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Boron (B)
What is boron?
B is a naturally-occurring element found in many types of rocks including shale. B is also found in fruits, vegetables, nuts and legumes. It is considered an essential nutrient and small amounts are necessary for good health.
What are the uses of boron?
B is used in making a wide variety of products including glass, ceramics, soaps, detergents, fire retardants, fertilizers and pesticides. Borates are used in the manufacture of adhesives, lubricants, brake fluids, metal working fluids, water treatment chemicals and fuel additives. B is used in pharmaceuticals, including multivitamins and nutritional supplements, cosmetics, and toiletries.
 
Boric acid and boron oxide are both used to reduce flammability of cellulose insulation, cotton batting in mattresses, and wood composites.
Is boron present in the environment?
Naturally-occurring B is found in soils, sediments, water and air; the concentration depending on local geologic formations. B does not breakdown in the environment.
 
B-containing dust can be released into the air when coal and other fossil fuels are burned. B compounds can also be released in the air during certain industrial and manufacturing processes. It is also released during the application of fertilizers and pesticides.
 
Surface water can become contaminated with B from industrial wastewater and municipal sewage, as well as from air deposition and soil runoff. Borates in detergents, soaps and personal care products can also contribute to the presence of B in water.
How are people exposed to boron?
The primary way people are exposed to B is by eating foods rich in the substance, or by using B-containing dietary supplements. The average daily dietary intake being 1.0 mg/d.
 
Exposure to B can occur when ground water containing it is used for drinking and food preparation. Swimming or bathing in water containing B may also result in exposure to this element.
 
Exposure to B can occur while working in factories where cosmetics, medicines, insecticides and other B-containing consumer products are made.
How does boron enter and leave the body?
B in food or water readily enters the body through the gut, but can also enter the body through the lungs. Small amounts can enter the body through broken skin. B distributes widely throughout the body, with the possible exception of fat. Small amounts of boron can accumulate in the bones.
 
Boron does not breakdown. Most of it leaves the body in the urine within a few days.
How harmful is exposure to boron?
Ingesting large amounts of boron (30 grams boric acid) over short periods of time can harm the stomach, intestines, liver, kidney and brain. Breathing large amounts of airborne boron can result in lung and/or eye irritation.
Can exposure to boron cause cancer?
The Department of Health and Human Services, the International Agency for Research on Cancer and the U.S. Environmental Protection Agency are all uncertain as to whether excess B can cause cancer.
Is there a medical test to show whether I’ve been exposed to boron?
There are tests that measure the amount of B in blood or urine. Concentrations of B in the general population range from 0.07 to 0.66 milligrams/100 milliliters (mg/deciliter). Past exposures to B are difficult to detect since it is rapidly removed from the body.
 
Normal blood B levels for infants and children range from 0 to 1.25 micrograms per milliliter (μg/mL).
What is the treatment for boron poisoning?
Emergency medical care should be sought in cases of suspected B poisoning. It is treated by removing the person from the source of exposure and then with supportive medical care in a hospital setting. No specific antidote exists for B poisoning.
Are there recommendations to protect public health?
EPA limits exposure to B in drinking water at concentrations of 4 milligrams per liter (mg/L) or 4000 parts per billion (ppb) or 4000 micrograms per liter (μg/L) for one day.  0.9 mg/L or 900 ppb or 900 μg/L for up to 10 days is not expected to cause any adverse effects in a child. Lifetime exposure to 1.0 mg/L (1000 ppb) of B is not expected to cause any adverse effects.
 
Occupational Safety and Health Administration (OSHA) sets a legal limit of 15 milligrams per cubic meter (mg/m3) boron oxide dust in air, averaged over an eight- hour work day or 40 hour workweek. The World Health Organization has a provisional drinking water guideline of 0.5 mg/L (500 μg/L) of B.
 
National Academies of Science, Institute of Medicine, Food and Nutrition Board suggests that Dietary Reference Intakes (estimated average daily requirement) for B are 3 to 6 mg/d for ages 1 to 8 and 11 to 20 mg/d for ages 9 and above.
What can I do to prevent exposure to boron?
Identify and limit sources of exposures. While tap and bottled water generally contain safe levels of B, well water may sometimes be contaminated with enough B to create a health hazard. Well water should be checked for B to ensure its concentration is below current guidelines. Reverse osmosis filtration can be used to remove B from drinking water but it has limited capabilities.
What should I do if I believe I am ill as a result of exposure to boron?
If you experience symptoms that you think may be related to B exposure, you should consult your health care provider for evaluation and possible treatment. 

References
(1) U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry (ATSDR). Updated November, 2010. Toxicological Profile for Boron.
(2) U.S. Department of Health and Human Services, Public Health Service, Agency for Toxic Substances and Disease Registry, Division of Toxicology and Environmental Medicine, ToxFAQsTM; Boron, November 2010.
(3) Progress in Food and Nutritional Science, The role of boron in nutrition and metabolism, Naghii MR, Samman S. 1991 Oct; 17(4): 331-349.