FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

it DAMES & MOORE ® A DAMES&Mt70RE GRotaP COMPgfVy `� Mr. Mick Hardin September 26, 1997 Page 2 L+ ' Collecting soil samples from each boring at 10, 15 and 25 feet bgs or the depth dictated by soil conditions and chemically testing the soil samples for total petroleum hydrocarbons as diesel (TPH-d) and benzene, toluene, ethyibenzene, and xylenes (BTEX) by EPA Methods 8015 modified and 8020; and, Preparing and submitting a data transmittal letter of the analytical results of the soil sampling with a plot plan and brief summary of the results. 3.0 Feld Methodology Prior to drilling, the location of the former UST was identified from the maps provided to Dames & i.. Moore by BNSF. Possible utility locations were located by Subdynamic Locating Services and PG&E. In accordance with health and safety protocol, an Organic Vapor Meter (OVM) was used to monitor the concentration of total organic vapors present during drilling and sampling. Geoprobe sampling of l six boreholes was conducted by Gregg Drilling of Martinez, California. Mr. Steve Sasson of the Stockton County Health Department was present during the boring and sampling activities. Samples were attempted at 10, 15 and 25 feet below ground surface. The dense clayey soil found at the Site prevented drilling to the desired depth in five out of the six boreholes. A log of the soil conditions encountered for each boring is presented in Appendix A. The following depths were achieved in each 4 of the boreholes: 251/2 feet in DM-1 with samples taken at 10, 15 and 25 feet; 8'/2feet in DM-2 with no samples taken, 61/2 feet in DM-3 with one sample taken at 6 feet, 4 feet in DM-4 with no samples LA taken, 2 feet in DM-5 with no samples taken, and 71/2 feet in DM-6 with one sample taken at 7 feet. A list of sample numbers and the corresponding identification numbers is presented in Table 1. Samples were collected in brass sample rings, capped and sealed in ziploc bags. All sample containers bound �. for the analytical laboratory were labeled with the following information: date, time, sample identification number, client name, and requested analysis. The sample containers were then placed in a cooler chilled with ice for transportation to the laboratory under chain of custody documentation. Chemical analysis of the soil samples was performed by Entech Environmental Laboratories, of Sunnyvale California, a state certified analytical laboratory. Soil samples were tested for TPH-D by modified EPA Method 8015, and BTEX by EPA Method 8020. The detection reporting limit was 1.0 mg/kg for TPH-d, and 0.005 mg/kg for BTEX. The final sampling locations were approved by Mr. Sasson as an adequate characterization of the subsurface conditions. i� j A 156551 G416nsfstkn.d- _ 1r