Believers in the "chemtrail" theory (the theory that the trails behind high-flying aircraft secretly contain chemicals intended to alter the climate or weather) often point to chemical analyses done on soil, air or water. Typically these tests are done for three metals: Aluminum, Barium, and Strontium (the fallacious "geoengineering signature"). Since these elements are all naturally found in the Earth's crust, they usually find some of each. Experts in geochemistry recently analyzed a typical set of these results, and determined they did not come from a secret spraying program.
However a very common misunderstanding here comes from the fact that these metals are not found in their metallic form in nature. Aluminum needs to be extracted from rock, and once in metallic form it oxidizes (rusts) over the years, and barium and strontium both are highly reactive to air. Typically the chemtrail believer will quote something like Wikipedia:
So the argument goes: if Aluminum (or Barium, etc) is never found in nature, then why are the chemtrail related tests finding it?Because of its high chemical reactivity, barium is never found in nature as a free element.
The answer is that the tests used for these metals do not distinguish between the A) metal and B) a mineral that contains the metal.
So it does not matter if you test an aluminum soda can, or a piece of rock made of aluminosilicates, or windblown dust that contains tens of different minerals that contain aluminum, the results will all return the presence of significant amounts of aluminum.
The most commonly used test for metals in water is EPA 6010B, a standard test for metals:
The important word there is plasma. Plasma is the fourth state of matter after solid, liquid, and gas. If you take some rock or aluminum and heat it up it will eventually melt. Heat it up more and it will turn to liquid, continue heating and it will become a gas. Finally if you heat it up incredibly high it will become a plasma - a cloud of individual atoms stripped of their electrons. As described in Wikipedia:METHOD 6010B - INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROMETRY
Samples are nebulized and the resulting aerosol is transported to the plasma torch. Element-specific emission spectra are produced by a radio-frequency inductively coupled plasma. The spectra are dispersed by a grating spectrometer, and the intensities of the emission lines are monitored by photosensitive devices.
Since the sample is just broken down into a soup of atoms, there's no way of knowing (from this type of test) if the individual atoms of aluminum (or other metals) were in their metallic form, or in their mineral (rock) form.
The argon gas is ionized in the intense electromagnetic field and flows in a particular rotationally symmetrical pattern towards the magnetic field of the RF coil. A stable, high temperature plasma of about 7000 K is then generated as the result of the inelastic collisions created between the neutral argon atoms and the charged particles.
A peristaltic pump delivers an aqueous or organic sample into an analytical nebulizer where it is changed into mist and introduced directly inside the plasma flame. The sample immediately collides with the electrons and charged ions in the plasma and is itself broken down into charged ions. The various molecules break up into their respective atoms which then lose electrons and recombine repeatedly in the plasma, giving off radiation at the characteristic wavelengths of the elements involved.
EPA6010B is the most common test used. Another test is EPA 200.8, which is also plasma spectrometry, so the same applies there. Sometimes the test is just described as ICP/MS or ICPMS (Inductively Coupled Plasma/Mass Spectrometry), which is, of course, the same thing.
So when you test samples of dirt, or air or water that has a little dust in it, then you are going to find the elements that are typically found in dirt. You are not finding the metallic form. You are finding minerals that are made from those metals, like feldspar, granite, bauxite, or aluminosilicates. It's just regular dirt.