🚀 go-pugleaf

In article <60cf2j$ipe@lynx.dac.neu.edu>,
Michael Kagalenko <mkagalen@lynx.dac.neu.edu> wrote:
>John B. Hines (jhines@enteract.com) wrote in article <342a7646.207312379@news.enteract.com> 
>]
>]Of far more concern, Plutonium is highly toxic, you'll die from
>]poisoning long before the radiation gets you.
>
> Plutonium is less chemically toxic then caffeine or tetracycline 
> hydrocloride (common medicine)

Something akin to arguing the "chemical toxicity" of a car making a bee-line
toward your head, is less than -- say -- that of milk. ;-)
Some would argue it's the "total dangerousness" that counts and -- anyway --
where's your cite on the measurement of the "chemical toxicity" of Pu?
(Do they feed a few milligrams to a rabbit and then see if it dies within
a few hours? Ignoring that it (say) dies from the effects of a massive
intrusive tumor within a few months?).

For a reputable authority -- e.g. Sax -- and not just uncited
factiods from the top of someone's head, I shall quote (yet again) 
things posted over the past few years when the topic of Pu toxicity comes up. 

Needless to say there are MANY provisos wrt toxicity (e.g. at what 
level we're specifying lethality -- 50% of those subjects exposed, 
10% of subjects exposed; whether human or small rodent; how ingested 
and under what conditions, etc, etc). But -- regardless -- for
someone to indicate that (e.g.) caffeine is "somehow" more toxic 
than Pu is at the very least misleading and (more likely) simply
citing propaganda. 

The highlights of the sequel (given anyone is too bothered to read 
through them) are:

	The LD50 for Pu is 50 microgram TOTAL (no matter how 
	ingested); 
	Sarin (GB nerve gas) LD50 (human/dermal) is 28 MILLI gram per 
	KILOGRAM bodyweight; 
	(The V agents are supposed to be 10 to 100 times "better");
	Prussic acid (aka "cyanide") is (human/inhalation) LD{minimum} 120 MILLI grams per KG 
	bodyweight. (*)

I.e. the lethality of of Pu where at least 50% of the subjects exposed
died from its associated effects (eventually) is at least 1000 times 
"greater" than GB nerve gas (presuming a human weighs => 2 kg -- a "safe" 
bet) -- the latter generally regarded as "damn well good enough" for 
casual military use in the indiscriminate mass-killing sphere.

Any substance with an LD50 less than 500 mg/kg is regarded as HIGHLY TOXIC.
Hence caffeine ALSO is "highly toxic", viz:
	LD50 (oral-rat)     192 mg/kg
		  (iv rat)      105
(which may come as a surprise to people that suck down chock-covered
coffee beans like they're going out of fashion -- each one of which gives
you a 10-50 mg jolt; but let's NOT talk about the average US consumption of 
several L of cola's per day).

We therefore find the ratio of CITED lethalities of Pu to caffeine is 
around 147,000 times (in "favour" of Pu) extrapolating to a typical 
70 kg human. (Of course, by denying that cancer is a cause of death,
you can make your mileage vary, here).

Finally -- for the possible hair-splitters -- how do high-energy particles 
manifest their effects on (say) biological materials?  
Yes, that's right, primarily via _chemical_ means (breaking bonds).


(*) From Sax et al "Dangerousness of Industrial Materials" (5th ed).


=== various other things regarding Pu vis a vis nasty poisons or
   Pu vis a vis other radio nuclides (references cited) ===

I shall repeat similar tables here as an indication of how dangerous
Pu might be regarded by non-quacks (as appearing in Sax, op cit).  The
limits below are those set for continuous exposure for a working lifetime
(40 h per wk) for occupational levels, and over a lifetime for
non-occup'l levels. While levels are not sacrosanct, if they are
exceeded by 100s of times the values cited it is recommended
(e.g. by the ICRP) that "immediate action is desirable" but it is not
expected any individual will suffer radiation damage as a result if
exposure is continued for 1 or 2 days.


        Occupat'l           Outside "restricted areas"
        air          water        air           water
        (microCi/ml)

238Pu   2e-12        1e-4         7e-14         5e-6
        3e-11        8e-4         1e-12         3e-5
239Pu   2e-12        1e-4         6e-14         5e-6
        4e-11        8e-4         1e-12         3e-5
240Pu   2e-12        1e-4         6e-14         5e-6
        4e-11        8e-4         1e-12         3e-5
241Pu   9e-11        7e-3         3e-12         2e-4
        4e-8         4e-2         1e-9          1e-3
242Pu   2e-12        1e-4         6e-14         5e-6
        4e-11        9e-4         1e-12         3e-5
243Pu   2e-8         1e-2         6e-8          3e-4
        2e-8         1e-2         8e-8          3e-4
244Pu   2e-12        1e-4         6e-14         4e-6
        3e-11        3e-4         1e-12         1e-5

(The upper line of each pair represents the contaminant in "soluble"
form; the lower is for "insoluble").

