How or why does swimming pool water turn blonde hair green?

i have another question, our teacher (chemistry) showed us a "water machine"(what's she called) today, she put 1/2 gallon of water in that machine and 2gallons water came out. can the water came out is GREEN! can anyone pleeeeeeeaz explain to me that happened to the original water???

If a pool is not properly tended, it can (and does) absorb copper salts. Pool hedaters are the common source. If the Ph is then allowed to get above 8.3, the copper salts will be taken up by hair. Since blobde hair has little pigment (colour) to mask the copper when it starts to precipitate out of the hair as the Ph changes (which is made worse by shampooing, by the way), blondes turn green. It happens to darker hair colours, too, but it just isn't so visible. Add bleach or blonding and the effect is even more dramatic. So...it isn't chlorine, it is copper in a poorly maintained pool.

Chlorine isn't what turns the hair green. A lot of pool chemicals (algae killers, ph adjusters, ionizers, etc.) tend to have a lot of copper in them. A lot of the pipes which carry the water are also made of copper. Copper will turn blonde hair green because it coats the hair. If a person had bleached blonde hair it will add to the problem because the cuticle of the hair shaft is open and does not lay flat. This gives the copper even more spots to collect on the hair shaft making the green color even more pronounced. If the water is chelated (additives to remove metals) then hair won't change color.

Well I also can't answer the question so I researched and this is what I find out from: http://chemistry.about.com/od/howthingsworkfaqs/f/greenhair.htm [i]"It isn't the chlorine that turns blonde hair green. Oxidized metals in the water bind to the protein in the hair shaft and deposit their color. The metal that produces the green tint is copper, which is most commonly found in algicides, though it naturally occurs in some water. The bleach that is added to a pool may be responsible for oxidizing the metal, but it's not the cause of the color. If your hair turns green, you can remove the discoloration by using a shampoo that chelates the metal. To some extent, you can prevent copper from binding to the hair by sealing the hair cuticle with a conditioner before swimming. Rinsing your hair immediately after leaving the pool will help protect it, too."[/i]

I guess the reason is due to the metal composites present in water

may her hair are allergic to the dirty water of that pool.