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M. Scott Mansholt - 2 - 13 December 2006
<br /> Chevron/UPRR — TAOC Trac 'ravel Pits
<br /> Previous Investigations
<br /> Kleinfelder, 1989
<br /> In 1989 Kleinfelder collected an "oily residue" (black, hard, and asphaltic appearance) sample
<br /> from a shallow hole found on the site. The sample was analyzed for oil and grease, total
<br /> recoverable petroleum hydrocarbons (TRPH), volatile organic compounds (VOCs), semi-
<br /> volatile organic compounds (SVOCs), California Assessment Manual (CAM) metals,
<br /> organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and dioxins/furans. The
<br /> sample contained 34,000 milligrams per kilogram (mg/kg) TRPH, 49,000 mg/kg oil and grease,
<br /> 10.5 mg/kg chrysene, 7.4 mg/kg toluene, xylene 5.9 mg/kg and 280 mg/kg zinc. Kleinfelder's
<br /> report did not provide analytical results of the other metals. Low concentrations of total
<br /> pentad ichlorobenzo-p-dioxin congeners (PeCDD, 0.0011 mg/kg) and total
<br /> heptachlorodibenzo-p-furan congeners (PeCDF, 0.00019 mg/kg) were detected. PCBs and
<br /> OCPs were not detected at or above the laboratory reporting limits.
<br /> Based on a 1963 aerial photograph, Kleinfelder advanced ten, 15-foot soil borings in certain
<br /> areas of the site where it was interpreted that oily waste might have been buried. Oily soil was
<br /> encountered in seven borings, generally in the upper five-feet of soil except one area where
<br /> affected soil was encountered at 10-feet. Soil samples from beneath the affected soil were
<br /> submitted for analysis of TPH; none was detected except for 33 mg/kg in a sample collected
<br /> 1.5 feet below the bottom of oily soil.
<br /> In addition, a surface water sample and a sediment sample were collected from a former
<br /> drainage pond in the southeast corner of the site. Samples were analyzed for TRPH, OCPs,
<br /> herbicides, metals (arsenic, copper, lead, selenium, and zinc), and total nitrate and sulfate
<br /> (surface water sample only); none were detected. Low levels of metals (copper and zinc at
<br /> 0.16 and 0.12 milligrams [mg/L], respectively, and sulfate (28 mg/L) were detected in surface
<br /> water. Arsenic at 11 mg/kg, copper at 44 mg/kg, 14 mg/kg lead and zinc at 59 mg/kg were
<br /> detected in sediment. Low concentrations of DDT, DDD, and DDE at less than 150
<br /> micrograms per kilogram (ug/kg; 0.150 mg/kg) were detected in the sediment; the U.S. EPA
<br /> Region 9 PRGs respectively, are - 1.7, 1.7, and 2.4 mg/kg (i.e, 1 ,700 and 2,400 ug/kg).
<br /> The analytical and visual results indicated that there was limited to no vertical migration of
<br /> petroleum hydrocarbons below visibly affected soil. Kleinfelder concluded that affected soil
<br /> appeared to be present primarily in the "northeast half of the site" and was limited to the upper
<br /> five feet with the exception of 33 mg/kg TPH at 11.5-feet in one boring.
<br /> Pacific Environmental Group, 1998
<br /> In September 1998, Pacific Environmental Group (PEG) identified and removed the wooden
<br /> pipeline and an 8-inch diameter steel pipeline that extended onto the northwest corner of the
<br /> site, along the existing railroad easement. Crude oil was observed and approximately 1 ,750
<br /> tons of impacted soil was removed and transported to Forward, Inc. Landfill for disposal.
<br /> NG Chemical (contractors to PEG) excavated 35 exploratory investigation trenches, generally
<br /> 10-feet deep, primarily within the gravel pit and throughout the northeast section of the site to
<br /> evaluate the vertical extent of affected soil (samples were not collected for analysis). Visual
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