ARCHIVED REPORTS_XR0011971 - Laserfiche WebLink

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- = Preliminary Investigation and£valuation_Rep(m a Multi-Campus Regional Center — E — — - - CSUS FeUu57 X00! Page 4 immoderate_petroleum .hydrocarbon odor was detected andioitve bray staining of soil was-observed to - - a _ -the sotE:at-a depth_of approximatelyrl6 feet bgs: A PID"lneasurernent'of 40_parts.per.millioii (ppin) at a �,. ' depth of 1-$ feet 6gs_indicated thle presence of organic vapors m the soil. m At a depth-of-approximately 30 -= feet .bgs the soil ,was still stained,.had a nioderate`.petroletiin liydrocarbon odor,-and.an-organic concentration of 37 pplrt-as ineasured by the PID-Groundwater had not been encountered`so the decision VP4 : was made,with the conc>irreiice of Ms.`Lofstrom'to coritinue advancement.of the-boring.-The intent was-. T = ;}to.coiitiiltie until indica#loris. of petro leuiii liydi•ocarbons were no longer,,pre_sen_t; groundwater was --encountered, or refusal was met, whichever occurred ftrst;;tn,orderwto b_ ' characterize the vertical: f p extent3ofpetroleum_hydrocarbon impact on oil_aiid grotii3dwater. :Gromtdwater_was,encountered at �. - �- approxinnately`42,feet.bgs:'.Tlie soil attliis depth was still stained and had arpetroleum<hydrocarboti odor-. The.groundwater also had a strong petroleum hydrocarbon odor:The groundwater level rose in the boring ' � = -.to a.depth of a roximatel---35.5 feetbas after-the' .soil-sain ling-device was withdrawn'front the baring: pl} Y b p � a' =A continuous soil sat>fple was cpllected from GP-1.for the purpose of'characterizing the sttbsi�rface;soils. -� With the concurrence of Ms=hofstrom;the decision was made to collect a 2-foot sail sample every,5 feet v in the"r emaining'soil-borings. beginning-at a.depth of approximately l5 feet.bgs, and to ad , borings to groundwater so thatz groundwater samples could lje-co.liected from each `boring to ,better:= � _ characterize the horizontal extent•of roundwater im acted bypetroleum hydrocarbons. - g p Y The subsurface encountered in.the GeoprobeOO borings generally_consisted.. silt clay, and silty sand In s i GP-1 theisoll was silty sand.-fill material from below the asphalt atahe-ground surface to a--depth of �t approximately 2.5 feet-bgs, c[ay between 2:5 and 11 .feet bgs; silt between 11 and 24 feet bgs,Aclay - . '- between 24 and 2$ feet-bgs, silt 16' silty between 28 and:30 feet bgs;aiid clay between 30 and.42 feet bgs. Soils -penetrated 'i n' GP=2 through_GP-Swere stn�iEarto-those:=encountered_iil GP 1 with some Variation in tie the at which the different soil liorizons were ncountered - -° #: ... .r p _ _ _ _ T; first Groundwater wasrst encountered��in GP-3 aiid G.P-4 at,approxintately.36 feet bgs. However, the volume . -!P of groundwater.in the bo"ings at this depth was.not siafficieiit for sampling, so tEre borings were continued. =' s ;Water rn Vol uni&great.enough to sample was-oenerally_eilco.6ntered-at a deptll_of-approximately 41 oto 42=-' feet-bas iii all-of the borin s. Water levels--in all of-the borin s rose to'a depth of approximately...-35 feet t r b g a- W_ g Ep _ - bgs once the soil-sampling device was removed from the borings.'PID_measuretnents-of samples from the = J toriIIgs izidicated organic vapor coiiceiitratrons'of 3 to 47 ppm .in Gl' 1 at depths between 16 and 42 feet= _ bgs, 140 to 979 ppm�in GP-2 at'depths between 20 to 41 feet,bgs,11 to''lndre than 1,000 ppm M.GP 3 at depths between 16 and 44 feet-�igs;.6 to52 pptit in GP-4 at depths between'30 and 41--feet-lags alzti_9 to _ __: 289 ppm in GP-5 at depths<between'30 and 41.,.feet'bgs. Petroleum ltydrocarbowstaining of soils was '§ observed in all borings and genetallly_coincided with-the PID measurements'that-indicated the.presence of organic vapors. ,> L - 42 r`=;5 RESULTS OF-LABORATORY ANALYSES - -- - -- -- - T—As described in Sections 3.2.1 and 3.2.2.of illis report soil-and groundwater samples from the-GeoprobeC� r._ 'borings wcre submitted for laboratory analyses. The laboratory,analytical results of.,the soil samples-are - =presented Iin.Table ], on the next page; and.are-shown in Figure 3-Appendtx-A:-4The laboratory analytical F . results of tlie"aroundwater samples-are included in Table 2, ,on_the.nezt page, and. in Figure 4, Appendix - A. Laboratory analytical results and-copses of;the chain of custody records for the samples are included m - - A endix C. A discussion of the soil'atid groundwater sample analytic results is Included in Section 5--7--- _ of this report.7. - - . ,— — _ 3. Y CONDOR x. 7 _.._ v