In 2018, A3 Environmental Consultants was contracted to review a Phase I ESA which was completed twenty years earlier. The Phase I ESA identified the property as a former gas station.
At the time of the Phase I ESA, several soil borings were advanced to determine if the former gas station adversely impacted the property. One soil sample, located in the area of the former pump islands, had impacts above Illinois EPA standards for petroleum products. The old Phase I ESA recommended no further action which was clearly incorrect.
Phase II Investigation / SRP Investigation
A3E was contacted through a friend in the industry who knew the property owners. A3E’s first step was to confirm the results of the investigation that occurred previously, and advanced a hand augur within the area of the previous boring to see if the impacts remain or if after 20 years, the hydrocarbons had degraded. The soil sample identified impacts at concentrations above those that were identified originally. The client was looking to sell the property and the prospective purchaser was requesting a No Further Remediation (NFR) letter from the Illinois Environmental Protection Agency (IEPA).
A3E recommended the site be enrolled into the voluntary Site Remediation Program (SRP) to obtain the NFR Letter. Once enrolled, A3E advanced additional soil borings and installed three groundwater monitoring wells to delineate the extent of impacts.
During the investigation, A3E discovered a former waste oil underground storage tank (UST) on the west side of the property building that was not mentioned in the original Phase I ESA. The UST was removed and the Leaking Underground Storage Tank (LUST) incident was rolled into the existing SRP investigation. Because of its location near the onsite building, a soil vapor investigation was necessary and completed as part of the ongoing investigation.
A major challenge of completing investigation and remediation activities at the site was the presence of a high-pressure natural gas supply main in the right-of-way along the northern property boundary. The natural gas utility company required that any investigations/remediation not take place within 25-feet of the main and that when activities took place, a representative of the natural gas company needed to be present. During investigations within the pump-island, located on the north side of the property and within 25-feet of the gas main, soil concentrations exceeded IEPA saturation limits. Corrective actions could not be developed until the soils exceeding saturation limits were addressed. Because the client was in constrained by time and budget, the fastest and most low-cost solution was to excavate the impacted soils and disposes them offsite. Because these soils were located within the 25-foot zone of the natural gas main, A3E had to carefully coordinate the excavation activities.
Environmental Remediation Activities
A3E has completed the following remedial activities to obtain a Focused No Further Remediation Letter for this site:
- Remove the UST and excavate any residual soil impacts within the UST cavity. The cavity was backfilled with stone and the ground surface restored with asphalt/concrete.
- Additional soil investigation/delineation around the former pump islands
- Installation of a groundwater monitoring well in the location of the former pump islands to assess the groundwater in the most impacted area of the site and two additional monitoring wells near the property boundaries to delineate groundwater impacts.
- Over excavate and dispose of soils exceeding saturation concentrations near the pump islands
- Perform a soil gas/vapor assessment near the north and west sides of the onsite building to evaluate vapor encroachment concerns.
- Perform risk-based assessments and modeling of any remaining impacts on site.
- Implement engineering barriers and/or institutional controls to eliminate exposure pathways
No Further Remediation Letter (NFR)
The IEPA is currently reviewing the Remedial Action Completion Report (RACR) and a NFR is expected by May 2020.
Rand River Auto
Streamwood, Illinois ( Chicago Suburb )
Alisa Allen – Professional Geologist, Project Manager, Final Review
2018 – 2020