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f . .r Ir• ,•- - r'�t 'IFS t�f,i ' +. I I• s ',. .. . � a n,:,7; :.i 4 .. r `F 'i t• r1 x k .r - i': 30,July 2003 AGE-NC Project No. 98 0504 Page 3 of 7 .2.5. PREVIOUS SITE ASSESSMENTS ; `. -Qn 31,July2002;'three soil probe b6_ring,(B3;;B4 and B5)were'advanced east and of the fon ier US T.excavation; and north of the foilhdr)dispenser area. Discrete soil.samples were collected at ' S-foot intervals be 'nein 'at 10 feet-bsg, to the totald depth of the wells at between 35 and 40 feet , . g g, eP . bsg. In addition, a grab ground water,sample was collected from each well-at total depth. TPH- an BTEX compounds were not detected in soil samples collected. MTBE was detected by, g p p .:EPA method-8260 in three soil samples at concentrations of 0.016 ii�g/kg (B3-30), 0.008_mg/kg (B4-20) and-0.006-mg/kg (B4-30): Analytical,tesults.ofsoil samples are,summarized in 'Tab 3i.TQlO11JJlc ' +- . . • .. - ` �'! 411 TPH-g was detected iii the grab-ground water samples from boring B3,B4 and B5 at concentrations' of 240 µg/1,'300'µg/1 and 180 µg/l, respectively. BTEX compounds were not detected,but MTBE and 1,2-DCA were detected by EPA method 8260 iri-each of the ground water samples at-maxiinum ' concentrations of 200 µg/1 (B4) and 13 µg/1 (BS). The distribution of dissolved MTBF„�is depicted ' in'Figure 3, and.analytical results from'ground water samples are summariied in Table 3. 'Che alis}ribet�':Ox of of;sselvr_d h1T85 is 1ofd¢�oraf'�at In Fi�vr�3 14610. 3 ,s nab- ir►etvdj-d i L -i's r .•ef \Ate_ A 0- a( +' j ancr! t.iear1 r,csuiis .,,�,�^ A, '• -+�V.0 m sn�l, �n4�.9ruvs�G�wa./r.•- a4 les 40011 rra•� 83 8anp[ t3 5, i•�dad 3.0. : GROUND WATER MONITORING WELL INSTALLATIONiL�`I��orrry 0n .3`and 1 � 2-,fsoil boriiigs MW-1 though MW; were advanced utilizi a follow Tfi ' stem auger drill rig for the collec ion and'anal sis of soil samples and installation of�eground g g � y • .water monitoring wells(Figure 2). Soil borings MW-1 and MW-2 were advanced approximately 10 :". feet north and south,respectively,of the farmer UST excavation,.sail boring MW'-�was established, .� `Thi s i s 6 f40r�ab� 'Field work w' s pr formed as described. in the_AGE-prepared Monitoring Well Installation Work . Plan; dated 0 . 2 , as arnerided and approved b the San Joaquin Country Environmental• HealthDepartment(EHD) by letter dated a5� °F6ea,*vzoo3 . � • 3.1. SOIL SAMPLE COLLECTION AND ANALYSIS . Soil borings were advanced using a,truck-mounted CME 75,-HT or CME 95 drill`rig equipped with ' 8=inch continuous flight hollow-sterni augers; the drill rig and two-�rhan crew were supplied.by Casca ie'Drilling ofRancho Cordova,California Soil borings MW-1 through MW-3 were advanced to a depth,of 45 feet bsg to be completed as ground water monitoring well"Auger returns generated ' by drilling were containerized in properly labeled DOT-approved model 17H 55-gallon drums and was stored on-site. " Advanced GeoEnvironmentai,Inc.