Live Science –
Does your tap water contain the radioactive element radium? You might be surprised to hear that tap water for more than 170 million Americans contains the compound, and a new interactive map shows the water systems where this potentially hazardous element was found.
The map was made by the Environmental Working Group (EWG), a non-profit advocacy organization in Washington D.C. that focuses on environmental issues and public health.
The data for the map comes from an EWG analysis of water quality tests from 2010 to 2015. Of the 50,000 water utilities, 22,000 utilities serving over 170 million people in all 50 states reported detectable levels of radium, EWG said. (The map includes only water systems with detectable levels of radium.)
Radium is found naturally in soil and rock, and can get into groundwater supplies. Exposure to the element in high doses — much higher than the levels seen in drinking water — are known to cause cancer. There is no amount of exposure to radium that’s considered “risk free,” but the risk of cancer decreases at lower doses, EWG says.