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Cadmium

CASRN 7440-43-9

Physical Properties

Cadmium is an element that occurs naturally in the earth’s crust. Pure cadmium is a soft, silver-white metal. Cadmium is not usually present in the environment as a pure metal, but as a mineral combined with other elements such as oxygen (cadmium oxide), chlorine (cadmium chloride), or sulfur (cadmium sulfate, cadmium sulfide). Cadmium is most often present in nature as complex oxides, sulfides, and carbonates in zinc, lead, and copper ores. Cadmium may change forms, but the cadmium metal itself does not disappear from the environment. Knowing the particular form of cadmium, however, is very important when determining the risk for potential adverse health effects.

Uses

Most cadmium used in the United States is extracted as a by-product of production of other metals such as zinc, lead, or copper. Use of cadmium compounds falls into five categories: active electrode materials in nickel-cadmium batteries; pigments used mainly in plastics, ceramics, and glasses; stabilizers against heat and light in polyvinyl chloride (PVC); engineering coatings on steel and some nonferrous metals; and components of various specialized alloys.

Sources of Exposure in Iowa

It is estimated that one-half of the cadmium released into the environment comes from the weathering of rocks into river water and the oceans. Manmade releases of cadmium into the environment come from mining activities and burning of fossil fuels. Food and cigarette smoke are the biggest sources of cadmium exposure for the general population. Cadmium exposure from smoking cigarettes may be a more serious health concern than cadmium in food. Workers can be exposed to cadmium in air from smelting and refining metals, or from the air in plants that make cadmium products such as batteries, coatings, or plastics. Workers can also be exposed by soldering or welding metal containing cadmium.

Health Effects from Large Acute Exposures

Breathing air with very high levels of cadmium can severely damage lungs, and can even cause death. Ingestion of high concentrations of cadmium causes severe irritation to the gastrointestinal tract causing nausea, vomiting, and abdominal pain.

Health Effects from Smaller, Chronic Exposures

Breathing air with lower concentrations of cadmium, or ingesting lower doses of cadmium over the years results in build-up in the kidney. Sufficiently high concentrations may result in kidney disease. Other effects that may occur after breathing or ingesting lower levels for a long time are lung damage and fragile bones. Cadmium and cadmium compounds are known human carcinogens. Inhalation exposure to cadmium has been shown to increase risk of death from lung cancer.

Protection from Exposure

Stopping smoking can reduce an average person’s exposure to environmental cadmium by one-half. A balanced diet that includes enough calcium, iron, protein, and zinc will help reduce the amount of cadmium absorbed into the body. Nickel-cadmium batteries should be kept away from children and properly disposed of without burning. Any person who works with cadmium or other heavy metal vapors should wear appropriate respiratory protection.

Carbon Monoxide

CASRN 630-08-0

Physical Properties

Carbon monoxide (CO) is a colorless, nonirritating, odorless, and tasteless gas. It is found in both outdoor and indoor air. Because carbon monoxide is odorless and tasteless its level within air can only be determined with some type of carbon monoxide detecting device.

Uses

Carbon monoxide is used by the chemical industry for the synthesis of many compounds such as acetic anhydride, polycarbonates, acetic acid, and polyketones. It finds application as a reducing agent in metallurgical operations, specifically for the recovery of nickel, in the manufacture of metal carbonyls, and in organic synthesis.

Source of Exposure in Iowa

Sources of exposure to carbon monoxide include unvented kerosene and gas space heaters; leaking chimneys and furnaces; back-drafting from furnaces, gas water heaters, wood stoves, and fireplaces; gas stoves; generators and other gasoline powered equipment; automobile exhaust from attached garages; and tobacco smoke. Incomplete oxidation during combustion in gas ranges and unvented gas or kerosene heaters may cause high concentrations of carbon monoxide in indoor air. Worn out or poorly adjusted and maintained combustion devices (e.g., boilers, furnaces) can be significant sources of carbon monoxide. High levels of carbon monoxide can occur if the flue is improperly sized, blocked, disconnected, or is leaking. Auto, truck, or bus exhaust from attached garages, nearby roads, or parking areas can also be a source of carbon monoxide. Natural sources of carbon monoxide include forest, field, and building fires.

