METALS – KNOWN CARCINOGEN (IARC 1)
- A soft metal found in mineral deposits with lead, zinc, and copper
- Associated cancer: Lung cancer
- Most important routes of exposure: Inhalation
- Uses: Found in batteries, pigments, coatings and plating, stabilizers, and alloys
- Occupational exposures: Approx. 25,000 Canadians are exposed at work, primarily welders and automotive service technicians
- Environmental exposures: Via food, forest fires, volcanic activity, and erosion of cadmium-containing rock
- Fast fact: Approx. 10-15% of cadmium produced in the western world is from recycled products.
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.[2,4]
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.
Regulations and Guidelines
Occupational exposure limits[6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]
|Canadian Jurisdictions||OEL (mg/m3)|
|Canada Labour Code||0.01*
|AB, ON||0.01 [cadmium]
0.002 [r, cadmium compounds]
|BC, MB, NB, NL, NS, PE||0.01*
|NT, NU, SK||0.01*
0.006 [stel, r]*
|YT||0.05 [Cd dust and salts; CdO fume, Cd oxide production (as Cd)]
0.15 [stel for Cd dust and salts]
|Other Jurisdictions||OEL (mg/m3)|
|ACGIH 2020 TLV||0.01*
* For cadmium and its compounds, as Cd
mg/m3 = milligrams per cubic meter
r = respirable fraction
stel = short term exposure limit (15 min. maximum)
em = exposure must be reduced to the minimum
CdO = cadmium oxide
ACGIH = American Conference of Governmental Industrial Hygienists
TLV = threshold limit value
Canadian environmental guidelines and standards*
|Drinking Water Guidelines (Canada, BC, MB) and Standards (ON, QC, SK)||0.005 mg/L||2003-2020
|Manitoba Ambient Air Quality Criteria||24 hour: 2 µg/m3 MALC||2005|
|Ontario Ambient Air Quality Criteria||Annual: 0.005 µg/m3
24 hour: 0.025 µg/m3
|Ontario’s Air Pollution – Local Air Quality Regulation||24-hour standard: 0.025 µg/m3; Prohibited discharge into the air if the concentration of cadmium exceeds the standard||2020|
|Quebec’s Clean Air Regulation||1 year limit: 0.0036 µg/m3; Prohibited discharge into the air if the concentration of cadmium exceeds the standard||2011|
|BC’s Contaminated Sites Regulation, BC Reg 375/96||Sets soil standards for the protection of human health:
Agricultural and low density residential sites: 20 μg/g
Urban park and high density residential sites: 40 μg/g
Commercial sites: 150 μg/g
Industrial sites: 3,500 μg/g
Drinking water: 5 µg/L
|Cosmetic Ingredient Hotlist||Not permitted||2004|
|Children’s Jewellery Regulations – SOR/2018-82 (Section 2)||Children’s jewellery, when tested using good laboratory practices, must not contain more than 130 mg/kg of cadmium if the jewellery item is small enough to be totally enclosed in the small parts cylinder illustrated in the schedule when a force of not more than 4.45 N is applied.||2018|
**Standards are legislated and legally enforceable, while guidelines (including Ontario ambient air quality criteria) describe concentrations of contaminants in the environment (e.g. air, water) that are protective against adverse health, environmental, or aesthetic (e.g. odour) effects
mg/L = milligrams per litre
µg/m3 micrograms per metre cubed
MALC = maximum acceptable level concentration
|Health Canada||DSL – low priority substance (already risk managed)||2006|
|CEPA||Schedule 1, paragraphs A and C for ‘inorganic cadmium’||1999|
|National Classification System for Contaminated Sites||Rank: “High hazard”||2008|
|PMRA list of formulants||List 4B: List 4B contains formulants, some of which may be toxic, for which there are sufficient data to reasonably conclude that the specific use pattern of the pest control product will not adversely affect public health and the environment.||2020|
|Canada-Ontario Agreement on Great Lakes Water Quality and Ecosystem Health||Tier 2 chemical: potential for causing widespread impacts, or that have already caused local adverse impacts on the Great Lakes Basin Ecosystem||2014|
|Environment Canada’s National Pollutant Release Inventory (NPRI)||NPRI Part (Threshold Category): 1B, Reportable to NPRI if manufactured, processed, or otherwise used at quantities greater than: 50 kg . Total of the pure element and the equivalent weight of the element contained in any compound, alloy or mixture.||2016|
DSL = domestic substance list
CEPA = Canadian Environmental Protection Act
PMRA = Pest Management Regulatory Agency
Cadmium was not included in other Canadian government guidelines, standards, or chemical listings reviewed.
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.
Canadian Production and Trade
In 2018, Quebec mined 148 tonnes of cadmium, which is considered one of the province’s top 10 critical minerals with economic importance.[41,42]
|Export:||1,332 t of ‘cadmium and articles thereof’||2021|
|Import:||25 t of ‘cadmium and articles thereof’||2021|
t = tonne
Environmental Exposures Overview
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 over 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.
Searches of Environment Canada’s National Pollutant Release Inventory (NPRI) and the US Consumer Product Information Database yielded the following results on current potential for exposure to cadmium in Canada:
NPRI and US Consumer Product Information Database
|Substance name: ‘Cadmium and its compounds’|
|Released into environment||9.7 t||Non-ferrous metal (except Aluminum)
production and processing, foundries,
pulp, paper and paperboard mills (347 facilities)
|Disposed of||1,658 t|
|Sent to off-site recycling||183 t|
|US Consumer Products 2015|
|Search Term||Quantity||Product Type|
|‘cadmium’||7||Ceramic glazes(1), gear and motor oils(4),
auto wax(1), cement colourant(1)
|‘cadmium compounds’||1||Ceramic glazes|
t = tonne
For more information, see the environmental exposure estimate for cadmium.
Occupational Exposures Overview
Inhalation is the main route of exposure to cadmium in occupational settings.
CAREX Canada estimates that approximately 25,000 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 automotive repair and maintenance, followed by sawmill and wood preservation (where workers are exposed through sawfiling or working near sawfiling areas), and commercial and industrial machinery repair and maintenance.
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 machinists and machining and tooling inspectors.
For more information, see the occupational exposure estimate for cadmium.
Photo: Wikimedia Commons, Hi-Res Images of Chemical Elements
- Agency for Toxic Substances and Disease Registry (ATSDR). ToxFAQs Document (2008)
- US National Library of Medicine. PubChem (Search term: ‘Cadmium’)
- US Geological Survey. Mineral Information: Cadmium – Statistics and Information, Minerals Year Book Publications (2006)
- Arctic Institute of North America (AINA). Northern Contaminants Program Publications (many studies contain information on cadmium)
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