Soil Gas Analysis
This site was an operating Air Force Base facility located in central Utah. An initial site investigation revealed the presence of volatile organic compounds in the soil. The project managers chose to delineate several contaminated plumes on the site by collecting soil gas samples utilizing hydraulically driven soil probe rigs. The samples were collected in Tedlar bags for storage and delivery to the mobile laboratory. The samples were then analyzed for volatile organic compounds. The results of the individual analyses were available for daily review by the project staff. The results were tabulated on a daily basis to direct drilling activities for the next day. By project end, more than 190 samples were analyzed by EPA Method 8260. In evaluating the cost effectiveness of utilizing a mobile laboratory for this project, let’t examine the most obvious values first, i.e. cost per sample. For simplicity, we will assume 190 samples were analyzed. The project required a maximum turnaround time of twenty-four hours for each sample because of the need for real time data for field decisions and the 24-hour holding time restriction for vapor samples collected in Tedlar bags.
- Mobile laboratory costs for the project totaled $22,000.
- Fixed laboratory fees for this project, assuming 190 samples analyzed for VOC’s (EPA Method 8260) with a 25-hour turnaround would have cost the client $47,500 (190 samples x $250.00/sample + 200% for rush delivery).
The cost difference between these two processes represented an 54% savings to the client in analytical fees alone. The field activities for this project were completed in two weeks representing a significant savings in professional fees incurred for the site project management. In addition, each of the 190 samples collected and analyzed were relevant to the projects completion.