Speciation of Selenium in Stream Insects Using X-Ray Absorption Spectroscopy

Journal Article · Thu May 28 04:00:00 EDT 2009 · Environ. Sci. Tech. 41:7683,2007

OSTI ID:953535

Andrahennadi, R; Wayland, M; Pickering, I J

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.

• Research Organization: Stanford Linear Accelerator Center (SLAC)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC02-76SF00515
• OSTI ID: 953535
• Report Number(s): SLAC-REPRINT-2009-348
• Journal Information: Environ. Sci. Tech. 41:7683,2007, Journal Name: Environ. Sci. Tech. 41:7683,2007 Journal Issue: 22 Vol. 41; ISSN ESTHAG; ISSN 0013-936X
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ABSORPTION SPECTROSCOPY
ALBERTA
CANADA
CONTAMINATION
DIPTERA
ELEMENTS
ENVIRONMENT
EPHEMEROPTERA
FILTERS
FOOD CHAINS
INSECTS
LEVELS
Other
OTHER
ENV
SELENIDES
SELENIUM
SPECTRA
STREAMS
UPTAKE