Developing and Testing a Method for the Analysis of Chemical Human Waste Markers in Groundwater and Identifying Sources of Nitrate Contamination
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Date
2014-11Author
Nitka, Amy L.
Publisher
University of Wisconsin-Stevens Point, College of Natural Resources
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Show full item recordAbstract
Groundwater supplies residents in Central Wisconsin with their drinking water.
This water is susceptible to contamination by nitrate and other compounds that pose
health risks to consumers. The contamination may stem from both agricultural and
human waste treatment practices. Understanding the relationship between nitrate and
other contaminants in groundwater can direct remediation efforts, as well as future
residential planning.
This research identified and quantified multiple chemical indicators of nitrate
contamination in groundwater. A reliable analytical method for identifying septic system
tracers was developed to simultaneously analyze a group of pharmaceuticals, personal
care products, and artificial sweeteners. The selection of septic waste tracers was based
on chemical characteristics, such as mobility in groundwater and water solubility, as well
as their common use. Method development included instrument optimization and
designing a sample preparation technique. Solid phase extraction (SPE) was used to
improved analyte detection. Four SPE methods were compared to determine which
method yielded the best and most consistent recoveries for the most analytes.
Once the analytical method was determined, groundwater samples were taken
from five wells in a suburban subdivision in Central Wisconsin and analyzed. Nitrate
concentrations in these wells ranged from less than half the drinking water standard of 10
mg/L to more than five times the standard. The method for septic system tracers was
used with existing laboratory methods for indicators of agricultural contamination. With
these methods, the presence of specific contaminants could be identified and their
concentrations quantified. The analytical results were used to identify the likely sources
of nitrate contamination in those wells.