Phosphorus Plume Remediation
Type |
- Feasibility Studies
- Site Characterization
- Performance Monitoring
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Location |
Massachusetts Military Reservation, Cape Cod, MA |
Partners |
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Technology |
Reactive Chemical Barriers |
Contaminants |
Phosphorus |
Description |
USGS scientists have conducted extensive studies of the fate and transport of phosphorus in the plume of contaminated ground water that emanated from a wastewater-treatment facility on the Massachusetts Military Reservation, Cape Cod, MA. Phosphorus is of particular ecological interest because part of the ground-water plume discharges into a freshwater pond, which is thought to be ecologically stressed because of the additional input of phosphorus and other elements from the plume. In many places phosphorus stresses the ecosystem of water bodies because phosphorus is often responsible for eutrophication of the water body. As a result of the USGS phosphorus studies, the Massachusetts Military Reservation Installation Restoration Program installed a geochemical barrier - commonly known as a permeable reactive barrier - to prevent the discharge of phosphorus into the pond. The permeable reactive barrier was constructed by excavating pond sediments to a depth of approximately three feet, mixing the pond sediments with iron filings (zero-valent iron), and then placing the sediment/iron mixture back into the excavated area.
Working cooperatively with the Air Force Center for Environmental Excellence (AFCEE) and their contractors, USGS scientists:
- Delineated the discharge area of the phosphorus plume to Ashumet Pond, Cape Cod, Massachusetts.
- Estimated the mass of phosphorus discharging into Ashumet Pond.
- Developed water-quality monitoring methods that could be used to assess the performance of the permeable reactive barrier.
- Conducted water-quality monitoring before, during, and after the installation of the permeable reactive barrier to assess the overall performance of the barrier.
The monitoring network consisted of:
- Temporary drive-point piezometers (small wells)
- Vertical multilevel samplers
- Horizontal multilevel samplers
- Diffusion samplers
- Seepage meters
Water-quality sampling was conducted before, 2 months, and 8 months after emplacement of the barrier. Preliminary monitoring results indicate that the barrier is removing phosphorus from the plume. |
Seepage meters were deployed to measure fluxes of water and associated phosphorus concentrations discharging into Ashumet Pond, Cape Cod, MA. A National Association of Geoscience Teachers http://www.nagt.org/ student intern is connecting a seepage bag to the meter
(Click on photo for larger version)
USGS scientists installing an experimental horizontal multilevel sampler to test its usefulness for monitoring the performance of the permeable reactive barrier's ability to remediate a phosphate plume discharging to Ashumet Pond, Cape Cod, MA
(Click on photo for larger version)
The sediment along the shoreline of Ashumet Pond, Cape Cod, MA, before the installation of the permeable reactive barrier. The black color of the sediment is the result of manganese in the plume precipitating to manganese oxide when ground water with very little dissolved oxygen encounters the oxygen rich pond water
(Click on photo for larger version)
Shortly following the installation of the permeable reactive barrier, the sediment along the shoreline of Ashumet Pond, Cape Cod, MA, turned red, indicating the oxidation of the iron filings in the barrier.
(Click on photo for larger version)
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More Information |
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Contact |
Denis LeBlanc, USGS, Massachusetts District, Northborough,
MA, |
Publications |
- Air Force Center for Environmental Excellence, 2006, Iron barrier removing phosphorus, in Ashumet and Johns Ponds Update: Air Force Center for Environmental Excellence, Fact Sheet, February 2006, p. 1.
- Air Force Center for Environmental Excellence, 2005, Ashumet Pond geochemical barrier for phosphorus removal installation summary report: Otis Air National Guard Base, 176585-SPEIM-ASHPO-WRKPLN-002, prepared by CH2M Hill for AFCEE/MMR/Installation Restoration Program, March 2005, variously paged.
- Air Force Center for Environmental Excellence, 2006, Final Ashumet Pond 2005 phosphorus barrier technical memorandum: Otis Air National Guard Base, MA, 337105-SPEIM-ASHPO-TECHMEM-001, prepared by CH2M Hill for AFCEE/MMR/Installation Restoration Program, April 2006, variously paged.
- Bussey, K.W., and Walter, D.A., 1996, Spatial and temporal distribution of specific conductance, boron,
and phosphorus in a sewage-contaminated aquifer near Ashumet Pond,
Cape Cod, Massachusetts: U.S. Geological Survey Open-File Report
96-472, 44 p.
- McCobb, T.D., LeBlanc, D.R., Walter, D.A., Hess, K.M., Kent, D.B., and Smith, R.L., 2003, Phosphorus in a Ground-Water Contaminant Plume Discharging to Ashumet Pond, Cape Cod, Massachusetts, 1999: U.S. Geological Survey Water-Resources Investigations Report 02-4306, 70 p.
- Parkhurst, D. L., Stollenwerk, K. G. and Colman, J. A., 2003, Reactive-Transport Simulation of Phosphorus in the Sewage Plume at the Massachusetts Military Reservation, Cape Cod, Massachusetts: U.S. Geological Survey Water-Resources Investigations Report 03-4017, 40 p.
- Walter, D.A., and LeBlanc, D.R., 1997, Geochemical and hydrologic considerations in remediating phosphorus-contaminated
ground water in a sewage plume near Ashumet Pond, Cape Cod Massachusetts:
U.S. Geological Survey Open-File Report 97-202, 20 p.
- Walter, D.A., LeBlanc, D.R., Stollenwerk, K.G., and Campo, K.W.,
1999, Phosphorus
transport in sewage-contaminated ground water, Massachusetts Military
Reservation, Cape Cod, Massachusetts, in Morganwalp,
D.W., and Buxton, H.T., eds., U.S. Geological Survey Toxic Substances
Hydrology Program--Proceedings of the Technical Meeting, Charleston,
South Carolina, March 8-12, 1999--Volume 3 of 3--Subsurface Contamination
from Point Sources: U.S. Geological Survey Water-Resources Investigations
Report 99-4018C, p. 305-315.
- Walter, D.A., Rea, B.A., Stollenwerk, K.G., and Savoie, J.,
1996, Geochemical and hydrologic controls on phosphorus transport
in a sewage-contaminated sand and gravel aquifer near Ashumet
Pond, Cape Cod, Massachusetts: U.S. Geological Survey Water-Supply
Paper 2463, 89 p.
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Links |
Other Toxics Remediation Studies on Cape Cod
Information on Sewage-Contaminated Ground Water
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Back to Toxics Program Remediation Activities Index
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