Z

Zinc

CASRN 7440-66-6

Physical Properties

Zinc is a lustrous blue-white metal. Zinc tends to react with acidic, alkaline, and inorganic compounds. Some of the common inorganic compounds containing zinc are: zinc chloride, zinc oxide, zinc sulfate, and zinc sulfide. In animals and humans, zinc is essential for membrane stability, as part of 300 enzymes, and in the metabolism of proteins and nucleic acids.

Uses

Zinc metal is most commonly used as a protective coating for other metals, such as iron and steel. This process is called galvanization. Zinc may be found in electrical components of many household goods, including batteries. Zinc oxide is used by the rubber industry, in paints, as an additive to annimal feeds, and in cosmetics and drugs as a fungacide. Zinc chloride is used in wood preservation, in medicine as an anticeptic and disinfectant, and as a primary ingredient in smoke bombs. Zinc sulfate is used in fertilizers, sprays, and animal feed as a nutrient and disease-control agent.

Sources of Exposure in Iowa

Zinc is one of the most common elements in the earth’s crust. Everyone is exposed to low levels of zinc and zinc compounds. Small amounts of zinc are essential for body processes. Highest concentrations of zinc are found in meats, fish, and poultry. Oysters contain the most zinc. Besides foods, individuals who weld; manufacture brass, bronze, or other zinc-containing alloys; manufacture machine parts, rubber, paint, or batteries are exposed to large amounts of zinc. Individuals with galvanized plumbing in their homes may be exposed to high levels of zinc.

Health Effects from Large Acute Exposures

Inhaling large amounts of zinc (from smelting or welding) can cause a short-term disease called metal fume fever. Metal fume fever is characterized by chest pain, cough, and shortness of breath. It is reversible after several days of no exposure. Taking too much zinc into the body through food, water, or dietary supplements can also affect health. Taking large doses of zinc (10 to 15 times the recommended daily allowance) by mouth, even for a short time, can cause stomach cramps, nausea, and vomiting. Ingesting high levels of zinc for several months can cause anemia, damage the pancreas, and decrease levels of high-density lipoprotein (HDL) cholesterol.

Health Effects from Smaller, Chronic Exposures

Zinc is an essential element; small amounts are needed for optimal health. Too little zinc in the diet may cause loss of appetite, decreased taste and smell, decreased immune function, slow wound healing, and skin sores. It may also cause poorly developed sex organs and retarded growth in young men. A pregnant woman who does not get enough zinc may have babies with birth defects. Little information is available to determine whether zinc is carcinogenic.

Protection from Exposure

Individuals who weld or work with metal should wear a respirator. Drinking water should be tested for zinc in homes with galvanized plumbing.