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Raqunt for of Clears 2 <br /> awwm U.8A FRoduds C'.aMM 3431 Wet Grant L kw Rood,Benin.CA $aptarnb r 22 1995 <br /> current structures on site(warehouse/office building)to operate as Petrie seed company. The site has <br /> been sold and is currently owned by Burns Seed Company. <br /> In 1992,during a geophysical investigation associated with the transfer of the property,hydrocarbon- <br /> impacted soil was noted in boring B-3(Figure 2)near the groundwater table(WHF, 1993). According <br /> to the Petrigs,B-3 was located near the former pump area. WHF was contracted to determine if <br /> hydrocarbon-Impacted soil noted in boring B-3 had Impacted groundwater. WHF installed and <br /> sampled one groundwater monitoring well(MM,Figure 2)appro)dmatey 20 feet east of boring B-3 to <br /> determine if groundwater was impacted downgradient(based on information provided from the <br /> CRWQCB-CVR)-of the former tank location(WHF,1993). Sol and groundwater samples collected <br /> from MW-1 were below method detection limits(MDLs)for benzene,toluene,ethylbenzene and <br /> xylenes(BTEX),end total petroleum hydrocarbons-"asoline(TPH-G). <br /> Groundwater Technology conducted two investigations in January and June of 1994. The January <br /> 1994 investigation consisted of the installation and sampling of one soil boring north of the former UST <br /> pit and two temporary groundwater monitoring wells installed northwest and southeast of the former <br /> UST pit. Soil samples collected from troth temporary wells were below MDLs for BTEX and TPH-G. <br /> The 10 feet BGS sample collected from SB-4 reported concentrations of benzene and sthylbenzene of <br /> 0.007 ppm and 0.005 ppm,respectively,and was below MDL9 for toluene,xylenes and TPH-G. The <br /> 15 feet BGS sample from SB-4 was below MDL for STEX and TPH-G. Groundwater collected from the <br /> temporary wells was below the MDL for STEX in both wells. TPH-G concentrations were below the <br /> MDL in TW-1 and 55 parts per billion(ppb)in TW-2. it was confirmed later that the rinse water blank <br /> collected while cleaning the sampling bailer used to sample TW-2 contained 61 ppb TPH-G,indicating <br /> a high probability of cross contamination of the TW-2 water sample from the previously contaminated <br /> sampling bailer(Groundwater Technology,April 7, 1994).Analytical results of soil samples are <br /> summarized in Table 1 and Figure 3. <br /> The second investigation conducted in June 1994,consisted of the Installation of two groundwater <br /> monitoring wells(MWs-2 and 3)(Groundwater Technology, August 2, 1994). The 5 and 15 feet BGS <br /> soil samples collected from MW-2 were below MDL for BTEX and TPH-G. The 10 feet BGS sample <br /> from MW-2 was below the MDL for benzene,but reported low(<0.1 ppm)concentrations of toluene <br /> ethylbenzene and xylenes,and 1 ppm TPH-G. The S.10,and 15 feet BGS samples from MW-3 were <br /> below the MDL for BTEX and TPH-G. Analytical results of soil samples are summarized in Table 1 <br /> and Figure 3. <br /> Subsequent groundwater monitoring and sampling conducted on MWs-1,2,and 3 have resulted in four <br /> consecutive quarters of analytical results below MDL for Ms-1,2 and 3(Table 2). The historical <br /> groundwater gradient is shown on Figure 3. MW-3 is located adjacent to the TW-2 location. The <br /> analytical results for the MW-3 groundwater samples confirm the conclusion that groundwater at the <br /> TW-2 location is not impacted by BTEX and TPH-G. <br /> 61"C".gA <br /> GROUNDWATER <br /> TECHNOLOGY s <br />