Recently many people have become concerned over the levels of nitrate in surface water supplies. Concern has been expressed that modern farming practices are contributing to the pollution of our state's and nation's drinking water, and some have gone so far as to suggest radical changes in farming techniques in hopes of solving the problem. An understanding of the relationship between agriculture and nitrate is necessary before reasonable decisions can be made. Nearly all surface waters show a low level of nitrate throughout the year and this has not been deemed a public health hazard. When nitrate nitrogen concentrations rise above 10 milligrams per liter, however, water suppliers in Ohio are required to issue an alert, and steps are normally taken to minimize the exposure of susceptible individuals to these higher concentrations.
Concentrations normally peak and decline within a few days.
The realistic problem facing the public with regard to surface water is not how to eliminate nitrate, but rather how to minimize the frequency and severity of those peak concentrations which exceed 10 milligrams per liter. The connection between agricultural activity and stream nitrate loadings cannot be denied. Elevated levels of nitrate have often been noted in streams draining watersheds with high levels of corn production, nitrogen fertilizer application, and tile drainage. Runoff from uncontained livestock operations can also be a contributing factor. The relative importance of cropland and livestock contributions will vary among Ohio streams.