Evaluating Chemical Tracers in Suburban Groundwater as Indicators of Nitrate-Nitrogen Sources

Nitrate-nitrogen concentrations exceed the drinking water standard in nine percent of Wisconsin’s private wells andforty-seven community water system wells. It has been estimated that up to ninety percent of the nitrogen that contaminates groundwater is from agricultural sources, but on-site wastewater systems may also be important sources of groundwater nitrate-nitrogen in some areas. It is important that the source of nitrate-nitrogen to an individual well be understood to make appropriate land management and treatment decisions.

The objective of this study was to develop a chemical method for distinguishing between fertilizer and on-site waste sources of nitrate to a well by analyzing other compounds that are likely present in groundwater recharge from those sources.