It gives water divining a new meaning: the water you drink leaves a record in your hair, which can be used to trace where you’ve been living.
Groundwater differs in the oxygen and hydrogen isotopes it contains, and this is recorded in hair as it grows. Jim Ehleringer of the University of Utah in Salt Lake City and colleagues analysed tap water and hair clippings from barbershop floors in 18 states. They were then able to construct maps of the isotope ratios you’d expect to find in the hair of people living in each state.
They found that 85…
