SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

page 2,2450 Taste Road The RAWP was submitter) to SJCIEHD on October 31, 2002. Based on snit sample data obtained during the site investigation, it was estimated that approximately 1,000. cubic yards-of petroleum impacted soil and 300 cubic yards of uncontaminated overburden soil would be removed. Proposed excavation.dimensions were 6v feet by 100 feet by 124 sleep.. 'Field screening tools would be used to separate the clean overburden.,.soil from the impacted soil; the clean soil would be used as backfill following. completion of the excavation, The A.WVc RP was approved in SJClEHD omspondence dated. March 1 '2t tl . Implerhentation of the.RAWP began in late May 2003. Almost immedlately it was discovered that there was much more impacted soil than had been expec#ed. Thi shallow soil, particularly in the area close to the farmer dispenser island,was more contaminated than anticipated. In the interest of making the remedial effort be the most. effective it could be, I called Robert Trommer at the SWRC8-CUF to discuss the problem. Mr. Trornrri r told me that as long as the soil being removed was documented. to be contaminated there should be no problem with obtaining reimbursement for any 0it ohal costs- Mr: Trommer specifically stated that PID readings taken from:samples of removed soil should be greater than 100 ppm., I relayed this information to the AGE :personnel working onsite,and directed the continuation of the remediation:. Implementation of the RAWP continued at the site. The final dimensions of the excavation were actually less than proposed, extending to only approximately 8 fleet bsg, rather than 12 feet bsg. Soil samples for analysis were collected approximately every 20 linear feet from the;sidewalls, at an intermediate depth of 4 feet bsg across the excavation, and at 8 feet bsg from across the floor of the excavation, for a total of 31 samples. Of all the samples analyzed, only four, two sidewall and two bottom samples were non-detect for all constituents analyzed. Concentrations in the 27 impacted samples ranged from 1.5 to 2,200 ppm total petroleum hydrocarbons as gasoline. The samples with the highest concentrations of contaminants were those samples taken from locations in the southeast corner of the excavation, towards the former dispenser island. These results indicate that while the bulk of the contaminated sail was removed,some residual contamination remains in the most impacted area. It also indicates that,as:M.r Trommer had conditioned; excessive excavation, or attempting to reach non-detect concentrations, was not done: It should be rioted that this remediation work was completed at a time .hen;outdoor temperaturesrWere averaging 95 degrees Fahrenheit. in addition, it was very windy. From the odors present onsite during the work it was apparent that volatilization of hydrocarbons from the excavation.pit,and removed soil was occurnrrg throughout the duration of the excavation.work, Sample analysis concentrations likely reflect less con#arriination than was actually there when the excavation work.began. ilii-summary; 1. The final dimensions of the total excavation area were actually 300 cubic yards less than proposed, and as AGE has pointed out,the actual costs of the excavation did fall within the:RAWP proposed.budget:of between $150;000-$200,000. 2 The significant change in the scope of work proposed in the RAWP was that there was more contaminated soil requiring haul off 1hanexpected,and less clean overburden available for use as backfill.