British Columbia Mine Reclamation Symposium

Selenium in terrestrial ecosystems and implications for drastically disturbed land reclamation Fisher, Scott E.

Abstract

Selenium (1) can be beneficial or toxic to plants and animals (including humans) depending on its concentration. It occurs in low crustal abundance in most geological materials but is found in higher concentrations in Cretaceous and early Tertiary age sedimentary rocks, tuffaceous sediments, roll front deposits, and in association with sulfide minerals in metaliferous deposits. In arid regions soils developed from such parent rocks can contain relatively high concentrations of selenium. Higher concentrations of selenium can occur in ecosystems impacted by human actives such as irrigation projects, air pollution, mining, or long term use of soil amendments (e.g. fly ash) containing elevated levels of selenium. Plant uptake and incorporation of selenium into tissue varies widely between species and ecotypes within plant species. Selenium may be essential to some plant species, particularly those that accumulate it in higher concentrations. The element is essential for animals but the range between deficiency and toxicity is relatively narrow. Selenium is frequently deficient in animal diets in higher moisture environments. In arid environments the higher dietary selenium intake from forage and water sources rarely leads to mortalities from acute selenium toxicity. To evaluate the impact of Se on land use several factors should be considered: 1) careful analytical definition of the total and available selenium content of earthen materials on the site; 2) identification of the new depositional environments for these materials; 3) description of post-disturbance planned and potential land uses; 4) an understanding of the components and interactions of the ecosystems.

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Attribution-NonCommercial-NoDerivatives 4.0 International