Content Information
Barium and Barium Compounds
CASRN 7440-39-3
Physical Properties
Barium is a silvery-white metal that takes on a silver-yellow color when exposed to air. Barium is highly reactive. It does not exist as a metal in the environment, but is combined with other elements in compounds. Some of the common inorganic compounds containing barium are: barium sulfate, barium carbonate, barium acetate, barium chloride, barium hydroxide, barium nitrate, barium sulfide. Barium sulfate and barium carbonate are found naturally in underground ore deposits.
Uses
Barium and its compounds are used in oil and gas drilling muds, automotive paints, plastics stabilizers, case hardening steels, bricks, tiles, lubricating oils, jet fuel, and various types of pesticides. Barium sulfate is sometimes used by doctors, to perform medical tests and take x-rays of the stomach and intestines.
Sources of Exposure in Iowa
Barium is normally present in the environment at very low levels. Some foods, such as Brazil nuts, seaweed, fish, and certain plants, may contain large amounts of barium. Barium is usually not found in food and water in amounts large enough to cause health concern. People working in industries that make or use barium compounds have the greatest risk of exposure.
Health Effects from Large Acute Exposures
Health effects associated with exposure to barium compounds depend on how well the specific compound dissolves in water. Barium sulfate does not dissolve well in water making it safe for use in medical tests. Eating or drinking very large amounts of barium dissolved in water (barium acetate, barium chloride, barium hydroxide, barium nitrate, and barium sulfide) can cause changes in heart rhythm and paralysis. Some people who eat or drink smaller amounts of barium for a short period may experience vomiting, abdominal cramps, diarrhea, breathing difficulties, increased or decreased blood pressure, facial numbness, and muscle weakness.
Health Effects from Smaller Chronic Exposures
Exposure to elevated barium in drinking water for longer periods of time may cause adverse cardiovascular system effects. There is not enough information to classify barium as carcinogenic.
Protection from Exposure
Individuals exposed to higher levels of barium in drinking water may wish to consider using a reverse osmosis treatment system to remove the excess.
Benzene
CASRN 71-43-2
Physical Properties
Benzene, also known as benzol, is a colorless liquid with a sweet odor. Benzene evaporates into air very quickly and dissolves slightly in water. Benzene is highly flammable. Most people begin to smell benzene in air at 1.5β4.7 parts of benzene per million parts of air (parts per million or ppm) and smell benzene in water at 2 ppm. Most people can taste benzene in water at 0.5β4.5 ppm.
Uses
Benzene was first discovered and isolated from coal tar in the 1800s. Today it is made mostly from petroleum. Benzene is widely used in the chemical industry, and is one of the top 20 chemicals produced in the United States by production volume. It is used in the production of plastics, resins, synthetic fibers, rubber, lubricants, dyes, detergents, drugs, and pesticides. Gas emissions from volcanoes and forest fires are natural sources of benzene. Benzene is also present in crude oil, gasoline, and cigarette smoke.
Sources of Exposure in Iowa
Everyone is exposed to a small amount of benzene each day in the outdoor environment, workplace, and home. General population exposure mainly occurs through breathing air containing benzene. The major sources of benzene exposure are tobacco smoke, automobile service stations, exhaust from motor vehicles, and industrial emissions. Vapors (or gases) from products containing benzene, such as glues, paints, furniture wax, and detergents, can also be sources of exposure. Small amounts of benzene can be present in private and public water supplies, resulting from leaking underground storage tanks that contained petroleum products. People who work in industries that use benzene have the greatest potential for exposure.
Health Effects from Large Acute Exposures
Brief exposure (5β10 minutes) to very concentrated benzene (10,000β20,000 ppm) in air can result in death. Lower concentrations (700β3,000 ppm) can cause drowsiness, dizziness, rapid heart rate, headaches, tremors, confusion, and unconsciousness. In most cases, these effects stop when exposure stops and fresh air is available. Eating foods or drinking liquids containing high levels of benzene may cause vomiting, irritation of the stomach, dizziness, sleepiness, convulsions, rapid heart rate, coma, and death. Spilling benzene on the skin may cause redness and sores. Benzene in the eye may cause general irritation and damage to the cornea.
Health Effects from Smaller Chronic Exposures
People who breathe benzene for long periods may experience harmful effects in the tissues that form blood cells, especially the bone marrow. These effects can disrupt normal blood production and cause a decrease in important blood components. Decreased red blood cells may lead to anemia. Reducing other blood components may cause excessive bleeding. Blood production may return to normal after exposure to benzene stops. Excessive exposure to benzene can be harmful to the immune system, increasing infection risk, and perhaps lowering the body's defense against cancer. Benzene is classified as a known human carcinogen. Exposure to benzene has been associated with development of a particular type of leukemia called acute myeloid leukemia (AML).
Protection from Exposure
Gasoline and cigarette smoke are two main sources of human exposure to benzene. Benzene exposure can be reduced by limiting contact with these sources. Both active and passive second-hand smoke contain benzene. Average smokers take in about 10 times more benzene than nonsmokers each day. Persons should not smoke in the house, enclosed environments, or near children.
