|
Site Background Inforrnatlon/SCM Former MBP-Mossdale
<br /> • AGE NC Project No 99-0570
<br />' Page 3 of 5
<br />' concentrations of 49 milligrams per kilogram(mg/kg), 180 mg/kg, 0 36 mg/kg, and 78 micrograms
<br /> per kilograms (µg/kg), respectively Laboratory analysis of grab ground water samples Indicated that
<br /> the highest concentrations of TPH-g, TPH-d, BTEX, and MTBE were in the vicinity of the former
<br />' dispenser Islands Based on the data collected,the dispenser islands appear to be the primary source
<br /> of the hydrocarbon release
<br /> I Soil from B-1,B-2,and B-7 at 15 feet bsg had low concentrations of hydrocarbons,while soil from
<br /> B-1,B-6,and B-7 at 10 and 15 feet, as well as B-2 at 10, 15,and 20 feet bsg had low concentrations
<br /> of fuel additives (MTBE) Hydrocarbon-impacted ground water a �ege t at B-1,B-6,B-7, and
<br /> B-8 and MTBE was detected in grab ground water samples fron��- and V MTBE was detected
<br />' by EPA Method 8260 in all grab ground water samples at a maximum of 150µg/l(B-6) The results
<br /> of the soil and ground water investigation are summarized in Tables 1 and 2 of this appendix
<br />' Ground water monitonn wells MW-1 through MW-5 were installed on 27 and 28 September 2000
<br /> g g
<br /> and monitored and sampled on 03 October 2000 TPH-g and TPH-d compounds were detected in•��,�,.,f7,,
<br />' only one of eleven soil samples, at similar concentrations of 170 mg/kg, In addition, BTEX and ' w•� � '
<br /> several additional volatile organic compounds were detected at concentrations up to 0 44 mg/kg The
<br /> soil data is summarized in Table 3 of this appendix TPH-g,TPH-d,and BTEX were d�t�e,yued maw
<br /> 114.
<br /> !
<br />' ground water samples collected on 03 October 2000 at maximum concentrations of 76"µg/1, , /ec
<br /> [Lg/l, and 160µg/1, respectively, in addition, MTBE was detected in three ground water samples at
<br /> a maximum concentration of 170 µg/]
<br />' On 09 December 2003 three soil bonn s CPT-1 CPT-2 and CPT-3 were advanced on-site
<br /> utilizing cone penetrometer testing(CPT)technology to a total depth of approximately 110 feet bsg
<br /> tAt each boring location, hthologic data was collected from the initial CPT boring, an immediately
<br /> adjacent twin boring was then advanced to collect grab ground water samples CPT-I was sampled
<br />' between 55 feet and 60 feet bsg and between 80 feet and 84 feet bsg, CPT-2 was sampled between
<br /> 55 feet and 60 feet bsg,between 89 feet and 94 feet bsg,and between 110 feet and 114 feet bsg, and
<br /> CPT-3 was sampled between 55 feet and 60 feet bsg, between 85 feet and 90 feet bsg, and between
<br />' 110 feet and 114 feet bsg The results of this investigation are sumrnanzed in Table 4 of this
<br /> appendix
<br /> 1 HYDROGEOLOGIC MODEL
<br />' Based on the CPT results,AGE has assigned names to four informal zones a vadose(unsaturated)
<br /> zone and three hydrogeologic units
<br />' Vadose Zone -This zone extends from surface grade to approximately 15 feet bsg, the depth to the
<br /> water table The vadose_zone is predominantly fine-grained material from surface grade to 15 feet
<br /> bsg, with a coar es grained sand u it'occurring between 20 fe nae d 25 feet bsg at CPT-2 Th one `
<br /> Advanced GeoEnvironmental,Inc14
<br /> T`
<br /> 1 M
<br />
|