Posted on 12/23/2004 9:15:54 AM PST by bruinbirdman
Dioxin has gained media attention since Ukrainian presidential candidate Viktor Yuschchenko was poisoned with the chemical. Alarmists refer to it as “the most deadly chemical known,” but such is not the case, says Michael Fumento of the Hudson Institute.
Dioxin is a byproduct of certain industrial processes such as incineration and bleaching. Humans carry small amounts of dioxin in their fat and blood, but the myth of “deadly dioxin” began with an experiment with guinea pigs, who were fed 1,000 times as much before they died.
Even though large amounts killed guinea pigs, the facts are:
Viktor Yuschchenko may not look that great for awhile, says Fumento, but he could have had it worse -- such as death by a few drops of strychnine or even a teaspoon of iron.
Source: Michael Fumento, “Viktory Over Alarmism,” Tech Central Station, December 16, 2004.
For more on Chemicals and Health Risks
As much as I like Michael Fumento, I have to point out that this statement is erroneous. The skin disease, chloracne, as well as other toxic effects, is brought about by ingestion of large quantities of dioxin (2,3,7,8-TCDD). TCDD's toxic effects are mediated through a single receptor, which interacts with nuclear DNA and causes up and down regulation of the expression of several genes. It is the inappropriate regulation of these genes that (eventually) leads to the symptoms of TCDD toxicity, including chloracne.
If a large enough dose of TCDD could be absorbed through the skin, it would cause the same symptoms as ingested TCDD--the effect is systemic, not topical.
(I earned my Ph.D. by researching how TCDD affects gene regulation.)
Cool backgrounder. Thank you.
Operative words, "large enough dose". What is a "large enough dose?"
yitbos
I remember back about the time Times Beach was fresh in the news, some guy was claiming dioxin was not very toxic and to prove his point drank a whole glass of the stuff. Was this guy nuts? Do you think he's still alive?
What is a "large enough dose?"
That is contingent on whether you are long or short on Ah, the receptor.
Sounds like what I kept saying.
Good for you, now exactly what stability exists for TCDD and how does that implicate the 400+ chemical compounds now included in the class, dioxin?
Are you sure you're not confusing this guy with Gordon Edwards who regularly drank a glass of DDT?
For it to get somehow mixed with cooking oil is a blunder worthy of the blind cook who baked a cake using only baking powder, water and eggs.
The short answer is, we don't really know. The dose would be several micrograms of TCDD per kilogram body weight (ug/kg), and there is reason to think, based on species homology of the dioxin receptor (the AhR), that we are somewhere between guinea pigs (lethal dose 50(LD50) is 0.6-2 ug/kg) and hamsters (LD50 = 1000-5000 ug/kg) in susceptibility. We don't know the human LD50.
Yeah, it would be nutty to drink dioxin. Difficult, too. It's not water soluble, for one thing. That rash is pretty nasty, for another.
I think the Italians you read about were exposed to TCDD; there was an industrial accident in July 1976 where over a kilogram of TCDD contaminated more than 200,000 people, mostly in Seveso, Italy. None of these people died from the TCDD, but EVERY animal in the area died or had to be put down.
First of all, I should have addressed reply #16 to you, too.
Dioxin is more or less a generic term; those of us in the field (or who have recently left it, like I did) use the term TCDD to mean the 2,3,7,8-tetrachloro molecule that is the most potent of these molecules. Not all dioxins are toxic; mostly the toxic ones are the ones with chlorine substitutions around the benzene rings. Even these have varying levels of toxicity. Other substitutions are possible besides chlorine, and these are generally less toxic or non-toxic.
As for the stability of these compounds, it is more or less proportional to their toxicity. Some chlorinated dioxins are susceptible to lysis by various microorganisms, and thus have a reduced stability. Because of the placement of the chlorines, TCDD is resistant to biological destruction. It has a half-life in the human body of ~7 years. It is destroyed by UV light, but tends to stick to dust and dirt particles that shield it from sunlight, so that in the environment, it has a half-life of 10 to 12 years. There are situations where chlorinated dioxins have apparently been stable for millenia, for instance, in clays that have been submerged in salt water at some time in the geologic past.
"None of these people died from the TCDD, but EVERY animal in the area died or had to be put down."
Interesting.
And thanks for the rest of your post as well. Very informative.
One of the reasons I love Free Republic is because so many of the posters are so smart and it seems like there is nearly always someone who has experience or education about the topic at hand.
Transformer explosions using ordinary mineral oils as insulating coolants caused so many fires that a deliberate re-design of the coolant oils led to compounding of PCBs; this cut down on the resultant fires to a level of incidental risk while the hue and cry from the toxicity and potential carcinogenity of the compound was only made to seem like an imminent threat based on laboratory studies of the type Bruce Ames rejected and regretted having introduced into the field of analysis to no avail and to his eventual shame and professional disapprobation and finally, virtual ostracism.
The simple fact remains that other than sloppy handling of the raw compounds or the unwise application prior to case study implication, these compounds present no clear and present danger to the public at large and, in my opinion, are undeserving of the reputation they have gained.
Unlike the iconic Nobel who redeemed his conscience at the expense of his fortune, not many modern scientists seem willing or able to make sufficient apology from the grave.
I think the notion that every animal died or had to be put down is a regressive analysis of the situation the authorities were faced with, more likely the politically correct means of damage control led to the wholesale euthanization of a large number of the domestic breeds and livestock.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.