Japan's TDI/"safe" dose; EU food analysis

[ttweed@wildrockies.org (Tony Tweedale)]

These European news reports that oversimplify the reporting of
concentrations of dioxins, furans & PCBs in possibly contaminated food,
such as the 22 June A.P. one that reported more contaminated foods have
recently been identified, make me (and others, I bet) wonder if there
aren't multiple sources of contamination all the time, some close to the
amount that "normally" works its way up the food chain, others a bit more,
some much higher.  Thus, analytical methods become more important, as does
the will to test our food supplies better (e.g., in the USA anyway,
pesticide residue testing is very inadequate, as are the analytical methods
used).  I do not believe current Eurpean preliminary screening for PCBs is
a safe method to determine safety from dioxin & furan cntamination, as many
sources of contmination of dioxins could easily not detect PCBs.  Plus,
there is no need to use high resolution GC/MS with isotope refinement for
purposes of screening dioxins/furans.  Sounds to me like a DELIBERATE
ATTEMPT (government & food corporations) TO AVOID THE MASSES BECOMING
SCARED, THEN EMPOWERED, BY KNOWLEDGE OF THEIR UNSAFE FOOD SUPPLY...
---

though others & I have recently addressed the TDI/ADI/MRL (all putative
safe dose methods), I am going to recap yet again the basic issue, because
I keep seeing these Japanese news posts that seem to indicate the
government there may be deliberatly avoiding the most valid of these doses,
US EPA's (or anyone else's, who uses the same data to input into their
model).  Certainly none of these posted articles have even listed, much
less discussed, EPA's 0.01 pg/kg/d acceptable dose.  Instead the articles,
perhaps reflecting the government's intent, always compare the safe level
Japan is thinking about adopting with various methods by various
organizations that happen to have acceptable doses that are 100 to a
thousand times higher.  This is crimminal (fraudulent and knowing) behavior
on the part of the goverment, IMO.  Generally, any valid study (that these
safe doses are directly based on) that finds an effect, or finds it a lower
doses, is more valid than one, a dozen, a hundred, etc. studies that find
no effect, or effect at higher dose.  Proving a positive may take many
iterations, but provong a negative will always be a logocal impossibility.
In short, so long as the data and assumptions in US EPA's safe dose are
accepted, you should throw all other estimates into the trash (as far as
using them for policy decisions, anyway).

Now, is even 0.01 pg/kg/d safe? (note: this is a irrelevant question for
the moment, as every person's intake is circa a hundred to a few hundred
times higher than this dose).

While it is certainly possible that antagonistic effects from other
exposures or natural biologic chemicals; or from  unknown/unquantified
mechanisms in the body (e.g. that cause a threshold exposure to be needed
before the effect results) can detoxify or get rid of dioxins; there is a
BOAT LOAD of evidence showing that these chemicals are very dangerous at
low doses, after all.

So, can governments say that 0.01 pg/kg/d is safe? How can they, when:

1) there are other chemicals we take in, with the same specific mechanism
of action, that are not included in this safe dose (risk) estimate.  E.g.,
the brominated analogues to the dioxins and furans are soemwhat prevalent,
but I don't believe they are often picked-up in analysis, or considered in
risk assessments (safe dose determinations).  But I believe many other
ubiquitous chemicals bind to the aryl hydrocarbon receptor (named for
ringed hydrocarbons--of which there are thousands of man-made chemicals);
and it seems plausible that many would engage in a similar several step
process that ends up in 2,3,7,8-TCDD's glomming on to DNA, from where it
presumably messes up the expression, by DNA, of proteins (built-up from the
image contained in gene of DNA) that keep us alive and functioning.

2) there are other, serious, health effects caused by the same chemicals
that the safe dose is based on, whose risk is not assessed.  E.g., various
reproductive effects are evident in controlled experiments at even lower
doses than the 0.01 pg/kg/d safe dose is based on (it's based on a dose
that cause cancer in rats, divided by "safety" factors of 10, 100 or 1,000
times, that are magically supposed to absorb all these unknown risks I'm
summarizing herein.  How can a risk of unknown magnitude be taken care of
by a finite (and not very large) number (factor)?!?  In the uncontrolled
experiment that is the world, the evidence is accumulating that the lab
animal effects are happening in humans and other species.  Though such
epidemiologic evidence is often criticized as insufficient to determine
risks, due to not knowing what doses people were exposed to; and due to not
controlling other variables that can mask, offset or otherwise interfere w/
the cause-effect being looked for; many opportunities exist and are used to
account for such problems, and the accumulation of epidemologic evidence
can prove that an effect does, after all, occur in actual people living in
the world.

3) there may also be additional risk from the same chemicals whose cancer
risk has been sassessed, but which are known to cause alterations in
various body systems, which may or may not be detrimental.  E.g., it is
hard to imagine the downregulation of the immune system that these
chemicals cause (indications are, at even lower doses than that estimated
to cause cancer) is of no consequence.

4) Just as there may be antagonstic effects that off-set bad effects, there
may be synnergistic effects that multiply the bad effect of a given dose.
Both phenomenon have been observed in some experiments.

Always recall that we are in delicate but dynamic homeostasis, with more
than 100,000 reactions/cell/second.  And from conception to 18 or so years
of age, your chromosones are incredebly active, directing millions of
changes with subtle biochemistry.  It's far more vulnerable than just
100,000 Rx/cell/sec.  Hormones, which dioxins and many other chemicals
mimic or interfere with, are used for many of these body functions, many of
which are critical (sexual differentiation & function, metabolism, the
development of the brain, etc.), and many of which seem to operate at
amazingly low doses.  But non-hormone biochemistry (as always, directed by
genes, themselves, a subtle, delicate biochemical system) may operate at
similar low levels and in simialr delicate balance.  Who is to say whether
dioxins or any other chemical [especially if it bioaccumulates/magnifies
and is stable (refractory, persistant) in the environment and in the body],
does not upset life's delicate, complex & dynamic homeostasis?
Governments?  Legally unaccountable corporations w/ a massive conflict of
economic interests as to these chemicals?  The press and media? Or you?

Tony Tweedale

Causality is a concept not subject to empirical demonstration. -David Hume
(1711-'76)

Temperate but endangered planet.  Enjoys weather, northern lights,
continental drift.  Seeks caring relationship with intelligent life form.
      -Friends of the Earth