Against any good sense, I have been reading some… alternative… news sources. It’s good for the mind to explore other points of view. I’m not afraid of madness. Indeed, I would prefer to flirt with insanity than be comfortably ignorant.
In any case, if you have not heard, some people think fluoridating water pollutes our body’s essential purity. The purity of our essence, in essence. I think that’s rather silly, myself. Our bodies are quite capable of handling a lot of junk (see my post on mercury) so I’m not worried. But still, if you want to cut down on fluoride intake, that seems like something we should be able to do.
Fluoride reacts with glass at low pH, so I got to thinking about how one might put drinking water in a glass pitcher with a drop of citrus juice and let it sit for a while. Maybe that would lower the concentration. Or maybe if you added a bit of calcium carbonate (chalk, or Tums brand antacid) that would cut it down.
It turns out that the calcium thing has been tried in order to remove fluoride from wastewater streams… I wonder why there is a lot of fluoride in wastewater at such high levels that it needs to be removed. Probably it’s being recovered for industrial purposes. In any case. It only works at high concentrations according to X. Fan et. al.
They looked at using a bunch of different materials like quartz, calcite, and apatite to see how much and how fast fluoride would attach itself. If you want to remove something from water, it’s a lot easier if it will attach itself to a solid – then you just let it settle out.
According to that paper, my glass idea was not so hot. Glass is a lot like quartz, and quartz doesn’t adsorb much fluoride at all at low concentrations. Drinking water has about 2 parts per million of fluoride. At that concentration, hydroxy apatite (a kind of rock) is much better. At pH 6 (a droop or two of lemon juice should do it) a bit of hydroxy apatite sand will remove 90% of fluoride.
There are commercial products that use activated alumina to remove fluoride, but that seems like overkill and it ends up putting aluminum into the water, which might be just as bad. Probably neither are really bad, but if you want to remove something because of superstition, it seems like you might not want to put something else in to be superstitious about.
Apatite is a mineral you can dig up or buy pure from a chemical supplier for ~$1 per gram. Don’t go blaming me if you end up drinking hydroxyapatite slurry and it makes you sick. I’m not recommending anything. I would wash and filter anything I was going to try along these lines. And I certainly would make sure I didn’t drink mineral slurry. But, honestly, I don’t mind the fluoride.
Addendum as of 10-12-2008: It looks like reverse-osmosis filtration is really the way to go for this. Reverse osmosis filtration removes basically everything and is a lot cheaper than bottled water (which probably has exactly the same crap you are trying to remove).