Health Effects from Acute or Large Exposures

The clinical presentation of acute carbon monoxide poisoning includes a wide range of symptoms. The severity of carbon monoxide poisoning is typically categorized as mild, moderate, or severe, based on clinical presentation. Signs and symptoms of mild carbon monoxide poisoning – exposure to carbon monoxide levels in air above 70 parts per million (ppm) – include headache, nausea, vomiting, dizziness, blurred vision, and occasionally cherry red lips and ski; headache and dizziness. Because these symptoms mimic flu-like viral illnesses, mild carbon monoxide poisoning can easily be misdiagnosed. Symptoms associated with moderate carbon monoxide poisoning – exposure to carbon monoxide levels between 70 and 150 ppm may include confusion, syncope, chest pain, dyspnea, weakness, tachycardia, tachypnea, and rhabdomyolysis. Effects of severe poisoning – extended exposure to levels 200 ppm and above – may be life-threatening, including cardiac arrhythmias, myocardial ischemia, cardiac arrest, hypotension, respiratory arrest, noncardiogenic pulmonary edema, seizures, and coma.

Health Effects from Smaller, Chronic Exposures

People who are exposed to smaller concentrations of carbon monoxide may first experience increased exhaustion and headaches. There is a risk of damage to your heart and brain from extended exposure to low levels of carbon dioxide. Breathing low levels of carbon monoxide during pregnancy may harm the mental development of your child. Epidemiological data do not show an increase in cancer risk in association with exposure to carbon monoxide.

Protection from Exposure

The U.S. Environmental Protection Agency has established a National Ambient Air Quality Standard for carbon monoxide of 35 parts per million (ppm) for a one-hour exposure. Maintaining low indoor levels of carbon monoxide can be made by proper maintenance of furnaces, stoves, heaters, and chimneys. Keeping gas appliances properly adjusted will limit the exposure to carbon monoxide. Consider purchasing a vented space heater when replacing an unvented one. Use proper fuel in kerosene space heaters. Install and use an exhaust fan vented to outdoors over gas stoves. Open flues when fireplaces are in use. Choose properly sized wood stoves that are certified to meet EPA emission standards. Make certain that doors on all wood stoves fit tightly. Have a trained professional inspect, clean, and tune-up central heating system (furnaces, flues, and chimneys) annually. Repair any leaks promptly. Do not idle the car inside garage. Consider installation of a carbon monoxide detector for your home.

Chlorine

CASRN 7782-50-5

Physical Properties

At room temperature, chlorine is a yellow-green gas and has a strong, irritating odor like concentrated bleach. The odor threshold of chlorine is 0.31 parts per million (ppm) or 0.90 milligrams per cubic meter (mg/m3) in air and 0.002 ppm in water. Chlorine gas is heavier than air and can collect in low-lying areas. Chlorine gas can be compressed and becomes liquid under pressure. Chlorine is slightly soluble in water and forms hypochlorous acid (HOCL) and hydrochloric acid (HCL). Chlorine is removed from the atmosphere by rainfall.

Uses

Chlorine plays a role in the production of a large number of commercial products that include refrigerants, aerosols, silicones, silicone rubber, plastics, solvents, polyethers, varnishes, foams, chlorinated rubber, polyurethane, detergents, dyes, insecticides, pesticides, disinfectants, bleaches, and white pigment enamel. Chlorine is also used in the manufacture of vinyl chloride to make polyvinyl chloride (PVC) plastics, in the manufacture of other organic and inorganic compounds, for water treatment, and in the bleaching of pulp and paper. A common misconception is that elemental chlorine (Cl2) is present in chlorinated water. During water chlorination, elemental chlorine gas may be added to the water at first, but the chlorine is quickly transformed into other chemicals which actually disinfect the water.

Source of Exposure in Iowa

Exposure of the general population to chlorine is not expected except in the case of an accidental spill or an industrial mishap. Occupational exposure to low levels of chlorine gas may occur with individuals who work at facilities that use or produce chlorine. Chlorine gas can be generated unintentionally when bleach, chlorine-containing cleaning products, or other chlorine compounds are mixed with acid, such as muriatic acid (at swimming pools), or an acid cleaning product, such as toilet bowl cleaner. A number of accidental exposures to chlorine have been reported that were caused by individuals mixing inappropriate chemicals.

