Zinc is a metal that is normally found in small amounts in nature. It is used in many commercial industries and can be released into the environment during mining and smelting (metal processing) activities. People living near smelters or industries using zinc could be exposed to higher levels of zinc by drinking water, breathing air and touching soil that contains the metal. Exposure to high levels of zinc over long periods of time may cause adverse health effects.
How does zinc get into the environment?
Although zinc occurs naturally, most zinc finds its way into the environment because of human activities. Mining, smelting metals (like zinc, lead and cadmium) and steel production, as well as burning coal and certain wastes can release zinc into the environment. A common use for zinc is to coat steel and iron as well as other metals to prevent rust and corrosion; this process is called galvanization. High levels of zinc in soil may result from the improper disposal of zinc-containing wastes from metal manufacturing industries and electric utilities. In soil, most of the zinc stays bound to the solid particles. When high levels of zinc are present in soils, such as at a hazardous waste site, the metal can seep into the groundwater.
Industries also can release dust containing higher levels of zinc into the air we breathe. Eventually, the zinc dust will settle out onto the soil and surface waters. Rain and snow also can remove zinc dust from the air. Most of the zinc in lakes, rivers and streams does not dissolve, but settles to the bottom. Some fish in these waters may contain high levels of zinc. High levels of zinc in the soil, water and air are often found along with high levels of other metals like lead and cadmium.
How might I be exposed to zinc?
Zinc can enter the body if you eat foods or drink water or other beverages containing zinc, or if you breathe zinc dust or fumes from the air. Very small amounts of zinc enter the body through skin contact. People living near a smelter or another zinc-producing industry who have a private well are most likely to be exposed through their drinking water. They also may be exposed to zinc through the air they breathe, or through vegetables grown in contaminated soils. Through frequent hand-to-mouth contact, children also can be exposed to zinc by playing in contaminated soils.
Foods naturally contain zinc but vary greatly in their zinc content. Very small amounts of the zinc in food are absorbed by the body. Drinking beverages stored in metal cans or drinking water that flows through metal pipes coated with zinc also are sources of zinc exposure.
How can zinc affect my health?
Zinc is an essential nutrient needed by the body for growth, development of bones, metabolism and wound-healing. Too little zinc in the diet also can cause adverse health effects such as loss of appetite, decreased sense of taste and smell, lowered ability to fight off infections, slow growth, slow wound-healing and skin sores.
A short-term illness called metal fume fever can result if workers breathe very high levels of zinc dust or fumes. This condition, which usually lasts from 24 to 48 hours, causes chills, fever, excessive sweating and weakness. Long-term effects of breathing zinc dust or fumes are not known.
Eating or drinking too much zinc in a short period of time can lead to adverse health effects, such as stomach cramps, nausea and vomiting. Eating large amounts of zinc for longer periods may cause anemia, nervous system disorders, damage to the pancreas and lowered levels of “good” cholesterol. There is no evidence that zinc causes cancer in humans.
How can I reduce my exposure to zinc?
Knowing possible sources of zinc in your environment is important in reducing exposure. Children are particularly at risk if they play in contaminated soil. Limiting play in contaminated areas and planting grass to provide ground cover can greatly reduce exposure. Practice good hygiene habits by washing children’s hands and faces often, especially before eating and bedtime. Practice good housekeeping techniques by removing shoes before entering your home to prevent tracking contaminated soils inside, and vacuum carpets, rugs and upholstery often.
If you live near a smelter or another zinc-producing industry and your drinking water comes from a private well, you may want to have the water tested for zinc. Public water systems are tested for zinc on a regular basis. If you live near a zinc smelter or another industry that produces zinc, you also may want to have your garden soil tested.
Is there a medical test that can tell me if I have been exposed to zinc?
Zinc can be measured in blood, feces, urine and hair. Different tests may be able to show the type of exposure to zinc. High levels of zinc in the blood or feces might show a recent high exposure. Zinc levels measured in hair would show long-term exposure. However, these tests are not routinely used. If you think you have been exposed to elevated levels of zinc, contact your doctor for more information.
Where can I get more information?
This fact sheet was supported in part by funds from the Comprehensive Environmental Response, Compensation, and Liability Act trust fund through a cooperative agreement with the Agency for Toxic Substances and Disease Registry, Public Health Service, U.S. Department of Health and Human Services.