Health and Environment
Health and Environmental Impacts
Human health and environmental impacts may result when exposure to Cd and Cd compounds occurs. The following is a brief summary of potential exposure routes and the associated human health and environmental impacts.
For the general population, the major route of exposure to Cd is ingestion of food. Smoking is another major source of Cd intake. Ingestion of drinking water and inhalation of Cd aerosols from the atmosphere are also potential sources of Cd exposure.
The primary route of occupational exposure is inhalation of dust and fumes. Accidental ingestion of dust from contaminated hands, cigarettes, or food can also occur. Occupational exposure occurs primarily in smelting and refining zinc, lead, and copper ores; welding or remelting of Cd-coated steel; working with solders that contain Cd; producing, processing, and handling Cd powders; spraying Cd containing pigments; and processing scrap metal containing Cd.
Human Health Effects
Acute (Short-term) Health Effects
- Cadmium is irritating to the nose and throat.
- Inhalation of very high levels of Cd can severely damage the lungs and may cause death.
- Ingestion of very high levels of Cd severely irritates the stomach, leading to vomiting, diarrhea, and sometimes death.
Chronic (Long-Term) Health Effects
Cadmium is carcinogenic to humans. The International Agency for Research on Cancer (IARC) classifies Cd and Cd compounds as Group 1 carcinogens (carcinogenic to humans). The U.S. EPA classifies Cd as a Group B1 (probable human) carcinogen by inhalation. NIOSH considers Cd (and Cd compounds) dust and Cd (and Cd compound) fumes to be potential occupational carcinogens.
Recent studies link exposure to Cd to bladder cancer and chronic obstructive airway disease (COAD).
Breathing airborne particles containing Cd over long periods of time may cause lung damage and fragile bones.
Breathing air with lower levels of Cd for long periods of time results in a build-up of Cd in the kidneys, which may result in kidney impairment.
Human and animal studies have reported limited evidence of an increase in risk of lung cancer from the chronic inhalation of Cd.
Cadmium is a potential reproductive and developmental toxicant. California has designated Cd as causing reproductive toxicity under its Proposition 65 regulation.
Animal studies indicate that eating or drinking Cd may cause high blood pressure, iron-poor blood, liver disease, or nerve or brain damage.
Cadmium enters the environment primarily through human activities such as mining and smelting operations, fuel combustion, disposal of metal-containing products, and application of phosphate fertilizer or sewage sludges. Cd that is in or attached to small particles can enter the air, especially during incineration. The main species of Cd found in the atmosphere is Cd oxide, though some Cd salts, such as Cd chloride, also exist. In water, Cd can exist as the hydrated ion, or as ionic complexes with other inorganic or organic substances.
Cadmium in its ionic form is toxic to a variety of eukaryotic cells, including human cells. Once cadmium is absorbed inside the body, it is very slowly eliminated from the body and thus accumulates in humans and animals. A tragic mass poisoning case in Toyama Prefecture, Japan in 1950 illustrates Cd’s toxicity. Cadmium had leached from wastes at a nearby lead-zinc mine and contaminated the village water supply, causing itai-itai disease in people exposed to the contamination. Symptoms of this disease include kidney dysfunctions and softening of the bones.
Endnotes: ATSDR, Toxicological Profile for Cadmium, 1999; Llewellyn, T.O. U.S. Bureau of Mines Information Circular 9380: Cadmium (Materials Flow), 1994; Butterman, W.C. et al., Open-File Report 02-238, Mineral Commodity Profiles: Cadmium, 2002; National Toxicology Program, Substance Profiles: Cadmium (CAS No. 7440-43-9) and Cadmium Compounds; TOXNET Hazardous Substances Data Bank (HSDB), Cadmium, Elemental; EPA Chemical Sampling Information: Cadmium; Bertin, G. et al, Cadmium: cellular effects, modifications of biomolecules, modulation of DNA repair and genotoxic consequences (a review), Biochimie, 2006; International Occupational Safety and Health Information Centre, International Chemical Safety Cards: Cadmium; The National Institute for Occupational Safety and Health, NIOSH Publication No. 2005-149: NIOSH Pocket Guide to Chemical Hazards: Cadmium dust (as Cd); Cadmium fume (as Cd); American Conference of Industrial Hygienists, ACGIH, 2005 TLVs and BEIs, 2005; The Office of Environmental Health Hazard Assessment (OEHHA) of the California Environmental Protection Agency, PROPOSITION 65 SAFE HARBOR LEVELS: No Significant Risk Levels for Carcinogens and Maximum Allowable Dose Levels for Chemicals Causing Reproductive Toxicity; Kellen, E., et al., Blood cadmium may be associated with bladder carcinogenesis: The Belgian case–control study on bladder cancer. Cancer Detection and Prevention, 2007; International Agency for Research on Cancer (IARC), Beryllium, Cadmium, Mercury and Exposures in the Glass Manufacturing Industry. IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Humans, vol. 58. 1993: Lyon, France; Wikipedia. Itai-itai disease.