In 1971 and 1972, we sampled streams across Kentucky for nitrate-nitrogen (NO3-N) during the high-water flow months of January through June. The results were variable and showed a dominant effect of geology and lesser effects of both time and land use on the results. Since that time, use of fertilizer nitrogen (N) has nearly doubled in Kentucky and, further, there is a high degree of concern among the public that NO3-N from fertilizer use may be contaminating streams. The US Environmental Protection Agency has set a maximum of 10 ppm NO3-N in water as being safe for human consumption
