NITRATE CONTAMINATION IN AQUIFERS OF OHIO

A literature-based investigation was conducted to study nitrogen contamination in the groundwater of Ohio and to establish the general trends between the types of aquifers and significant nitrogen sources. Inorganic fertilizers are found to be the major source of nitrogen fixation and their use has contaminated many aquatic ecosystems with Nitrates (NO3-). Nitrates can be toxic to humans, and harms the water quality (Bendula et al. 1998.). The results of this study indicate the shallow aquifers of the area may be severely contaminated, and hydrogeologic environments with thin glacial cover are correlated to the intensity of nitrogen contamination. High concentrations of nitrogen are limited to the shallower aquifers; below the depth of 100 feet the nitrate-nitrite concentrations decrease with depth; as water moves to greater depths it becomes more isolated from the oxygen rich atmosphere, and the reducing condition in the deeper layers ultimately restrict the presence of nitrate to shallower ground water systems. These correlations appear to be typical of southwestern Ohio, and can be inferred to be valid throughout the state. Generally nitrogen contamination in the aquifers of Ohio appears to be a shallow phenomenon, however an increasing trend may be a threat for groundwater in near future. Managing nitrogen sources on the surface to reduce the transport of nitrate into vulnerable aquifers is clearly the favored management approach to protect an aquifer and to assure the most cost effective use of farm nutrients.