Cd, Kadmium och kadmiumföreningar, som Cd
Cadmium and compounds
Cadmium is a silver-grey metal that belongs to the transition metals. This description refers to cadmium and cadmium compounds.
Cadmium has for a long time been used in rechargeable batteries (NiCd accumulators), in galvanized metal sheet, as a plastic stabilizer and as a pigment. Today, the use of cadmium is strictly regulated and about to be phased out. Cadmium is however still allowed to be used in batteries for emergency and alarm systems and for medical equipment as well as a pigment in artist paints.1 2 3
Sources and transportation pathways
Cadmium occurs naturally in the environment and is easily absorbed by plant roots. Consequently, some of the cadmium in the soil ends up in cultivated crops, food and wood raw material. As the ability to absorb cadmium from the soil varies between different plants, cultivation of certain plants may be used to reduce the cadmium levels in contaminated soils.
Cadmium is emitted to the environment by combustion of fossil fuels and waste and by spreading sewage sludge and fertilizers on farmland.4 5 In Sweden, emissions to water from point sources are larger than emissions to air. Wastewater treatment plants are the largest emission source to water. Some cadmium is also released to water during production and processing of paper and wood since cadmium is present in the wood raw material. Spain is the largest emitter of cadmium of the European countries, both to air and to water. The use as well as the emissions of cadmium have decreased over time, however cadmium may still be present in old products.
Effects on environment and health
Cadmium is harmful to the environment and may inhibit the plant’s growth by reducing the ability to produce chlorophyll (chlorosis) and cause reproductive disorders in terrestrial animals and birds.6 7 Organisms and processes in the soil may also be affected by cadmium.8
Non-smokers are primarily exposed to cadmium through food such as potato and crops.9 Cadmium affects the kidneys and may cause kidney failure. Other effects from long-term exposure include osteoporosis, increased risk of fractures and cancer .10 11
International agreements and regulations
Cadmium is regulated by the UN Convention on Long-range Transboundary Air Pollution (CLRTAP) and the EU Air Quality Directive (2008/50/EC), the EU Water Framework Directive (2000/60/EC), the EU Groundwater Directive (2006/118/EC), the EU Drinking Water Directive (98/83/EC), the EU Sewage Sludge Directive (86/278/EEC) and the EU Regulation on setting maximum levels for certain contaminants in foodstuffs (EC 1881/2006). Limit values for cadmium in drinking water is also regulated in the provision of the Swedish National Food Agency. 12 In addition, the presence of cadmium in products is regulated in different EU directives and regulations, such as REACH. The UN Protocol on PRTRs and the EU E-PRTR regulation regulate how data on cadmium emissions is made available.
6Scheumammer, 1987. The chronic toxicity of aluminium, cadmium, mercury, and lead in birds: A review. Environmental Pollution. 46(4): 263-295.
7Neathery & Miller, 1975. Metabolism and Toxicity of Cadmium, Mercury, and Lead in Animals: A Review. Journal of Dairy Science. 58(12): 1767-1781.
8Friberg et al. 1974. Cadmium in the environment.
11Friberg et al. 1974. Cadmium in the environment.