[Dioxin-l] "normal background level"

[superjicb]

David,

I daresay that you are unlikely to find anyone on this board that does not
support sound science.  I consider it pure dribble that you even ask me this
question.  I recognize this question as a much over-used tactic to ignore
science and logic by the person who asks it, when they find themselves faced
with something they don't want to hear.  Move on.  Share sound science,
instead of sharing the obvious notion that science should be sound.  Also
remember that because we are discussing science, that these issues are not
always black and white.  Think of your school days when you learned about
hypothesis, theories, proofs and facts. I think that we would all agree that
it is a fact that dioxin is a deadly toxin.  I think that we would all agree
that it is a fact that under certain conditions dioxin is created in
incineration.  I believe I could easily name a level of dioxin that none of
us would be willing to ingest for any advantage, be it cheaper car panels,
or a higher paycheck.   What is in contention is how much dioxin we believe
we can ingest over time before it kills us, and how much we are willing to
risk that we've picked the correct number.   The complication comes in
because our willingness to take on risk is always balanced by expected
rewards.  Environmental advocates see little reward to taking on the risk,
and can be expected to err on the side of caution.  Industries that make
mega bucks off of products that contribute to dioxin can be expected to err
on the side of risk.

> it rapidly became impossible to state
> that the hole was a fabrication or, that CFCs were not plausibly involved.
> This was the basis for incredibly convincing argument.

Glad to see that you are not outright denying that there was a period that
some groups pooh-poohed the need to move away from CFCs. I was there to read
the published reports and they became so strong that at one point I remember
wondering if the issue would go away.  Part of my point was that industry,
scientists and environmental groups all had reason to support CFC
elimination.  When most everyone's motives are in accord, things get done.

> I think you are right about some of the practical problems which you
raised
> about the difficulties of reducing dioxin emission, but for my money, I
> would point out to you that there is considerable lack of consensus about
> the 'safe' level for dioxin. For example, Canada and the UK have an
> Tolerable Daily Intake (for TCDD) 1000 fold bigger than in the US; the WHO
> limit is 100-400 x bigger than the US TDI. The point I am making (without
> taking sides !!) is that there is no clear scientific consensus.

Thank you for acknowledging this distinction.  I'll put my money towards
erring on the side of caution.

> Given the recent postings about production of dioxins from uncontrolled
> burning, it may well be that the level of dioxin in the 1800s largely
> stemmed from the incineration that the local populace undertook. It
clearly
> wasn't the chemical industry.

Why is it clear chemicals were not implicated?

Connie