The Risk Assessment Information System

RAGs A Format for Cadmium - CAS Number 7440439

Cadmium is a natural element in the earth's crust. It is usually found as a mineral combined with other elements such as oxygen (cadmium oxide), chlorine (cadmium chloride), or sulfur (cadmium sulfate, cadmium sulfide). These cadmium compounds have varying degrees of solubility ranging from very soluble to nearly insoluble. The solubility affects their absorption and toxicity. All soils and rocks, including coal and mineral fertilizers, contain some cadmium. Most cadmium used in the United States is extracted during the production of other metals like zinc, lead, and copper. Cadmium does not corrode easily and has many uses, including batteries, pigments, metal coatings, and plastics. Cadmium compounds have varying degrees of solubility ranging from very soluble to nearly insoluble. The solubility affects their absorption and toxicity. Environmental exposure can occur via the diet and drinking water.

Breathing high levels of cadmium severely damages the lungs and can cause death. The 1-minute and 10-minute lethal concentration of cadmium for humans has been estimated to be about 2,500 and 250 mg/m³, respectively. Eating food or drinking water with very high levels severely irritates the stomach, leading to vomiting and diarrhea. Acute oral exposure to 20-30 g have caused fatalities in humans. Cadmium is absorbed more efficiently by the lungs (30 to 60%) than by the gastrointestinal tract. Long-term exposure to lower levels of cadmium in air, food, or water leads to a buildup of cadmium in the kidneys and possible kidney disease. Other long-term effects are lung damage and fragile bones. Animals given cadmium in food or water had high blood pressure, iron-poor blood, liver disease, and nerve or brain damage.

There is limited evidence from epidemiologic studies for cadmium-related respiratory tract cancer. Based on limited evidence from multiple occupational exposure studies and adequate animal data, cadmium is placed in weight-of-evidence group B1 - probable human carcinogen.

The following is a presentation of the toxicity information associated with Cadmium:

• The Oral Chronic Reference Dose for Cadmium in the diet is 1.00E-03 (mg/kg-day).
• The Oral Chronic Reference Dose for Cadmium in water is 5.00E-04 (mg/kg-day).
• The Oral Chronic Reference Dose has a modifying factor of 1.
• The Oral Chronic Reference Dose has an uncertainty factor of 10.
• The Oral Chronic Reference Dose is based on the U.S. EPA study from 1985.
• The Oral Chronic Reference Dose study critical effect is significant proteinuria.
• The overall confidence in the Oral Chronic Reference Dose is high.
• The Dermal Chronic Reference Dose for Cadmium in the diet is 1.00E-05 (mg/kg-day).
• The Dermal Chronic Reference Dose for Cadmium in water is 5.00E-06 (mg/kg-day).
• The Dermal Chronic Reference Dose for Cadmium in the diet is based on a gastrointestinal absorption factor of 0.0100.

• The Inhalation Unit Risk is 1.8E+00 (mg/m³)^-1.
• The Inhalation Unit Risk study target organ is lung.
• The Inhalation Unit Risk study cancer type is tumors.
• The Inhalation Unit Risk is based on the Thun et al. study from 1985.