Operating Successfully; Additional Source Area Discovered
The Air Sparging/Soil Vapor Extraction (AS/SVE) System at the
site has been
ECSMarin collected groundwater samples from the monitoring wells
at the site in December 2002. Laboratory analysis
of samples from the former underground storage tank area indicated
that while groundwater quality in the
in operation in the northern portion of the site for approximately
eleven months. The consultant for the site, ECSMarin
of Richmond, Vermont estimates that approximately 327 pounds,
or 54 gallons of gasoline have been removed by the AS/SVE system
from the former gasoline underground storage tank area since the
system began operation in August of 2002.
area of the treatment system had improved over time, concentrations
of contaminants in groundwater downgradient of the treatment system
area did not seem to be falling as predicted. A series
of subsurface soil borings were drilled on May 21 to try and determine
the cause. The contractor discovered an underground steel
culvert near the entrance to the site. It appears that over
the years since the original release petroleum has migrated in
the subsurface and accumulated in and around this culvert.
It now serves as an additional source of groundwater contamination.
Additional subsurface investigation is planned for August
to determine the extent of this additional source area, with the
goal of developing a plan to address it and allow the cleanup
Groundwater samples were also collected from the site monitoring
wells on May 21. The
results were consistent with the December 2002 monitoring round,
showing decreased contaminant concentrations in the AS/SVE treatment
area; and concentrations consistent with historical levels in
the downgradient wells.
In the southern portion of the site, samples from monitoring
wells located near the former drywell that was removed in 2002
continued to contain very low levels of contaminants. These
levels are below the cleanup standards for groundwater. However,
of these wells will continue, with the hope that contaminant concentrations
will fall to non-detectable levels.
ECSMarin personnel will continue to visit the site regularly
to perform maintenance activities and to collect data and samples
in Area I that will allow the effectiveness of the AS/SVE system
to be evaluated.
Questions about the Gerrish Motors / Woodstock
East cleanup? Contact the VTDEC Project Manager