Ok, with the power of copper. But copper is all about science! So it counts.

The Ignobel prize in chemistry goes to Johan Pettersson of Sweden for determining why people in the town of Anderslv were suffering from a strange epidemic ofgreen hair. Pettersson, an engineer in environmental hygeine, dyed his own beard green for the ceremony, and was very thrilled to win the Ignobel, noting that it teaches you to look at the strange.

(Source)

The mystery began in the charming (ok, I dont know what it looks like, but I have to imagine its charming) town of Anderslov, located on the very southern tip of Sweden. People started complaining that their hair was turning green. When confronted with sudden hair changes, people are inclined to blame the drinking water, and of course, since its drinking water, you have to wonder what something in there will do to you, if its already turning your hair green.

Enter environmental hygiene engineer Pettersson. He and a team took samples of the local drinking water from several houses. They immediately suspected copper, which, well, turns things green.

(Source. Observe the older copper is green, due to exposure to water and air, while the newer copper is bright and shiny)

Imagine their surprise when they found that the copper levels in their current set of samples were totally normal. Where was the copper? The water was from the same source. Pettersson started going to the houses where people had complained, and tested THEIR water. And there was the copper, up to four times normal concentrations.

It turned out that the people who complained of the green hair were all living in new houses. New houses with shiny bright new COPPER piping. When the water sat overnight in the pipes, and was then exposed to heat from the water heater for showers in the morninghello green!

But was it harmful? Well, other than the somewhat green eggs and ham fashion, no. Copper levels high enough to dye things green are not high enough to hurt you. But, well, the green, in a country like Sweden, full of ice blondesit was a bit noticeable (Pettersson noted to me that other countries like Germany might have similarly high copper levels, but too many brunettes to notice the hair changes). It was especially noticeable in teenagers and young women, possibly because they were showering the most.

Petterssons solution? Move houses! The newer the house, the more likely you were to have copper leaching from your pipes. Of course, if you didnt want to MOVE, you could always get new pipes. If youre really desperatetake cold showers (which I think somehow would not go over well in Sweden). The heat required for hot water increases the leaching of the copper, so cold showers could help. Finally, you could, you know, do the sensible thing and let the water run for a few minutes in the morning to get the residual copper out.

Link:
IgNobel Prize in Chemistry: Turning hair green with the power of SCIENCE