|
• •
<br /> for total petroleum hydrocarbons quantified as aviation fuel (TPH-ag), benzene, toluene,
<br /> ethylbenzene, xylenes (BTEX), and methyl-tertiary butyl ether (MTBE) by EPA methods 5030,
<br /> modified 8015, and 8020 or 602. No analytes were detected in the sample above the method
<br /> reporting limits.
<br /> On 02 June1999, based upon PHS-EHD direction, AGE submitted an addendum to the
<br /> aforementioned work plan to remove dispenser island/associated piping and perform soil sampling
<br /> prior to in-place abandonment of the USTs.
<br /> On 18 June 1999,AGE decontaminated and removed the product piping and advanced angled soil
<br /> probe borings for soil sampling prior to UST abandonment and product piping removal. Two soil
<br /> samples, SB-1-20' and SB-2-20'were collected approximately 20 feet below surface grade(bsg)near
<br /> the bottom of the USTs and five soil samples were collected beneath the piping at an approximate
<br /> depth of2-3'bsg extending from the dispenser island to the USTs and are identified as P-1,P-2,P-3,
<br /> P-4,and P-5.TPH-g,BTEX,and lead were reported detected through laboratory analysis in the soil
<br /> samples collected from soil borings SB-1 and SB-2 at maximum concentrations of 760 mg/kg TPH-
<br /> g, 112 pg/kg benzene, 2,370 µg/kg toluene, 1,230 µg/kg ethyl-benzene, 2,510 µg/kg total xylenes
<br /> and 6.0 mg/kg lead.TPH-g,Toluene,Ethyl-benzene,total xylenes and lead were reported in the soil
<br /> samples collected from locations P-1 through P-5 at maximum concentrations 6,400 mg/kg TPH-g,
<br /> 43 gg/kg toluene, 600 µg/kg ethyl-benzene, 4,360 µg/kg total xylenes and 61.0 mg/kg lead.
<br /> Due to field decisions made by AGE and PHS-EHD, on July 9, 1999 AGE removed 3 aviation
<br /> gasoline USTs (Tanks #39-1808-01, 5,000 gallon storage capacity; #39-1808-02, 4,000 gallon
<br /> capacity; #39-1808-03,4,000 gallon capacity) from the site instead of in-place abandonment. The
<br /> tanks were certified to be properly cleaned and free of hydrocarbon residue by EHD and transported
<br /> off the site by West Coast Equipment of Turlock,California. TPH-g,BTEX,MTBE and lead were
<br /> reported detected through laboratory analysis in soil samples collected from the former UST pit at
<br /> maximum concentrations of 103 mg/kg TPH-g, 74 µg/kg benzene, 1,093 pg/kg toluene,443 gg/kg
<br /> ethyl-benzene,2,182 µg/kg total xylenes, 27 ltg/kg MTBE and 324 mg/kg lead.Lead was the only
<br /> constituent of concern reported detected in the stockpiles and dispenser locations at a maximum
<br /> concentration of 35 mg/kg.
<br /> On 18 November 1999,PHS-EHD placed the site in their Local Oversight Program and required a
<br /> work plan be submitted to investigate contamination at the site.
<br /> On 23 February 2000,AGE submitted a work plan to investigate a suspected unauthorized release
<br /> of petroleum hydrocarbons to soil and ground water at the site. The laboratory results of analyses
<br /> of samples confirmed the presence of a petroleum hydrocarbon-impact to soil and ground water in
<br /> the former UST area. The San Joaquin County Environmental Health Department (EHD)
<br /> subsequently required an investigation to determine the extent of petroleum hydrocarbon-impact to
<br /> soil and ground water.
<br /> On 21 and 22 June 2000,three ground water monitoring wells were installed (MW-I through MW-
<br /> 3)to 85 feet below surface grade. Quarterly ground water monitoring was initiated on 05 July 2000
<br /> and continued through 31 May 2002.
<br /> On 12 December 2001, two soil borings (B-5 and B-6)were advanced at the site using a CME-75
<br />
|