Nitrates and nitrites are families of chemical compounds containing atoms of nitrogen and oxygen. Occurring naturally, nitrates and nitrites are critical to the continuation of life on the earth, since they are one of the main sources from which plants obtain the element nitrogen. This element is required for the production of amino acids which, in turn, are used in the manufacture of proteins in both plants and animals.

One of the great transformations of agriculture over the past century has been the expanded use of synthetic chemical fertilizers. Ammonium nitrate is one of the most important of these fertilizers. In recent years, this compound has ranked in the top fifteen among synthetic chemicals produced in the United States.

The increased use of nitrates as fertilizer has led to some serious environmental problems. All nitrates are soluble, so whatever amount is not taken up...