|
Soil and Groundwater Investigation Report
<br /> Vernalis Pump Station August 2006
<br /> Joaquin Valley oil fields in Bakersfield to a refinery in Richmond, California. The OVP was located
<br /> along the northeastern side of the site and parallel to the existing UPRR tracks and Highway 33.
<br /> Historical site features included a boiler house, a pump house, a sump, an incinerator, a rubbish pit,
<br /> cottages, and three bulk-storage tanks with secondary containment structures. These surface structures
<br /> were located on the Arcos property. Several pipelines entered the pump station from the east corner of
<br /> the Arcos property, conveying flows to the heater house and exiting to the north across the Bellini
<br /> property.
<br /> The property located immediately southeast of the Arcos property was the former Tidewater Associated
<br /> Oil Company(TAOC)Ohm pump station. The TAOC pipeline was located on the east side of Highway
<br /> 33 within the UPRR ROW. According to the 1995 Environmental Site Assessment,the former TAOC
<br /> Ohm pump station was owned by Vernalis Enviropur-West and was used for bulk storage of petroleum
<br /> and oil products (Geological Technics, Inc. [Geologic Technics], 1995).
<br /> 2.2 HYDROGEOLOGIC SETTING
<br /> The site is situated within the Central Valley Physiographic Province of California,has a relatively flat
<br /> topography that slopes gently downward to the northeast, and is at an elevation of approximately 107 feet
<br /> above mean sea level. Groundwater in the upper water-bearing zone flows in a northeasterly direction at
<br /> a gradient of 0.001 feet per foot(ft/ft)and is hydraulically controlled by low-permeability,unconsolidated
<br /> sediments. Generally, depth to groundwater near the site varies from 20 to 40 feet bgs. Soils encountered
<br /> appear to be fine-grained unconsolidated sediments, consisting mainly of lean clays and silts and clayey
<br /> and silty sands,with smaller quantities of poorly graded sand and gravel.
<br /> 2.3 PREVIOUS ENVIRONMENTAL ACTIVITIES
<br /> Bellini Property
<br /> 1994 and 1995 Site Investigations. Geological Technics performed a Preliminary Environmental Site
<br /> Assessment(Geological Technics, 1995),which included the review of public records and aerial
<br /> photographs, a site reconnaissance,personal interviews, and a subsurface investigation. On January 20,
<br /> 1995, Osterberg and Stewart, Inc.,under the supervision of Geological Technics, drilled soil borings SB-I
<br /> and SB-2. Total extractable petroleum hydrocarbons were detected in soil samples collected from SB-2 at
<br /> concentrations ranging from 11,800 milligrams per kilogram(mg/kg)to 17,200 mg/kg. In addition,total
<br /> recoverable petroleum hydrocarbons were detected in the soil sample collected from SB-2 at a
<br /> concentration of 17,600 mg/kg.
<br /> 1998 Site Investigations. In July of 1998, Gregg Drilling and Testing,Inc. (Gregg Drilling),under the
<br /> supervision of Radian International LLC (Radian), drilled six soil borings(SB-3 through SB-8) and
<br /> installed four groundwater monitoring wells(MW-I through MW-4). TPH quantified as diesel(TPHd)
<br /> and TPH quantified as motor oil(TPHmo)were detected in soil samples from SB-3 through SB-8,
<br /> MW-I, and MW-2. Maximum concentrations of TPHd and TPHmo were 9,800 mg/kg and 9,000 mg/kg,
<br /> respectively. TPH quantified as gasoline(TPHg)were detected in SB-8,MW-1, and MW-2,with a
<br /> maximum concentration of 270 mg/kg. TPHd concentrations were also present in groundwater samples
<br /> collected from MW-2 through MW-4,with a maximum concentration of 230 micrograms per liter(gg/L).
<br /> Approximately 6 inches of separate-phase oil(SPO)was present in MW-1;therefore, groundwater from
<br /> this well was not sampled(Radian, 1998).
<br /> In October and November of 1998, Geomatrix Consultants,Inc. (Geomatrix) sampled groundwater from
<br /> monitoring wells MW-2 through MW-4. TPHd were not detected in any of the samples.
<br /> 2002 Site Investigations. In May of 2002, Gregg Drilling,under the supervision of Geomatrix, advanced
<br /> soil borings SB-9 through SB-14. TPH quantified as crude oil(TPHc)were detected in soil samples
<br /> 2 From Science to Solutions-
<br />
|