Ecological risk assessment of irrigation drainage selenium to the endangered razorback sucker
- Bureau of Reclamation, Salt Lake City, UT (United States)
The razorback sucker is an endangered species in the Colorado River Basin that is nearing extinction. A remnant population is threatened by contamination from irrigation drainage and other sources. Biomarkers and toxicity tests indicate reproductive impairment to adults and acute and chronic toxicity to larval fish. Adult fish are generally more than 20 years old, and no recruitment is occurring. The assessment evaluates all selenium sources, natural and man induced, to the Green River. Selenium discharged directly to the river as inorganic selenate represents a decrease in exposure compared to organic dietary sources introduced to a critical habitat. Fate and transport modeling, biotransformation, and profiling exposure at critical life history ecological boundaries are all important considerations in the risk analysis. Determining realistic safety factors for naturally occurring and essential but potentially toxic trace elements is also essential to formulate alternatives that make common sense. Establishing an obtainable cleanup criteria must consider natural background concentrations, cost effectiveness, and public acceptability. In this case it is more cost effective and provides a greater overall benefit to the river basin to remediate a non-irrigation selenium source. A multi-agency task force has been formed to select and implement remediation that is economically feasible, scientifically sound, politically acceptable, makes common sense, and that protects the razorback sucker.
- OSTI ID:
- 230907
- Report Number(s):
- CONF-9511137--; ISBN 1-880611-03-1
- Country of Publication:
- United States
- Language:
- English
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