ARCHIVED REPORTS_XR0004201 - Laserfiche WebLink

Home Browse Search

F ' March 1998 - Four soil borings (B 1 through B4) were advanced to maximum depths of 25 feet below surface grade (bsg) near the three former 10,000-gallon USTs and former fuel ' dispenser island areas TPH-g and BTEX compounds were not detected In any of the analyzed samples,however,MTBE was detected from soil boring B1 at 20 feet bsg near the northeast end of the former USTs.at a concentration of 0 25 milligrams per kilogram A letter ' of findings (Analytical Results of Pre-removal Assessment, dated 25 March 1998) was submitted by AGE to the SJCEHD • September 1999- Three soil borings (P-1 through P-3) were advanced to maximum depths of approximately 60 feet bsg near the former UST and fuel dispenser island areas TPH-g was detected In the 50-foot soil sample from P-1 at a concentration of 2 6 mg/kg, low ' concentrations of BTEX compounds were detected from P-1 between 45 feet and 55 feet bsg at concentrations as high as 0 16 mg/kg Significant MTBE was detected from P-1 at depths between 25 feet and 55 feet and from P-2 at 25 feet bsg at concentrations as high as 38 mg/kg ' (P1-25) Laboratory analysis of a grab water sample collected from P-1 detected TPH-g at 1,500 micrograms per liter(µg/l),BTEX compounds as high as 690µg/1 benzene and MTBE at 420 gg/l A report of findings (Preliminary Investigation &Evaluation Report, dated 30 ' October 2000) was submitted by AGE to the SJCEHD • November 1999-Ground water monitoring wells MVi-1 through MW-4 were installed at the ' site to depths of 65 feet bsg TPH-g was detected in the 45-foot soil sample from MW-2 at a concentration of 3 1 mg/kg, low concentrations of BTEX compounds were detected at 45 feet bsg from MW-1 and MW-2 at concentrations as high as 0 82 mg/kg Significant MTBE twas detected from MW-3 at depths of 15 feet and 20 feet bsg at concentrations of 8 5 mg/kg ie and 11 mg/kg, respectively, MTBE was detected in the 45-foot soil sample from MW-2 at a concentration of 0 1 mg/kg Laboratory analysis of initial water samples collected from i MW-1 through MW-4 detected TPH-g as high as 1,400 gg/l(MW-3),BTEX compounds as high as 190 µg/1 and MTBE as high as 95 jag/1 (MW-2) A report of findings (Preliminary Investigation &Evaluation Report, dated 30 October 2000) was submitted by AGE to the ' SJCEHD • November 2001 -AGE advanced four cone penetrometer testing(CPT) soil borings(CPT-1 ' through CPT-4)to depths of approximately 100 feet bsg on-and off-site to assess the vertical extent ofpetroleum-impact and identify potential hydrologic units Based on CPT data,AGE interpreted the CPT data to identify seven potential hydrogeologlc units informally identified ' as HUI between 55 and 63 feet bsg,HU2 between 63 and 68 feet bsg,HU3 between 68 and 75 feet bsg, HU4 between 75 and 78 feet bsg, HU5 between 78 and 90 feet bsg, HU6 between 90 and 95 feet bsg and HU7 located at depths greater than 95 feet bsg Laboratory ' analysis of grab water samples detected MTBE from CPT-1 at depths of 60 feet and 76 feet bsg at concentrations of 88 µg/1 and 16 µg/1, respectively, from CPT-2 at depths of 74 feet, 80 feet and 100 feet at concentrations as high as 49 µg/1, and from CPT-3 at depths of 68 feet and 100 feet bsg at concentrations of 37 µg/1 and 4 3 gg/l, respectively MTBE was not detected In water samples collected from CPT-4 (Table 1) A report of findings (Cone Penetrometer Testing(CPT)Report-November 2001 , dated 21 June 2002) was submitted ' by AGE to the SJCEHD • July 2003 - Ground water monitoring wells MW-6 and MW-7 were installed at the site to depths of 65 feet bsg and 90 feet bsg, respectively, installation of off-site well (MW-5)was Advanced GcoEnvironmental,Inc