Re-posting this from another conversation so that it can be linked to directly (as requested by +Greg S.)
Recently I was reading a discussion about the safety of vaccines, and someone essentially asked what the levels of toxic compounds found in vaccines is vs. the levels found in a typical urban environment. This was my (slightly edited) response:
This isn't that hard to get a general idea of just as a thought experiment. What's the average volume of a vaccine? Not very large. How much mercury is there in the environment, considering we burn coal like it's going out of style? Rather a lot. If you really want, we can look up specifics, and finding quality information is the primary function of my job, so here we go.
Per the CDC (http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/appendices/appdx-full-d.pdf
) it looks like most vaccines are a total volume of 0.5ml, with the Rotovirus vaccine being abnormally large at 2.0ml, possibly because it is taken orally (http://www.immunize.org/askexperts/experts_rota.asp
). Now, we know some of that is attenuated or dead viral or bacterial matter, some of it is water, etc. Some of this volume, depending on the vaccine, is formaldehyde or mercury or something of potential concern, or so we might believe based on current popular knowledge. Several milliliters of mostly mercury would be scary, sure, but we know it's not that much. Still, if you want more specifics, we can find that too.
For one, we see that mercury containing compounds are no longer in use except in multi-dose flu vaccines since 2001, and even before then it wasn't straight up elemental mercury, or methyl mercury, the stuff you ingest when you eat certain kind s of seafood, but more on that later (http://www.cdc.gov/vaccinesafety/Concerns/Thimerosal/thimerosal_faqs.html
). Currently, one's exposure to mercury is typically going to be infinity percent higher from, e.g. breathing the air or touching the soil anywhere on earth than it is from vaccines. Even from those that did/do contain it, the volumes were/are tiny, around 25µg per dose (http://www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/UCM096228#t1
I could link information on each potentially harmful ingredient, but mercury is the only one that bio-accumulates Your body can process formaldehyde in relatively short order, and in fact produces more of it than is found in these vaccines (http://www.fda.gov/BiologicsBloodVaccines/ScienceResearch/ucm349473.htm
), so it is far less concerning, and the volumes are similarly minuscule.
As for how much one is exposed to in typical urban environment, that depends on a lot of factors. For mercury, it's mostly how much seafood you eat (http://www.epa.gov/mercury/about.htm
). However, mercury is all over the place, in more or less tiny amounts, so some exposure is inevitable. Since it is entirely possible to avoid all mercury from vaccines without skipping any of the recommended vaccines, and with barely any effort, it is likely that one's environmental exposure, being more than 0, will be far higher than the 0 they got from vaccines. Formaldehyde is a great deal more common, being produced by many organisms and found in many products, especially particle board (http://www.epa.gov/airtoxics/hlthef/formalde.html
) but, as noted, it is easier for your body to handle it. From this source, note that "The Reference Dose (RfD) for formaldehyde is 0.2 milligrams per kilogram body weight per day (mg/kg/d)". One is not likely to absorb that much from any source. Further, as they note, the most common source is from the gas being released by building and furniture materials, and then breathing the air in an enclosed space containing or built out of, you know, lumber. So it is extremely likely that a baby living in a house will get a lot more formaldehyde from breathing the indoor air than he or she will from any and all shots, and nowhere near 0.2 miligrams per kg of body weight, even considering the low body weight of the average infant.
I don't have time to do this for EVERY potentially harmful component of vaccines, but honestly those are the two most notable ones, really the only things of any concern at all. The other ingredients can be found as listed by vaccine here: http://www.cdc.gov/vaccines/pubs/pinkbook/downloads/appendices/B/excipient-table-2.pdf
and you can look for whichever of those sound scary if you like. Furthermore, with the tiny dose size and the majority of that being water and in some cases sucrose, it is extremely unlikely that anyone would get more exposure of any of this from a shot than from doing nearly anything else.