- Supervised and documented the removal of the underground structure following the format and requirements outlined for underground storage tanks in 06-096 CMR Chapter 691, Appendix P;
- Supervised the removal and disposal of diesel fuel impacted soil;
- Completed a water supply well survey;
- Completed a limited Phase I ESA;
- Supervised the installation of overburden monitoring wells;
- Collected soil and groundwater samples for laboratory analysis; and
- Attended public meetings to provide information to the community.
Removal of the underground structure revealed impact to the subsurface soils by diesel fuel. Utilizing Maine DEP cleanup goals, the impacted soil was excavated and taken offsite for disposal at a licensed disposal facility. Due to the sites close proximity to water supply wells, CEG completed a neighborhood water supply well survey, which revealed the presence of four bedrock drinking water supply wells and one dug drinking water supply well. One well served as a public water supply for a condominium complex adjacent to the site. The water supply wells were sampled and three of the five water supply wells (bedrock) exceeded the drinking water guideline for diesel range organics. The homeowners were notified of the sampling results, and carbon filters were installed on the three impacted water supplies shortly after notification. CEG also facilitated communication between the impacted parties and the Maine DEP's Third Party Damage Claims Unit.
Based on the results of the investigation, CEG was contracted by the Maine DEP to complete a Phase I ESA of the facility. This provided a better understanding of historic and current property uses. CEG then completed an extensive subsurface investigation to evaluate the risk of impact from the site to the neighborhood water supply wells. Utilizing the information obtained during the Phase I ESA, CEG installed soil borings and monitoring wells across the site, including in a detention pond, which is located adjacent to a public water supply well. Select soil and groundwater samples were collected and submitted to the laboratory for analysis based on the contaminants of concern.
The site is closely monitored by the town's selectmen. With the Maine DEP, CEG has attended town meetings to inform the public of the status of the site and answer questions. CEG's greatest accomplishment for this site was assisting the Maine DEP in negotiations with the property owner to cease fueling operations at this facility. This resulted in eliminating the continued releases of diesel fuel to the unpaved soil, which will assist in protecting the public and private water supply wells.