Specialized Research
Case Study
Selenium Criterion Technical Support
In response to new information and concerns about the protectiveness
of EPA’s aquatic life criteria for selenium, EPA has initiated
a major effort to research the effects of selenium on aquatic life.
GLEC provides general technical support for this selenium research
through literature review, studying tissue residue-based effects, selenium
toxicity/bioaccumulation, and reseaching toxicokinetic issues.
In 2006 and 2007 GLEC conducted a special laboratory experiment
to determine the effect levels of selenium exposure on the common
bluegill (Lepomis macrochirus).
A custom laboratory was designed and constructed at GLEC’s Traverse City facility to accommodate the
special requirements of the experiment, including temperature control and flow-through exposure systems.
The experimental goal was to determine the effect levels of selenium exposure on bluegill over a
simulated winter season at two temperature regimes. GLEC used a selenium-enriched diet that had been
accumulated in an oligochaete, Lumbriculus variegatus, by feeding it selenized-yeast to get an estimate
of an effect level at two temperature regimes: 20°C decreasing to 4°C and 20°C decreasing to 9°C. Three
separate exposure systems were employed to achieve the study objectives. Two of the exposure systems
(1 and 3) were comprised of six selenium treatments (and an appropriate control) with the objective of
obtaining a dose response relationship sufficient to derive a sound EC value (e.g., EC10, EC20). The third
exposure system exposed juvenile bluegill to aqueous selenium and seleno-L-methionine in TetraMin under
a 20 to 4°C temperature regime. Juvenile bluegill sunfish were exposed to each treatment concentration
under flow-through conditions for a total of 182 days. They were fed selenium-laden Lumbriculus worms
at a rate of 4% of the fish body weight per day. Selenium levels were being monitored in worm and bluegill
tissues. Effect levels for selenium in bluegill tissue were determined for each temperature treatment at the
end of the 182 day study.
Contact: Dennis McIntyre, Senior Research Scientist
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