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and MW#5 showed contamination and MW#1, MW#4, and MW#6 did not detect <br /> contamination at a detection limit of 1.0 ppb for STEX. <br /> 06-14-93 PHS/EHD receives first quarter 1993 quarterly report dated May 14, 1993. The report <br /> discusses the monitoring and sampling of the six site wells and the results of the March <br /> 1993 excavation work. <br /> The six wells at the site were monitored and sampled on March 3 and 4, 1993. Depth to <br /> water was approx. 73' to 76' bgs with the flow direction was variable. MW#1, MW#2, <br /> MW#3, and MW#5 ail showed contamination. MW#4 and MW#6 did not show <br /> contamination at a detection limit of 1.0 ppb for BTEX. <br /> The over-excavation of the former tank pit cavity occurred during the week of March 8, <br /> 1993. Soil was removed to a total depth of 32' bgs. The finished excavation was approx. <br /> 33' x 33' x 32'. Twelve confirmation soil samples were obtained, two from the bottom of <br /> the excavation and ten from the sidewalls at varying depths. The two bottom and nine of <br /> the sidewall samples showed residual levels of contamination remaining in the pit in the <br /> areas that also showed visual and olfactory evidence of contamination. Three of the <br /> sidewall samples from the western portion of the excavation were nondetect at the proper <br /> detection limit. PHS/EHD insisted the confirmation samples be analyzed in a lab using <br /> the appropriate methods and not in the mobile lab using an extreme modified method, <br /> which they were. 600 cubic yards of contaminated soil was removed from the excavation <br /> and transported to REMCO in Richmond CA for treatment. <br /> Sample M TPH-G Benzene Toluene XyleneI Ethylbenzene <br /> Number mg/Kg mg/Kg mg/Kg mg/Kg mg/Kcr <br /> BE6 3z'j 0.610 I ND��`'y, 0.035 I 0.069 ND! <br /> BW6 52, 0.0013 ND0.6 0.19 0.026 Z <br /> N20W ND'�� , N�rF� ; STDG: I NDS i ND G ° <br /> NWT23E 0.070 I ND��P" ND L 'j 0.0055 <br /> N30E $$3$-' ND` ND <br /> 0.0x7 ND�.rn�i i <br /> N30W NDe 02- ND ND ND oo�� ND <br /> S30 0.2 ND'`' ND 4-1x�'P 0.063 0.028 ! ScvY <br /> E15 ND--.cJND`x" ND�-.Ox� NDz- <br /> S25 2.5 ND�-A ND�.-34 0.0$9 <br /> W30 0.0$ ND s-ra}� ND�r�s'I 0.025 t4D �� f (1•G <br /> l� <br /> W22 ND ND ND L- ` ND � y� <br /> E30 0.87 NDi-c1'- 0.071 0.070 I LgD, <br />