(Before It's News)
Certain kinds of granite contain high levels of fluoride, increasing the concentration in private wells drawing it from the water. Newly available data, released in recent months, indicates dangerously high levels of fluoride in private wells. In some cases, the wells contain more than double the level that the U.S. Environmental Protection Agency has deemed the acceptable maximum exposure level and the end result on human health may be appearing on IQ scores in children.
Source:
http://www.preventdisease.com/cgi-bin/cornews11/viewnews.cgi?id=EuplyAVyuVdERiTzVj