Aquifer Susceptibility in Virginia

Comment: Thanks to Anne for this article, our county water is susceptible to contamination from things such as uranium mining and milling!!

Data on Chemical and Isotopic Composition, Recharge Temperature, and Apparent Age of Water from Wells and Springs, 1998-2000Authors: David L. Nelms; George E. Harlow Jr.; GEOLOGICAL SURVEY WASHINGTON DC

Abstract: The determination of aquifer susceptibility to contamination from near-surface sources by the use of ground-water dating techniques is a critical part of Virginia's Source Water Assessment Program.

As part of the Virginia Aquifer Susceptibility study, water samples were collected between 1998 and 2000 from 145 wells and 6 springs in various hydrogeologic settings across the Commonwealth.

Samples were analyzed to determine water chemistry including nitrate (NO3), dissolved organic carbon (DOC), and radon-222 (222Rn), major dissolved and noble gases nitrogen (N2), argon (Ar), oxygen (O2), carbon dioxide (CO2), methane (CH4), helium (He), and neon (Ne), environmental tracers-chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), tritium (3H), and tritium/helium-3 (3H/3He), carbon isotopes carbon-14 (14C) and carbon-13 (delta13C), and stable isotopes of oxygen (delta18O) and hydrogen (delta2H).

The chemical and isotopic composition, recharge temperatures, and apparent ages of these water samples are presented in this report.

Data collected between 1999 and 2000 from 18 wells in Virginia as part of two other studies by the U.S. Geological Survey also are presented. Most of the sites sampled serve as public water supplies and are included in the comprehensive Source Water Assessment Program for the Commonwealth.

http://va.water.usgs.gov/NEWS_RELEASE/PressRelease.1.28.04.pdf


News Release

U.S. Department of the Interior

U.S. Geological Survey

Release: January 28, 2004

For questions about the study, contact David Nelms, USGS, Richmond, VA, 804-261-2630

Email: dlnelms@usgs.gov

For questions about drinking-water safety, contact Kelly Lobanov, Virginia Department of Health, Richmond, VA, 804-864-7553 Email: kelly.lobanov@vdh.virginia.gov

Many Virginia Wells Contain "Young and Susceptible" Water

A new study by the U.S. Geological Survey (USGS) found that west of Interstate 95, most of Virginia’s regional aquifers that serve as public water supplies contain relatively young water, less than 50 years old.

This is significant because young ground water is more susceptible to contamination by sources near the land surface.

Ground water is an important source of drinking water for a growing number of Virginians.

USGS did the study in cooperation with the Virginia Department of Health (VDH) Office of Drinking Water, in support of Virginia’s Source Water Assessment Program, a program required of every state by the Safe Drinking Water Act Amendments of 1996.

USGS scientists collected and analyzed water from 165 wells and 6 springs across Virginia, most of which are public water supplies.

They determined ground-water ages using an innovative technique that can measure extremely low levels of compounds in water—primarily chlorofluorocarbons (CFCs), sulfur hexafluoride (SF6), and tritium. CFCs (or Freons) were used as refrigerants, aerosol propellants, and cleaning agents; SF6 is a gas used to prevent arcing in high-voltage electrical switches; tritium is a radioactive isotope of hydrogen that was released into the atmosphere by thermonuclear weapons testing.

These compounds, most of which have been introduced since 1950, dissolve in precipitation and are carried to ground water when precipitation percolates down through the soil.

Wells and springs sampled west of the Fall Line (which follows I-95) and wells less than 100 feet deep in the Coastal Plain of Virginia contained at least a portion of young water and thus are considered susceptible to contamination.


David Nelms, principal USGS scientist on the study, credited the success of the study to the novel ground-water-age-dating method designed by USGS researchers, as well as the support USGS received from VDH.

"This technique lets us measure very low levels of these tracer compounds, so that we can date the age of young ground water more precisely than ever before," says Nelms.

"We were surprised by the results, which indicate that we need to rethink basic concepts about Virginia’s regional aquifers, especially the fractured rock and karst terrains west of the Fall Line.

We need to understand and protect our ground-water resources all over Virginia." (SO COUNTY LEADERS, WHAT ARE YOU GOING TO DO ABOUT THE WELLS IN OUR COUNTY AND PROTECT THE WATER FROM URANIUM MINING, WE WANT A CHEMICAL ORDINANCE AND BAN URANIUM MININING BEFORE IT RUINS OUR LIVES!!!)

Read the complete report in USGS Water-Resources Investigations Report 03-4278 Aquifer Susceptibility in Virginia, 1998-2000 by David L. Nelms and others, available from the USGS Branch of Information Services (1-888-ASK-USGS) and online at http://pubs.water.usgs.gov/wri034278 .
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