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Water-sediment controversy in setting environmental standards for selenium
1Columbia Environmental Research Center, Ecotoxicology Research Station, 31247 436th Avenue, Yankton, South Dakota, 57078-6364, USA. steve.hamilton@usgs.gov
Ecotoxicology and Environmental Safety
|December 3, 1999
Summary
New research supports a lower national water quality criterion for selenium, proposing 2 microg/L to protect aquatic life from adverse effects. This addresses concerns about current selenium levels impacting biota.
Area of Science:
- Environmental toxicology
- Aquatic ecology
- Environmental chemistry
Background:
- Extensive research on selenium's effects on biota has occurred since the 1987 water quality criterion.
- Adverse effects on aquatic organisms have been documented below the current chronic criterion of 5 microg/L.
Purpose of the Study:
- To present evidence supporting a revised national water quality criterion for selenium of 2 microg/L.
- To critically review alternative sediment-based criteria proposals.
Main Methods:
- Literature review of laboratory and field research on selenium toxicity.
- Analysis of data from federal, state, university, and international sources.
- Critical evaluation of proposed sediment-based selenium criteria models.
Main Results:
- Evidence indicates adverse selenium effects on biota occur below 5 microg/L.
- A proposed national criterion of 2 microg/L is supported by a broad research base.
- Critiques of sediment-based criteria highlight potential issues and higher calculated values.
Conclusions:
- The current national water quality criterion for selenium should be lowered to 2 microg/L.
- Existing research strongly supports a more protective selenium standard for aquatic ecosystems.
- Concerns exist regarding the methodology and implications of sediment-based selenium criteria.