Waste Site Cleanup & Reuse in New England
Wells G & H Fact Sheet
Site History
Wells G & H were two municipal groundwater wells developed in 1964
and 1967 to supplement the water supply of the city of Woburn. The
wells were shut down due to chemical contamination in 1979. No one
has drank the water since then. Until that time, the wells supplied
30 percent of the city's drinking water. The Wells G & H Superfund
Site was placed on the National Priority List to receive federal
money for cleanup in 1982.
Site Description
The Site is located in East Woburn. Five properties within the approximate
330 acres of the site were found to be contaminated. The entire
site is defined by the boundaries of Route 128 to the north, Route
93 to the east, the Boston and Maine railroad to the west, and Salem
Street to the south. The area includes light industry, commercial
and residential properties.
What was contaminated?
The groundwater was contaminated with industrial solvents, called
volatile organic compounds (VOCs), such as trichloroethylene
(TCE) and tetrachloroethylene (PCE). Soil on the five properties was contaminated with VOCs, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and pesticides. Sediments in the Aberjona River were contaminated with PAHs and heavy metals such as chromium, zinc, mercury and arsenic.
How far along is the clean-up at the five properties found to
be contaminated?
W.R. Grace & Company
All the contaminated soil identified has been removed. W.R. Grace
has successfully completed its sixth year of operating a system
to pump up water from the shallow aquifer under their property.
The groundwater is treated using hydrogen peroxide and ultraviolet
light to remove the contaminants. Clean water is discharged from
the system. In the last six years of operation, 53 pounds of total
VOCs have been destroyed in 20 million gallons of water.
UniFirst Corporation
The most heavily contaminated soil was dug up and removed from the
former UniFirst property. Low level VOC-contamination remains present
in the soil beneath the building and paved parking lot. UniFirst
has been operating a groundwater treatment system for six years.
This system pumps groundwater from deep below both the UniFirst
and W.R. Grace properties. The groundwater is treated with ultraviolet
light and hydrogen peroxide to destroy the contaminants. In the
six years of operation, 1307 pounds of total VOCs have been destroyed
in 135 million gallons of groundwater.
Wildwood Conservation Trust
Much of the contaminated soil has been removed from the Wildwood
property. All stumps, rubbish, sludge, debris and drums have been
taken away. Beatrice removed 67 tons of hazardous sludge, 354 tons
of non-hazardous sludge, 255 tons of debris soils, 45 drum carcasses,
and 987 tons of mixed-contaminant soils from the Wildwood property.
The remaining soil contamination is due to low level VOCs. Groundwater
contaminated with VOCs remains.
In April 1998, a treatment system to clean up both the remaining soil and groundwater contamination began operating. The system includes wells to pump groundwater, wells to inject air into the ground to bubble contaminants to the surface, and wells to pull contaminants to the surface with a vacuum. A cap will cover the entire area to trap gases at the surface. A treatment system that changes the gases to carbon dioxide and water at elevated temperatures will destroy the VOCs from the soil and groundwater.
New England Plastics
Low level VOC-contaminated soil and VOC-contaminated groundwater
remain at the New England Plastics property. A system to remove
contaminants from the soil began operation on February 2, 1998.
It uses wells and a cap, similar to the Wildwood system, to pull
VOCs from the ground and into a treatment system where they will
be captured. The contaminants are trapped in 55-gallon drums that
are sent away for treatment. New England Plastics will begin to
consider how to address the groundwater contamination at their property
after this soil treatment system has had a chance to remove some
the remaining source contamination in the soil.
Olympia Nominee Trust
The owners of this property never reached an agreement with EPA
to clean up their property. Money has finally become available for
EPA to begin to do the job itself. EPA representatives took groundwater
samples and surface soil samples in September, 1997. The groundwater
data will be used to design a system to pump and treat contaminated
groundwater from beneath the property. The limits of contaminated
soil will be confirmed by additional soil sampling at deeper depths,
allowing EPA to plan for its future removal from the property.
What about the future of the groundwater aquifer?
The goal is to clean
the groundwater to the standards that are set for safe drinking
water. These standards are set by the Commonwealth of Massachusetts
and the Federal government. EPA has been investigating other properties
within the site boundary that may also have contributed to contamination
of the groundwater. EPA and MA Department of Environmental Protection
(DEP) have an open dialogue with the City of Woburn regarding the
future of the groundwater aquifer.
What did EPA's 1997 sampling in the Aberjona River tell us?
Sediments in the river are contaminated with PAHs and metals. EPA
took some additional sediment samples during November 1997. This
data gave us the rest of the information we need to complete a risk
assessment of the Aberjona River from Route 128 in Woburn to Sandy
Beach at the Upper Mystic Lake in Winchester. The risk assessment
will tell us what, if any, specific contaminants are posing any
hazard to people or plant and animal life along the river.