Reports
Pilot study of carcinogens in well water in Anne Arundel County, Maryland
1999, Bolton, D.W., and Hayes, M.A.
Open File Report 99-02-10
Abstract
A pilot study of carcinogens in domestic well water in Anne Arundel County was conducted by the Maryland Geological Survey (MGS) in cooperation with the U.S. Geological Survey (USGS), the U.S. Environmental Protection Agency (USEPA), the Anne Arundel County Health Department (AAHD), and the Anne Arundel County Department of Public Works. This study resulted from the recommendation of the Environmental Risks Subcommittee of the Anne Arundel County Advisory Task Force on Cancer Control.
Untreated water samples were collected from wells in areas where ground water is potentially at risk for the presence of carcinogens. Three areas were targeted: (1) areas of commercial and industrial land use or high-density residential development that are located in the general outcrop areas of the Patapsco, Magothy, and Aquia Formations, where well water may be susceptible to contamination by volatile organic compounds (VOCs) (referred to as VOC-targeted areas); (2) areas near current and former cropland in the general outcrop areas of the Patapsco, Magothy, and Aquia Formations, where well water may be susceptible to contamination by pesticides (“pesticide-targeted area”); and (3) areas throughout Anne Arundel County (particularly in the Aquia Formation in southern part of the county), where few data were available on radon and other naturally occurring radionuclides and trace elements that may be dissolved in the water (“radon-targeted areas”). Areas potentially at risk were identified by use of a Geographic Information Systems (GIS) approach, which employed land-use and other digital coverages to generate maps of the targeted areas. Prioritized areas were visited to verify land use, interview residents about their wells, and obtain permission to sample. Because of the targeted selection process, the data from the study are not considered representative of all domestic wells in the county.
Untreated (“raw water”) samples were collected from 47 wells (20 wells in each of the VOC- and pesticide-targeted areas and 7 wells in the radon-targeted area). Samples were collected from September through December 1997, and were analyzed for major ions (including iron, manganese, nitrate, and ammonia), the herbicides atrazine and metolachlor, radionuclides (uranium, radium-226, radium-228, radon, gross alpha- and gross beta-particle activity), arsenic, beryllium, lead, E. coli, total coliform bacteria, and a suite of volatile organic compounds. Because the radium concentrations from most of the wells from the Magothy and Patapsco Formations exceeded federal drinking water standards, resampling of selected wells took place in March 1998; samples were analyzed for radium-226, radium-228, radium-224 and short-term (measured within 3 days of sampling) and long-term (measured at about 30 days) gross alpha- and gross beta-particle activity.
