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Re: TEQ

In article <Pine.GSO.4.05.9911020858400.26909-100000@Tubtim.cri.or.th>,
Sittisak Pui-ock (HS5DRL) <sittisak@tubtim.cri.or.th> writes
>Hi everybody,
>
>I have seen word like "TEQ" for unit of Dioxin, but really don't have an
>idea what it's about? Does anyone please explain to me that TEQ means?
>

(Taken from Dr Schecter's presentation 'Dioxin and Health,' Salem Public
Library April 13 1996  

Dr. Schecter explained the current use of dioxin toxic equivalents,
whereby each dioxin and furan isomer is assigned a toxicity rating as a
faction -1/10, 1/100, 1/1000, etc. - of the toxicity of most toxic
dioxin, 2,3,7,8-TCDD. For any given mixture or exposure, these fractions
are added together to estimate total toxicity as equivalent to
2,3,7,8-TCDD. This concept also originated from the Binghamton PCB fire
when the building was contaminated with a large number of dioxin and
dibenzofurans. At the time no-one has ever thought about those other
than TCDD, the famous dioxin from Agent Orange, Seveso, Love Canal and
Times Beach. “But we had a building which was mostly dibenzofurans, then
dioxins, then PCBs, said Dr. Schecter. “So experimentally some very
clever chemists and toxicologists at the New York State Health
Department dosed animals with the actual soot from the building and a
simulated mixture of known - purchased chemicals. They found that the
mechanism was the same: it killed the animals, it caused liver damage
and so on, but it varied in toxicity, and so the idea of dioxin toxic
equivalents came into being.”  


>Regards,
>Sittisak
>
>++++++++++++++++++++++++++++++++++++
>+  Sittisak  Pui-ock, HS5DRL       +
>+  Environmental Toxicology,       +
>+  Chulabhorn Research Institute   +
>+  Bangkok, Thailand 10210         +
>+  http://www.cri.or.th/~sittisak  +
>++++++++++++++++++++++++++++++++++++
>
>
>

**************************************************************** 
Ralph Ryder
Communities Against Toxics
PO Box 29
Ellesmere Port
Cheshire UK
CH66 3TX
Email ralph@tcpublications.freeserve.co.uk
Tel/Fax 0151 339 5473
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