Bisphenol A
CASRN 80-05-7
Physical Properties
Bisphenol A exists as a white to light brown flake or powder. It has a mild phenolic odor and low solubility in water.
Uses
Bisphenol A is a manufactured substance that does not occur naturally. It is used in the synthesis of polyesters, polysulfones, and polyether ketones, as an antioxidant in some plasticizers, and as a polymerization inhibitor in polyvinyl chloride. It is a key monomer in production of polycarbonate plastic and epoxy resins. Polycarbonate plastic, which is clear and nearly shatter-proof, is used to make a variety of common products including baby and water bottles, sports equipment, medical devices, CDs, and household electronics.
Sources of Exposure in Iowa
People who work in industries using bisphenol A in the manufacture of plastics are most at risk for exposure. Exposure to bisphenol A in the industrial setting is mostly through inhalation and dermal exposure. Since bisphenol A is used in making many consumer products, including containers for food and drink, the general population can be exposed orally to small amounts that leach from these containers. The current estimated exposure of very young children and infants to bisphenol A is up to 0.4 Β΅g/kg/day, or 4 ten-millionth of a gram of bisphenol A per kg body weight per day. For an average sized 6 to 11 month old infant this means about four millionth of a gram per day or about 1.5 ten-millionth of an ounce per day.
Health Effects from Large Acute Exposures
There is a relatively small amount of information regarding human health effects from large acute exposures to bisphenol A, since large acute exposures are uncommon. Some individuals have developed allergic contact dermatitis from exposure to plastics; bisphenol A may have caused these allergic reactions. Eye, nose, and throat irritation have been reported by workers exposed to larger amounts of bisphenol A. Laboratory animals exposed to large amounts of bisphenol A have reduced body weight.
Health Effects from Smaller, Chronic Exposures
No adverse human health effects have been documented from long-term exposure to the small amounts of bisphenol A that may leach into food or drink from plastic containers manufactured with bisphenol A. Evidence from laboratory animal tests shows that exposure to small amounts of bisphenol A causes delayed puberty and growth reduction in the animals tested. Doses given to these animals far exceed typical human daily exposure. Recently, additional test were done with rodents given extremely low doses of bisphenol A, similar to human daily exposure. These tests produced neural and behavioral alterations, pre-cancerous lesions in the prostate and mammary glands, delayed puberty in female test rodents, and altered prostate gland and urinary tract development. There is some concern in the scientific community about the relevance and applicability of these results to human health. The bisphenol A was injected under the animalsβ skin rather than ingested orally and the study results lack reproducibility. The Iowa Department of Public Health believes that extremely low exposures to bisphenol A from the normal use of plastic food containers or bottles and other consumer products manufactured with bisphenol A will not cause adverse health effects to humans, including infants and children.
Protection from Exposure
Proper protective equipment is recommended for any person exposed to bisphenol A in an occupational setting.
1,3-Butadiene
CASRN 106-99-0
Physical Properties
1,3-Butadiene is a colorless gas with a mild gasoline-like odor. It is heavier than air and has an odor threshold of about 1.6 parts per million (ppm). It is soluble in organic solvents such as ether, ethanol, and acetone.
Uses
1,3-Butadiene is used in the manufacture of the rubber that is mostly used in car and truck tires. It is also used in the manufacture of certain types of plastics such as acrylics and high impact polystyrenes.
Source of Exposure in Iowa
The most likely way you can be exposed to 1,3-butadiene is by breathing air containing it. Larger levels of exposure are primarily found in the workplace, and workers in the rubber and plastics industries are the most likely to be exposed to 1,3-butadiene. A person can also be exposed to 1,3-butadiene through exposure to vehicle exhaust, tobacco smoke, wood burning, burning of rubber and plastic, and forest fires.
Health Effects from Acute or Large Exposures
Breathing larger amounts of 1,3-butadiene irritates the eyes, nose and throat. It may also cause drowsiness and lightheadedness. Reports of difficulty focusing has also been reported from exposure to larger amounts of 1,3-butadiene. There have been no reports of death as a result of people being exposed to large amounts of 1,3-butadiene in the workplace.
Health Effects from Smaller, Chronic Exposures
Exposure to smaller amounts of 1,3-butadiene may cause lethargy and mild drowsiness. The National Toxicological Program within the Department of Health and Human Services (DHHS) has determined that 1,3-butadiene is known to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in humans, including epide-miological and mechanistic studies.
Protection from Exposure
Proper safety equipment and respiratory protection should be used when there is a potential to be exposed to large concentrations of 1,3-butadiene in the workplace. Monitoring of 1,3-butadiene levels in the air is needed to assure that levels are safe for people to work. 1,3-Butadiene is a component of tobacco smoke. Avoid smoking in enclosed spaces like inside the home or car in order to limit exposure to children and other family members.