ARCHIVED REPORTS XR0006434 - Laserfiche WebLink

Home Browse Search

' Working To Restore Nature below surface grade, with a direction of flow toward the northeast and approximate hydraulic gradient of 0 001 Gasoline hydrocarbons have been detected in soil near the tank cavity and groundwater beneath the site Data collected from the three wells during previous monitoring ' events are presented in Table 1 In addition, water quality data for an onsite domestic water well are provided in Table 1 ' In October 1993, RESNA observed dnlling of three offsite (HP-2, HP-3 and HP-4) and three onsite soil borings (HP-1, HP-5, and HP-6) to groundwater (RESNA, January 26, 1994, Report 123020 01) Groundwater samples were collected from these bonngs using a Hydropunch ' sampling device RESNA also observed drilling of three additional soil borings onsite near the UST's (B-1, B-2, and B-3), these borings were converted to vapor extraction wells VW-1, VW- 2, and VW-3 Residual gasoline hydrocarbons were detected in soil samples obtained from ' borings B-1, B-2, and B-3, but were not detected in the other onsite or offsite borings. Dissolved gasoline hydrocarbons were not detected in groundwater from onsite or offsite ' borings GROUNDWATER MONITORING: SECOND QUARTER 1994 ' On June 9, 1994, a technician from RESNA measured the depth to water and subjectively analyzed groundwater samples from the three monitoring wells (Table 1) The technician observed sheen in wells MW-1 and MW-2 Groundwater samples were collected from well 1V-W-3 and the onsite supply well; wells MEW-1 and MW-2 were not sampled because they had product sheen Our field procedures are described in an attachment to this report ' The surveyed elevations and the depth to groundwater measurements, summarized in Table 1, were used to evaluate the potentiometnc surface beneath the site The groundwater flow ' direction on June 9, 1994, was generally to the southwest with the hydraulic gradient of approximately 0 005 (Plate 3) The water samples were analyzed for total petroleum hydrocarbons as gasoline (TPHg) using modified Environmental Protection Agency (EPA) Method 8015 and benzene, toluene, ethylbenzene, and total xylene isomers (BTEX) using EPA Method 8020 The samples were ' analyzed at Sparger Technology, Inc. in Sacramento, California (Hazardous Waste Testing Laboratory Certificate No 1614) Results of analyses indicated TPHg and BTEX concentrations were below laboratory detection limits in well MW-3 and the supply well The results of ' analyses are summarized in Table i Copies of the laboratory Analysis Reports and Chain of Custody Record are attached 06211gou 123620.1 2