Selenium in soil

Elrashidi, M.A., Adriano D.C., Lindsay W.L. Solubility, Speciation, and Transformations of Selenium in Soils. In Selenium in Agriculture and the Environment, L.M. Jacobs, ed. Madison, IL Soil Science of America, Inc. 1989. 

Losi M.E., Frankenberger W.T. Microbial oxidation and solubilization of precipitated elemental selenium in soil. J Environ Qual 1998 27 836-843. 

National Research Council (NRC). 1983. Selenium in Nutrition. Subcomm. on selenium, Comm, animal nutrition, Board on Agricul., Natl. Res. Counc., National Academy Press, Washington, D.C. 174 pp. Nielsen, M.G. and G. Gissel-Nielsen. 1975. Selenium in soil-animal relationships. Pedobiologia 15 65-67. Niimi, A.J. and Q.N. LaHam. 1975. Selenium toxicity on the early life stages of zebrafish (Brachydanio rerio). Jour. Fish. Res. Board Canada 32 803-806. 

Similar regions were monitored in other sites of Russia, especially in the South Ural mountains, where the elevated contents of selenium in soils and natural waters coincide with increasing rates of corresponding animal diseases. The analogous biogeochemical provinces have been also monitored in Uzbekistan. 

The optimal reaction conditions for the generation of the hydrides can be quite different for the various elements. The type of acid and its concentration in the sample solution often have a marked effect on sensitivity. Additional complications arise because many of the hydrideforming elements exist in two oxidation states which are not equally amenable to borohydride reduction. For example, potassium iodide is often used to pre-reduce AsV and SbV to the 3+ oxidation state for maximum sensitivity, but this can also cause reduction of Se IV to elemental selenium from which no hydride is formed. For this and other reasons Thompson et al. [132] found it necessary to develop a separate procedure for the determination of selenium in soils and sediments although arsenic, antimony and bismuth could be determined simultaneously [133]. A method for simultaneous determination of As III, Sb III and Se IV has been reported in which the problem of reduction of Se IV to Se O by potassium iodide was circumvented by adding the potassium iodide after the addition of sodium borohydride [134], Goulden et al. [123] have reported the simultaneous determination of arsenic, antimony, selenium, tin and bismuth, but it appears that in this case the generation of arsine and stibene occurs from the 5+ oxidation state. 

Neutron activation analysis has been used to determine selenium in soil [144-148], Nadkarni and Morrison [149] estimated 47 elements in lake sediments and found 0.3-1.01pg selenium per gram using neutron activation analysis. Dong et al. [162] used mixtures of phosphoric acid, nitric acid and hydrogen peroxide in the digestion of soils prior to the determination of selenium. 

Dowdle PR, Oremland RS (1998) Microbial oxidation of elemental selenium in soil slurries and bacterial cultures. Environ Sci Technol 32 3749-3755... 

Elrashidi MA, Adriano DC, Workman SM, Lindsay WL (1987) Chemical equilibria of selenium in soils a theoretical development. Soil Sci 144(2) 141-152... 

Adsorption of anions at mineral surfaces is important in soils because of the limit this process imposes on the availability of plant nutrients such as P, S, and Mo which occur naturally as anions and are added in anionic form in fertilizers. Anion adsorption is also relevant in geochemistry, ore processing, and other fields where minerals with high surface areas are brought into contact with aqueous solutions of anions. Selenite and goethite were chosen for this study because in Western Australia a selenium deficiency in pastures has been shown to be related to the incidence of white muscle disease in sheep (3), and according to workers quoted by Rosenfeld and Beath (9) selenium in soils of higher... 

Azad et al. [ 186] used a similar technique for the determination of selenium in soil extracts using a nondispersive spectrometer, with which it was possible to observe fluorescence from the 196.1, 214.3 and 204.0 lines simultaneously, thus enabling a detection limit of 10 ng/ml to be observed using discrete sample introduction via the hydride generation technique. In this method, soil... 

A method has been reported [200] for determining total arsenic (and selenium) in soils based on atomic absorption spectrometry and flow injection analysis. The method exhibits good recoveries and detection limits below 1 ig/l for an injection volume of 160 pi. 

Martens et al. [202] and McCurdy et al. [203] have employed hydride generation atomic absorption spectrometry and inductively coupled plasma mass spectrometry, respectively, to determine selenium in soils. 

Square-wave cathode stripping voltammetry [212] and PIXIE [213] and neutron activation analysis have been used to determine selenium in soil [205-212],... 

Agemian and Bedek [209] have described a semi-automated method for the determination of total selenium in soils. 

Further work on the determination of selenium in soil is reported under Multi-Cation Analysis Methods including atomic absorption spectrometry (Sect. 2.55), inductively coupled plasma atomic emission spectrometry (Sect. 2.55), and neutron activation analysis (Sect. 2.55). 

Kang, Y. et al., Selenium in soil humic acid, Soil Sci. Plant Nutr., 37, 241-248, 1991. 

Sillanpaa, M., andjansson, H. (1992). Status of cadmium, lead, cobalt and selenium in soils and plants of thirty countries. FAO Soils Bull. 65, Food and Agricultural Organization of the United Nations, Rome, Italy. 

The behavior of selenium in soils mirrors that of the pure oxides (Goldberg, 1985). In acid soils, selenium is likely to occur mainly as Se(lV) strongly adsorbed to iron oxides. Less commonly, Se(IV) may form highly insoluble iron compounds such as ferric selenite (Fe2(0H)4Se03) or iron selenide (FeSe). In alkaline, oxidized and selenium-rich soils, most of the selenium is likely to be present as Se(Vl) which is very weakly adsorbed. Furthermore, there are no common insoluble selenate minerals. Hence, selenate accumulates in soluble form particularly in arid and semi-arid areas where evaporation tends to concentrate selenium along with other soluble salts (Deverel et al., 1994). 

In sediments and soils, the chemistry of selenium differs from that of sulfur in that the stability of selenite is similar to that of sulfate. The reduction of selenite to elemental selenium, which tends to immobilise selenium in soils and water, is an important process in the natural environment. Selenates are only stable under alkaline oxidising conditions and have been found, for example, in the Chilean nitrate deposits. 

Ponce de Leon, C. A., de Nicola, K., Montes Bayon, M., and Caruso, J. A. (2003). Sequential extraction of selenium in soils from Stewart Lake total selenium and speciation measurements with ICP-MS detection. J. Environ. Monit. 5, 435-440. 

Martens, D. A., and Suarez, D. L. (1999). Transformations of volatile methylated selenium in soil. Soil Biol. Biochem. 31, 1355-1361. 

The average content of selenium in soil forming rocks (dark) is about 0.3 ppm. The elevated contents of Se occur in some sedimentary rocks (sandstone, shale), volcanic sulfur, sulfides and phosphorites. The contents of this trace element in most soil types are between 0.01 and 1.0 ppm. Chernozems, Kastanozems, Serozems and Floodplain soils are relatively more enriched, 0.3-1.0 ppm, and Podsoluvisols and Arenosols are relatively depleted, 0.05-0.2 ppm. 

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