Toxic chemicals and other wastes pose a serious threat to the Nation's ground-water resources. Municipal and domestic wastewater, the most common waste, is discharged to aquifers nationwide through septic systems and community treatment plants. Wastewater-contaminated ground water typically contains a broad range of toxic organic and inorganic chemicals. The restoration and protection of ground-water quality depend on knowledge of the physical, chemical, and microbiological processes that affect the movement and fate of these chemicals in aquifers. Hydrologists at the USGS Cape Cod Toxic Substances Hydrology Research Site at the Massachusetts Military Reservation are conducting field-oriented research to understand the interaction of these processes in the subsurface and the additional complexity caused by the natural variability of aquifer materials. This understanding is needed to develop practical methods to clean up and protect ground-water resources.

August 2007 –Tracer Tests and Sampling of Wastewater Plume Are Highlights of Ongoing Field Season
During June-September 2007, Cape Cod Toxics scientists are using ground-water tracer experiments to examine denitrification in the presence of dissolved iron, the chemotaxis of mobile subsurface bacteria, and the development of antibiotic resistance of subsurface bacteria exposed to antibiotics typically present in municipal wastewater. The Cape Cod group also is conducting an extensive sampling of the wastewater plume to examine the hydrologic and geochemical evolution of the plume since the plume was first described in 1978-79.

Water Resources Research - July 2007
Modeling the movement of a pH perturbation and its impact on adsorbed zinc and phosphate in a wastewater-contaminated aquifer
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Advances in Water Resources - June-July 2007
Role of chemotaxis in the transport of bacteria through saturated porous media
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Federation of European Microbiological Societies - May 2007
In situ hydrogen consumption kinetics as an indicator of subsurface microbial activity
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USGS Data Series - February 2007
Ground-Water-Quality Data for a Treated-Wastewater Plume Undergoing Natural Restoration, Ashumet Valley, Cape Cod, Massachusetts 1994-2004
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Journal of Contaminant Hydrology - September 2006
Tracer test with As(V) under variable redox conditions controlling arsenic transport in the presence of elevated ferrous concentrations
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Water Resources Research - June 2006
Hydrogeophysical tracking of three-dimensional tracer migration--The concept and application of apparent petrophysical relations
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June 2007 – Chemotactic Bacteria May Be Able to “Swim” Toward Ground-Water Contaminants
Cape Cod Toxics scientists report in a recent issue of Advances in Water Resources that some ground-water bacteria may be able to “swim” in the direction of increasing concentrations of some chemicals. This chemotactic response may be useful for biorestoration of contaminated aquifers. Field experiments are ongoing at the Cape Cod site to study this microbial transport process in granular aquifers (Ford and Harvey, 2007).

April 2007 - LeBlanc Presents the MIT Freeman Lecture
Denis LeBlanc, coordinator of the Cape Cod Toxics Site, presented the 2007 John R. Freeman Lecture at MIT on April 6. The talk, titled "Cape Cod's Billion Dollar Ground-Water Cleanup - The Hydrologic Story," was well-attended by a diverse group of environmental professionals from the academic, regulatory, scientific, and consulting communities. The annual Freeman Lecture is sponsored by the Boston Society of Civil Engineers and the MIT Dept. of Civil and Environmental Engineering (http://web.mit.edu/newsoffice/2007/capecodclean.html).

March 2007 - Presentations Given by Cape Toxics Scientists at Scientific Meeting
Findings from the Cape Cod Toxics Site were described in presentations at the 2007 Northeastern Section GSA Meeting in Durham, NH, in March 2007. Denis LeBlanc organized a special session on the effects of aquifer recharge with treated wastewater and urban runoff on ground-water quality. Work from Cape Cod on the natural restoration of a treated-wastewater plume, borehole-dilution tests, phosphorus removal by a geochemical barrier, and numerical modeling to estimate nitrate loading to coastal estuaries was presented.