contact: David Bolton (dbolton@mgs.md.gov)
| Hydrogeology & Hydrology Program | |
| Radium GIS Project |
contact: David Bolton (dbolton@mgs.md.gov) |
[Introduction | Project Objectives | Products | References | Aquifer Diagram]
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Introduction: |
In 1997, high concentrations of radium were detected in well water in the Magothy, Patapsco, and Patuxent Formations in central and northern Anne Arundel County, Maryland in beginning in late 1997 (Bolton and Hayes, 1999; Bolton, 2000). Since then, more than 800 well-water samples in this area have been analyzed for radionuclides, and approximately half of the wells tested for gross alpha-particle activity (an indicator of radium) exceeded the Federal drinking water standard of 15 picocuries per liter (pCi/L). There is currently no single database containing all these data; rather, they are stored in separate databases maintained by the Anne Arundel County Health Department (AAHD), Maryland Geological Survey (MGS), Maryland Department of the Environment (MDE), and the U.S. Geological Survey (USGS). As a result, it is necessary to consult several sources whenever there is a request for data in order to get information to make decisions concerning well depths, water treatment, land use, and other issues.
The purpose of this project is to (1) consolidate all radium data (including water-quality and well-construction data) into a single database; and (2) use this data, in conjunction with hydrogeologic data, to develop an interactive geographic-information system (GIS) that will provide a three-dimensional visualization of zones of relative radium risk in ground water.
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Project Objectives: |
Develop digital coverages of the altitudes of the tops of the significant geologic formations in Anne Arundel County. Significant geologic formations include the major water-bearing formations in the county (the Patuxent, Patapsco, Magothy, and Aquia Formations) and the major confining and non-water-yielding units (including the Arundel Clay and the basement crystalline rocks).
Compile a comprehensive database of the physical, chemical, hydrogeological, and geographical attributes of wells and water samples collected by the Maryland Geological Survey and the U.S. Geological Survey that will be used to create GIS coverages.
Develop a 3-dimensional GIS coverage (using ArcView 3D Analyst) that identifies zones of relative risk with respect to radium concentrations within the Patuxent, Patapsco, and Magothy Formations. This will be done using the database developed in Objective #2 and data provided by AAHD.
| Products: |
Digital GIS coverages and hard-copy maps showing generalized altitudes of the top of the Aquia Formation, Magothy Formation, Patapsco Formation (Upper and Lower), Arundel Clay, Patuxent Formation, and basement complex.
Spreadsheet files in appropriate formats that contain all appropriate physical, chemical, geological, and geographical attributes of wells and water samples that have been collected in the AAHD pilot study and the MDE regional study.
| References: |
Bolton, D.W., 2000, Occurrence and distribution of radium, gross alpha-particle activity, and gross beta-particle activity in ground water in the Magothy Formation and Potomac Group aquifers, upper Chesapeake Bay area, Maryland, Maryland Geological Survey Report of Investigations No. 70, 97 p.
Bolton, D.W., and Hayes, M.A., 1999, Pilot study of carcinogens in well water in Anne Arundel County, Maryland: Maryland Geological Survey Open-File Report 99-02-10, 58 p.
updated 3/3/05
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