Compiled by: Ike Iyioke
SUMMARY: The highest exposure to cadmium happens most often in the workplace where cadmium
products are made. The general public is exposed from breathing cigarette smoke or eating
cadmium contaminated foods. Cadmium damages the lungs, can cause kidney disease, and may
irritate the digestive tract. Cadmium has been found in at least 388 of the 1,300 National
Priorities List sites identified by the EPA.
What is cadmium?
Cadmium is an element that occurs naturally in the earth's crust. Pure cadmium is a soft, silver-white metal. However it is usually found as a mineral combined with other elements such as oxygen (cadmium oxide), chlorine (cadmium chloride), or sulfur (cadmium sulfide). These compounds are solids that may dissolve in water but do not evaporate or disappear from the environment. All soils and rocks, including coal and mineral fertilizers, have some cadmium in them. As small particles in the air or in water, cadmium is odorless and colorless.
Cadmium has many uses in industrial and consumer products, such as batteries, metal coatings and plastics.
Exposure to cadmium:
Cadmium enters the air from burning of coal and household waste, metal mining and refining processes, disposal of waste from households or industries, fertilizer application to the soil, spills and leaks from hazardous waste sites, as well as other sources.
Food and cigarette smoke are the largest potential sources of cadmium exposure. Average cadmium levels in US foods range from 2-40 parts of cadmium per billion parts of food (ppb). This results from plant uptake of cadmium from soil, and fish from water. The level of cadmium in most drinking water supplies in US is less than 1 ppb. The average person eats food with about 30 micrograms of cadmium in it each day.
Industrial workers who make batteries and paints are at high risk of cadmium exposure in air. Working with metal by soldering or welding also may result in cadmium exposure.
Health effects:
Cadmium has no known beneficial effects on human health. Breathing air with very high levels of cadmium severely damages the lungs and can cause death. Inhaling lower levels over a long time can cause kidney disease, lung damage and increased chance of getting lung cancer. Other tissues that could be injured include the liver, the testes, the immune and nervous systems, and the blood.
Eating food or drinking water with high cadmium levels severely irritates the stomach, leading to vomiting and diarrhea. Research findings are yet inconclusive on the effect of cadmium on the developing fetus or the potential for cadmium ingestion to cause cancer.
Regulations to protect human health:
The Environmental Protection Agency (EPA) allows only 10 ppb of cadmium in drinking water. This level is under review and is expected to be reduced further. The EPA also limits how much cadmium can be put into lakes, rivers dumps and cropland, and does not allow cadmium in pesticides. The Food and Drug Administration (FDA) limits the amount of cadmium in food colors to 15 parts of cadmium per million parts of food color (15 ppm).
The Occupational Safety and Health Administration (OSHA) limits workplace air to 100 micrograms cadmium per cubic meter as cadmium fumes and 200 microgram cadmium per cubic meter as cadmium dust averaged over an eight-hour workday. This level is also under review and is expected to be reduced further.
The Food and Drug Administration (FDA) limits the amount of cadmium that can be used in ceramic plates and cups. In view of the carcinogenic risk from inhalation of cadmium, the National Institute for Occupational Safety and Health (NIOSH) recommends that controls be used to reduce workers' exposure to the fullest extent possible.
For more information about cadmium in food, contact:
Jenny Bond
Food Science and Human Nutrition
236 Food Science Building, MSU
Phone: 517-355-1756
For more information about cadmium toxicity, contact:
Agency for Toxic Substances and Diseases Registry
Division of Toxicology
1600 Clifton Road NE
Mailstop E-29
Atlanta, GA 30333
Phone: 404-639-6000
