|
ChevronTexaco—U.S. Can/Welty Road, Vernalis, CA. Project No. 06-6102-00-5394-101
<br /> March 10, 2004,2004 Page 2 of 6
<br /> liquid and dry fertilizers since 1969. In addition, a former Union Oil gas station,reportedly located
<br /> northeast of the site, operated from approximately 1972 until the mid 1980s.
<br /> BACKGROUND
<br /> The following information is a brief history of previous environmental investigations conducted at and in
<br /> the vicinity of the site:
<br /> 1995: March 30—ERM, Inc. collected 11 surface soil samples (S-1 through S-11)in the vicinity of the
<br /> can fabrication plant waste/bum pit area. Oil and grease (O&G)was detected in four of the soil
<br /> samples(S-4, S-5, S-6, and S-8)and concentrations ranged from 1,500 milligrams per kilogram
<br /> (mg/kg)to 5,200 mg/kg. Gasoline was detected in two of the soil samples(S-4 and S-5)and
<br /> concentrations ranged from 20 mg/kg to 6,000 mg/kg.
<br /> May 9—ERM,Inc. conducted four hand borings(HB-3,HB-4, HB-5, and HB-6)to 10 feet below
<br /> ground surface (bgs)in order to establish the lateral and vertical extent of petroleum-affected soil
<br /> near the northeastern side of the can fabrication plant. Petroleum-affected soil was identified in
<br /> three borings. Benzene,toluene, ethylbenzene,xylenes(BTEX), and trichloroethene(TCE)were
<br /> the main compounds detected in the soil samples. Concentrations of these constituents varied
<br /> from 0.4 mg/kg to 16 mg/kg.
<br /> November 29—WHF, Inc. and SEMCO excavated an exploratory trench to 19 feet bgs(near the
<br /> northeastern side of the can fabrication plant)and collected one soil sample at 14 feet bgs. Total
<br /> petroleum hydrocarbons as diesel (TPHd),total petroleum hydrocarbons as motor oil(TPHmo),
<br /> BTEX, and TCE were detected in this sample. Concentrations of TPHd and TPHmo were 8,600
<br /> mg/kg and 3,400 mg/kg,respectively. The contents of the wastelbum pit were also removed.
<br /> 1996: March 6—WHF, Inc., advanced six hand borings(RB-1 through RB-6)to a depth of 2.5 feet bgs
<br /> in the vicinity of the waste/bum pit area. TPHmo was detected in four soil samples: RB-1,RB-2,
<br /> RB-3, and RB-5. Concentrations of TPHmo ranged from 50 mg/kg to 80 mg/kg.
<br /> September 30—Three soil borings(SB-1, SB-2, and SB-3)and one monitoring well (MW-1)
<br /> were installed by Geological Technics in the vicinity of the former condensate pipe outlet. Total
<br /> petroleum hydrocarbons as gasoline(TPHg),TPHd, and TPHmo were detected in the majority of
<br /> the soil samples. Concentrations ranged from<1 mg/kg to 11,300 mg/kg.
<br /> 1997: February 27—Three cone penetration test(CPT)borings(CPT-1, CPT-2, and CPT-3)were
<br /> advanced by Gregg Drilling under the supervision of Radian International (Radian).
<br /> Groundwater samples were collected during this investigation in order to determine if TCE had
<br /> impacted groundwater. Groundwater samples were collected at depths of 35 feet and 50 feet bgs.
<br /> No TCE was detected in any of the samples. Cis-1-2-dichloroethene(C-1-2-DCE), a degradation
<br /> product of TCE,was detected in one of the groundwater samples analyzed.
<br /> 1998: July 15, 22, and 23—Six soil borings(B-1 through B-6)and three monitoring wells(MW-2,
<br /> MW-3, and MW-4)were installed at the site by Radian. Concentrations exceeding 100 mg/kg of
<br /> TPHg, TPHd, and TPHmo were detected in borings B-1, B-4, B-5,B-6, and well boring MW-2.
<br /> Concentrations were detected up to 21,000 mg/kg in these samples.
<br /> 1999: November 9 and 11 —Gregg Drilling,under the supervision of Geomatrix Consultants,advanced
<br /> seven soil borings(GMX-1 through GMX-7) for soil and groundwater samples. Total petroleum
<br /> hydrocarbons as crude oil (TPHc)were detected at a concentration of 10,000 mg/kg in one soil
<br /> sample from GMX-3 collected at the depth of 37 feet bgs. TPHg and TPHd were detected in
<br /> groundwater sample GMX-6 at concentrations of 110 micrograms per liter(ug/L)and 92,ug/L,
<br /> respectively.
<br />
|