USGS

U.S. GEOLOGICAL SURVEY
Open-File Report 03-246

Aquifer Susceptibility in Virginia: Data on Chemical and Isotopic Composition, Recharge Temperature, and Apparent Age of Water from Wells and Springs, 1998-2000

Prepared in cooperation with
Virginia Department of Health
Office of Drinking Water

By David L. Nelms and George E. Harlow, Jr.

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 (d13C), and stable isotopes of oxygen (d18O) and hydrogen (d2H). 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.

CONTENTS

Abstract
Introduction
       Purpose and scope
        Definition of apparent age
        Sampling locations
        Acknowledgements
Sample collection, analytical methods, and quality assurance
        Water chemistry
        Major dissolved and noble gases
        Chloroflourocarbons
        Sulfur hexaflouride
        Tritium
        Tritium/helium-3 and noble gases
        Stable isotope ratios of oxygen and hydrogen in water
        Quality assurance
Analytical and quality assurance data
        Water chemistry
        Major dissolved and noble gases, recharge temperature, and excess air
        Chlorofluorocarbon concentrations and apparent ages
        Sulfur hexafluoride concentrations and apparent ages
        Tritium, helium, and neon data, and apparent tritium/helium-3 ages
        Carbon isotope data and adjusted radiocarbon ages
        Stable isotope ratios of oxygen and hydrogen in water
        Quality assurance
References Cited

This report is available online in Portable Document Format (PDF). If you do not have the Adobe Acrobat PDF Reader, it is available for free download from Adobe Systems Incorporated.

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Send questions or comments about this report to David Nelms (804) 261-2630.

For more information about USGS activities in Virginia, visit the USGS Virginia District home page.


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