Primary Contaminants – cis-1,2 Dichloroethene (cis-1,2 DCE), Perchloroethene (PCE), Trichloroethene (TCE), phosphates and nitrates

• Former Firefighter Training Area 1 (FTA-1). Approximately 42,500 tons of contaminated soil excavated and thermally treated. Action completed Sept. 1997

• Chemical Spill 16/17 (Former wastewater plant drying beds). Approximately 6000 tons of contaminated soil was removed from the site and taken off-base for disposal.

• Remedial action: Extraction, treatment, and infiltration gallery system, axial alignment, three extraction wells and 2 infiltration galleries
• Design rate capacity: 1200 gallons per minute (gpm)
• System start date: November 22, 1999
• Nutrient (phosphorus) input to nearby surface water bodies:
• 1997 decision outlined goals for Ashumet Pond investigation
• Alum treatment completed for Ashumet Pond in August 2001
• Nutrient (nitrate) input to surface water bodies:
• In lieu of treating nitrate in the Ashumet Valley Plume, AFCEE is funding an $8.5 million effort to pay for actions to reduce nitrogen loading to salt coastal ponds.

Primary Contaminants – Ethene Dibromide (EDB) and Perchloroethene (PCE)

• A portion of the CS-4 source area was remediated as part of multiple site thermal treatment of soils. Over 13,000 tons of soil was thermally treated. An action memorandum covering the remaining soils was submitted on 11/6/01.

• Remedial action: extraction, treatment, and infiltration gallery system. Thirteen extraction wells (eight operating) and two infiltration trenches.
• System start date: November 3, 1993

• Design rate capacity: 195 gpm, currently operating at 145 gpm
• New wellfield modification proposed for 2002-03.

Primary Contaminants – 1,2 Dichloroethene (1,2 DCE), Perchloroethene (PCE) and Trichloroethene, (TCE)

• Partial remedial action: 15 drainage structures removed in 1996 as part of the basewide Drainage Structure Removal Program (DSRP).
• Proposed Plan: September 1998
• Record of decision (ROD): November 1998
• Remedial action: Soil vapor extraction (SVE), combined with excavation and off-site disposal of contaminated soils. SVE system started in Feb. 2002.
• Over 1500 tons of soil has been removed and taken off-site for disposal.

• Separated into three plume cleanup areas:

CS-10 In-Plume

• Remedial Action: Three extraction wells and two infiltration galleries.
• Design rate capacity: 2760 gpm (combined with the southern/southwest system)
• System start date: June 24, 1999.
• The placement of the treatment system within the body of the plume targets higher contaminant concentration areas before the contaminants reach the Sandwich Road Fence. The in-plume system minimizes the hydrological impacts to the aquifer and surface water bodies, and improves the performance of the system

CS-10 Sandwich Road Fence

• Remedial Action: Eight extraction wells and six reinjection wells.
• Design rate capacity: 820 gpm
• System start date: May 18, 1999.
• A pilot test of recirculating well technology was conducted in the CS-10 plume near Sandwich Road during 1998. Four recirculating wells were installed, in the higher contaminant concentration area north of Sandwich Road. Over the 26 months of operation, approximately 312 pounds of TCE were removed. These wells were removed from operation once the Sandwich Road Fence system began operating.

CS-10 Southern and Southwest Fence

• Remedial Action: Five extraction wells and two infiltration galleries.
• Design rate capacity: 2760 gpm (combined with the in-plume system)
• System start date: April 27, 2000.
• The southern and southwestern system will increase the speed at which contaminants are removed from the aquifer and minimize cleanup timeframes. It also is designed to help slow further spreading of the groundwater plume.

Primary Contaminants – High Melting Explosive (HMX), Royal Demolition Explosive (RDX)

• Remedial Investigation: June 2000, with a supplemental draft RI report submitted in January 2002.
• The CS-19 study area contains an inactive site of about 0.32 acres (approximately 100-foot by 150-foot area) located in the west-central region of the Impact Area. The primary sources of contamination at the CS-19 source area are ordnance and military waste disposal.

• Remedial Action: A Feasibility Study is currently scheduled for March 2002, with a Proposed Plan in July 2002.

Primary Contaminant – Perchloroethene (PCE)

• Not linked to a specific source area

• First detected in 1997 during the FS-28 RI drilling program to define the upgradient extent of EDB groundwater contamination. The plume underlies the Crane Wildlife Management Area, where no current human exposure pathways exist.
• Proposed Plan: March 1999
• Record of Decision: February 2000
• Data gap collection began in early 2001 and will continue through 2002.
• Wellfield design and construction of remedial system set for 2003-2004.

Primary Contaminant – Trichloroethene (TCE)

• Not linked to a specific source area

• First detected as low concentrations of TCE in residential well samples collected north of Route 151 in 1997. The plume was further defined in the SWOU RI.
• Proposed Plan: March 1999
• Record of Decision: February 2000
• Data gap collection began in early 2001 and will continue through 2002.
• Wellfield design and construction of remedial system set for 2003-2004.

Primary Contaminants – Ethene Dibromide (EDB) and Trichloroethene (TCE)

• The specific source area of the Eastern Briarwood plume is not known. Potential source areas include SD-2, SD-5, FS-6, FS-8, FS-10, and FS-11

• Remedial Action: Long-term monitoring with no active remediation system in place, or planned for the future. Currently, the Eastern Briarwood plume is no longer depicted on maps since all monitoring well detections have been below the state and federal MCLs.

