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Site Background Information: Lodi Airport
<br /> AGE-NC Project No. 98-0533
<br /> Page 2 of 3
<br /> The Modesto, Riverbank and Turlock Lake Formations and overlying Recent alluvium are the
<br /> principal sources of domestic ground water in the 13,500-square mile San Joaquin Valley Ground
<br /> Water Basin(Basin 5-22).
<br /> /U1NDERGROUND STORAGE TANK REMOVAL
<br /> pori 19 March 1999,the San Joaquin County Environmental Health Department(EHD)directed EHD
<br /> to collect one grab ground water sample from on site domestic well DW-1.Contaminants of concern
<br /> were not reported at or above laboratory reporting limits.
<br /> On 18 June 1999, associated piping for three USTs were decontaminated and removed by AGE.
<br /> Angled soil probe borings were advanced beneath the USTs to collect soil samples prior to UST
<br /> abandonment. Two soil samples, SB-1-20' and SB-2-20', were collected at approximately 20 feet
<br /> below surface grade(bsg),near the bottom of the USTs. In addition,five soil samples(P-1 through
<br /> P-5)were collected at a approximately 2-3 feet bsg from along the route of the former piping,which
<br /> extended from the dispenser island to the USTs. Laboratory analysis reported total petroleum
<br /> hydrocarbons quantified as aviation fuel (TPH-ag),L)3'enzene,toluene, ethyl-benzene,total xylenes
<br /> (BTEX), and lead in the soil samples collected from soil borings SB-1 and SB-2 at maximum
<br /> concentrations of 760 milligrams per kilogram(mg/kg),0.112 mg/kg,2.37 mg/kg, 1.23 mg/kg,2.51
<br /> mg/kg,and 6.0 mg/kg,respectively.Additionally,TPH-ag,toluene,ethyl-benzene,total xylenes,and
<br /> lead were reported in soil samples collected from P-1 through P-5 at maximum concentrations of
<br /> 6,400 mg/kg, 0.043 mg/kg, 0.6 mg/kg,4.36 mg/kg and 6 1.0 mg/kg, respectively.
<br /> On 9 July 1999, three aviation gasoline USTs were removed from the site. The tanks were
<br /> transported off site by West Coast Equipment of Turlock, California. Five soil samples were
<br /> collected beneath the USTs,four soil samples were collected from the excavated soil, and two soil
<br /> samples were collected from the former dispenser area for laboratory analysis.
<br /> Laboratory analysis reported TPH-ag, BTEX, methyl-tert-butyl-ether(MTBE) and lead in the soil
<br /> samples collected from the former UST excavation at maximum concentrations of 103 mg/kg,0.074
<br /> mg/kg, 1.093 mg/kg, 0.443 mg/kg, 2.182 mg/kg, 0.027 mg/kg, and 324 mg/kg,respectively. Lead
<br /> was the only constituent of concern reported in the stockpile and dispenser samples,at a maximum
<br /> concentration of 35 mg/kg.
<br /> PREVIOUS SITE INVESTIGATIONS '
<br /> In June 2000,four soil borings (B-1 through B-4)were advanced and sampled at the site by AGE.
<br /> Three of the borings(B-1,B-3 and B-4)were completed as ground water monitoring wells MW-1,
<br /> Advanced GeaEnviranmental,Inc.
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