ARCHIVED REPORTS XR0000629 - Laserfiche WebLink

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• Installed three (3) soil borings to a depth of 25 feet on 20 and 21 March 199L Fouvm"ch monitoring.wells were installed in each boring to monitor the free-water table in order to intersect light non-aqueous phase liquids(LNAPLs). 3 • Collected soil samples from each soil boring at a minimum of five foot intervals throughout the unsaturated zone. One sample from each boring was submitted for laboratory analysis for total petroleum hydrocarbons (TPH) by EPA Method 418.1, and for the fuel constituents benzene, toluene. ethyl benzene and xylene X (BTEX)by EPA Method 8020. • Screened the soil headspace in the field with an organic vapor analyzer (OVA) to evaluate relative concentrations of organic vapors in the soil. Soil samples that were submitted for analysis were selected based on these OVA field readings. v � r Developed all three monitoring wells on 22 March 1991 by mechanical surging g , and bailing. Sampled the monitoring wells on 25 March 1991 after following applicable sampling protocols. Samples from each well were analyzed for TPH by EPA _ Method 418.1 and BTEX by EPA Method 602. 004 • Surveyed each monitoring well for exact elevation using the USGS Mean Sea Level (MSL)datum. • Measured water levels at well completion, before and after well development, and before and after water sampling, i • Monitored each well for possible free-product (LNAPL) on top of the water table at the completion of each well. • Comple-'A a sensitive receptor survey in accordance with Exxon guidance information and was submitted as a separate document. L This report serves as a Final Report which summarizes field activities and w investigation reports. In addition to the above scope of work, a detailed Workplan and a site-specific Health& Safety Plan for this site investigation was prepared as part of permitting requirements for Public Health Services, San Joaquin County, L 1-2 175-07.85 4/24N1