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concentrations up to 9.6 mg/kg and TPH concentrations up to 3,300 mg/kg (Table 1). The ths in the concentrations of TPH in the soil samples oulndwac r samples weat various pe collectedther wells were less from the six wells. On 15 November 1988,g ples collect. than 1 mg/kg. and 6,800µg/L TPH,were measured in same The highest concentrations,9,30(1}tg/L ed from wells MW3 and MW4,respectively (Table nd�G[eod a dewngradienpdirec direction north- east. ground surface,and the survey and gauging east. 2,4 REMOVAL OF STORAGE TANKS ound l tank, During the borehole drilling of wcll MWS,an a�ddSubsequent excavation reveicipated aled three under- apparently abandoned in place, was encounter ground storage tanks. The smallest wQhthe ssndf three, t500-gallon o a tanks were still lxcavateea dren removed in two larger tanks had been filled January 1989(Figure 3). 2.5 INSTALLATYON AND SAMPLING OF TWO GROUNDWATER FEBRUARY 989 FIVE VADOSE MONITORING WELLS,23 JANUARY- Two additional groundwater monitoring wells(MW7 and Ml��8,Figure igure3 were installed te twoeg o the nd- site to further assess the extent of petroleum hydrocarbonsgroundwater. water.monitoring wells and five soil vapor extraction wells (VI-V5,Figure 3)were installed between 23 and 25 January 1989. The five vapor extraction wells were installed in and around n of petroleum ro- io the former underground storage tank area to be used for in-situ anamediaats ar- carbon impacted soil. Soils were sampled during drilling Y for petroleum hydrocar- bons ydro bons(Table 1). sampled on All eight groundwater monitoring wells were e 25Qµg/L detec�on limit MW 1,MW2,MW7,and MW8 contained no levels of TPH above Satmrles from wells MW3,MW4,MWS, and MW6 contained and 5,200µrg/1-(MW4}e oable levels of f found in 32,000 lag/L. Levels of benzene between 0.61tg/1-(MW2) wells MW2,MW3, MW4,MW5,MW6,and MW8,but not in MW 1 or MW7 (detection limp 0.2 n/Q. 2,6 SOIL VAPOR EXTRACTION AND PERMEABILITY TESTING,24 APRIL 1989 On 24 April 1489,four of the five vapor extraction wells were tested to determine design-cfrn vacuum Pump Was at- ite. A eters for a vapor extraction and 4,and V5tment 5 Atsmpleem at hofsthe vacuum discharge from each well --- - - --- - -----_tached to_extraction wells V2,V4,a h The concen- was collected and analyzed on the site using EA's mobile IiNU-gas c mma o - - trations measured in vapors from wells V2,V4,and V5 averaged 4,SQ0,50,ODQ,and 1b,000 ppm of TVH,respectively. 3 - c7g9191>U1