And, just for devilment,

228Th   9e-12         2e-4        3e-13         7e-6
        6e-11         4e-4        2e-13         1e-5
230Th   2e-11         5e-5        8e-14         2e-5
        1e-11         9e-4        3e-13         3e-5
232Th   3e-11         5e-5        1e-12         2e-6
        3e-11         1e-3        1e-12         4e-5
(nat)Th 3e-11         3e-5        1e-12         1e-6
        3e-11         3e-4        1e-12         1e-5
324Th   6e-8          5e-4        2e-9          2e-5
        3e-8          5e-4        1e-9          2e-5

And, just for comparison,

220Rn   3e-7            -          1e-8          -
222Rn   1e-7            -          3e-9          -


Such exposure levels implicitly take into account the affect of uptake
of material by the human body by inhalation and ingestion.  I.e. if we
say that the above limits can be exceeded 100 times before some effect
is observable over human lifetimes then we are saying, e.g., if air is
breathed that contains more than 7e-12 microCi per mil of Pu238/9
(i.e. the "civilian" number above) then it will have some effect via
whatever vector is appropriate.

We note elsewhere (i.e. Sax):

  Plutonium:
  ...
  Acute tox data: Permissible body burden = 0.6 microgram;
  permissible lung burden = 0.25 microgram. Chemical toxicity
  is trivial compared to radiation effects. LD [Lethal Dose -- look
  up def'n for yourself] is calculated at 50 microgram. HIGH carc [carcinogen]
  and leuemogen.
  THR = The permissible levels for plutonium are the lowest for any
		 ===========================================================
  of the radioactive elements. This is occasioned by the conc [concentration]
		 ===========================================================
  of plutonium directly on bone surfaces, rather than the more uniform bone
		 ===========================================================
  distribution shown by other heavy elements. This increases the possibility
		 ===========================================================
  of damage from equivalent activities of plutonium and has led to the
		 ===========================================================
  adoption of the extremely low permissible levels given.
		 ===========================================================

Interestingly this compares with "toxicological" data for other agents
such as GB (Sarin nerve gas) or prussic acid (again, from Sax):

  Prussic acid ("cyanide"):
    inhal LC_LO     (human) 120 mg/kg for 1 hr
    inhal LC_LO     (human) 200 for 10 min
    i.v. LD_LO (human)        1 
    inhal LC50 (rat)        544 ppm for 5 min
    oral LD50 (mouse)       3.7 mg/kg
    ip LD50 (mouse)         3
    im LD50 (rabbit)        1.1

  Sarin (GB nerve gas):
    dermal LD50 (human)     28 mg/kg
    LD50 (human)            70
    dermal TD_LO            .1
    oral LD50 (rat)         .55
    iv LD50 (rat)           .05
    dermal LD50 (rabbit)    .925

Generally a substance with LD of less than 500 mg/kg is regarded
officially as HIGHLY TOXIC. A substance with doses greater or equal
15,000 mg/kg is regarded as having NO toxic effect.

Which category does Pu ostensibly fit into?

Alternatively, apply the same "not dangerousness" logic to nerve gas or
prussic acid.
Elsewhere some argue that "X is not dangerous because it is rare" --
somewhat confusing the notions of "risk" and "danger" -- would that
make Sarin or tigers "non-dangerous" in Australia?

===

My evidence for the claim that "Pu limits are less than other rad 
nuclides" include:

(1) Dangerous Properties of Ind'l Materials (5th ed)
   where Sax et al indicate
   (a) permissible body burden = .6 microgram
   (b) permissible lung burden = .25 microgram
   (c) lethal dose 50 microgram
   (d) "The permissible levels for plutonium are the lowest
   for any of the radioactive elements" (p 919).

(2) "Radiation Protection (Improvement of practical countermeasures:
the agricultural environment post-Chernobyl) EC pub # 12554EN, 1991.

Table 4.1.37 p 145:

Max permitted rad levels for foodstuffs and feeding stuffs Bq/kg in
different foodstuffs:
Nuclide         Baby food   Dairy    Other food  Liquid food Feeding stuffs

Isotopes
of Sr,                75       125       750         125       no max 
notably Sr90                                                   laid down

Isotopes of          150       500      2000         500       "
I, notably I131

Alpha emitters         1        20        80          20       "
of Pu and trans-Pu
notably Pu239 and Am241

All other rad nuc    400      1000      1250        1000       pigs 1250
with t_1/2 > 10 days                                            poultry, 
notably Cs134 and Cs137                                        lambs, calves
                                                               2500
                                                               others 5000

Hence the relevant permissible levels of isotopes of "Pu and Am" are between 
1 and 10% of their nearest "competitor" -- Sr90 et al. We would regard that
as some evidence that Pu/Am are regarded as around 10 times more
"dangerous" than other radio nuclides.

===