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FEB-18-99 THU 0M9 AN P. 12 <br /> FEB. -11' 99(TH11) 15: 19 UNOCAL Yr NORTH RE TEL:510 94 '81 P. 011 <br /> DRAFT <br /> Contentlon: The petitmi ner contaids its case should be closed pause sail and <br /> groundwater assessment is complete and corrective actions conducted have diminished the <br /> presexcee of rcaidusl parolm m hydrocuban consdtuc rs to a point whwm thW pum a <br /> "low risk" to public health and safety,the envirotrmemt, and to current or probable frim e <br /> beneficial uses ofwater. <br /> Findings: Petitioner's ronteation has merit. As explained below, the facts is the <br /> record support the Sinding that additional sg8 and groundwater invesugatkm or additional <br /> resne diafJinn is not necessary and that residual peacleurn hydrocarbon=wtiimemts m <br /> pedoaet's site do=pose a threat to humahealth and sefe ty, or the envrromnet, and <br /> do not adversely affem or threman to affem current or antiawied fu2ur+e beneficial uses <br /> of water. In addtioa,the level of site cleearmp is c=dOAM with the mwmun benefit to <br /> the people of the stere and will meet the applicable*e cbvees in the Cemtrg Valley <br /> RWQCB Basin Plan wkrin a reasonable time frame. <br /> The primary sourom of the r*W=(the UM6.dispen-w, and associated p1pino, <br /> have beers removed as well as a subsran4al Yoh=of affected'sod from the immediate <br /> vic unty of the former USTs. Free product has never been observed m any site monitor <br /> wells and SVE has remwved a subs mass of residual petroleum krye racazbons in the <br /> vi anity Of the f:)nner primp idad& <br /> With regard to a#fmied Vwndwater and iq Vora Ual to advasoly impact current <br /> or anticipated £i Wm beneficial uses, substantial ewideam in the record indicates that <br /> eoae:adtra:iotm of dissolved phue hydrocarbons ares decreasing the plume is rLWAe., <br /> MTBE is not presere, and aftenuafion and biologic degradation afresidual petroleum <br /> hydrocarbons in site soil and groundwater is occurring. Furdw, avaulabie dam in&cwe <br /> that the affected groun&o ter monitored by site wells, in addition to being of ld'Mor <br /> quality, is rat hyaraukAlly conned to the d aeW groundwater aqufts that are used <br /> locally for mwi cipaL industrial or agricultural supply. <br /> Concentrations of TPH-S and benzene de to&e:d in groundwater franc monitor well <br /> MW-2 (at the location of theformer pump island)typically ranged from 100,600 to <br /> 200,000 ppb and 6,000 to 7.5;004 ppb, respectively, froth 1988 through 1994: <br /> concentmdons of cheese cvnstituems have de cAned to about 80,000 and 1,064 ppb, <br /> a . <br />