Here, fluoride hippies:
http:// www.oregon.gov/oha/PH/HEALTHYENVIRONMENTS/DRINKINGWATER/SOURCEWATER/DOMESTICWELLSAFETY/Documents/Contaminant%2520Factsheets/Fluoride.pdf
"How much fluoride is found naturally in drinking water sources?
Fluoride is present in all water sources at concentrations ranging from minimally perceptible to greater than 10 parts per million (ppm). Rivers, lakes and surface waters contain 0.1 to 0.2 ppm fluoride reflecting rainwater contact with windblown soils and other elements in
the environment. Well water fluoride levels vary depending on the minerals in the rock and ores that the water passes
through. Fluoride in ocean water (96.5 % of Earth’s water) is typically in the range of 1.2 to 1.4 ppm.
Groundwater with high fluoride concentrations, affects up to 60% of populations of Pakistan, East Africa (Sudan, Ethiopia, Uganda, Kenya and Tanzania), West Africa, Thailand, China, Sri Lanka, and Southern Africa.1 2
In the United States, fluoride levels vary
less significantly. Less than one-half of one percent of U.S. residents on community water systems have drinking water that exceeds 2 ppm and less than one-tenth of one percent have water that exceeds 4 ppm. Water samples from Colorado, analyzed when studying the
association between Colorado children with yellow/brown stains and reduced tooth decay in the early 1900’s, contained 2 to 12 ppm fluoride."