|
Case Closure Report
<br /> Former Tosco(Unocal) SS No 5421, Stockton,California
<br /> July 8, 1998
<br /> • KEI again returned to the site on December 7, 1989, in order to complete sampling of the
<br /> southerly half of the fuel tank pit Two soil samples, labeled SW3(20/13) and
<br /> SW3(20/19), were collected from the tank pit sidewalls at depths of 13 feet below grade,
<br /> respectively hi addition, one soil sample, labeled NSW, was collected from the northerly
<br /> sidewall of the new fuel tank pit at a depth of 13 5 feet below grade On December 13,
<br /> 1989, KEI completed sampling of the old fuel tank pit when three sidewall soil samples,
<br /> labeled SW4(3), SWS, and SW6, were collected from the northerly half of the old fuel
<br /> tank pit at depths of approximately 16 feet below grade Also on December 13, 1989,
<br /> four additional soil samples, labeled P1(6), P2(17), P3(5), and P4(8), were collected from
<br /> the product pipe trenches beneath sample point locations P1, P2, P3, and P4, respectively
<br /> These sample depths ranged from 5 to 17 feet below grade After sampling, the product
<br /> pipe trenches were excavated to the sample depths Upon review of the laboratory
<br /> analyses for these samples, a 15-inch diameter casing (14 feet deep) was installed near
<br /> sample location P2(17) Sample analytical results and locations are presented in
<br /> Appendix A Table 1A, Figures 2A and 3A
<br /> After completion of the soil sampling on December 13, 1989, a water sample was
<br /> collected from the on-site domestic well system (after the well was purged of a minimum
<br /> of three casing volumes) The sample was collected while the pump was operating in
<br /> order to avoid drawing water from the existing holding tank
<br /> •7 All soil samples were analyzed for total petroleum hydrocarbons (TPH) as gasoline,
<br /> benzene, toluene, xylenes, and ethylbenzene (BTEX), tetraethyl lead, and ethylene
<br /> dibromide The waste oil tank bottom sample and the waste oil remote fill piping sample
<br /> were analyzed for total extractable petroleum hydrocarbons (TEPH), BTEX, EPA Method
<br /> 8010 constituents, PCBs, and the metals cadmium, chromium, lead, and zinc The water
<br /> sample collected from the domestic well system was analyzed for TPH as gasoline,
<br /> BTEX, EPA Method 8010 constituents, tetraethyl lead, and ethylene dibromide
<br /> Analytical results of the final soil samples collected from beneath the fuel storage tanks
<br /> [samples Al, A2(25 5), B1, and B2(26 5)] indicated levels of TPH as gasoline ranging
<br /> from non-detectable to 17 parts per million (ppm), with non-detectable levels of ethylene
<br /> dibromide Analytical results of the soil samples collected from the sidewalls of the fuel
<br /> storage tank pit indicated levels of TPH as gasoline ranging from non-detectable to 16
<br /> ppm, levels of ethylene dibromide ranging from non-detectable to 0 014 ppm, and levels
<br /> of benzene ranging from non-detectable to 0 58 ppm Analytical results of the soil
<br /> sample collected from the new tank pit indicated non-detectable levels of all constituents
<br /> analyzed Analytical results of the final soil samples collected from product pipe trenches
<br /> [samples P1(6), P2(17), P3(5), and P4(8)] indicated levels of TPH as gasoline ranging
<br /> from non-detectable to 17 ppm, with non-detectable levels on benzene, except for sample
<br /> ., P2(17), which showed 7,200 ppm of TPH as gasoline and 170 ppm of benzene
<br /> 140162 03 3
<br />
|