The principal sources of nitrogen in water are domestic sewage, garbage, industrial wastes, and the agricultural industry - animal wastes, nitrogenous fertilizers, and products from the decomposition of plant material in soil. The contribution from precipitation and atmospheric sediments is about 1.0 ppm or 5.8 lb/acre/year at Hamilton (15).
In this paper, we present results of our current research on the transport of nitrogen compounds by water in a porous medium. During this transfer, chemical and microbiological reactions take place that determine the concentration and distribution of nitrogen in a soil profile at a given time. Data are presented that indicate the levels of NO3--N in ground waters from several sources as well as a discussion of possible sources of nitrate contamination.