Nitrate-nitrogen data collected during 1976-79 from 333 wells in western, central, and eastern Kansas were summarized and statistically analyzed on the basis of area, aquifer, and well depth. Concentrations exceeding 10 milligrams per liter occurred generally in wells less than 100 feet in depth, indicating that nitrate-nitrogen concentrations in ground water greater than 10 milligrams per liter commonly are derived from nitrogen sources at or near the land surface, although soluble nitrogen may be derived from fine-grained sediments in some aquifers.
Water from shales in central and eastern Kansas and from limestone in eastern Kansas exhibited the highest median concentrations and highest incidence of concentrations above 10 milligrams per liter. Water from 10 percent of the wells in unconsolidated Quaternary deposits in western Kansas and almost 30 percent of the wells in eastern Kansas had nitrate-nitrogen concentrations that exceeded 10 milligrams per liter. Shallow wells in shales, limestones, and unconsolidated Quaternary deposits are highly susceptible to nitrate contamination. Water from unconsolidated Tertiary deposits produced a low incidence of nitrate-nitrogen concentrations greater than 10 milligrams per liter, indicating minimal nitrate contamination from sources at or near the land surface. Sandstones in all areas exhibited the lowest median and lowest incidence of nitratenitrogen concentrations above 10 milligrams per liter.
