![]() |
||||
PUBLICATIONS—Water-Resources Investigations Report |
By Mark E. Savoca, Eric M. Sadorf, S. Mike Linhart, and Kymm K.B. Akers
U.S. Geological Survey, Iowa City, IA
The full report is available in pdf. Link to the pdf.
Ground-water samples were collected from monitoring wells at 31 agricultural and 30 urban sites in the Eastern Iowa Basins study unit during June–August 1997 to evaluate the effects of land use and hydrogeology on the water quality of alluvial aquifers. Ground-water samples were analyzed for common ions, nutrients, dissolved organic carbon, tritium, radon-222, pesticides and pesticide metabolites, volatile organic compounds, and environmental isotopes.
Calcium, magnesium, and bicarbonate were the dominant ions in most samples and were likely derived from solution of carbonate minerals (calcite and dolomite) present in alluvial detrital deposits. Chloride and nitrate were dominant anions in samples from several wells. Sodium and chloride concentrations were significantly higher in samples from urban areas, where roads are more numerous and road salts may be more frequently applied, than in agricultural areas. Nitrate was detected in 94 percent of samples from agricultural areas and 77 percent of samples from urban areas. Nitrate concentrations were significantly higher in agricultural areas than in urban areas and exceeded the U.S. Environmental Protection Agency maximum ontaminant level for drinking water (10 milligrams per liter as N) in 39 percent of samples from agricultural areas. Nitrate concentrations in samples from urban areas did not exceed the maximum contaminant level. Greater use of fertilizers in agricultural areas most likely contributes to higher nitrate concentrations in samples from those areas.
Tritium-based ages indicate ground water was most likely recharged after the 1950’s at all but one sampling site. Agricultural and urban land-use areas have remained relatively stable in the study area since the 1950’s; therefore, the effects of current land use should be reflected in ground water sampled during this study. Radon-222 was detected in all samples and exceeded the U.S. Environmental Protection Agency’s previously proposed maximum contaminant level for drinking water (300 picocuries per liter) in 71 percent of samples.
Pesticides were detected in 84 percent of samples from agricultural areas and 70 percent from urban areas. Atrazine and metolachlor were the most frequently detected pesticides in samples from agricultural areas; atrazine and prometon were the most frequently detected pesticides in samples from urban areas. None of the pesticide oncentrations exceeded U.S. Environmental Protection Agency maximum contaminant levels or lifetime health advisories for drinking water. Pesticide metabolites were detected in 94 percent of samples from agricultural areas and 53 percent from urban areas. Metolachlor ethane sulfonic acid and deethylatrazine were the most frequently detected metabolites in samples from agricultural areas; metolachlor ethane sulfonic acid and alachlor ethane sulfonic acid were the most frequently detected metabolites in samples from urban areas.
Abstract.
Introduction
Purpose and Scope
Description of the Study Area
Acknowledgments
Study Design and Methods
Site Selection
Well Installation
Land-use Classification
Sample Collection
Water-Quality Analysis
Statistical Analysis
Effects of Land Use and Hydrogeology on Water Quality
Common Ions
Nutrients
Radiochemicals
Pesticides and Metabolites
Volatile Organic Compounds
Summary and Conclusions
References
Appendix
Savoca, M.E., Sadorf, E.M., Linhart, S.M., and Akers, K.K.B., 2000, Effects of landuse and hydrogeology on the water quality of alluvial aquifers in Eastern Iowa and Southern Minnesota, 1997: U.S. Geological Survey Water-Resources Investigations Report 99-4246, 38 p.
The text and graphics are presented here in pdf format (print quality):
Document Accessibility: Adobe Systems Incorporated has information about PDFs and the visually impaired. This information provides tools to help make PDF files accessible. These tools convert Adobe PDF documents into HTML or ASCII text, which then can be read by a number of common screen-reading programs that synthesize text as audible speech. In addition, an accessible version of Acrobat Reader 5.0 for Windows (English only), which contains support for screen readers, is available. These tools and the accessible reader may be obtained free from Adobe at Adobe Access.
AccessibilityFOIAPrivacyPolicies and Notices | |
U.S. Department of the Interior, U.S. Geological Survey
Persistent URL: http://pubs.water.usgs.gov/wri994246 Page Contact Information: Publishing Service Center Last modified: Friday, December 02 2005, 10:42:42 AM |
![]() ![]() |