Originally Posted By: ToadU
There are no "official reasons" for chemtrails because chemtrails don't exist. Nothing has been found in contrails, which do exist, other than H2O. I am aware of the test results that were published by a news station reporting heavy metals. However, this was sensationalized, could not be reproduced and was not a scientific test by any means. The reason there are more contrails today than in years past is because there are more airplanes today. I saw a graph somewhere and I can't find it but it had a line for the number of visible contrails over North America and a line showing the number of turbine powered aircraft flying. Amazingly!!!!! the number of visible contrails increases with the increased number of plane flying. The only thing you you find in contrails is water vapor and small amounts of engine exhaust from the combustion of fuel.
Fuels can contain metals, though they are regulated. See the spec for JP-8, which is a military Jet-A:
http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-DTL/MIL-DTL-83133J_53582/
It limits a whole host of metals to be only 0.1 ppm in the H spec. In the older specs, like the F revision, there is no mention of metals content.
However some crudes do have higher metals content, for metals such as Vanadium.
Naval distillate (high flashpoint diesel) F-76 fuel can still have half a ppm of Pb and V as an example. And it was higher.
At some point and in some places, some of these things may be less/unregulated.
So it is possible for there to be trace metals solubilized in fuels and emitted. But the dilution ratio would be so low, by solubility if nothing else, that upon combustion they would be barely there, and its not a big concern.