Se is also used as catalyst in some chemical reactions. In X‐ray crystallography, incorporation of one or more Se atoms in place of sulfur helps with multiple or single wavelength anomalous dispersion. Se is widely used for toning of photographic prints and it intensifies tonal range of black and white photographic images, resulting in improved permanence of prints (Wall 1924). The worldwide consumption of Se in different applications is presented in Figure 3.2.
Figure 3.2 Global consumption of Se (USGS 2020).
3.6 Conclusions
This chapter summarized the occurrence, sources, and importance of Se in environment. The major source of Se is from natural activities and nowadays anthropogenic sources are also releasing a huge amount of Se into the environment. The Se from the soil and water enters into the food chain where it is bioaccumulated and transferred into humans and animals through diet.
Earlier, the deficiency of Se was of major concern as it could be one of the important factors in various diseases such as Keshan and Kashin–Beck diseases, infertility in female, etc. However, augmented consumption can also lead to the adverse health impacts.
Demand for Se has increased due to the growth of industrialization and the use of Se in different manufacturing processes. Major Se production is from refineries and copper smelting processes. In the United States fish and wildlife poisoning occurred due to elevated concentration of Se in water. Such episodes have grabbed the attention of researchers for data generation and possible implications of excessive Se and its hazards to human health. Se is an important trace element due to its Janus nature. It is an essential nutrient to human and animal while it can also act as potent toxin if consumed beyond certain limits. Timely dealing with this issue in connection with an environmental Se database can be useful to avoid any adverse impact on humans and the environment.
References
1 Aston, F.W. (1922). The isotopes of selenium and some other elements. Nature: 664. https://doi.org/10.1038/110664a0.
2 Awika, J.M. (2011). Major cereal grains production and use around the world. ACS Symposium Series 1089: 1–13. https://doi.org/10.1021/bk‐2011‐1089.ch001.
3 Back, T.G. (2006). Selenium: organoselenium chemistry. Encyclopedia of Inorganic Chemistry https://doi.org/10.1002/0470862106.ia214.
4 Barron, E., Belcher, R., Bogdanski, S.L. et al. (2009). The case for re‐evaluating the upper limit value for selenium in drinking water in Europe. Journal of Water and Health 7 (4): 630–641. https://doi.org/10.2166/wh.2009.097.
5 Belcher, R. et al. (1980). Molecular emission cavity analysis. Part 14. Determination of selenium utilizing hydrogen selenide generation. Analytica Chimica Acta 113 (1): 13–20. https://doi.org/10.1016/S0003‐2670(01)85109‐6.
6 BIS. (2012). Indian Standards Drinking Water Specifications IS 10500: 2012. Bureau of Indian Standard, Indian Standards Drinking Water Specifications, 2(May): 11. http://cgwb.gov.in/Documents/WQ‐standards.pdf.
7 Brown, F.C. (1914). The crystal forms of metallic selenium and some of their physical properties. Physical Review 4 (2): 85–98. https://doi.org/10.1103/PhysRev.4.85.
8 Bureau of Mines. (1970). Mineral Facts and Problems. Washington, DC: U.S. Dept. of the Interior, Bureau of Mines.
9 Chapman, P.M. (2009). Is selenium a global contaminant of potential concern? Integrated Environmental Assessment and Management https://doi.org/10.1897/1551‐3793‐5.3.353.
10 Conde, J.E. and Sanz Alaejos, M. (1997). Selenium concentrations in natural and environmental waters. Chemical Reviews 97 (6): 1979–2003. https://doi.org/10.1021/cr960100g.
11 Du, X.H., Dai, X., Song, R.X. et al. (2012). SNP and mRNA expression for glutathione peroxidase 4 in Kashin‐Beck disease. British Journal of Nutrition 107 (2): 164–169. https://doi.org/10.1017/S0007114511002704.
12 Duce, A. (1987). A global atmospheric selenium budget. 92 (D11): 13289–13298. https://doi.org/10.1029/JD092iD11p13289.
13 Dudley, H.C. (1938). Selenium as a potential industrial Hazard. Public Health Reports 53 (8): 281–292.
14 El‐Ramady, H. et al. (2014a). Selenium in soils under climate change, implication for human health. Environmental Chemistry Letters 13 (1): 1–19. https://doi.org/10.1007/s10311‐014‐0480‐4.
15 El‐Ramady, H.R. et al. (2014b). Selenium and nano‐selenium in agroecosystems. Environmental Chemistry Letters 12 (4): 495–510. https://doi.org/10.1007/s10311‐014‐0476‐0.
16 EPA (2020) National Primary Drinking Water Regulations (NPDWRs). Available at: https://www.epa.gov/ground‐water‐and‐drinking‐water/national‐primary‐drinking‐water‐regulations#Inorganic.
17 Fernández‐Martínez, A. and Charlet, L. (2009). Selenium environmental cycling and bioavailability: a structural chemist point of view. Reviews in Environmental Science and Biotechnology 3: 81–110. https://doi.org/10.1007/s11157‐009‐9145‐3.
18 Fishbein, L. (1983). Environmental selenium and its significance. Toxicological Sciences 3 (5): 411–419. https://doi.org/10.1093/toxsci/3.5.411.
19 Fordyce, F.M. (2013). Selenium deficiency and toxicity in the environment. In: Essentials of Medical Geology. Rev. Ed. (eds. O. Selinus, B. Alloway, J.A. Centeno, et al.), 375–416. Dordrecht: Springer Netherlands https://doi.org/10.1007/978‐94‐007‐4375‐5_16.
20 Gaillardet, J., Viers, J., and Dupré, B. (2003). Trace elements in river waters. Treatise on Geochemistry 3: 225–272. https://doi.org/10.1016/B0‐08‐043751‐6/05165‐3.
21 Gilbert, R.D. and Fornes, R.E. (1980). Exchange of comments on neutron activation analyses for simultaneous determination of trace elements in ambient air collected on glass‐fiber filters. Analytical Chemistry 52 (7): 1153. https://doi.org/10.1021/ac50057a037.
22 Guoxiong Hua, J.D.W. (2011). Organic phosphorus‐selenium chemistry. In: Selenium and Tellurium Chemistry from Small Molecules to Biomolecules and Materials (ed. J.D., R. Woollins, Laitinen), 1–39. Springer Nature https://doi.org/10.1007/978‐3‐642‐20699‐3.
23 Hoffmann,