Health Effects from Acute or Large Exposures

Chlorine is irritating and corrosive to the respiratory tract, eyes, and skin. Exposure to high levels in the air can cause burning of the eyes and skin, rapid breathing, narrowing of the bronchi, wheezing, blue coloring of the skin, accumulation of fluid in the lungs, and pain in the lung region. Exposure to very high levels in the air can produce severe eye and skin burns, lung collapse, and death. Drinking small amounts (less than a cup) of hypochlorite solution (household bleach) can produce irritation of the esophagus. Drinking concentrated hypochlorite solution can produce severe damage to the upper digestive tract and even death. These effects are most likely caused by the caustic nature of the hypochlorite solution and not from exposure to molecular chlorine. Direct contact of the skin with household chlorine bleach can cause skin irritation.

Health Effects from Smaller, Chronic Exposures

Exposure to low concentrations of chlorine gas (1 to 10 ppm) in the air may cause sore throat, coughing, and eye and skin irritation. No significant harmful health effects were observed in workers exposed for years to concentrations of chlorine in the air at around 1 ppm or below. Exposure to chlorine in drinking water is expected to be very low. Extended exposure to chlorine compounds in swimming pools can cause skin and eye irritation and can cause discoloration or bleaching of hair. There is not enough information to classify chlorine as carcinogenic.

Protection from Exposure

Proper safety equipment should be used when handling chlorine. Rubber gloves, respirators, and chemical splash goggles should be worn. Chlorine’s odor and irritating properties usually provide adequate warning of its presence; however, olfactory fatigue can occur. Inhaling large amounts of chlorine can result in death. People should leave areas where the smell of chlorine is present. Household cleaning chemicals should never be mixed with bleach, to prevent potential exposure to chlorine gas.

Chloroform

CASRN 67-66-3

Physical Properties

Chloroform is a colorless liquid with a pleasant, nonirritating odor and a slightly sweet taste.. The odor threshold of chloroform is 85 parts per million (ppm) or 422 milligrams per cubic meter (mg/m3) in air and 2.4 ppm in water. Chloroform evaporates very quickly when exposed to air. Chloroform also dissolves easily in water, but does not stick to soil very well. Chloroform lasts for a long time in both the air and in groundwater.

Uses

Chloroform was one of the first inhaled anesthetics to be used during surgery, but it is not used for anesthesia today. Nearly all the chloroform made in the United States today is used to make other chemicals. Chloroform is used primarily in the production of HCFC-22 (a refrigerant for home air conditioners or large supermarket freezers) and in the production of fluoropolymers. Chloroform has also been used as a solvent, a heat transfer medium in fire extinguishers, and an intermediate in the preparation of dyes and pesticides.

Source of Exposure in Iowa

The most likely source of exposure may occur from small amounts of chloroform that may be formed as a by-product of the chlorination of drinking water, municipal and industrial waste water, and swimming pool and spa water; and from other water treatment processes. Occupational exposure to low levels of chloroform may occur with individuals who work at facilities that manufacture or use chloroform.

Health Effects from Acute or Large Exposures

In humans, chloroform affects the central nervous system (brain), liver, and kidneys after a person breathes air or drinks liquids that contain large amounts of chloroform. Chloroform was used as an anesthetic during surgery for many years before its harmful effects on the liver and kidneys were recognized. Breathing about 900 parts of chloroform in a million parts of air (900 ppm or 900,000 ppb) for a short time causes fatigue, dizziness, and headache.

Health Effects from Smaller, Chronic Exposures

Results of studies of people who drank chlorinated water showed a possible link between the chloroform in chlorinated water and the occurrence of cancer of the colon and urinary bladder. Chloroform is reasonably anticipated to be a human carcinogen based on sufficient evidence of carcinogenicity from studies in experimental animals. Cancer of the liver and kidneys developed in rats and mice that ate food or drank water that had larger amounts of chloroform in it for a long time.

Protection from Exposure

Proper safety equipment should be used when handling chloroform or potentially exposed to chloroform in an industrial setting. Rubber gloves, respirators, and chemical splash goggles should be worn.

Chromium

CASRN 7440-47-3

Physical Properties

Chromium is a natural occurring element found in rocks, animals, plants, and soil. Pure chromium is a hard, steel-gray metal. Cadmium is not usually present in the environment as a pure metal, but as a mineral combined with other elements and exists in three main forms known as chromium(0), chromium(III), and chromium(VI). Small amounts of chromium(III) are considered to be a necessity for human health. Knowing the particular form of chromium is very important when determining the risk for potential adverse health effects.

