It is summer time and we get calls all the time about patients with blonde hair turning green. But what actually causes the hair to change color? It seems that the obvious answer would be the chlorine.
But in order to get a more complete answer, we need to review the components of pool water. Many pools are chlorinated but have other metals and chemicals that your hair is exposed to while swimming. So what exactly is the main cause?
It could be that the water is considered "hard " and is damaging the hair. Hard water is water that is filled wth heavy metals.
According to a recent study, the effects of hard water on hair have been shown to have a minimal effect on overall hair tensile strength.
According to the study, "It can be concluded that there was no statistical difference in the tensile strength and elasticity between the hairs treated with hard water and distilled water, hence we conclude that hard water does not interfere with the tensile strength and elasticity of hair."
Influence of pH
Another study showed that the pH influenced metal uptake since increasing alkalinity increases deprotonation. This increases the uptake of water hardness metals by human hair.
"The condition of the hair, a key representation of the binding capacity, was most influential. Interestingly, water hardness levels had only a small effect on uptake; hair became saturated with notable amounts of water hardness metals even after repeated exposure to soft water. Water pH influenced metal uptake since side chains of hair proteins deprotonate with increasing alkalinity."
The Effects of Copper
So then what exactly is causing the hair to turn green? Surprisingly the answer is copper. The copper is oxidized by the chlorine and binds the hair which is composed of protein.
What could be the sources of copper in swimming pools? Well, many algaecides used to treat pool agae contain copper. The metal in the water then turns the hair green. It can happen with any hair color, but it is more noticeable with blonde hair.
How to Prevent Green Hair
Prevention with a good water filter or purification system helps, as well as using algaecides without copper.
By using a good water filter you can remove many of the hard water elements and prevent a head full of green hair.
Finally, using a good hair conditoner to coat the hair before it is exposed to chlorine and copper may act as a protective shield.