Several people have brought up the large cost associated with the contamination clean up at the DPW Barn (approx. $1 million) and have asked why the cost projections in the proposal for the Smith property clean up are so much lower.
Firstly, there have been substantial funds already expended at the Smith site. Since 2005, the owners of the Smith property have incurred costs for soil borings, monitoring wells, soil and groundwater sampling and analytical costs, reporting, and the removal of large underground storage tanks. As a result, the majority of delineation and analysis is complete. The cost estimates provided in the financial pro formas are not all inclusive from day one and therefore do not include these previously incurred costs. The pro forma estimates represent costs from now to closure.
In addition, the nature and extent of contamination at these two sites is very different. The Smith site is not nearly as serious and it is contained. Below is a summary. For a more detailed report, click here.
Highway Dept. Site
- Historic gasoline release(s) caused significant soil impacts, which served as an on-going source of groundwater contamination. The geological characteristics of the soil rendered excavation and off-site disposal the only feasible remedial alternative. 4,809 tons of soil were removed.
- Extensive soil impacts and separate-phase gasoline around the former underground storage tanks caused an uncontrolled source and migration of the dissolved phase gasoline plume, which required interim remediation (product removal and groundwater extraction and treatment), extensive excavation and installation of a treatment system on a nearby water supply well.
- Large groundwater plume required extensive monitoring well network and monitoring of area water supplies.
Smith Site
- The majority of the delineation has already been completed.
- Groundwater impacts are relatively low and the plume is stable, which is not indicative of a significant soil source. Any potential uncharacterized soil impacts found to be contributing to groundwater contamination would be relatively minor and localized.
- Based on the contaminant concentrations, active groundwater remediation is not warranted (as it was with the DPW Barn).
Bolton Center Historic Neighborhood Blog 