Monitoring program with fixed station networks and intensive surveys and producing chemical, physical, and biological analyses. Ambient monitoring deals with conditions in the aquatic environment--streams, lakes, bays, estuaries, and oceans. By contrast, effluent (discharge) monitoring involves sampling and analysis of wastewater.

Monitoring within natural systems (lakes, rivers, estuaries, and wetlands) to determine existing conditions.

Continuous or repeated measurement of agents in the environment to evaluate ambient exposure and health risk by comparison with appropriate reference values based on knowledge of the probable relationship between exposure and resultant adverse health effects.