IDENTIFYING NITRATE POLLUTION SOURCES AND CONTAMINATION FOR GROUND WATER QUALITY USING A STABLE ISOTOPE APPROACH IN NORTHERN CEDAR COUNTY, MISSOURI

Suburban land use is expanding out into rural areas, which have led to higher concentrations of nitrates in shallow groundwater areas as well as deeper groundwater areas. Groundwater is analyzed for stable isotopes of nitrogen and oxygen. Nitrogen and oxygen isotopes (δ¹⁵N and δ¹⁸O) of nitrate (NO₃-) can be used to interpret its nitrogen transformation processes such as nitrification, assimilation, and denitrification. Elevated nitrates in groundwater can also occur from atmospheric deposition, mineralization of soil, and possibly from anthropogenic sources. Those sources include chemical fertilizers/pesticides, sewage waste, animal waste, past mining activity, and industrial wastewater. Using the stable isotopes, δ¹⁵N and δ¹⁸O values, which is commonly used to identify nitrate sources in groundwater, we’ll be able to identify and differentiate the contaminants around various areas of Cedar County, MO. The primary objective for this study is to investigate land use in rural/agricultural and suburban/residential areas to determine if the higher nitrate concentration is from human influence or natural sources, predominantly around El Dorado Springs, MO which is in northern Cedar County, Missouri. By having well water sampled on a regular basis, sampling water from creeks, rivers, and other waterways, it can lead to a better understanding of nitrates and other possible pollutants leaching into groundwater systems which can help avoid future contamination.