Originally posted by ipsedixit
Here in tabular form, Chemistry Figure 1, is the USGS breakdown of what was found in the dust from the WTC.
The methodologies used to arrive at these findings are explained at the following link. Suffice it to say that a number of dust samples from different parts of ground zero and from other locations in lower Manhattan were were gathered to arrive at an overall representative sample of the WTC dust.
On the evenings of September 17 and 18, the field crew collected samples of dust and airfall debris deposits from 33 outdoor locations within a 1-kilometer radius of the WTC; this sampling occurred after a major rainstorm on September 14. Two samples of indoor dust deposits unaffected by rainfall, and two samples of material coating a steel beam in the WTC debris close to Ground Zero were also collected.
One of the interesting things about this list and other more detailed expositions of what was found in the dust of the WTC, issued by the USGS, is that they are not exhaustive and complete.
Don't get me wrong. They went a country mile for America in publishing what they did publish.
However, they themselves acknowledge that their study is not the whole story. (All emphases in the following are mine.)
The trace metal compositions of the dust and girder coatings likely reflect contributions of material from a wide variety of sources. Possibilities include metals that might be found as pigments in paints (such as titanium, molybdenum, lead, and iron), or metals that occur as traces in, or as major components of, wallboard, concrete, aggregate, copper piping, electrical wiring, and computer equipment. Further detailed SEM studies of dust and beam coating samples are needed to develop a better understanding of the residences of metals in the samples. A detailed review of the materials used in construction, and the elemental composition of materials commonly found in office buildings would also be useful to understand more completely the potential sources and compositions of the materials in the dusts.
Let us take one of the elements from Chemistry Figure 1, above and do our best, as laymen, to come to a better understanding of what the table is or is not telling us about the element in question.
Let's look at the element Uranium.
The first thing to note about it, on the list in the table, is that the exact isotope or, nuclide, of uranium found in the WTC dust is not given.
What are isotopes and nuclides? They are basically different names for the same thing. A good explanation is given on the following Wikipedia page.
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation of the atom as a particular element. . . .
A nuclide is an atom with a specific number of protons and neutrons in the nucleus, for example carbon-13 with 6 protons and 7 neutrons. The nuclide concept (referring to individual nuclear species) emphasizes nuclear properties over chemical properties, while the isotope concept (grouping all atoms of each element) emphasizes chemical over nuclear.
In very basic terms an element like uranium can have several isotopes or nuclides and still be considered uranium.
There are three, naturally occurring nuclides of uranium. They are listed in this useful article on uranium from Wikipedia.
In nature, uranium is found as uranium-238 (99.2742%), uranium-235 (0.7204%), and a very small amount of uranium-234 (0.0054%).
The average person, knowing this, would say to himself,
"Well, they must have found Uranium 238 in the WTC dust, since that is by far the most common naturally occurring nuclide of uranium. There is a 99.2742% chance that they found U238. Hey, they might have found all three nuclides in naturally occurring amounts."
That takes us back to the table. How much uranium did they find in the dust?
The table is a little hard to read, but it would appear that uranium was found in the WTC dust in an amount between 7 and 10 parts per million (ppm). One commentator I read on the web put the figure at 7.75 ppm. He represents himself as a nuclear physicist, but since I am a layperson, I'm going to err on the side of caution and use the figure 7 ppm of uranium found in the WTC dust by the USGS study.
7ppm. Is that natural? Does everything contain 7ppm of uranium?
The short answer is no.
Antiques can be a source of small amounts of radiation because they were manufactured before the hazards of radioactive materials were well understood.
These figures are so called "vaseline" glass, which contain uranium as a colorant and glow a yellowy green under black light.
Although uranium can be found almost everywhere in trace amounts, even in our bodies, the amounts for naturally occurring environmental uranium are significantly below 7ppm and more in the range of 1 to 3 or 4 ppm or even lower ppm.
Here is a list of some common building materials and their naturally occurring amounts of uranium, thorium and potassium in parts per million (ppm) and also in amounts of radiation released per gram.
It is the amount of uranium in parts per million, in which we are interested.
If you put a million "parts" of each one of these materials into a blender and then checked the blended mixture to see how many ppm of uranium were present, in the mixture, it should equal the total number of ppm in the table, divided by the number of materials in the table, as follows:
total ppm of uranium in mixed materials / number of materials = ppm of uranium in mixture
Total ppm in mixed materials (35.65), divided by number of materials (10) equals ppm of uranium in mixture (3.565).
If the dust of the WTC were composed of these ten building materials and if, as the USGS says, the WTC dust contained 7 ppm of uranium, then we could say that there is almost exactly twice as much uranium in the WTC dust as there should be.
At that point we could legitimately, and with serious concern, ask,
"Where did the extra uranium come from?"
Did it come from depleted uranium shaped charges for example?
We know that uranium exists in trace amounts in the environment and in building materials and human bodies, but the trace amounts are much less than 7 ppm.
Where did the extra uranium come from?
But of course the number crunching above is based on an artificial situation. In reality there would be more of some materials than others in the mix and this would alter the ppm of uranium present.
Let's look at the table again.
Clay brick, at 8.2 ppm and "By-product" gypsum, at 13.7 ppm, if present in sufficient quantities might act to boost the ppm of uranium in the mixture of building materials up to 7ppm.
That situation would serve to account for the USGS findings in a way that implied no unusual circumstances at all with regard to the presence of uranium.
Was there a lot of clay brick in the WTC, or rather, I should ask, was there clay brick in the WTC in sufficient quantities to overwhelm the volume of concrete and other building materials plus other environmental sources of uranium, as the predominent factor determining the amount of uranium in the WTC dust?
