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<br /> OmMERLY GR0uNOWATm mow roma REPORT
<br /> 1605 SOLth Et Dorado.Stockton.Cwitorni,7 - -
<br /> 1 1.0 INTRODUCTION
<br /> This report documents the results of the first quarterly groundwater monitoring conducted
<br /> by Aegis Environmental, Inc. (Aegis),on October 17, 1991,at the Exxon Company, U.S.A.
<br /> (Exxon),service station located at 1605 South El Dorado in Stockton,California(Figure 1).
<br /> The monitoring included collection of depth-to-ground-water measurements and water
<br /> samples from the three wells, MW-1, MW-2, and MW-3, located on site (Figure 2). This
<br /> i report is based, in part, on information obtained by Aegis from Exxon, and is subject to
<br /> modification as newly acquired information may warrant.
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<br /> 2.0 SITE DESCRIPTION
<br /> f p The subject site is located between South EI Dorado Avenue and Center Street in the City
<br /> of Stockton, San Joaquin County, California (Figure 1). The site is situated in a
<br /> P1 commercial/residential/light industrial area of southern Stockton. The site is bound on
<br /> t.i the north by East 2nd Street, on the east by South El Dorado Avenue, on the south by
<br /> a car wash facility, and on the west by Center Street.
<br /> i The Exxon service station is presently an active station. The store retails regular-leaded,
<br /> regular-unleaded, and extra-unleaded gasolines. The station facilities include a building,
<br /> I` Y three dispenser islands, and three underground storage tanks (UST) with associated
<br /> E product piping. The three UST are located immediately south of the dispenser islands
<br /> on the southern half of th site. The type of construction and the installation dates of the
<br /> (° UST are unknown. Figure 2 shows the location of the site's above-ground and
<br /> uriderground features.
<br /> 3.0BACKGROUND
<br /> On February 5, 1991, a ground penetrating radar (GPR) survey was performed by
<br /> NORCAL Geophysical Consultants; Inc., of Petaluma, California. The survey was
<br /> performed in the area of the existing UST basin to locate existing underground facilities
<br /> i for avoidance during drilling. Upon completion of the GPR survey, two soil borings were
<br /> drilled on February 22, 1990, at an angle of 30 degrees from vertical, adjacent to the
<br /> existing UST basin (Figure 2). The borings were advanced using an 8-inch-diameter
<br /> hollow-stem auger. A total of 60 feet of auger was utilized in each boring, with a final
<br /> sample drive of 18 inches achieving a total depth of 61.5 feet along the 30-degree angle.
<br /> The actual vertical depth penetrated by the borings was approximately 53 feet below
<br /> existing grade. Soil samples collected from the two soil borings were analyzed for total
<br /> petroleum hydrocarbons (TPH), as gasoline, benzene, toluene, ethylhonzene, total
<br /> xylenes(BTEX),ethylene dibromide, 1,2-dichloroethane,and total lead. Results of the soil
<br /> boring and sampling were reported by Aegis to Exxon, in a "Pre-Tank Replacement Site
<br /> E Assessment Results Report," dated March 5, 1991.
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