Boron (Symbol B, Latin borium)-A non-metallic element occuring in crystal form and as a powder. In the early 20th century, boron was demonstrated to be an essential nutrient for plants. However, it has yet to be established in the role of human metabolism. The average human diet provides a few milligrams per day. Boron is absorbed in the gut and is excreted in the urine and faeces.

RDA of boron

Although there is no known RDA for boron, some multivitamins include 50 or more micrograms of boron as a component.

Toxicity of boron

Boron is toxic to human at about 100mg. Like toxicity for many other substances, the toxicity of boron depends on weight, metabolism, health, and other factors. Boron is used industrially with other elements to make cleaning agents [ie., borax (Na₂B₄O₇)], propellants (ie., pentaborane), antiseptics (boric acid), and other chemicals. Different exposure limits and toxicities exist for each different boron-containing prepararion. For example, 0.1-0.5g/kg of boric acid can be fatal. Interestingly, boric acid was once used as a food preservative. Boron can also be united with carbon to create boron carbide, (B₄C). Boron carbide was used in nuclear reactors to absorb neutrons and as an abrasive in medicine and dentistry.