Demonstrator China Starshine holds up signs outside of City Hall in Portland last week.
Ross William Hamilton/The Oregonian/AP
September 12, 2012 Portland, Ore., is the largest American city not to add fluoride to its drinking water. Activists have been vocal, for and against a proposal to change that. The science shows that fears of side effects from small amounts of fluoride to protect teeth are unfounded.
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Pakistani boys collect water from a hand pump on the outskirts of Islamabad.
May 8, 2012 Adding dirt and salt can help make drinking water cleaner, and is far cheaper than fancy filtration systems for getting rid of harmful bacteria, scientists say. It just takes a little patience and the sun.
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