ARCHIVED REPORTS XR0003751 - Laserfiche WebLink

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e n v iros. Soil chemical analytical data are presented in Table 2 and shown on Plate 2 Certified analytical reports for soils are contained in Appendix B 3 3 Ground Water Chemical Analytical Data Ground water samples were collected from the newly installed wells (Wells MW-6, MW-7, and MW-8) on February 6, 1997 as part of the normal first quarter 1997 monitoring event The results of this monitoring event have been reported in Enviros' March 4, 1997 "Quarterly Monitoring Report-First Quarter 1997" The chemical analytical data from this monitoring event has been included with this report as Table 3 The results of the ground water sampling of the three newly installed wells are summarized below Ground water samples collected from Wells MW-6 and MW-7 contained ND levels of TPPH and benzene MTBE was detected in Well MW-6 at a concentration of 79 parts per billion (ppb) and was ND in MW-7 Ground water samples collected from Well MW-8 contained TPPH at a concentration of 76,000 ppb, benzene at a concentration 800 ppb, and MTBE was ND at <1250 ppb The ground water chemical analytical data are presented in Table 3 and shown on Plate 2 . 4.0 CONCLUSIONS Lithology encountered during the drilling of the exploratory soil borings consisted of clay, silt, clayey sand, silty sand, sand, and gravel to a depth of approximately 46 fbg First encountered ground water occurred in the borings at depths of 8 5 to 9 fbg Ground water in the wells later stabilized at approximately 5 6 to 7 8 fbg Ground water flow direction was determined to be generally southwesterly across the site and northwesterly north of the site The hydraulic gradient was calculated to be 0 006 Petroleum hydrocarbons were not detected in soil samples from Borings MW-6 and MW-7 Petroleum hydrocarbons were not detected in soil samples collected at the depths of 5, 10, and 15 fbg in Boring MW-8 The soil sample collected at 20 fbg from Boring MW-8 contained 960 ppm TPPH and 5 2 ppm benzene Boring RW-B 1 was drilled within the former source area of the release to a depth of 46 5 fbg to delineate the vertical extent of petroleum hydrocarbons in the soil Soil samples from this boring contained TPPH concentrations ranging from ND to 82 ppm and benzene concentrations ranging from 0 014 to 16 ppm The deepest sample collected from this boring was collected at the depth of 46 5 fbg and contained ND levels of TPPH and 0 014 ppm benzene Ground water samples collected from Well MW-6, located northeast of the site and northeast of Well MW-4, contained ND levels of TPPH and BTEX MTBE was detected in Well MW-6 at a concentration of 79 ppb • The lateral extent of petroleum hydrocarbons in ground water has been delineated to the northwest by Well MW-7 which contained ND levels of TPPH, BTEX, and MTBE 371 4