COMPLIANCE INFO - Laserfiche WebLink

Home Browse Search

Ms. Donna DiRocco May 29, 1997 Page 2 of 3 Subsurface Investigation Versar performed a subsurface investigation at the Site the evening of May 16, 1997. The investigation was conducted by Versar Associate Geologist Mr. Vernon P. Elarth, and the soil boreholes were drilled by Vironex, Incorporated (C57 License No. 705927). City and County permits were obtained prior to conducting the subsurface investigation. Prior to conducting the subsurface investigation, Versar contacted Underground Service Alert(USA), as required by law, and contracted California Utility Surveyors to locate potentially unmarked, underground utilities at the Site. Based on a review of a USGS topographic map of the Site area, the direction of groundwater flow at the Site was inferred to be to the southwest. The investigation included collecting soil and groundwater samples from four soil boreholes installed at the locations shown on Figure 3, in Attachment I. Boreholes BH-1, BH-2, and BH-3, were drilled southwest of and downgradient from the former auto repair facilities to assess if there are releases to soil or groundwater from former Site activities. Encountered subsurface conditions at the Site comprised poorly sorted, moderate-brown silty sand from just below the asphalt to the maximum depth explored of approximately 26 feet below ground surface (bgs) . Stabilized groundwater levels were recorded at approximately 18 feet bgs during the investigation on May 16. Laboratory Results Three soil samples and one groundwater grab sample were collected from each of the four boreholes drilled at the Site. Soil samples were collected from depths of 5.5, 10.5 and 15.5 feet bgs from each borehole. One soil and groundwater grab sample from each borehole were submitted to McCampbell Analytical Laboratories (California Department of Health Services Certification No. 1644) for analysis for total petroleum hydrocarbons as gasoline (TPH-G), TPH as diesel (TPH-D); benzene, toluene, ethylbenzene, and xylenes (BTEX); oil and grease; and Leaking Underground Fuel Tank(LUFT) 5 Metals, which include: cadmium, chromium, lead, nickel, and zinc. Total metals were reported in soil results and dissolved metals were reported in groundwater results. The soil sample submitted for analysis was collected from a depth of 15.5 feet bgs from each borehole which corresponds to the approximate depth of the soil groundwater interface (capillary fringe). The soil samples analyzed from the capillary fringe of each borehole did not contain TPH-D, TPH-G, BTEX, or oil and grease at or above the laboratory's reporting limit for each test method. Concentrations of chromium, nickel, and zinc were detected in the soil samples analyzed from the Site. These levels are consistent with the USGS's published background H:\PROJECTS\BOFA\FUPON\IUPON.WPD