Delineating Discharge Areas of Contaminant Plumes with Diffusion Samplers
| Type |
Site Characterization
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| Location |
Johns Pond, Cape Cod, Massachusetts |
| Partners |
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| Technology |
Passive-Vapor-Diffusion Samplers |
| Contaminants |
- Chlorinated Solvents (Volatile organic compounds VOCs)
- Trichloroethene (TCE)
- Tetrachloroethene (PCE)
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| Description |
| USGS scientists and their partners tested the use of passive-vapor-diffusion samplers to characterize and delineate the discharge area of a plume of volatile organic compounds (VOCs) discharging into Johns Pond, Cape Cod, Massachusetts. Passive-vapor-diffusion samplers are empty glass vials placed inside of two layers of polyethylene membrane tubing. When placed in contaminated sediments, the air in the vial equilibrates with the VOCs in the pore water of the sediments. The VOCs contained in the air of the vial indicate the presence and likely magnitude of VOCs in sediments. Common
everyday zipper-locking polyethylene bags available at grocery stores can be used instead of the polyethylene tubing.
The objective of the test was to confirm that VOCs contained in the Massachusetts Military Reservation's Storm Drain-5 (SD-5) plume were discharging into Johns Pond from the bottom of the pond. USGS scientists placed and retrieved samplers at 267 locations along several lines in the sediments of Johns Pond at three different times. Scuba divers buried each of the samplers about half a foot into the pond-bottom sediments.
The samplers were allowed to equilibrate for two weeks before they were retrieved. The scientists unexpectedly detected a localized spot of higher concentrations of VOCs separate from the other grouping of contaminants nearby. Further investigations revealed that a previously unidentified plume of trichloroethene (TCE) was responsible for the spot of high TCE concentrations. The newly discovered plume is a branch of another plume (CS-10) that emanated from an abandoned missile site on the military base more than 3 miles from the pond.
The new passive-vapor-diffusion samplers are potentially an inexpensive and effective method to locate discharge areas of contaminated ground water in streams and ponds. A newly released USGS report prepared in cooperation with the U.S. Environmental Protection Agency provides guidance on the use of the diffusion samplers. |
Map of the extent of discharge for storm drain-5 (SD-5) plume in Johns Pond, Massachusetts. Contour lines are TCE concentrations in parts per billion (ppb). Note the TCE "hot spot" separate from the main discharge area. Further investigations showed that the "hot spot" was from another plume.
(Click on photo for larger version) |
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Map of the extent of discharge for storm drain-5 (SD-5) plume in Johns Pond, Massachusetts. Contour lines are TCE concentrations in parts per billion (ppb). Note the TCE "hot spot" separate from the main discharge area. Further investigations showed that the "hot spot" was from another plume.
(Click on photo for larger version) |
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| More Information |
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| Contact |
- Jennifer Savoie, USGS, Northborough, MA,
- Denis R. LeBlanc, USGS, Northborough, MA,
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| Publications |
- Church, P.E., Vroblesky, D.A., and Lyford, F.P., 2002, Guidance on the use of passive-vapor-diffusion samplers to detect volatile organic compounds in ground-water-discharge areas, and example applications in New England: U.S. Geological Survey Water-Resources Investigations Report 02-4186, 79 p.
- Savoie, J.G., LeBlanc, D.R., Blackwood, D.S., McCobb, T.D., Rendigs, R.R., and Clifford, Scott, 2000, Delineation of discharge areas of two contaminant plumes by use of diffusion samplers, Johns Pond, Cape Cod, Massachusetts, 1998: U.S. Geological Survey Water-Resources Investigations Report 00-4017, 30 p.
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| Links |
Other Toxics Remediation Studies on Cape Cod
Information on Ground-Water Contamination on Cape Cod
- Cape Cod Toxics Research Project, Cape Cod, Massachusetts
- Massachusetts Military Reservation Installation Restoration Program, Information on the cleanup of the Massachusetts Military Reservation, Cape Cod, Massachusetts
- Maps of Contamination Plumes on the Massachusetts Military Reservation, Cape Cod, Massachusetts
- Fact Sheet, Summer Update, Ashumet and Johns Ponds Area, Jul-02, Massachusetts Military Reservation, Air Force Center for Environmental Excellence, Installation Restoration Program
Information on Site Characterization
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