First, describing dropping aluminum from the sky, in any context, is not innocuous. Even if the immediate effects are unknown you can pretty much guarantee it will effect something, even if it just is the weather forecast. (which you should view as proven at this point.

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Second, lets back up. My comment I left after quoting escher conflated chemtrails and chaff purposefully, as his response was vapid and came off as he was doing so as well. Notice how in my original comment to you I didn't mention chemtrails.
"and if they are absolutely not spraying anything at all, ever, then explain why meteorologist are having to explain to people that what's showing up on radar definitely isn't rain?"
I did that partly because I knew you wouldn't watch the fucking video

as it would have been really easy for you to have made this distinction at the beginning of the conversation.
OK, so we're all on the same page that chaff has absolutely zero to do with "chemtrails" now? Excellent, a rather convoluted route but at least we got there at the end.
Now, as far a me gathering evidence myself, it's in the works. But increased barium levels have been found all over the place, and has even been attributed to
cloud seeding
http://www.ncbi.nlm.nih.gov/pubmed/15236778
"Attributed" - by a farmer from that prestigious of all scientific institutions "High Barn Farm" 8)
For starters, some background on
Mark Purdey - he was an advocate for organic farming and purveyor the widely discredited hypothesis that organophosphates and heavy metals caused mad-cow disease. This (non-peer reviewed) paper expands on that and tries to link barium to another degenerative brain disease. Now, just because something is catalogued by the NCBI doesn't make it true. You still need to apply critical thinking (it's hard, I know, but bear with me) when assessing 'evidence' like this. For starters, there isn't a single reputable peer-reviewed study that in anyway supports the link between heavy metals and CWD, indeed the causative agents of CWD
are well understood.
So now that we know the main contention of the paper is complete bunkum, let's have a look at the periphery claims about barium in a little more detail. 1). Have barium levels increased as you claim? 2). If so, is cloud-seeding REALLY a primary source for these elevated levels? 3). And, even if barium levels HAVE increased, as claimed, what are the likely health consequences?
1. So, on this point, I really couldn't find any definitive data and couldn't be arsed wasting all morning trawling through reams of research papers to find an answer (because, really, that should be your job under the burden of proof) so I will be magnanimous and assume that you are indeed correct and barium levels in the environment have indeed increased (over what period and what region etc, who knows, maybe you can enlighten us all?)
2. So what are the sources of barium in the environment?
According to the WHO, barium is leached naturally from igneous and sedimentary rocks in the form of various compounds, it is routinely found in groundwater and the main source of barium in water is from these natural sources. It is probably safe to assume that this source of barium in the environment hasn't increased over recent years. So where DOES the assumed increase in barium levels actually come from. Luckily for us,
the EPA has collated extensive data on this point.
In terms of usage: ba metal is used for television tubes; barium peroxide is used as a bleach, in dyes, fireworks and tracer-bullets, in igniter and welding materials, and in manufacture of hydrogen peroxide and oxygen; barium nitrate is used in fireworks, ceramic glazes, electronics, tracer bullets, detonators, and neon sign lights. Barium cyanide is used in electroplating and metallurgy; barium carbonate is used in glass, brick and clay, as raw materials for barium ferrites, and photographic paper; barium hydroxide is used in lubricating oils and greases and as a component of detergents in motor oils. It is also used in plastics stabilizers, papermaking additives, sealing compounds, vulcanization accelerators, pigment dispersants and self-extinguishing polyurethane foams and to protect limestone objects from deterioration; barium chloride is used in pigments, glass, dyeing, leather tanning, chlorine and sodium hydroxide manufacture and in water softening. Barium-based dyes are widely used in inks, paints, cosmetics and drugs.
So now we now what barium is primarily used for, how does it get into the environment? Well, happily enough, the EPA also has voluminous data on that point too!
Barium metal gets into the soil and water primarily from mining tailings, the smelting of copper and the manufacturing of automobiles. it gets into the atmosphere by way of the mining, refining, and production of barium and barium-based chemicals and from the burning of coal and oil. Between 1987 - 1993, 57 million lbs of barium compounds were released into the environment, these primarily came from copper smelting and 99% thereof was dumped on land (i.e. the soil).
Note that "cloud-seeding" isn't mentioned once? (although that's probably just evidence that the gubberment is covering it up, amirite?)
