Selenium and its compounds in aquatic plant Veronica anagallis-aquatica

Area of Science:

• Environmental Science
• Analytical Chemistry
• Plant Biology

Background:

• Long-term selenium (Se) supplementation in animal feedstuffs is common in agricultural areas.
• Understanding Se bioaccumulation in aquatic macrophytes is crucial for ecological risk assessment.
• Veronica anagallis-aquatica is a common macrophyte in European freshwater ecosystems.

Purpose of the Study:

• To investigate the uptake, distribution, and speciation of selenium in Veronica anagallis-aquatica.
• To assess the impact of 25 years of Se feedstuff addition on Se levels in macrophytes and sediments.
• To determine the extractability and chemical forms of Se in V. anagallis-aquatica.

Main Methods:

• Sampling of V. anagallis-aquatica and sediments from Slovenian watercourses (2009-2011, 2013).
• Determination of total Se content using dry weight analysis.
• Separation of extractable Se compounds via ion exchange chromatography with online inductively coupled plasma-mass spectrometry detection.
• Enzymatic extraction using Protease XIV to assess Se bioavailability.

Main Results:

• Se concentrations in sediments ranged up to 0.86 μg g⁻¹, and in whole plants from 0.186 to 1.535 μg g⁻¹ (dry weight).
• Highest Se content was observed in roots, while stems had the lowest.
• Only ~24% of total Se was extracted; extractable Se varied from 10.5% (roots) to 29.6% (leaves).
• Se(IV) and Se(VI) were identified, but no Se-amino acids were detected.

Conclusions:

• Long-term Se feedstuff addition showed minimal impact on Se content in the studied agricultural area.
• The low extractability of Se suggests limited bioavailability within the macrophyte.
• Se distribution within V. anagallis-aquatica is organ-specific, with roots acting as a primary accumulation site.