Speciation of selenium in stream insects using X-ray absorption spectroscopy

Journal Article · Thu Nov 15 00:00:00 EST 2007 · Environmental Science and Technology

DOI:https://doi.org/10.1021/es071399v· OSTI ID:20969920

Andrahennadi, Ruwandi; Wayland, Mark; Pickering, Ingrid J ^[1]

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1. University of Saskatchewan, Saskatoon, SK (Canada). Department of Geological Sciences

Selenium contamination in the environment is a widespread problem affecting insects and other wildlife. Insects occupy a critical middle link and aid in trophic transfer of selenium in many terrestrial and freshwater food chains, but the mechanisms of selenium uptake through the food chain are poorly understood. In particular, biotransformation of selenium by insects into different chemical forms will greatly influence how toxic or benign the selenium is to that organism or to its predators. We have used X-ray absorption spectroscopy (XAS) to identify the chemical form of selenium in insects inhabiting selenium contaminated streams near Hinton, Alberta (Canada). Selenium K near-edge spectra indicate a variability of selenium speciation among the insects that included mayflies (Ephemeroptera), stoneflies (Plecoptera), caddisflies (Trichoptera), and craneflies (Diptera). Higher percentages of inorganic selenium were observed in primary consumers, detritivores, and filter feeders than in predatory insects. Among the organic forms of selenium, organic selenides constituted a major fraction in most organisms. A species modeled as trimethylselenonium was observed during the pupal stage of caddisflies. These results provide insights into how the insects cope with their toxic cargo, including how the selenium is biotransformed into less toxic forms and how it can be eliminated from the insects. More broadly, this study demonstrates the strengths of XAS to probe the effects of heavy elements at trace levels in insects from the field.

• OSTI ID: 20969920
• Journal Information: Environmental Science and Technology, Vol. 41, Issue 22; Other Information: [e-mail]; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
01 COAL, LIGNITE, AND PEAT
SELENIUM
INSECTS
X-RAY SPECTROSCOPY
ABSORPTION SPECTROSCOPY
STREAMS
ALBERTA
CANADA
HEAVY METALS
CONTAMINATION
CHEMICAL STATE
WATER POLLUTION
UPTAKE
DIPTERA
PUPAE
TRACE AMOUNTS
SELENIDES
COAL
POLLUTION SOURCES
FOSSIL-FUEL POWER PLANTS
BIODEGRADATION