So, even if we assume that barium levels have been elevated in the soil (probably a very sound assumption given the evidence presented) - what is the likelihood that any more than a fraction of a percent of the overall total has been contributed by cloud-seeding? I think we can safely conclude that the answer is, to use the technical phrase, sweet fuck all. Now, I'm happy to be proved wrong so if you have any better estimations than mine then I am all ears.
So now that's been established, onto the third question.
3. Just how harmful is barium anyway? Well, again, the WHO and the EPA have extensive data on this point too! (I know right, who could ever have guessed, I thought that Youtube and Rense were the only sources of information on barium toxicity too, it's amazing what a bit of cursory and critically minded research can uncover).
"EPA has found barium to potentially cause gastrointestinal disturbances and muscular weakness resulting from acute exposures at levels above the MCL. No Health Advisories have been established for short-term exposures. Chronic: Barium has the potential to cause hypertension resulting from long-term exposures at levels above the MCL. Cancer: There is no evidence that barium has the potential to cause cancer from lifetime exposures in drinking water."
So acute exposure can make you want to run to the toilet, prolonged acute exposure can cause hypertension. There is no doubt that high level exposure above the MCL is not advised, however, as
this epidemiological study (
cited here, if you can't access that paper, under the first paragraph headed 'epidemiological studies' found when comparing two communities - one with elevated levels at or above the MCL, while the other significantly below the MCL - found "(n)o significant differences in mean systolic or diastolic blood pressures or in rates of hypertension, heart disease, stroke, or kidney disease were observed between the two communities. Since no differences were observed between the populations of these two communities, a subpopulation of the McHenry and West Dundee subjects who did not have home water softeners, were not taking medication for hypertension, and had lived in the study community for more than 10 years was evaluated. There were 85 subjects from each community in this subpopulation. No significant differences were observed between these two subpopulations for any of the endpoints measured"
So even in instances of acute exposure the side-effects really are minimal, the effects of the minute amounts of barium dispersed by cloud-seeding activities would, again, be lucky to be a minute fraction of a percent of the levels found in this community's drinking water.
So, in summary, you've cited a bunkum non-reviwed paper that has been widely discredited; barium levels in the environment have likely increased in the environment but cloud seeding activities wouldn't even be a blip on the radar in terms of contributing to that rise; and the health impacts of barium are pretty much negligible anyway.
Chemtrails schmemtrails.
When I am able to actually test areas around where I live I'll post the results here for everyone.
Oh. My breath is bated. And how do you intend to discern one source from another of any barium contamination you might discover? Or will you just falsely assume that all barium is coming from the sky?
(Not that I actually believe in chemtrails, I don't 'believe in' much. although I am suspicious because they always form and persist for the same duration of time, and adopt the same spreading patterns without any variety, despite presumably changing conditions in the atmosphere. You should watch the original video I posted now. I posted it here because it was odd and that's about it. I was hoping someone could explain that actually. [/QUOTE]
Have you bothered to look at the actual SCIENCE behind the dispersal of contrails in the stratosphere, or are you just coming up with wild-eyed assumptions based on how you FEEL that they should disperse?
I do take any claim of threat to health extraordinarily seriously. I'll give you a quick example. Everyone I know thinks I'm crazy when I tell them to avoid air fresheners, among many other things like new shower curtains, driving newer model cars without the windows open, canned food, anything with an added fragrance such as smell good soaps, shampoos, and conditioners, consuming anything out of plastic etc etc etc etc. extra etc's because that's only scratching the surface. The reason I avoid these things myself and try to inform others is because exposure to
plasticizers which leech from plastics and are added directly to most fragrances wreak havoc on ones endocrine system. heres a link, please do your own research if you are unaware, this isn't even close to an alternate theory by the way.
http://www.nrdc.org/health/home/airfresheners/fairfresheners.pdf )
You're right, it's not an "alternative theory" - but chemtrails are apples and oranges. Just because there are genuine environmental hazards out there doesn't mae the chemtrail hoax any truer. The difference here is that there is data that actually supports the claim, whereas "chemtrails" are dismissed by everybody except for the dribbling, wide-eyed, armchair conspiracy theorists who have never set foot in a lab much less collated any data to support their feelings about how contrails should disperse in the stratosphere. A subtle but important distinction, don't you think?