[Dioxin-l] "Acceptable Daily Intake" and Dioxins

[david bell]

I found this comment interesting, mainly because of the implications for 
policy. I take the view that it is essential to decrease the levels of 
dioxin, and that there are significant costs associated with this policy.

><snip>I want to be clear that it is my perspective that there is
>insufficient information about the processes of human conception,
>gestation, and maturation and the routes and mechanisms of action
>of dioxin during these processes to establish an acceptable daily
>intake for dioxins and dioxin-like chemicals.  And, until such
>knowledge is sufficiently complete,  the only rational course is to
>establish an acceptable daily intake of zero.

It is the last sentence that is interesting; the only acceptable intake is 
zero. I find it difficult to support because:
1) it is impossible to measure 'zero' dioxin. The EPA acceptable daily limit 
of 0.01 pg/kg is about a million molecules of dioxin per kilo body weight. 
As far as I understand, the current method "1613" of the EPA cannot detect 
as low as this- but I would welcome someone more knowledgeable correcting 
me. There certainly is no routine way to detect a million times lower than 
this, and so the wish for 'zero' dioxin rings hollow.

2) The issue of natural production of dioxin has its reverberations here. 
There is some natural production of chlorinated dioxins through natural 
fires, lightning strikes, whatever the level may be- it may be 10x, or 100x 
lower than current levels- but it is there.

3) I guess the final issue is pragmatic- how would you do it ? Even if you 
could wave a magic wand and stop all 'industrial' production of dioxins, the 
amount of dioxin in the environment is huge- compared with zero ! I cannot 
think of any practical measure for establishing zero intake of dioxin- 
although I welcome suggestions.


The reason I find it an interesting issue to discuss is the policy 
implications that spring from it. If you ask for something which is not 
realistic, it may impair your chances of getting something good.

I suspect that a similar issue arises with the EPA dioxin limit of 0.01 
pg/kg for dioxin; this level is so low, compared with current intake levels 
of approx 1pg/kg, that it simply cannot be reached. To enforce it, you would 
have to ban all meat, fish and dairy products- which would have unfortunate 
consequences. EPA cannot support a ban on everything, and so it has to 
completely ignore the TDI for dioxin- hence its stand on incinerators. 
Perhaps a more realistic level would have more chance of being implemented ?


>[The following is excerpted from the report: Costner, P., 1999.
>Dioxin Elimination:  A Global Imperative,” Amsterdam:
>Greenpeace International. (The citations, which have been removed
>for inclusion in the body of this email message, are available in the
>report).]

I would be really interested in seeing the references, because the issue is 
important. Is there an electronic version of this report, or is there some 
way to get hold of it  ?

many thanks
david bell



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