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December 22, 1998
<br /> 41017 002 Harding Lawson Associates
<br /> Mr Michael Kath
<br /> ' PHS/EHD
<br /> Page 6
<br /> ' • Detected TPHd concentrations ranged from 1,700 to 3,000 milligrams per kilogram (mg/kg)
<br /> • Detected TPHmo concentrations ranged from 3,200 to 5,200 mg/kg
<br /> • Maximum detected concentrations of benzene, toluene, ethylbenzene, and total xylenes were 0 022
<br /> mg/kg, 0 010 mg/kg, 0 054 mg/kg, and 0 14 mg/kg, respectively
<br /> • Four discrete soil samples (SP-1, SP-2, SP-3, and SP-4) were collected from stockpiled soils adjacent to
<br /> the excavation that were potentially to be used in backfilling the excavation
<br /> • TPHd concentrations ranged from less than reporting limits to 540 mg/kg
<br /> • TPHmo concentrations ranged from less than reporting limits to 2,000 mg/kg
<br /> ' • No detectable BTEX was present in these samples
<br /> Second Sampling Round
<br /> Twelve soil samples were collected on July 15, 1998, following the complete removal of the UST and the first
<br /> phase of overexcavation of impacted soils adjacent to the former UST sidewall (Plate 3) One stockpile
<br /> composite sample was collected on July I6, 1998 to profile impacted soils stockpiles for offsite disposal
<br /> These samples consisted of the following
<br /> • Two UST removal soil samples (T-5 and T-6) were collected from soil beneath the former concrete bottom
<br /> of the UST in the northern portion of the excavation
<br /> • No detectable TPHd, TPHmo, or BTEX was present in either sample
<br /> o Ten soil samples (T-7 through T-16) were collected from along the ditch created by overexcavation of
<br /> impacted soil adjacent to the former UST sidewall
<br /> ' • S ix of these samples (T-7, T-10, T-13, T-14, T-15, and T-16) did not contain detectable TPHd,
<br /> TPHmo, or BTEX
<br /> • Four of these samples (T-8, T-9, T-11, and T-12) were collected from soils which were then
<br />' subsequently excavated in the second-round of overexcavation These samples contained the
<br /> following detectable petroleum hydrocarbons
<br /> • TPHd concentrations ranged from 8 1 to 8,100 mg/kg
<br /> • TPHmo concentrations ranged from less than reporting limits to 9,600 mg/kg
<br /> • Benzene was not detected in any of these four samples
<br /> • Maximum detected concentrations of toluene, ethylbenzene, and total xylenes were 0 038
<br />' mg/kg, 0 0093 mg/kg, and 0 16 mg/kg, respectively
<br /> • Sample T-8 was selected by PHS/EHD staff for semivolatiles analysis by EPA 8270
<br /> • With the exception of 2-methylnaphthalene (6 0 mg/kg) and phenanthrene (3 0 mg/kg)
<br /> none of the other EPA 8270 analytes were detected
<br /> • One composite sample (SP-5A, 513, 5C, 5D mislabeled on COC as T-5A, 5B, 5C, 5D) was collected from
<br />' the stockpile of impacted soil to chemically profile the stockpile for disposal
<br /> • No detectable benzene, toluene, or ethylbenzene was reported for the sample
<br /> • TPHd and TPHmo were detected with concentrations of 1,700 and 3,000 mg/kg, respectively
<br /> • TotaI xylenes were detected with a concentration of 0 0075 mg/kg
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