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KLEINFELDER <br /> 1 EXECUTIVE SUMMARY <br /> According to Chevron Pipeline Company, an 18-inch crude oil pipeline ruptured on December 4, <br /> 2003 at the subject site, releasing an estimated 750 barrels of crude oil to site soil (approximately <br /> 31,500 gallons). The pipeline carries crude oil from oil fields near Bakersfield to refineries in the <br /> +a Bay Area. The pipeline was reportedly ruptured during ripping of the soil for agricultural <br /> purposes. <br /> Chevron subsequently conducted emergency response activities in an attempt to limit migration <br /> of crude oil. Chevron reportedly created soil berms to restrict lateral migration of oil, recovered <br /> free oil with a vacuum truck and removed oil-impacted soil. Chevron estimated that <br /> approximately 400 barrels were recovered (16,800 gallons) and that approximately 350 barrels <br /> still remain in onsite soil at the site (14,700 gallons) at that time. Based upon aerial photos <br /> (provided by Chevron shortly after the release) of the spill area, it appears the largest amount of <br /> oil settled to the east and northeast of the rupture following the crop lines and surface <br /> topography. <br /> San Joaquin County Environmental Health Division (SJC/EHD) requested a workplan for the <br /> purpose of assessing the limits of contaminated soils and groundwater quality beneath the site. <br /> That workplan (File no. 42428 / ST04P118) was written by Kleinfelder, dated March 22, 2004 <br /> and was submitted to SJC/EHD for review and comment. This workplan was subsequently <br /> approved by SJC/EHD. This document details Kleinfelder's findings from implementation of <br /> that workplan. <br /> On May 19 and 20 2004 a pushprobe soil and <br /> Y p p groundwater assessment was conducted. A total <br /> of twenty nine (29) push probes were advanced during the field activities. A total of twenty two <br /> 1 <br /> 4-point composite soil samples, 26 discrete soil samples and four groundwater samples were <br /> submitted for chemical analyses for purgeable and extactable petroleum hydrocarbons and <br /> benzene,toluene, ethylbenzene, and xylenes (BTEX) compounds. Twenty five (25) shallow probes <br /> were advanced to total depths ranging from approximately 8 to 24 feet below ground surface <br /> (bgs). Four deeper groundwater pushprobes were advanced to total depths ranging from 44 to 58 <br /> �{ feet bgs. Groundwater was noted approximately 43 feet bgs in these four deeper borings. <br /> A summary of Kleinfelder's findings are summarized as follows: <br /> 1) Twelve discrete soil samples were collected and analyzed from perimeter pushprobe <br /> borings at depths ranging from 5 to 43 feet bgs. Based on this data, it is Kleinfelder's <br /> opinion that petroleum impacted soil has not migrated laterally a significant distance <br /> beyond the footprint area. Please note this finding does not include potential soil vapor <br /> o <br /> migration of volatile compounds, since soil vapor sampling was not conducted as part of <br /> i this assessment. <br /> 2) A total of four grab groundwater samples were collected, one in the footprint area and <br /> three from perimeter locations. Relatively low concentrations of petroleum constituents <br /> 44843.T03/ST04RIO25 Pagel of 16 <br /> Copyright 2004 Kleinfelder,Inc. August 6,2004 <br /> 1 <br />