Relating selenium concentrations in a planktivore to selenium speciation in lakewater

Area of Science:

• Environmental Chemistry
• Ecotoxicology
• Aquatic Ecology

Background:

• Metal smelters can release selenium (Se) into aquatic environments.
• Understanding selenium speciation is crucial for assessing its bioavailability and ecological risk.
• Chaoborus larvae are proposed as a suitable biomonitor for selenium exposure in planktonic food webs.

Purpose of the Study:

• To measure selenium speciation in lake waters near metal smelters.
• To compare waterborne selenium concentrations with selenium levels in Chaoborus larvae.
• To evaluate the effectiveness of Chaoborus as a biomonitor for selenium exposure.

Main Methods:

• Water samples from 16 lakes near metal smelters were analyzed for selenium speciation.
• Selenium concentrations in Chaoborus larvae were measured and compared to water chemistry.
• Statistical correlations were performed between Chaoborus selenium levels and dissolved selenium species.

Main Results:

• Selenium speciation varied with lake pH; acidic lakes had higher selenate and organo-selenium, while alkaline lakes had higher selenite.
• Chaoborus selenium concentrations showed significant variation among lakes.
• Chaoborus selenium levels strongly correlated with dissolved organo-selenium and selenate (Se(VI)) concentrations, excluding one high-sulfate lake.

Conclusions:

• Chaoborus larvae are effective biomonitors for assessing selenium exposure in lake planktonic food webs.
• Selenium speciation in lake water influences selenium uptake by Chaoborus.
• The study provides a basis for using Chaoborus in environmental monitoring programs for selenium contamination.