTACHMENT 2, SUMMARY OF LAB RESULTS included with the report