Primary Contaminant – Ethene Dibromide (EDB)

• Remedial Investigation and Feasibility Study completed in 1998.
• FS-1 is located adjacent to abandoned Taxiway E, east of the main MMR runways near the eastern MMR boundary. EC-121 Super Constellation fuel dump valves were tested between 1955 and 1970. It is estimated that 1 to 6 million gallons of aviation gas (AVGAS) was potentially released from aircraft to the ground.

• Remedial Action: 1 extraction well and 175 shallow well points to treat EDB near the Quashnet River cranberry bogs. An axial system is scheduled to be installed within the body of the plume in 2002-2003.
• Design rate capacity: 750 gpm (300 [extraction well], and 450 [shallow well points]
• System start date: April 7, 1999.
• New wellfield modification scheduled for Fall 2002.

Primary Contaminant – Benzene and Ethene Dibromide (EDB)

• FS-12 is the location of a leak in a 3-inch diameter underground fuel line. The study area is located approximately 3,000 feet north of Snake Pond. The pipeline is now abandoned and owned by a private company. Computer modeling estimated that approximately 70,000 gallons were released.
• Remedial action: Soil vapor extraction/air sparging (SVE/AS)
• System operated from October 23, 1995 to February 25, 1998
• Free product recovery effort removed 75 gallons of product, SVE/AS removed approximately 44,579 pounds of product (11% of estimated mass)
• FS-12 source area closure approved by regulators on March 1, 1999 with continued monitoring in source area

• Remedial action: Twenty-six extraction wells and 22 reinjection wells.
• Design rate capacity: 800 gpm
• System start: September 24, 1997
• Wellfield modification completed in May 2001, converting one reinjection well to an extraction well to capture a small portion of FS-12 outside of designed capture zone.

Primary Contaminants – 1,2,4-Trimethylbenzene and 1,3,5-Trimethylbenze

• No further action

• Remedial Action: Long-term monitoring with no active remediation system in place, or planned for the future. Currently, the FS-13 plume is no longer depicted on maps since all monitoring well detections have been below the state and federal MCLs.

Primary Contaminant – Ethene Dibromide (EDB)

• Not linked to a specific source area

• The FS-28 plume was first discovered in 1993 beneath the leading edge of the CS-4 plume. Subsequent investigations defined the lateral and vertical extent of the plume, as well as the leading edge, which was discovered to be upwelling into the Coonamessett River, and associated cranberry bogs.
• Remedial Action: 1 deep extraction wells and 204 shallow well-points (SWP) with surface discharge of treated water to Coonamessett river system
• Design rate capacity: 750 gpm (400 gpm from extraction well, and 350 gpm from the shallow well points).
• System start date: October 14, 1997 (extraction well), and April 6, 1999 (SWP)
• Note: In 1996, AFCEE completed construction of a wellhead carbon filtration system for the Coonamessett Water Supply Well (CWSW) as a precaution, even though this well has never been impacted by the FS-28 plume.

Primary Contaminants – Carbon Tetrachloride (CCl₄) and Ethene Dibromide (EDB)

• Not linked to a specific source area

• First discovered in 1998. The plume is defined by EDB and CCI4, which are distributed within two parallel lobes, one deeper than the other. The upper lobe underlies 30 to 70 feet of clean water, extends approximately 8000 feet in length, and has a maximum plume thickness of 50 feet. The lower lobe lies at the bottom of the aquifer, extending approximately 7000 feet in length, and has a maximum thickness of 50 feet. The upper and lower lobes are separated by 30 to 80 feet of clean water.
• Data gap collection began in early 2001 and will continue through 2002.
• Wellfield design and construction of remedial system set for 2003-2004.

Primary Contaminants – Carbon Tetrachloride (CCl₄), Perchloroethene (PCE) and Trichloroethene (TCE)

• Landfill cap completed October 1995
• 60 acres, more than 5,000,000 square feet of cap material installed
  Monitoring showing effectiveness as indicated by decreased levels of contaminants in wells adjacent to and downgradient of the landfill

• Remedial Action: Five extraction wells and two infiltration galleries, combined with monitored natural attenuation (MNA).
• Design rate capacity: 700 gpm
• System start date: August 26, 1999.
• Natural Resources Trustee Council began study on resource injury in 1999.

Primary Contaminants -- Perchloroethene (PCE), and Trichloroethene (TCE)

• Remedial action: Partial – 17 underground storage tanks removed March 1995
• Proposed Plan: November 1997
• Remedial action: Excavation and offsite disposal of soils. Remediation of soils began in May 2001. Almost 6,500 tons of soil was removed and taken off-site for disposal.
• Record of Decision: February 20, 1998

North

• Remedial action: Ten extraction wells and eight reinjection wells. Currently, one extraction well is pumping.
• Design rate capacity: 355 gpm (currently operating at 30 gpm)
• System start date: August 4, 1997

South (combined recirculating and extraction well systems)

• Remedial action: 2 recirculating wells. One well was shutdown due to no further action (i.e. no detection of chemicals in the well).
• Design rate capacity: 120 gpm (currently operating at 60 gpm)
• System start date: June 17, 1999
• Remedial action: 2 extraction wells
• Design rate capacity: 225 gpm
• System start date: January 22, 2000

Primary Contaminant – Ethylbenzene

• Remedial Action: Currently there is long-term monitoring with no active remediation system in place, or planned for the future. Currently, the Western Aquafarm plume is no longer depicted on maps since all monitoring well detections have been below the state and federal MCLs.