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Dioxins and furans - as WHO TEQ

polychlorinated-p-dioxins (PCDDs) , polychlorinated dibenzofurans (PCDFs)

SPRI Emission Reporting Threshold
0.00001 Kg/yr Pollutant Emissions to Air
0.0001 Kg/yr Pollutant Emissions to Water
0.0001 Kg/yr Pollutant Emissions to Waste Water
0.0001 Kg/yr Pollutant Emissions to Land
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?
Dioxins and furans are families of complex chemicals containing chlorine. There are several hundred dioxin substances. They are crystalline solids which dissolve in organic (carbon-containing) solvents, fats and oils - but not in water.
What is it used for?
Other than for research and analytical purposes, dioxins and furans do not have any use and are not intentionally manufactured for other purposes.
Where does it come from?
Dioxins and furans are released as by-products from waste incineration, the burning of fuels (industrial, domestic and transport) the processing of metals and paper manufacture. Cigarette smoke also contains trace amounts. They are released naturally from forest fires and volcanoes.
How might it affect the environment?
On a local scale, air-borne (gaseous and particle-bound) dioxins are deposited at ground level. Livestock may then ingest them from soil or vegetation, as can fish from aquatic sediments. Wildlife experimentally exposed to dioxins experience reduced fertility, growth defects, immuno-suppression and cancer. Due to their low solubility in water, dioxins persist in the environment and concentrate through food chains - they are "persistent organic pollutants" (POPs). As well as having local impacts, dioxins can be transported thousands of kilometres from their emission because they can be deposited and then re-suspended into the atmosphere. There is a net transfer of dioxins from warm to cold polar regions.
How might exposure to it affect human health?
Dioxins and furans can enter the body either by inhalation of air containing dioxins and furans, ingestion of contaminated water or food, or by dermal contact. The health effects associated with dioxins and furans are dependent upon the composition of the mixture. Ingestion of dioxins and furans in contaminated food, primarily dairy produce, meat and fish, is the most significant route of exposure for humans. One of the major dioxins is 2,3,7,8 ¿ TCDD, and exposure to high levels of this compound can lead to adverse effects on the skin, including a condition called chloracne, skin rashes or discolouration, and excessive body hair. High levels may also give rise to changes in the blood and urine, liver damage or changes in hormonal levels. Other effects seen in individuals accidentally exposed to very high levels of dioxins or furans include vomiting, diarrhoea, lung infections and damage to the nervous and immune systems. Health effects associated with dioxins have, generally, only ever been reported in the event of extreme accidental or occupational exposure. The International Agency for Research on Cancer has designated 2,3,7,8 ¿ TCDD as a carcinogen, and a range of other dioxins and furans have been designated as being not classifiable as to their carcinogenicity to humans. However, exposure to dioxins and furans at normal background levels is unlikely to have any adverse effect on human health.
What steps are being taken to limit the potential impacts?
UK (including Scottish) releases of dioxin are controlled under the pollution prevention and control (PPC) regulations. In the future, they will also be controlled under the proposed new European Incineration Directive. The UK is also a signatory to the UNECE convention on long-range transboundary air pollutants (LRTAP) which includes a protocol to develop a legally binding global agreement to reduce risks to health and the environment posed by persistent organic pollutants (POPs) such as dioxins. Dioxins are also listed as "priority action" substances under the the convention for the protection of the marine environments of the north-east Atlantic (OSPAR) and of the Baltic sea (Helsinki).