Author
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Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 2/1/2003 Publication Date: 3/1/2004 Citation: Nielsen, F.H. 2004. Boron. In: Merian, E., Anke, M., Ihnat, M., Stoeppler, M., editors. Elements and Their Compounds in the Environment: Occurrence, Analysis and Biological Relevance, Volume 3, Nonmetals, Particular Aspects. 2nd Edition. Weinheim, Germany: Wiley-VCH. p. 1251-1260. Interpretive Summary: Boron chemistry, analysis, environmental exposure, metabolism, anthropomorphic sources, beneficial physiological effects, and toxicity are reviewed. Boron is widely distributed in nature and always occurs bound to oxygen. Boron biochemistry is essentially that of boric acid, which forms ester complexes with hydroxyl groups (preferably when they are adjacent and cis) of organic compounds. To date, several naturally occurring boroesters have been identified; these include antibiotics produced by microorganisms; the plant cell wall component, rhamnogalacturonan-II, and a bacterial extracellular signaling molecule. The preferred method for analysis of boron is inductively coupled plasma mass spectrometry. Boric acid and disodium borate (borax) are used to produce a large variety of diverse products including fiberglass, borosilicate glass, fire retardants, fertilizer, enamels, ceramic glazes, soaps, detergents, cosmetics, pharmaceuticals, and pesticides. Boron does not accumulate in any environmental compartment, or bioaccumulate. Since the 1920s, boron has been recognized as an essential element for plants. In the last 15 years, evidence has emerged indicating that boron is needed or beneficial in higher animals and humans for many of life processes including embryogenesis, bone growth and maintenance, immune function, psychomotor skills, and cognitive function. Boron is not very toxic when administered orally; this is evidenced by the use of boric acid and borax as food preservatives and in oral medicinal products in the late 19th and early 20th centuries. A World Health Organization report stated that a suggested acceptable safe range of population mean intakes for boron for adults could be 1-13 mg/day. Technical Abstract: Boron chemistry, analysis, environmental exposure, metabolism, anthropomorphic sources, beneficial physiological effects, and toxicity are reviewed. Boron is widely distributed in nature and always occurs bound to oxygen. Boron biochemistry is essentially that of boric acid, which forms ester complexes with hydroxyl groups (preferably when they are adjacent and cis) of organic compounds. To date, several naturally occurring boroesters have been identified; these include antibiotics produced by microorganisms; the plant cell wall component, rhamnogalacturonan-II, and a bacterial extracellular signaling molecule. The preferred method for analysis of boron is inductively coupled plasma mass spectrometry. Boric acid and disodium borate (borax) are used to produce a large variety of diverse products including fiberglass, borosilicate glass, fire retardants, fertilizer, enamels, ceramic glazes, soaps, detergents, cosmetics, pharmaceuticals, and pesticides. Boron does not accumulate in any environmental compartment, or bioaccumulate. Since the 1920s, boron has been recognized as an essential element for plants. In the last 15 years, evidence has emerged indicating that boron is needed or beneficial in higher animals and humans for many of life processes including embryogenesis, bone growth and maintenance, immune function, psychomotor skills, and cognitive function. Boron is not very toxic when administered orally; this is evidenced by the use of boric acid and borax as food preservatives and in oral medicinal products in the late 19th and early 20th centuries. A World Health Organization report stated that a suggested acceptable safe range of population mean intakes for boron for adults could be 1-13 mg/day. |
