FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

' CGe'l' cafTechinics Inc. • • Page age 2 SGWI Report Project No.: 774.2 April 1, 1999 ' 1.0 SCOPE OF INVESTIGATION On March 11, 1999, Geological Technics Inc. drilled 10 boreholes using GeoProbe direct ' push method to further investigate the extent of soil and groundwater impacted by petroleum hydrocarbons. These boreholes were drilled in the following locations: 1. Four boreholes were drilled around the Former Storage Area 2. Four boreholes were drilled around the outside of the Warehouse 3. One borehole was drilled south of the Aboveground Hot Melt/Asphalt Storage Tanks ' 4. One borehole was drilled west of the Former Paint/Ink Storage Shed 1.1 Borehole Drilling& Soil Sample Collection ' The Site Map in Figure 2 shows the locations that the boreholes were drilled. The boreholes were drilled with a GeoProbe rig owned and operated by V&W Drilling of Rio ' Vista, CA (C57# 720904). The GeoProbe advances a continuous coring tool with a pneumatic hammer to a selected depth. The soil sample enters an acetate cylinder contained in the coring tool. Upon filling, the coring tool is pulled from the hole and the cylinder is ' removed. The cylinder is then cut and the selected interval is preserved for laboratory analysis. The remainder of the sample was used for geologic logging. All soil samples were capped with plastic end caps, labeled and placed in a cooler at 4° Celsius for transport to the laboratory following Chain of Custody protocol. ' The GeoProbe borings were advanced to a depth of 12 feet bg s, the depth to groundwater P during the drought of the early 1990's. Soil samples were generally collected at three-foot intervals for geologic logging and laboratory analyses. • 3 feet • 6 feet (current capillary fringe) • 9 feet • 12 feet(former capillary fringe) Two soil samples, from most of the boreholes and 3 or 4 in selected other boreholes, were ' submitted to the Sherwood Labs for analysis. Since only selected samples were to be submitted for laboratory analysis, a screening process was used to gather additional information through field observation. This information was used to determine which ' samples were to be analyzed. All current capillary fringe samples (6 foot) and the historic capillary fringe samples (12-foot) were tested. ' The following characteristics were noted in the screening process: • sediment type, especially grain size and clay content • moisture content • visible evidence of contamination, i.e., color change due to reduction of iron or discoloration from hydrocarbons and other pollutants • readings above background on a organic vapor meter (OVM) ' The OVM is a portable photo ionization detector that uses a 10.0 eV lamp to detect compounds with ionization potential below 10.0 eV (hydrocarbon range). Boring logs,