Developing and Testing a Method for the Analysis of Chemical Human Waste Markers in Groundwater and Identifying Sources of Nitrate Contamination
Nitka, Amy L.
University of Wisconsin-Stevens Point, College of Natural Resources
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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.