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Detection of Fresh Ground Water and a Contaminant Plume beneath Red Brook Harbor, Cape Cod, Massachusetts, 2000

 

Water Resources Investigations Report 02-4166



By Timothy D. McCobb and Denis R. LeBlanc

ABSTRACT

Trichloroethene and tetrachloroethene were detected in ground water in a vertical interval from about 68 to 176 feet below sea level beneath the shoreline where the contaminant plume emanating from a capped landfill on the Massachusetts Military Reservation intersects Red Brook Harbor. The highest concentrations at the shoreline, about 15 micrograms per liter of trichloroethene and 1 microgram per liter of tetrachloroethene, were measured in samples from one well at about 176 feet below sea level. The concentrations of nutrients, such as nitrate and ammonium, and trace metals, such as iron and manganese, in these same samples are typical of uncontaminated ground water on Cape Cod. Fresh ground water (bulk electrical conductance less than 100 millisiemens per meter) is present beneath the harbor at 40 of 48 locations investigated within about 250 feet of the shoreline. Fresh ground water also was detected at one location approximately 450 feet from shore. The harbor bottom consists of soft sediments that range in thickness from 0 to greater than 20 feet and overlie sandy aquifer materials. Trichloroethene was detected at several locations in fresh ground water from the sandy aquifer materials beneath the harbor. The highest trichloroethene concentration, about 4.5 micrograms per liter, was measured about 450 feet from shore.

CONTENTS

Abstract

Introduction 

Acknowledgments 

Field Investigation and Results 

Ground-Water Quality 

Geophysical Survey of Monitoring Wells 

Survey of Bulk Electrical Conductance of Harbor-Bottom Sediments.

Point Measurements of VOC Concentrations in Pore Water from Harbor-Bottom Sediments

Detection of Fresh Ground Water beneath Red Brook Harbor 

Detection of the Contaminant Plume Upgradient from and beneath Red Brook Harbor.

Summary 

References Cited 

FIGURES

1, 2. Maps showing:

1. Location of the Massachusetts Military Reservation, the Landfill-1 plume, Buzzards Bay, and the altitude of the water table (1995), western Cape Cod, Massachusetts 

2. Location of the Landfill-1 plume and geophysical logging sites in the vicinity of Red Brook Harbor, Cape Cod, August 2000

3. Conceptual model of ground-water-flow patterns and the interface between freshwater and saltwater in an idealized coastal aquifer 4

4. Graph showing vertical distribution of volatile organic compounds in (A) screened-auger boring 27MW0065, on Red Brook Harbor Road, February 1996 and (B) well BHW 493-0181 and multilevel sampler BHW 493-M01, on the shore of Red Brook Harbor, Cape Cod, August 2000

5. Plots showing natural gamma and electromagnetic-induction logs from wells near Red Brook Harbor, Cape Cod, August 2000 

6, 7. Maps showing:

6. Locations of sites where electrical conductance profiles were taken in sediments beneath Red Brook Harbor, Cape Cod, August 2000 

7. Lowest bulk electrical conductance measured at profile sites, and contoured thickness of soft sediments, Red Brook Harbor, Cape Cod, August 2000 

8. Plot showing vertical electrical conductance profiles from beneath Red Brook Harbor, Cape Cod 

9, 10. Maps showing:

9. Locations and site identifiers for pore-water samples collected from temporary well points beneath Red Brook Harbor, Cape Cod, August 2000

10. Concentrations of trichloroethene measured in pore-water samples collected from temporary well points beneath Red Brook Harbor, Cape Cod, August 2000 

TABLES

1. Well-construction data and field water-quality analyses for well BHW 493-0181 and multilevel sampler BHW 493-M01, Cape Cod, Massachusetts, August 2000

2. Nutrient analyses of water samples collected from well BHW 493-0181 and multilevel sampler BHW 493-M01, Cape Cod, August 2000 

3. Major cation and trace-metal analyses of water samples collected from well BHW 493-0181 and multilevel sampler BHW 493-M01, Cape Cod, August 2000 

4. Volatile organic compound analyses of water samples collected from well BHW 493-0181 and multilevel sampler BHW 493-M01, Cape Cod, August 2000 

5. Well-construction data for natural-gamma and electromagnetic-induction geophysical logging, Cape Cod, August 2000 

6. Location, depth, and water-level data for electrical-conductance profiles beneath Red Brook Harbor, > Cape Cod, August 2000 

7. Values of measured bulk electrical conductance for profiles beneath Red Brook Harbor, Cape Cod, August 2000

8. Sampling data, field water-quality analyses, and volatile organic compound detections for temporary well points in Red Brook Harbor, Cape Cod, August 2000

AVAILABILITY

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Errata Sheet Version History
Errata sheet is available as a pdf (3.0MB)

The citation for this report, in USGS format, is as follows:

McCobb, T. D., and LeBlanc, D. R., 2002, Detection of Fresh Ground Water and a Contaminant Plume beneath Red Brook Harbor, Cape Cod, Massachusetts, 2000: U.S. Geological Survey Water-Resources Investigations Report 02-4166, 36 p.

For more information about USGS activities in Massachusetts-Rhode Island District, visit the USGS Massachusetts-Rhode Island Home Page.



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