Related Experiment Videos
Selenium impacts on razorback sucker, Colorado: Colorado River III. Larvae
Steven J Hamilton1, Kathy M Holley, Kevin J Buhl
1US Geological Survey, Columbia Environmental Research Center, Field Research Station, 31247 436th Avenue, Yankton, SD 57078-6364, USA.
Ecotoxicology and Environmental Safety
|May 11, 2005
Summary
Selenium contamination in Colorado River water and food sources negatively impacts Razorback sucker (Xyrauchen texanus) larvae survival and development. High dietary selenium, especially in zooplankton, causes mortality and deformities, threatening this endangered fish recovery.
Area of Science:
- Environmental toxicology
- Aquatic ecology
- Conservation biology
Background:
- Razorback sucker (Xyrauchen texanus) is an endangered species in the Colorado River basin.
- Selenium contamination from agricultural and industrial sources poses a threat to aquatic ecosystems.
Purpose of the Study:
- To investigate the effects of waterborne and dietary selenium exposure on Razorback sucker larvae.
- To determine safe selenium levels for larval survival and development.
Main Methods:
- Larvae from selenium-exposed adults were subjected to a 30-day study with varying waterborne and dietary selenium concentrations.
- Selenium levels in water and dietary items (brine shrimp, zooplankton) were measured.
- Larval survival, growth, and deformities were assessed.
Main Results:
- Lowest survival occurred in larvae fed zooplankton compared to brine shrimp.
- Larval survival was reduced in site water from Adobe Creek and North Pond compared to reference water.
- Deformities in larvae from North Pond resembled known selenium-induced teratogenic effects.
- Dietary selenium concentrations of 4.6 microg/g led to rapid mortality in larvae from multiple sites.
Conclusions:
- Selenium toxicity in the Colorado River, particularly from dietary sources like zooplankton, can significantly limit the recovery of the endangered Razorback sucker.
- Arsenic in brine shrimp may offer some protection against selenium toxicity through antagonistic interactions.
- Further research is needed to establish safe selenium thresholds for this species.