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Cadmium

cadmium and compounds of cadmium

SPRI Emission Reporting Threshold
1.00 Kg/yr Pollutant Emissions to Air
1.00 Kg/yr Pollutant Emissions to Water
1.00 Kg/yr Pollutant Emissions to Waste Water
5.00 Kg/yr Pollutant Emissions to Land
Disclaimer
This sheet is a generic summary, designed to give the reader a basic level of background information about the substance in question. Great care has been taken to represent as effectively and correctly as possible the broad range of (not necessarily consistent) information which is available from a variety of sources. The reader must accept therefore that this sheet has no legal status and cannot be relied upon in any legal proceedings. SEPA disclaims any responsibility or liability whatsoever for errors and omissions in this sheet.
What is it?
Pure cadmium is a soft silvery white metal, with a relatively low melting point for a metal (321 degrees celsius). In nature, it usually occurs in combination with other elements - particularly zinc, which has similar properties.
What is it used for?
Cadmium has a variety of uses: for corrosion-resistant metal plating, batteries (such as nickel-cadmium batteries), in pigments and plastic stabilisers, in bearings and in low-melting point alloys (mixtures of metals).
Where does it come from?
The biggest sources of cadmium into the environment are man-made: from metal processing (zinc, aluminium, iron and steel), from mine waters, from battery re-cycling plants, from coal and oil combustion in power plants and from phosphate fertiliser application. It is also found in trace amounts in cigarette smoke. Small amounts are released naturally from the earth's crust.
How might it affect the environment?
Cadmium affects the way in which plants produce food from sunlight (photosynthesis) and take up water (transpiration). It also affects the growth and reproduction of micro-organisms in soil and water and of larger organisms (such as fish) in water. Micro-organisms and molluscs also readily accumulate it to high levels, so it is easily concentrated in the food chain.
How might exposure to it affect human health?
The most significant exposure of humans to cadmium is from tobacco smoke. Otherwise, food can be contaminated with cadmium following deposition from the atmosphere or application of phosphate fertilisers. Cadmium is carcinogenic when inhaled at levels found in cigarette smoke for example. Experimental exposure has also been linked to birth defects and damage to the reproductive system. Long-term exposure could cause anaemia, kidney damage, loss of the sense of smell and staining of the teeth.
What steps are being taken to limit the potential impacts?
In the UK (including Scotland) releases of cadmium are controlled through legislation governing the regulation of dangerous substances in surface waters; the Pollution Prevention and Control (PPC) regulations; and it is a "red list" substance (highlighted as something whose presence in the environment is of particular concern). European Directives covering cadmium include those concerned with: pollution of the aquatic environment by dangerous substances (76/464); restriction on the marketing and use of certain dangerous substances (76/769); combating air pollution from industrial plants (84/360); and cadmium is also one of the eleven priority substances identified as requiring action under the proposed European Water Framework Directive. International leglisation covering releases of cadmium include the OSPAR convention for the protection of the marine environment of the north-east Atlantic; the UNECE Convention on long range transboundary air pollution; the Basel convention on the transboundary movements and disposal of hazardous wastes; and the Helsinki convention on protection of the marine environment of the Baltic sea.