I think not. I think there was little clay brick in the WTC. Undoubtely some, but my guess would be that clay brick usage in the WTC was very small, practically negligible, when compared to other materials to be found there.
Consequently, clay brick probably had almost no effect on the ppm figure for uranium in the WTC dust, as determmined by the USGS.
What about "By-product Gypsum" (at 13.7 ppm) and what the heck is by-product gypsum anyway, and, most important of all, was it used extensively in the WTC, . . . enough to make a significant difference in the ppm total for uranium?
It turns out that those questions lead to an interesting little niche of information that is not well known by the general public.
In our table of building materials, above, there is listed "Dry wallboard" (1.0 ppm uranium), "By-product gypsum" (13.7 ppm uranium) and "Natural gypsum" (1.1 ppm uranium).
Most people are quite familiar with "Dry wallboard". Basically it consists of sheets of what looks like plaster sandwiched between layers of paper. It is a substitute for lath and plaster construction in the finishing of interior walls in houses and is screwed into sheet metal (formerly wooden) "studs" to create the wall surfaces of rooms. The hardened substance in the middle of the paper is gypsum.
I haven't consulted experts but I am assuming that "Natural gypsum" is the powdered form of dry wall gypsum. This would be used to make old fashioned "plaster of paris" and other materials applied with trowels or poured into molds.
"By-product gypsum" is the most interesting of the three.
Gypsum produced as a byproduct of the flue-gas desulfurization process at electric power plants provides an economical, environmentally sound raw material for making high-quality gypsum board.
In other words "by-product gypsum" comes out of the smoke stacks of coal fired power plants.
The relatively (within the terms we are discussing) high quantity of uranium found in it (13.7 ppm) originates in the coal. (See link below.)
Now we know what "by-product gypsum" is and we know that it is used to make wallboard. Surely, there was a lot of wall board in the WTC?
Some people might say no. The WTC was mostly "open concept" office space with few partitions and consequently not much wallboard, certainly less per square foot of floor space than the average bungalow.
Others might say, "You're wrong. There were gypsum containing ceiling tiles, a significant amount of gypsum wallboard for interior rooms and a massive amount of gypsum board used as fire retardant material lining the core of the building.
It is true. There was a large amount of gypsum board used in the core of the buildings as fire retardant material, lining the walls and covering girders.
How much wallboard was used in the towers? Here is what one knowledgeable poster on a physics forum said about the materials used to build the towers. (Emphasis mine.)
I have certainly never seen a detailed calculation of the mass of WTC 1 or 2; but there are plenty of references on the web for the weight of the materials used in the construction of the WTC Towers. For example, the weight of structural steel used in each Tower is generally reported to be 96,000,000 kg and the weight of concrete is said to be 48,000,000 kg per Tower. I have also seen the weight of aluminum cladding reported to be 2,000,000 kg, and the weight of wallboard quoted at 8,000,000 kg per Tower, giving a total weight of structural materials of 154,000,000 kg per Tower.
The above quoted figure for gypsum wallboard in each tower is obviously not exact. I don't even know where the poster got the figure. But if it were accurate and if the figure for concrete were accurate, it would mean that the mass of concrete in the towers was six times the mass of the wallboard. The ppm uranium of the concrete could be multiplied by six, added to the ppm uranium of the "by-product gypsum" and the result divided by seven to give a ppm of the mixture that is still less than 7 ppm uranium in the WTC dust, determined by the USGS.
And that is not including other materials that would dilute the ppm uranium even further.
But it gets worse.
According to an overview of the gypsum building products industry published by The Athena Sustainable Materials Insititute in Canada,(Page 2-9)
Use of by-product, chemical gypsum is new to the North American continent. In the U.S., by-product gypsum represented only 3.6% of the total gypsum supply in 1994.
Prior to the 1980s, virtually all the gypsum used to manufacture gypsum board and gypsum plaster was natural gypsum. While the technology to create synthetic ("by-product"-ipsedixit note) gypsum was developed in Europe in the 1930s and scattered references to its existence are found in industry records prior to World War II, the wholesale use of synthetic gypsum to manufacture gypsum board did not occur in the U.S. until the 1980s.
Thus the likelihood of "by-product" gypsum at 13.7 ppm uranium even coming into the calculations at the outset is diminished to near zero.
Upgrades of fire protection, in later years may have included "by-product" gypsum boards at 13.7 ppm uranium, but these would have been in the minority compared to standard gypsum wallboards rated at 1.0 ppm uranium.
Overall, the mathematics is against by-product gypsum boards at 13.7 ppm of uranium having enough of an effect to lift the ppm uranium of the WTC dust even over the level of 5 ppm uranium and that is leaving a lot of diluting factors out of the calculations.
We have already found, earlier in the thread, that Boeing 757s and 767s never used depleted uranium as balancing weights. So. . . .
Where did the extra uranium come from?
edit on 15-10-2012 by ipsedixit because: (no reason given)
Originally posted by CosmicEgg
The UK was most definitely checking DU levels in their troops from the beginning of the whole fiasco. Obviously the US would check as well, but I don't know that absolutely first. I do know about the UK. They both knew the results of such contamination so it was deliberate application to the Iraqi people.
Both countries have more to answer to for their actions of the past dozen years than probably any other nation in the span of this civilization.
Originally posted by steppenwolf86
So to draw a parallel from your argument, would you also say that the use of Agent Orange was to poison and kill future generations, rather than to eliminate cover for the enemy?