Chemical quality of ground water on Cape Cod, Massachusetts

Water-Resources Investigations Report 79-65
By:  and 



Cape Cod is a 440 square mile hook-shaped peninsula which extends 40 miles into the Atlantic. Freshwater in Pleistocene sand and gravel deposits is the source of supply for nearly 100 municipal and thousands of private domestic wells. Most ground water on Cape Cod is of good chemical quality for drinking and other uses. It is characteristically low in dissolved solids and is soft. In 90 percent of the samples analyzed, dissolved solids were less than 100 mg/l (milligrams per liter) and pH was less than 7.0. Highway deicing salt, sea-water flooding due to storms , and saltwater intrusion due to ground-water withdrawal are sources of sodium chloride contamination. Chloride concentrations have increased from 20 to 140 mg/l, owing to saltwater intrusion at Provincetown 's wells in Truro. In Yarmouth, contaminated ground water near a salt-storage area contained as much as 1,800 mg/l chloride. Heavy metals, insecticides, and herbicides were not found at concentrations above the U.S. Environmental Protection Agency 's recommended limits for public drinking-water supplies, but iron and manganese in some samples exceeded those limits. Ninety percent of 84 samples analyzed for nitrate reported as nitrogen contained less than 1.3 mg/l and 80 percent contained 0.5 mg/l or less of nitrate as nitrogen. Water containing nitrogen in excess of 0.5 mg/l has probably been affected by municipal or domestic sewage or fertilizer, and water with less than this amount may have been affected by them. (Woodard-USGS)

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Additional publication details

Publication type Report
Publication Subtype USGS Numbered Series
Title Chemical quality of ground water on Cape Cod, Massachusetts
Series title Water-Resources Investigations Report
Series number 79-65
DOI 10.3133/wri7965
Year Published 1979
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Description Report: iv, 11 p.; 2 Plates: 45.02 x 34.52 inches and 34.44 x 45.17 inches
Country United States
State Massachusetts
Other Geospatial Cape Cod
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