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Mr.H.C.Winsor <br /> February 23, 1988 <br /> Page 7 <br /> 'Fable 2. Anal,lical Results--(groundwater <br /> November 13, 1987 <br /> Concentrations,ugA <br /> Total fuel hydrocarbon <br /> Well number Benzene Toluene Xylene concentrations,mg/l <br /> Action level 0.7a 100a 620a -b <br /> W-1 1,600 2,300 6,900 147.2 <br /> 4., # W-2 6,200 5,300 13,000 343.9 <br /> W-3 3,400 3,200 8,500 176.9 <br /> — W-4 2 9 32 c <br /> W-5 1 -c 2 c <br /> W-6 _c 0.5 1.3 c <br /> W-7 -c c c c <br /> W-8 c c l c c <br /> aDrnking water action levels recommended by DHS,January 1987. <br /> bio standard is established for total fuel hydrocarbons. <br /> cBelow detection limits as shown in laboratory reports(EAdbit D). <br /> Groundwater samples from the five off-site monitoring wells (W-4, W-5, W-6, W-7, nd W-8) . <br /> were again collected by BC personnel on February 2; 1988. Groundwater samples were <br /> 1 ?zalyzed for BTX (EPA Method 602). R,-.sults are summarized in Taff',. 3 and laboratory <br /> k reports are shown in Exhibit D. BTX constituents in four or the five off-sits wells (W-4, <br /> NV-6; IV-7' and W-8) were nondetectable in the February 2, 1988, samples. The benzene <br /> i concentraticn in groundwater sampled from Well W-5 on February 2, 1988,.was measured at <br /> i 2 parts .!aer billion. Benzene coni.-ntrat.ons in groundwater for all monitoring wells are <br /> shown on Figure .4. The benzene concentrations shown are for samples collected on <br /> April 10, 1987,August 23, 1987,November 13, 1987,and February 2, 1988. <br /> Armour Petroleum removed free product on the groundwater surface in Wells W=i, W-2, and. <br /> r W-3, on a biweekly basis, between Juiy 22, 1987, and November 25, 1987. A total of <br /> 30.5 gallons of product were. removed between July 22 and November 25, 1987. Product ? <br /> removal data is summarized in Table 4. Product removal records are included in Exhibit E. <br /> Recharge of product into the three wells significantly decreased in Iate November 1987. ! <br /> Since product was last removed in November 1987, BC has monitored depth to groundwater <br /> and product thickness in all eight wells. No significant recharge of floating product into <br /> any well 16m occurred since November 1987._ Table_5 summarizes.this BC monitoring data._______.__ <br /> and W-3. No free product has been detected in any off-site well. <br /> ' BFIOWN AND CALDWELL <br /> r <br /> - <br /> III 55Tf1'cET SACPAl.IENTO.CA959tG•1916)444-0123 <br />