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Open-File Report 2010–1197

Prepared in cooperation with the
New York State Department of Environmental Conservation

Groundwater Quality in the Lower Hudson River Basin, New York, 2008

By Elizabeth A. Nystrom


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Water samples were collected from 32 production and domestic wells in the study area from August through November 2008 to characterize the groundwater quality. The study area, which covers 5,607 square miles, encompasses the part of the Lower Hudson River Basin that lies within New York plus the parts of the Housatonic, Hackensack, Bronx, and Saugatuck River Basins that are in New York. The study area is underlain by mainly clastic bedrock, predominantly shale, with carbonate and crystalline rock present locally. The bedrock is generally overlain by till, but surficial deposits of saturated sand and gravel are present in some areas. Of the 32 wells sampled, 16 were finished in sand and gravel deposits and 16 were finished in bedrock. The samples were collected and processed by standard U.S. Geological Survey procedures and were analyzed for 225 physiochemical properties and constituents, including major ions, nutrients, trace elements, radon-222, pesticides, and volatile organic compounds (VOCs); indicator bacteria were collected and analyzed by New York State Department of Health procedures.

Water quality in the study area is generally good, but concentrations of some constituents exceeded current or proposed Federal or New York State primary or secondary drinking-water standards; the standards exceeded were color (2 samples), pH (6 samples), sodium (8 samples), fluoride (1 sample), aluminum (3 samples), arsenic (1 sample), iron (7 samples), manganese (14 samples), radon-222 (17 samples), tetrachloroethene (1 sample), and bacteria (7 samples). The pH of all samples was typically neutral or slightly basic (median 7.2); the median water temperature was 11.8°C. The ions with the highest concentrations were bicarbonate [median 167 milligrams per liter (mg/L)] and calcium (median 38.2 mg/L). Groundwater in the study area ranged from very soft to very hard, but more samples were classified as very hard (181 mg/L as CaCO3 or more) than soft (60 mg/L as CaCO3 or less); the median hardness was 140 mg/L as CaCO3. The maximum concentration of nitrate plus nitrite was 2.38 mg/L as nitrogen, which did not exceed established drinking-water standards for nitrate plus nitrite (10 mg/L as nitrogen). The trace elements with the highest concentrations were strontium [median 189 micrograms per liter (μg/L)] and barium (median 50.6 μg/L). The highest radon-222 activities were in samples from crystalline bedrock wells [maximum 13,800 picocuries per liter (pCi/L)]. Seventeen samples had radon-222 activities that exceeded a proposed U.S. Environmental Protection Agency (USEPA) drinking-water standard of 300 pCi/L; activities in two samples exceeded a proposed alternative drinking-water standard of 4,000 pCi/L. Ten pesticides and pesticide degradates were detected among 14 samples at concentrations of 0.183 μg/L or less; most were herbicides or their degradates. Eight VOCs were detected among six samples; these included solvents, gasoline components, and a trihalomethane. Total coliform bacteria were detected in seven samples; fecal coliform bacteria, including Escherichia coli, were detected in one sample.

First posted September 17, 2010

For additional information contact:
U.S. Geological Survey
New York Water Science Center
425 Jordan Road
Troy, NY 12180

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Suggested citation:

Nystrom, E.A., 2010, Groundwater quality in the Lower Hudson River Basin, New York, 2008: U.S. Geological Survey Open-File Report 2010-1197, 39 p., available only at




Purpose and Scope

Hydrogeologic Setting

Methods of Investigation

Well Selection

Sampling Methods

Analytical Methods

Groundwater Quality

Physiochemical Properties

Major Ions

Nutrients and Organic Carbon

Trace Elements and Radon-222


Volatile Organic Compounds



References Cited

Appendix 1: Results of Water-Sample Analyses

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