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0~/0~/99 1~:38 $503 588 5237 MARION C0. COM. -~• • --~ ••-•- - ... . - C~ 003/00~ 47-I9.0', and 6-48-1 ~.5', rcpresent contaminated soil wkich v+ras left in piace. Tliese fiv~ ~amples aro located, ia thc south~ast comer of thc exczva[iosi, wher~ further excavativt~ was i2ot physicalty practical due to the adjacent streets_ The remaini~~g confirmation sainples indicate that the laterai 'and vertical extent of soil excavatian sufficiently removed contamit~ated soi1, Nonc of thc soil eonfirmation samples exc,eeded the DEQ levol2 cleanup concentration of 500 mg/kg for TPH-D. PAHs wtre not detected in the four soi! samples aaaly2ed, except for 550 µglkg naphthslene detected in sample 5-46-15.5'. These tesults indicate that PAI~s ate not contaminants af concern in soil at this site. Samples collected fYOm the fust thr~e uon-impacted overbeirden soil piles (identified as SP 1 thrau~h SP3} shovti+ed non-detectable TPH; therefbre, this soil was suitabie for disposai at the Browa's Island Landfill. Oil-range getroleum hydroc~rbo~ were detected in samples collected from the fourth non-impacttd averburden soil pile (SP4), so this soil pile wa.s disposed at the Riverbend Landflll. Select soil samples were addikionally analyzed for the potential gasoline addiuves lead, 1,2- dibmmoethane (EDB), 1,2-dichloraethane (E~C), and methyl tertiary-butyl ether (iv1TBE). Non-dct¢ctsblc to ttacc conccntrations of thcsc gasolinc additiv~s in soil samples (Table 2) indicates that they are not constituents of concern in soil at this site. ' out~dwaX~r Analytica~results fnr graundwater samples collected fram the excav'$don followin~ dewatering atid overnight recharge are presented in Table 3. Non-detectabic to trace conccntrations of BIEX in each gtvundwatar samgle indicates that groundwater coataminants do not appear to extend beyond the cor~fines of the excavatiori This was expected because most of the contaminated source material had been removed. Additional analysis of samples 5-2-GW, 6~- GW, and 6-5-GGV showed non-detectable PAHs, indicating that PA,Hs are not contaminants of concam in groundwater at this Site. As shown in T'able 4, EDB, EDC, and MTBE were not detected ia on site samples collectad on August 6, 1947 from groundwater monitoring wells NiW l-, MW-4-, and MW-5~ (Century West, August 27, 1997b). EDB and EDC were not deterted in the September 9, 1994 rnonitoring event at ofF site wells MW-10 and MW-11, and dissolved lead was less than 2 µg/L in MW-10 and 3 µg/L ia MW-11 (Pacific Er~vironmental Gtoup, December 5,1994). '~'hese results indica.te that the gasoline additives EDB, EDC, MTBE, and lead ate not contaminants of concern in groundwater at the sabject site. Conective Action PIRU - i~ - 4080t>-OOI-19 Chevron Parcel - Courthouse Squara Apri123, 1998