ARCHIVED REPORTS XR0008126 - Laserfiche WebLink

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R604 :UPDATE 9-MARCH, 1992 • 4. Sample for fecal coliform from MW3, MW4, MW5 and MW6 on a quarterly basis during the quarterly sampling. 5 . Perform monthly monitoring and sampling of the vapor stream using the GC-PID 10 S 50 chromatograph and include the results in a monthly update status report . 6 . Drill two confirmation sample borings, one near P3 and the other near SB-2, to obtain soil samples for certified laboratory analysis of TPH-BTEX, see Figure 4 . 7 . Destroy vapor recovery wells P1, P3-Swarm and EX. WORK PLAN FOR THE DESTRUCTION OF VAPOR EXTRACTION WELLS P1, P3-SWARM AND EX, ALONG WITH CONFIRMATION SAMPLE BORINGS . As stated above, vapor hydrocarbon production from P1, P3-Swarm and EX was very manor to nonexistent. Two periods of "re- equilibration" have shown that these wells and their consequential surrounding areas are most likely void of petroleum hydrocarbons. • This completes the vadose zone remediation for this site, to the 40 foot depth. Western Geo-Engineers along with Hogate Drilling will destroy these wells ( P1 , P3-swarm, EX) at this time, so the surface of the lot can be brought up to grade and resurfaced to the specifications of the land owner, who wishes to lease out this property, it has been vacant during this initial vacuum extraction phase. The wells will be destroyed, by drilling them out with 10" augers to remove all well materials . Once the wells are drilled out, neat cement with 6% bentonite will be tremied to the surface, to seal the wells and prevent these areas becoming potential conduits for vertical migration. CONFIRMATION SAMPLE BORING To verify that vacuum extraction has removed the recoverable gasoline range hydrocarbons from the vadose zone ( 25-40 foot depth) two confirmation soil borings will be drilled. One ( SB- 3 )near the location of P-3 and the other, ( SB-4 ) located near SB2 , which showed the highest concentration of contamination outside the initial tank and product line sampling, see Figures 3B and 4. These borings will be advanced to the forty foot depth and field screened using a HNu PTD with 10 . 2 ev bulb. Soil samples will be obtained at 5 foot intervals beginning at the 20 foot depth and continuing to the termination of the borings at the 40 foot depth . These samples along with the boring activities will be field screened using a HNu PID with 10 . 2 ev bulb. Any samples that field screen positive will be sealed, preserved, and chain of page 11