SEDL / STP / STP737-EB / STP34143S

Margins of Safety for Aquatic Communities

Mount, DI
Research biologist, Environmental Research Laboratory—Duluth, U.S. Environmental Protection Agency, Duluth, Minn.

Pages: 5    Published: Jan 1981

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Abstract

The margin of safety is the difference between the expected effect concentrations and the expected ambient concentrations. Two sources of variability, error in the test data and unknown information, necessitate a margin of safety. Inclusion of site-specific considerations can substantially reduce needed margins. The choice of the appropriate confidence level should be based on the importance of the decision and not on habit.