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EXECUTIVE SUMMARY objectives of the project were to further investigate the extent of impacted sal and The jpossible groundwater gnd survey roundwater, establish a groundwater monitoring these+lobiect ves,t the ifouar on-site g hive sensitive receptors in the site vicinity T Were installed, and possible lens monitoring wells (MW-1, MW-2, MW-3, and MW-4) receptors within 2,000 feet of the site were surveyed All waste soil and water generated during the project was properly disposed onsisted of clay and silt Sods observed to the total drilling depth of 35 feet below 9ena Q ntered n the four monitoring mixtures,With sandy intervals Saturated soil wath to The at rowmately 18 5 to 19 0 feet below grade et static grade intMW 3 The he groundwater well borings pp54 table, ranged from 22 20 feet below grade in MW-1 to ears as an irregular plane dipping to the east-southeast at a resulting groundwater surface app gradient of approximately 0 029 foot/foot 1 a total of 7 of the 12 samples collected during ame l rills gected at 1contained 5andfeet from ed table In soil, hydrocarbons The sol P contain concentrations of gasoline y compounds The 20 25, MW-1, and all five soil samples collected from a d at least a of the BTEX comp u detectable concentrations of TPH-as-gasolin 63 mg/kg of benzene, 52 mg/kg of toluene, le collected at 15 feet from MW-2 contained the highest concentrations 8,00 soli same m Ik of TPH-as-gasoline,, 9 milligrams per kilogram ( 9 g) of xylenes TPH-as-diesel, TPH-as-motor oil, 130 mg/kg of ethylbenzene, and 210 mg1k9 of the soil samples analyzed Vertically, the s oxygenates and 1,2 is were not detected n any The lateral extent of impacted soil below Of im acted soil +s undefined The lateral extent of impac#ed soil above 25 feet app er extent o p of the former UST system to be limited to the vicinity probably due to migration n groundwater 25 feet appears to be more extensive and undefined, p Y r the samples collected from MW-1, MW-2 sn aso11 MW-3 BTEX and 1 detectable The In groundwater, drocarbons, including TPH 9 concentrations of gasoline by groundwater samples Since r sample collected from MW-4 was free of gasoline compounds MTBE, TP -as- - groundwate p diesel and TPH-as-motor oil were not detected m any o groundwater is undefined the groundwater flow direction was calculated to be toward the east-southeast instead of Hort northeast as expected, the downgradient extent of impacte g nit seven water well completion reportswected to California Water Service, � f these For the site vicinity, appears to be wells exist within the site vicinity The Site vicinity is almost entirely wells were found The entire site vicinity pp The nearest school to the site and none of its water supply government buildings approximately 1,800 feet commercial property, and city and county Lutheran School at 444 American Street, Sensitive receptors were appears to be the Trinity hools, hospitals, or other possible northeast of the site No otherhe nearest surface water body to the site is McLeod Lake at observed in the site vicinity rox++mately 1,000 feet west of the site Weber Point, app at the four ing Based on these con ci usions, Ramage Environmental recommeends t roundwater monitornngwel S be monitored and sampled on a quarterly basis The first quarterly event is scheduled for October 2002 4