Organic nitrogen plus ammonia, total

Overview

Nitrogen is a nutrient necessary for growth and reproduction. Primary sources of nitrogen are fertilizers, animal wastes, and degradation of plant material. However, excessive inputs of nitrogen and phosphorus compounds to an aquatic environment can cause excessive algal growth resulting in eutrophication.
When algal blooms die, concentrations of dissolved oxygen are depleted, which can stress aquatic organisms and may cause taste-and-odor problems in water supplies.

Water-quality standards and criteria are developed by the States, approved by the U.S. Environmental Protection Agency (USEPA), and then promulgated (passed into law) as standards by each State. Graphs on this website allow comparison of measured and computed data to these standards and criteria by plotting them as straight lines. When evaluating data to decide whether water quality is suitable for the intended use, viewers are cautioned to consider the uncertainty associated with these computed data.