This is a bit outside my normal focus on Arizona-related topics but I found the results fascinating and possibly reflective of the U.S. situation.
The first issue of the newsletter for the EuroGeoSurveys describes a recent book the European Surveys compiled on analyses of the geochemistry on 1785 bottled water samples from 1247 wells representing 884 locations plus additional 500 tap water samples. Some minerals have a 7 orders of magnitude variation, although 3-4 orders of difference is more typical. They conclude that the water variations follow natural variations found in groundwaters across the continent.
Is anyone working on a similar study of U.S. bottled water? And do we have as many brands and sources as in Europe?