ARCHIVED REPORTS_XR0011971 - Laserfiche WebLink

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- - - _ - �. PreHi iin3ry _Investibation and-Evaluation Report CSUS Milf i i-Ca mptts'Regionlil Center r naary 7 20 eb �. dl 1,hoe G , 5.0 DISCUSSION OF RESULTS r - � Laboratory analytical r=esults indicate that soil has-been impacted by petroleum hydrocarbons at the site__;_._ 1 - BTEX, TPN-Glad TEP.H_quan.tified as kerosene were detected in soiLsain les fram:GPl 'GP-2 CGP- 6 T and GP 5._Total xylenes.were detected in the soil sample from GP-4 MTBE Was detected'in.sot[ samples 4 -- from GP-1 and GP-2: MTBE was not detected at or.above the laboratory detection lirnit.in'soml samples ' _ from GP-3,:GP-4, and GP7%5-.However, the laboratory detection liixiits were raised for one of the soil _ { � 'samples frorn'each of GP-3 and GP-5 due to high_colic entrations=of icon-target analytes. TEPN'quaritified {_ as diesel was detectediirt one s_ofl samplefron.GP-4. TEPH quantified .as diesel was not detected_°at or-- Above the laboratory detection limit in soil samples aoni':GP-7',--GP�2;.GP-3, and GF=Sn-Tt" -quantified - as`motor oil was not detected'a-6r-above' the lahoratocy detecfion limit iii'aiay of the soil samples: Based on field'observation_s and PID iieasurements, soil above-l5 feet bgs in GP-1, GP72, and GP-31 and above 25 feet bgs-in GP-4 and-GP-5 has not been impacted by pefroleiii hydrocari ons._ - - - _ s n _ Laboratory;analytical results indicate that groundwater has.b n,impacted by petroleum hydrocarbons at K the site. TPH-G,;BTEX;and TEPH uanhfied as kerosene were detected in the groundwater samples from _ _y b q; z . : all borings. However, the laboratory_jeport�indicates-the-sampie`chromatogram-for'kerosene 01hb - _ groundwater samples from—G- P-1 GP-2, and GP-3 does:not match the standard kerosene chrbrnato_ grarn -' r :The detection of kerosene range petroleum liydiocarbons may be'indicative of weathered gasolirme and/or ' c.om auiads that were not selective[ �uai - p y q attfied:MTBE and TEPH quantified_as:diesel and iaiotor otl..were .: riot detected at or'above the laboratory.detection limits in any. of the•groundwater samples. However;theme A laboratory' detectioia limits :for these analytes=were raised ;due to blah co�acentratioras of non-target - analytes_ MTBE was not detected-by EPA'Method 8260 at or above the laboratory detection"Inuit in theme _I groundwater sample froth GP-3.' I-,2-DCA and'E_DB were detected in.the groundwater sample from GP-3.-&- v - . ,. The other gasoline oxygenates/additives were not detected at'-6r above the laboratory detection limits .111;-_ _ ' $the groundwater sample from_G]?' .Jota1-lead.was.also detected in the--groundwater,sample-from GP73..,- ' The groundwater samples=from GF 1, GP-2,.GP-4, and.GP-5 were not analyzed for gasolineloxyge nates other than MTBE or.for-total.lead' o _ .. _ _ _ r _ G oundwater was first encountered ,m three of. a tl e borings at a depth of approximately 4] to 42,feet_tigs. -.:Irl.the other two bort- s rouiidrwater.was encountered'at a de th of approximately 36 feet b s'however Q . I" the volume of water�.that entered these borings at°thas-depth was .insufficient to samvle:Groundwater _-°levels in all borings rose to.a depth of approximately 35;feet after the soil sampling device was withdrawn 'fr'otn the borings:indicati�ag the aquifer�aay be under setiai'confined_to confincd_coaditions at tlie-site.:k. - _ - - — _ �r. 6f 0._CONCLUSIONS AND RECOMMENDATIONS _ _ A Based on:the results of tlae-soil:and-gr_ouiadwater investigation Condor.concludes that additibnal soil=and groundwater_investigation at the site- is_iaecessary to evaluate the lateral . -:d vertrcai distribution of pTz etroleum,liydrocarbotls in site�sorl and groundwater. Condor recommends_;the additional-investigatiou u include the,following _ - - 3 - - - - •:� The installation of.a miniiaa>lm-of-three cone penetrometer-(CPT)-lor-rngs:to,investtgate_the,= geology at depth at alae site r a .. - � - -tet • The liistallatiori of a tninimunr°of tlueednect pmishPborrngs to 'collect soil satnples:and_the =iii stallation of_ a in hill of three-Hydroptiinch borings to collect discrete groundwater = - - = sanaples,._at depths, be determined by the°results of the GPT: borings;_for the purpose of evaluating-the vertical and horizontal"distribution of�petroleam"hydrocarbon compacted and groundwater at the site. - � = - ^ ,. - _. _ CONDOM t