Vapor-diffusion samplers installed by divers in water up to 30 ft deep at two sites in Johns Pond were used to delineate the discharge areas of two volatile organic compound (VOC) plumes. An array of diffusion samplers was buried about 0.5 feet below the pond bottom in the presumed discharge area of the Storm Drain-5 (SD-5) plume, a groundwater plume that contains trichloroethene (TCE) and tetrachloroethene (PCE) and originates on the Massachusetts Military Reservation. VOCs from the SD-5 plume and a previously unidentified plume were found in the pond-bottom sediments. An array of samplers was subsequently installed to map the unexpected area of elevated TCE discovered in the first round of sampling, which led eventually to the delineation of a previously unknown lobe of the Chemical Spill-10 plume that had migrated beneath Ashumet Pond before discharging into Johns Pond. Vapor-diffusion samplers proved to be a valuable tool in the investigation of the fate of groundwater contaminant plumes as they discharge to ponds.

Savoie, J.G., LeBlanc, D.R., Blackwood, D.S., McCobb, T.D., Rendigs, R.R., and Scott Clifford, 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.

More information can be obtained on the New Diffusion Samplers Track Contamination Entering Lakes and Ponds web page.

Location of study area, the Storm Drain-5 plume, Johns Pond, and altitude of water table. Discharge area into Johns Pond was unknown before investigation.

USGS Scientific Investigations Report 2005-5010
Comparison of diffusion- and pumped-sampling methods to monitor volatile organic compounds in groundwater, Massachusetts Military Reservation, Cape Cod, Massachusetts, July 1999-December 2002

USGS Water-Resources Investigations Report 02-4186
Guidance on the use of passive-vapor-diffusion samplers to detect volatile organic compounds in groundwater-discharge areas, and example applications in New England

USGS Scientific Investigations Report 2005-5155
Field Tests of Nylon-Screen Diffusion Samplers and Pushpoint Samplers for Detection of Metals in Sediment Pore Water, Ashland and Clinton, Massachusetts

USGS Water-Resources Investigations Report 01-4060
User’s guide for polyethylene-based passive diffusion bag samplers to obtain volatile organic compound concentrations in wells, Part 1: Deployment, recovery, data interpretation, and quality control and assurance

USGS Water-Resources Investigations Report 01-4061
User’s guide for polyethylene-based passive diffusion bag samplers to obtain volatile organic compound concentrations in wells, Part 2: Field tests

Vertical path of Storm Drain-5 plume in groundwater along section A-A’.

Location of Storm Drain-5 plume and vapor-diffusion samplers collected in August 1998 to delineate the Storm Drain-5 plume discharge area, Johns Pond, Cape Cod, Massachusetts.

Discharge areas of Storm Drain-5 plume and a previously unidentified trichloroethene plume based on concentrations in diffusion samples, August 1998, Johns Pond, Cape Cod, Massachusetts.

Discharge area of Chemical Spill-10 trichloroethene plume based on concentration in diffusion samples, December 1998, Johns Pond, Cape Cod, Massachusetts.