What type of substance is it?
Chromium is a naturally occuring metal which has a steel-grey colour when pure. It is a hard metal which has important application in the production of steel. There are many different chromium containing compounds, some of which are toxic. Chromium and its compounds may cause cancer and genetic damage. The Environment Agency aims to ensure that there is no appreciable risk of these effects from environmental exposures.
How is it released?
The major sources of release are coal-fired power stations and iron and steel producers. A smaller but significant source is glass manufacture. Since chromium is also a naturally occurring element in the earth's crust it is also present in rocks, soils, sediments and some natural waters at low levels.
Detailed information
Scientific name:
Chromium, Cr
Other names:
Chrome, chromium element
CAS Number:
7440-47-3
The principal ore from which chromium is extracted is chromite. Chromium has three main valence forms - metallic chromium (0), chromium (III) and chromium (VI). Chromium (III) or trivalent chromium occurs naturally in the environment and is an essential dietary nutrient. Chromium (0) and chromium (VI) or hexavalent chromium are produced by industrial processes.
The major use of the element chromium is as an essential alloy in stainless steel. Chromium is also used to form many useful high performance alloys, for example for high temperature parts of jet engines. Chromium compounds are used for making bricks in furnaces, as dyes and pigments, for chrome plating, in leather tanning and wood preserving.
Chromium is an odourless, hard, steel-grey coloured metal that takes a high polish. It melts at about 1860 degrees Celsius. The principal ore is chromite, which is found in Zimbabwe, Russia, South Africa, Turkey and Iran. All compounds of chromium are coloured.
Where is it released?
In general, the largest man-made sources of chromium emissions to the environment are chemical manufacturing, the combustion of fossil fuels, waste incineration and steel making. A significant but smaller source is glass production. Emissions have declined steadily since 1970. Since chromium is also a naturally occurring element in the earth's crust it is also naturally present in the environment at low levels, found in rocks, soils, plants and animals in trace quantities.
Local environmental effects
Some chromium compounds will be toxic to certain wildlife species although toxicity will depend on the level of exposure. In terms of local environmental impacts, certain aquatic species bioaccumulate chromium although fish do not appear to do so. Chromium (VI) compounds are more toxic and are readily absorbed by biological systems whereas Chromium (III) compounds are less toxic and are not readily absorbed by living species.
Global environmental effects
No significant global impacts are considered likely.
Possible health concerns
Chromium and its compounds may cause cancer and genetic damage. The Environment Agency aims to ensure that there is no appreciable risk of these effects from environmental exposures. Excessive exposure may affect the digestive system, kidney, liver, lung, nose, skin and the unborn child. The Environment Agency aims to ensure that environmental exposures are too low to cause such effects.
Legislation
Why was this substance selected for the Pollution Inventory?
For releases to air included in : European Pollutant Emission Register (EPER) reporting requirements; Heavy metals of Agency concern & included under Annex 1 of the European Union IPPC Directive. For releases to water included in : European Pollutant Emission Register (EPER) reporting requirements.
Standard risk phrases for the pure substance
The standard risk phrases provided here are generally those used by suppliers of chemicals to describe substances - for example on packaging materials. The most important source of these phrases are the CHIP Regulations - Chemicals (Hazard Information and Packaging for Supply) - provided by the Health and Safety Executive. Some substances do not have CHIP risk phrases and in these circumstances we have used other risk phrases, the sources of which are indicated.
Because this is a large family of chemicals rather than a single substance, it is not possible to provide risk phrases, which are generally provided for a single substance whose properties can be precisely determined.
Controlling legislation and international agreements
The UK legislation controlling releases of chromium, implementing the EC Directives, are the Surface Waters (Dangerous Substances) (Classification) Regulations, 1997 (SI 1997/2560) and PPC (Pollution Prevention and Control) Regulations. At a European level, EC Directive 76/464 'Pollution of the aquatic environment by dangerous substances (plus daughter directives)' covers the release of chromium into aquatic environments. At an international level, the release of chromium is covered by the OSPAR Convention for the protection of the marine environment of the North East Atlantic
These factsheets have been compiled to provide users with information on the Pollution Inventory substances and represent our best efforts to summarise a large number of disparate and sometimes conflicting data sources. We emphasise that this information describes potential hazards rather than actual effects and that the Environment Agency seeks to regulate releases to minimise emissions and hence any risk of detrimental effects occurring.
