SITE INFORMATION AND CORRESPONDENCE

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Pg. 2 , I can only presume that Mittlehauser Corp. (' by strictly ad- hering to the site plan boundaries as outlined in the June 91 ' prelimininary site assessment prepared by PHR, Enviromental Consulants }, assumed that the scope of analysis was limited to the temporary fence line. It would follow then, that the rear of the subject lot, which is labelled on the various site maps as "vacant lot" , was -not indeed. part of the property. under Unocal 's lease and : therefore, was not investigated! ! ! My recollection is that this land, which was. never fenced off from the station,.was sporadically used for auto storage and, besides , who knows what was dumped there, during some twenty years of service station operation. My reasons for concern regarding the status of the rear of the lot are threefold: i 1 . The Close- roximit ('Ii some' 10/15 . feet.— ) of the principal sources of hydrocarbon contamination,:. 'namely the UST' s and the former f waste oil tank, 'to this " vacant :lot" . Data relating to this particular area is found 'in your geologist ' s report relating to monitoring wells MW3 and MW3A., The report also mentions that apx . 1370 gals . of free product contaminated ground water were purged from the excavation when the UST ' s were removed in June 1990, without site remediation to correct any soil or ground water contamination. These two factors suggest to me that this area has been exposed to medium term contamination of the surrounding soil and probably the underlining aquifer . 2 . -- Direction of ground water flow. Table ( 1 ) of Mittlehauser ' s ` ground water elevations shows almost a 60degree swing in direct- ional variance of ground water at the test wells according to seasonal rise in the watertable. This occurance is supported ; in the same report by Mr. Harlin Knoll of SJCDPHs , who mentions variances of up to 110degrees in seasonal groundwater direction. This apparent swing to a N.E. direction ( 12/11/91 ) during the winter high water. months co-incides with the highest level of hydrocarbon contamination measured at the old UST location (MW3 ) -see table ( 3 ) M.P.D.S . services ' summary of water analysis . This data would suggest that contaminated ground water flowed from the location of the highest level of pollution in a N.E. direction, which clearly would impact portions of the "vacant lot" by its immediate proximity. k The fact that the new well site ('MW3A) , 'activated in Dec . 1993 when the UST' s were removed; shows a non-detection of measurable hydrocarbons , hardiy, gives the "vacant lot." a- clean bill of health , as the main immediate sources � of pollution were re- moved along with the purging of the tank pit water. The report clearly does not document the .condition of the aquifer beyond I the fence lime in an area, where the geologic analysis would seem to indicate, was the .recipient of seasonal ground water contamination, due to changes .in direction of the ground water flow. I am at a loss to understand Mittlehauser Geologist . r