Cadmium (Cd) is a soft, silver-white or blue, lustrous metal typically found in mineral deposits with lead, zinc, and copper. Cadmium is normally found in cadmium oxide, cadmium chloride, or cadmium sulfate/sulfide forms. The metal most frequently occurs in zinc deposits as cadmium sulfide and is a byproduct of zinc concentrates, making its production dependent on the demand for zinc.
Cadmium and its compounds have been classified by the International Agency for Research on Cancer (IARC) as Group 1, carcinogenic to humans, on the basis of sufficient evidence of carcinogenicity in humans and animals. IARC's 2012 review of Class 1 carcinogens reaffirmed the classification for cadmium and its compounds. Epidemiological studies reviewed by IARC showed consistent evidence that cadmium workers were at increased risk of lung cancer. Other studies suggested elevated risks of prostate, kidney, and bladder cancers.[3,5]
Acute inhalation of cadmium at high concentrations affects the lungs, causing severe damage and possibly death. Chronic inhalation at low concentrations affects the kidneys, resulting in cadmium accumulation and possible kidney disease. Chronic ingestion of cadmium at low levels can result in kidney damage and bone effects.
Schedule 1, paragraphs A and C for 'inorganic cadmium'
DSL = domestic substance list
CEPA = Canadian Environmental Protection Act
The most common use of cadmium is in producing batteries, specifically as cadmium hydroxide, one of two electrode materials used in rechargeable nickel-cadmium (Ni-Cd) batteries. More than 80% of global consumption of cadmium in 2014 was for NiCd batteries, while the remainder was used for, in order of descending use: pigments, coatings and plating, stabilizers, alloys, and other minor uses.
Cadmium sulphide is used as a pigment in plastics, ceramics, glasses, enamels, and artists colours (yellows and reds). Cadmium salts are used as stabilizers in polyvinyl chloride (PVC) plastics, and also in coatings for electronics, steel and aluminum for corrosion resistance. Other minor uses for cadmium include alloys, solar cells and semiconductors. Other than for batteries, production and use of cadmium has decreased significantly over the past 50 years.
Approximately 10-15% of cadmium produced in the western world is from recycled products. There are 9 recycling facilities in the US, Japan, and Europe capable of recycling industrial and commercial Ni-Cd batteries and manufacturing scrap.
Production and Trade
In 2006, Canada was the fifth largest producer of cadmium, refining a total of 2,094 tonnes of cadmium. This is an increase of 21% from the previous year.
Cadmium is mined as a byproduct in New Brunswick, Quebec, and Ontario and refined at all four Canadian zinc smelters (located in Valleyfield, Quebec; Trail, BC; Timmins, Ontario; and Flin Flon, Manitoba). The majority of Canada's exports are sent to Belgium, Japan, China, and the Netherlands.
Export: Mainly to China, Sweden
1,095 t of 'cadmium and articles thereof'
Import: Mainly from the US
46 t of 'cadmium and articles thereof'
t = tonne
Inhalation is the main route of exposure to cadmium in occupational settings.
CAREX Canada estimates that approximately 31,000 Canadians are exposed to cadmium at work, with most of these exposures occurring in the moderate exposure category.
In Canada, the industry with the largest number of workers occupationally exposed to cadmium is sawmill and wood preservation, where workers are exposed through sawfiling or working near sawfiling areas. Other industries with large numbers of workers exposed to cadmium include automotive repair, and commercial and industrial machinery repair.
When exposure is examined by occupation, the largest occupational group exposed is welders. Welders are employed in diverse industries, and this exposure can occur when welding cadmium-coated surfaces or stainless steel that contains cadmium. Other important exposed groups include automotive service technicians and sawfilers.
For more information, see the CAREX Canada occupational exposure estimates for cadmium.
Food is the major source of cadmium exposure for the general population in Canada (nearly 100% of daily exposure for non-smokers). However, cadmium is not expected to be carcinogenic upon ingestion. Cigarette smoking increases the daily intake of cadmium by about 25% (for those smoking 1 pack/day).
Forest fires and volcanic eruptions contribute to cadmium levels in the environment; however, the most important natural source is eroding or weathering cadmium-containing rocks. Cadmium particles can be dispersed very long distances before settling. Some particles are soluble in water, while others bind tightly to soil. Cadmium may also occur in phosphate deposits, leading to possible environmental contamination when phosphate rock deposits are mined, and when phosphate fertilizers are manufactured and applied. CAREX Canada's environmental estimates indicate that cadmium levels in outdoor air do not result in higher risks of cancer (moderate data quality). No data on indoor concentrations and exposures was available for cancer risk assessment.
For more information, see the CAREX Canada environmental exposure estimates for cadmium. Searches of environmental and consumer product databases yielded the following results on current potential for exposure to cadmium in Canada:
Searches of Environment Canada's National Pollutant Release Inventory (NPRI) and the US Household Products Database yielded the following results on current potential for exposure to cadmium in Canada:
NPRI and US Household Products Database
Substance name: 'Cadmium and its compounds'
Released into environment
Non-ferrous metal (except Aluminum) production and processing, foundries, pulp, paper and paperboard mills (347 facilities)
Sent to off-site recycling
US Household Products 2015
Ceramic glazes(1), gear and motor oils(4), auto wax(1), cement colourant(1)
t = tonne
Our team has performed a detailed scan of exposure control resources and assembled a compilation of key publications and resources. These are organized by type of exposure (environmental or occupational) and by specificity (general or carcinogen-specific). Please visit our Exposures Reduction Resources page to view.
We also recommend exploring the Prevention Policies Directory, a freely-accessible online tool offering information on policies related to cancer and chronic disease prevention. Providing summaries of the policies and direct access to the policy documents, the Directory allows users to search by carcinogen, risk factor, jurisdiction, geographical location, and document type. Click here to learn more about policies specific to cadmium in the Directory. For questions about this resource, please contact a member of the Prevention Team at the Canadian Partnership Against Cancer at firstname.lastname@example.org.