Uses

Chromium is widely used in the manufacturing process. The steel industry is the leading consumer of chromium materials. In the refractory industry, chromium is a component in chrome and chrome-magnesite, magnesite-chrome bricks, and granular chrome-bearing and granular chromite, which are used as linings for high temperature industrial furnaces. In the chemical industry, both chromium(III) and chromium(VI) are used primarily in pigments. Other uses include chromium(VI) in metal finishing, chromium(III) in leather tanning, and chromium(VI) in wood preservatives.

Sources of Exposure in Iowa

One source of exposure to chromium is in the food that we eat, with the highest concentration of chromium in meats, fish, fruits, and vegetables. People who work in industries that have chrome-plating operations, chrome pigment production, and those working in tanning industries have the potential to being exposed to larger amounts of chromium. People can be exposed to larger amounts of chromium if they are exposed to chromium in soil or within groundwater from the improper disposal of chromium-wastes from industries that utilize chromium. People can be exposed to small amounts of chromium during the use of consumer products that contain chromium, such as wood treated with copper dichromate or chromated copper arsenate and leather tanned with chromic sulfate.

Health Effects from Large Acute Exposures

Chromium(VI) is much more toxic than chromium(III). Workers within industries utilizing chromium and exposed to chromium(VI) within air can experience irritation of the lining of the nose, runny nose, and breathing problems (asthma, cough, shortness of breath, wheezing). Workers have also developed allergies to chromium compounds, which can cause breathing difficulties and skin rashes.

Health Effects from Smaller, Chronic Exposures

Chromium(VI) compounds are known to be human carcinogens based upon sufficient evidence of carcinogenicity from studies in humans. An increase in lung cancer in workers engaged in chromate production, chromate pigment production, and chromium plating due to inhalation exposure to chromium(VI) has been observed in these studies.

Protection from Exposure

Personal protective equipment should be used by individuals working in industries that have chrome-plating operations, chrome pigment production, and tanning operations. Wearing of appropriate respiratory protection, use of gloves and eye protection is required. Exposure to open burning of wood treated with wood preservatives should be avoided.

Copper

CASRN 7440-50-8

Physical Properties

Copper is a reddish metal that naturally occurs in rock, soil, water, sediment, and, at low levels, air. Copper has unique properties of being easily molded, high thermal and electrical conductivity, and low corrosion potential. It can be combined with two or more other elements to form copper compounds.

Uses

Copper is primarily used as a metal or alloy in the manufacture of wire, sheet metal, pipe and pipe fixtures (brass fixtures), and other metal products. Copper compounds are used a fungicides and to prepare copper fungicidal products, algaecides for reservoirs and streams (copper sulfate) and nutritional supplements in animal feed and fertilizers. Copper is also used in the production of chromated copper arsenate wood preservatives, electroplating, and dye manufacture.

Sources of Exposure in Iowa

Copper occurs naturally in the environment, but most of the potential for higher concentrations throughout the environment come from human activities. The most common exposure to copper can come from small amounts of copper that can get into drinking water from piping and plumbing fixtures in homes and businesses. Contact with available copper also may result from the use of copper fungicides and algaecides. Workers can be exposed to copper in agriculture, metal plating, and industries that utilize copper compounds.

Health Effects from Large Acute Exposures

Intentional high intakes of copper or copper compounds can cause liver and kidney damage and even death. Other health impacts from short-term exposure to large amounts of copper or copper compounds are nausea, vomiting, diarrhea, or abdominal pain.

Health Effects from Smaller Chronic Exposures

Copper is an essential nutrient that is needed in small amounts. The recommended requirement for dietary copper is 1 to 2 milligrams (mg) for adults and 0.5 to 1 mg for children. Chronic exposure to levels of copper in drinking water above the EPA drinking water standard of 1.3 mg per liter may cause some gastrointestinal discomfort or possible liver or kidney damage. Copper is not known to cause cancer in humans or animals.

Protection from Exposure

Personal protective equipment should be used by individuals working in industries that utilize copper and copper compounds and individuals that apply copper fungicides and algaecides. Wearing of appropriate respiratory protection, use of gloves and eye protection is recommended. To reduce copper in drinking water, run the water for at least 15 to 30 seconds before using if the water has sat in copper piping and/or brass faucets overnight.