U.S. Department of the Interior

U.S. Geological Survey

Fact Sheet 2006–3096

June 2006 Printed on recycled paper

Toxic Substances Hydrology Program

Cape Cod Toxic Substances Hydrology Research Site

Physical, Chemical, and Biological Processes that Control the Fate of Contaminants in Ground Water

Research on Contamination Issues of 

National and Global Concern

Ground-water contamination has many causes. Activities such as fuel and industrial-chemical use, hard-rock mining, fertilizer application, and land disposal of solid waste 

and wastewater can introduce organic and inorganic contaminants into the subsurface. Once there, the contaminants are 

carried by flowing ground water and can eventually reach 

water supplies, streams, lakes, and the ocean. Many physical, chemical, and biological processes alter and disperse 

contaminants in the subsurface. Understanding these processes is essential for predicting the fate of contaminants that 

are of global concern and determining how best to manage 

and remediate the contamination.

The U.S. Geological Survey (USGS) Toxic Substances 

Hydrology (Toxics) Program conducts research to develop 

and improve our understanding of the processes that control the fate and effects of major types of contaminants. A 

three-part approach is employed that combines in-depth, 

long-term field studies at representative sites with laboratory 

experiments and computer modeling to identify and quantify 

specific processes. Hydrologists, chemists, microbiologists, 

computer modelers, and geophysicists collaborate at the field 

sites to address these complex multidisciplinary contamination problems. Knowledge built up over many years at these 

representative field sites is then applied to aquifers around 

the world.

The Cape Cod Field Research Site 

The Cape Cod field research site is near the wastewatertreatment facility at the Massachusetts Military Reservation 

(MMR). A treated-wastewater plume originates from the 

facility’s infiltration beds, which were used from about 1936 

to 1995. The plume extends more than 6 kilometers from 

the disposal site in the sand and gravel aquifer and contains 

a complex mixture of phosphate, nitrate, metal ions, detergents, organic chemicals, and microbes. The plume and 

adjacent parts of the aquifer serve as an ideal field laboratory 

in which to investigate how contaminants are transported in 

ground water.

 Since 1983, USGS scientists and their university 

colleagues from more than a dozen institutions in several 

nations have examined many aspects of the treated-wastewater plume. More than 1,500 wells have been drilled and 

Southeast view of wastewater-disposal beds and Ashumet Pond

Location map showing MMR and plume of treated wastewater

Atlantic Ocean

Massachusetts

Military Reservation MASSACHUSETTS

Cape Cod

0 10 20 MILES

0 20 KILOMETERS

Plume of

treated wastewater

10
For additional information contact: 

Denis LeBlanc, Hydrologist 

U.S. Geological Survey 

Massachusetts-Rhode Island Water Science Center 

10 Bearfoot Road 

Northborough, MA 01532 

<http://toxics.usgs.gov> 

<http://ma.water.usgs.gov/capecodtoxics>

thousands of water samples have been collected and analyzed to characterize the plume and to investigate processes 

such as the movement of bacteria and viruses in the plume 

and the dispersion that is caused by the geologic structure of 

the aquifer. An important aspect of research at the Cape Cod

site is the use of controlled ground-water tracer experiments. 

More than 100 experiments have been conducted in which 

water containing chemical and biological tracers is injected 

into the plume and the tracers are tracked as they move and 

are altered in the subsurface. Several well arrays have been 

constructed for the experiments; one is a large-scale array 

with more than 12,000 sampling points. The U.S. Environmental Protection Agency, the National Science Foundation, 

the U.S. Departments of Agriculture, Defense, and Energy, 

and the Nuclear Regulatory Commission are among the 

agencies that have cofunded this research. The diversity of 

funding sources reflects the wide-ranging significance of the 

scientific results.

Contributions from Field Research at the 

Cape Cod Site

Scientific knowledge gained from research at the USGS 

Cape Cod site is used widely by resource managers, regulators, educators, and other scientists. This knowledge has 

been disseminated in more than 120 scientific articles, 140 

federal reports, and 45 Masters and Ph.D. dissertations from 

15 universities (http://toxics.usgs.gov/bib). Scientists working at the site have been featured participants at national 

meetings on topics such as the subsurface fate and transport 

of microbes, the fate of arsenic in ground water, and the 

discharge of contaminant plumes to lakes. The National 

Research Council recently used information from Cape 

Cod and other Toxics Program research sites to evaluate the 

potential for more reliance on natural processes to clean up 

ground water. Results from the Cape Cod site are featured in several textbooks, thus helping to educate the next 

generation of environmental professionals. Groups ranging 

from the National Academy of Sciences to the Upper Cape 

Cod Technical High School have visited the site to learn 

about the ongoing ground-water studies.

The Cleanup of the Massachusetts 

Military Reservation

The ground-water cleanup at the Massachusetts 

Military Reservation is one of the most complex and expensive environmental restoration projects conducted by the 

U.S. military. More than $1 billion will probably be spent 

before the effort is completed. Results and methods from 

the USGS research on the treated-wastewater plume and 

surrounding aquifer have been applied to the investigation 

of other plumes on the MMR. USGS scientists from the 

Toxics group have worked directly with the military and its 

consultants to model ground-water flow, locate contaminant 

plumes discharging to ponds and the ocean, and develop 

more cost-efficient ground-water-sampling methods. Information about environmental programs at the MMR can be 

accessed online at <http://groundwaterprogram.army.mil>, 

<http://www.mmr.org>, and <http://www.mass.gov/guard/

E&RC>.

Array with more than 12,000 sampling points used for ground-water 

tracer experiments

Nonbiodegradable detergents in wastewater plume cause foaming on 

water from monitoring well

USGS scientists sample ground water in the wastewaterdisposal beds