Toxicity of selenate and selenite to the potworm Enchytraeus albidus (Annelida: Enchytraeidae): a laboratory test

Abstract

Little information is available about the toxicity of inorganic selenium forms in soil animals. Therefore, the effects of selenate and selenite on the mortality and reproduction of Enchytraeus albidus were examined in standard laboratory tests with chronic exposure. Total and available amount of selenate and selenite were tested in a calcareous loamy chernozem soil. The LC(50) of selenate was 5.69 (2.7-8.12) mg kg(-1) dry wt. for total Se and 4.74 (2.14-6.98) mg kg(-1) dry wt. for available Se. Selenite LC(50) was as high as 22.5 (19.6-25.7) mg kg(-1) dry wt. for total Se and 8.10 (6.8-9.6) mg kg(-1) dry wt. for available Se. The EC(50) of selenate was 0.41 (0.35-0.48) mg kg(-1) dry wt. for total Se and 0.28 (0.24-0.34) mg kg(-1) dry wt. for available Se. Selenite EC(50) was as high as 7.3 (6.2-8.5) mg kg(-1) dry wt. for total Se and 2.46 (2.05-2.91) mg kg(-1) dry wt. for available Se. The response in reproduction was more sensitive to Se toxicity than the response in mortality. Selenate proved to be more toxic than selenite. Available data show that E. albidus may function as a biological indicator for some inorganic selenium forms in the soil.

Analysis of Saccharomyces cerevisiae null allele strains identifies a larger role for DNA damage versus oxidative stress pathways in growth inhibition by selenium

“…A third form of Se that is sometimes used as a dietary supplement is sodium selenate. While considerably less toxic to mammals than selenite, presumably because it is not enzymatically reduced to selenite, selenate has also been reported to be an environmental toxin, particularly in species that have been shown to be more sensitive to selenate than selenite [12]. This along with the fact that Se cytotoxicity can be circumvented in some species of plants that have evolved to utilize Se hyperaccumulation as a defense mechanism [13, 14] provide strong evidence for a highly complex relationship between Se status and toxicity depending on environmental conditions and the species being analyzed.…”

Selenium Analysis and Speciation in Dietary Supplements Based on Next-Generation Selenium Ingredients

“…Selenite is the dominant selenium species in aquatic habitats. Selenite was found to be more toxic than selenate [ 208 , 209 , 210 ], and is, therefore, the most investigated form of selenium species, although the opposite order of toxicity was also reported [ 211 ]. Optical detection techniques include colorimetry, absorbance, and photoluminescence, but their accuracy depends on the characteristics of the sensory material.…”

Can a Low-Dose Selenium (Se) Additive Reduce Environmental Risks of Mercury (Hg) and Arsenic (As) in Old Gold Mine Tailings?

“…Soil [Se] of 77 mg Se/kg resulted in reproductive effects in the earthworm Eisenia fetida (Fischer and Koszorus 1992). The pot worm Enchytraeus albidus appears more sensitive with an LC50 of 22.5 mg selenite/kg and EC50 (reproduction) of 7.3 mg selenite/kg (Somogyi et al 2007). While Se additives hold significant promise for reducing Hg and As toxicity and improving nutritional health of recovering biota, care must be taken to ensure that Se dosages are below toxicity thresholds.…”