Nitrate study of Lyon County, Kansas private wells, 1990-1991.

Abstract

An investigation into the water quality of private wells from Lyon County, Kansas concentrating on nitrates was conducted from July, 1990 through April, 1991. Eleven wells, located throughout Lyon County, were analyzed monthly for nitrate concentrations studying the seasonal and local variations of each well. This is a continued study started by Paul Thompson from June, 1988 through February, 1989. Excessive fertilization of crops with nitrogen-based compounds is largely responsible for the high amounts of nitrates found in ground water. Nitrogen-fixing legumes, plant residues, and animal feces and urine remains are sources of high organic nitrogen compounds. Nitrogen compounds are converted to ammonia, in the soil, which can be oxidized to nitrate through a process known as nitrification. At high concentrations, nitrates can be very harmful to adults and even fatal to infants. Local bedrock and soil geology have an influence on the flow of ground water, which varies throughout Lyon County and the different well sites. Nearby agricultural crops and livestock are major sources for nitrates found in ground water. Monthly samples were analyzed for nitrates by HPLC and UV Molecular Adsorption techniques. Resulting nitrate concentrations were recorded and compared for local and seasonal fluctuations between the different well sites. Comparison with previous studies show similar values for nitrate samples from corresponding site locations and overall seasonal trends. The highest overall nitrate concentrations were observed in September of 1990, which coincides with the fertilization of winter wheat crops in the early fall. An increase in concentrations during the late fall months corresponded to a decrease in nitrogen fixation, from legume plants, due to dropping temperatures.