Cadmium is a naturally occurring element, (chemical symbol Cd) present in rocks, soil, water, air, plants and animals.
Until recently the industrial use of cadmium was quite limited but now it has become an important metal with many uses. Cadmium is a component of rechargeable nickel-cadmium batteries; it is used in electroplating or galvanizing alloys for corrosion resistance and has uses as a pigment in some paints and plastics. Cadmium is also used in solders for welding, as a plastics stabiliser and in some special application alloys.
Cadmium in the environment
Cadmium is generally present in the environment at low levels; however human activity has greatly increased levels in environmental media relevant to human exposure.
Cadmium is typically found in with other metals, and is commercially produced as a by-product of zinc and lead smelting, which act as point sources of environmental contamination of the soil, air and water in the surrounding regions. Cadmium can be a contaminant of fertilizers and of sewage sludge. The widespread use of fertilizers and the use of municipal sewage sludge as a soil improver for agricultural and municipal soils can cause significant and widespread contamination of the environment.
How can cadmium affect my health?
Cadmium is not required for any normal bodily function.
Cadmium exerts toxic effects on the kidney, the skeletal system and the respiratory system and is classified as a human carcinogen.
The human body can only get rid of cadmium slowly and this can result in a build-up of cadmium in the body primarily in the kidneys and the liver.
How can I be exposed to cadmium?
Human exposure occurs mainly from the consumption of contaminated food, active and passive inhalation of tobacco smoke, and inhalation by workers in a range of industries. Skin contact is not a common way you can get exposed to cadmium.
Many plants, including food plants, readily accumulate cadmium from the soil. Shellfish accumulate relatively high levels of cadmium and animal liver and kidneys can have high levels of cadmium. To protect the community from the effects of cadmium contamination of the food supply, the Australia New Zealand Food Standards Code has established maximum limits on cadmium in commonly consumed food commodities (Standard 1.4.1 Contaminants and Natural Toxicants, Australia New Zealand Food Standards Code).
The tobacco plant naturally accumulates relatively high concentrations of cadmium from the soil in its leaves. Therefore, smoking tobacco is an important source of exposure and – in the case of heavy smokers – the daily intake may exceed that from food. Cigarette smoking can cause significant increases in the concentration of cadmium in the kidney, the main target organ for cadmium toxicity.
Occupations potentially at risk of cadmium exposure include those involved in the refining zinc and lead ores, iron production, cement manufacture and industries involving fossil fuel combustion, all of which can release airborne cadmium. Other occupations include the manufacture of paint pigments, cadmium-nickel batteries and electroplating.
Cadmium exposure from drinking ground water and ingestion of surface soils is relatively unimportant compared with exposure from the diet – with exceptions for localised point sources of cadmium contamination in the community. The Environment Protection Authority (EPA) can tell you where areas these are.
Reducing your exposure to cadmium
There are simple precautions you can take to reduce your exposure to cadmium:
- Stop smoking
- Try to avoid inhaling other people’s cigarette smoke.
- Eat a health balanced diet with only moderate amounts of shellfish and animal organ meats (offal).
- If your job or hobbies involve handling cadmium, always use appropriate personal protective equipment and consider having your cadmium levels checked regularly by your doctor.
Common alkaline batteries do not contain cadmium. However, nickel-cadmium rechargeable batteries used in mobile phones, cordless tools, laptop computers and digital cameras do contain cadmium. These batteries and equipment should be disposed of at appropriate waste disposal sites at the completion of their serviceable life. Your local council may have a battery recycling scheme – check the web site.
Been exposed, now what?
If you think that you have been exposed to high levels of cadmium, you should seek advice from your local doctor.
Your doctor may recommend you have a urine or blood test to measure cadmium levels in your body. Tests are also available to check the health of the kidneys and liver.
There is no specific treatment for cadmium poisoning, but supportive medical care may be required.
For further information on benzene, contact SA Health's Scientific Services on DLHealthPublicHealthServices@sa.gov.au.