Laserfiche WebLink
Metadata
Document management portal powered by Laserfiche WebLink 9 © 1998-2015 Laserfiche. All rights reserved.
Project No S8100-06-IIB <br /> April 19, 1996 <br /> ' 3 0 ]l:IWESTIfGATWE METHODS <br /> ' 3 1 Drilling and Soil Sample Collection <br /> Soil borings were advanced utilizing a truck mounted drill rig equipped with 254-millimeter(10-inch) <br /> outside diameter hollow stem augers Four soil borings (MW-9 through MW-12) were advanced to a <br /> maximum depth of 24 4 meters (80 feet) bgs in an attempt to define the vertical and lateral extent of <br /> residual petroleum hydrocarbons in soil Groundwater monitoring wells were constructed in each <br /> boring to evaluate the groundwater flow direction and gradient, and to attempt to define the lateral <br /> ' limits of tlit;.dissolved phase petroleum hydrocarbon groundwater plume The placement of the <br /> monitoring wells was based upon the location of the existing monitoring wells and the historical <br /> groundwater data <br /> One soil boring (VW-2), advanced to a maximum depth of 213 meters (70 feet) bgs, was located <br /> adjacent to the former UST excavation to aid in evaluating the maximum TPHg and TPHd <br /> concentrations in the vadose zone soil in the central portion of the plume and for the subsequent <br /> installation of a vapor extraction well Soil boring SB3, located within the former pump island, was <br /> advanced to a maximum depth of 6 1 meters (20 feet) bgs in order to evaluate vadose zone soil <br /> immediately beneath the former pump island The locations of the vapor extraction and monitoring <br /> wells are depicted on the Site Plan,Figure 2 <br /> Soil samples were collected from the borings at approximate 1 5 meter (five-foot) vertical intervals <br /> utilizing a 50 8-mm (two-mch) diameter split spoon sampler equipped with 152 4-mm-long by 50 8- <br /> mm(six-inch-long by two-inch)diameter stainless steel sample tubes to facilitate sample handling and <br /> storage The borings were logged under the supervision of a California Certified Engineering <br /> Geologist utilizing the Unified Soil Classification System The sample tubes were capped, labeled <br /> and chilled pending transport to an analytical laboratory Soil samples were field screened with a <br /> flame-ionization detector (FID) to assess possible qualitative indicators of volatile organic <br /> compounds The soil sample locations and FID readings are recorded on the boring/well logs <br /> presented in Appendix B <br /> Quality assurance/quality control procedures provided during the field exploration activities included <br /> cleansing/rinsing of the sampling equipment and steam cleaning the augers prior to and between <br /> borings Cleansing/rinsing of the sampling equipment was performed prior to the collection of each <br /> soil sample by washing the equipment with a trisodium phosphate solution followed by subsequent tap <br /> water and deionized water rinses <br /> i <br />' Drill cuttings generated from the drilling operations were placed in DOT 17-H 55-gallon drums and <br /> stored onsite pending the receipt of analytical data and subsequent disposal following regulatory <br />' protocol Ecologix Environmental Services removed the drums from the site on April 11, 1996 for <br /> disposal at the TPS Technologies Incorporated Soil Recycling Facility in Richmond,California <br />' 5 <br />