Answer to Question #2377 Submitted to "Ask the Experts"

Q

We have been notified by our mayor that the city water is contaminated by radium. We were told nothing else. Could you please tell me what this is and if it is harmful to me and my family. What needs to be done about this problem? Thank you!

A

Radionuclides in drinking water, including radium-226 and radium-228, are regulated by the U.S. Environmental Protection Agency (EPA) by means of monitoring requirements and maximum contamination levels (MCL). The rules apply to community water systems, which are water systems with at least 15 service connections or that serve 25 or more persons year-round.

The current MCL is 5 picocuries per liter for radium-226 and radium-228 combined, and levels at or below this value carry very little risk. Persons drinking water contaminated at the MCL would receive a dose of only about 5 millirem per year, which may be compared to the average annual dose received by U.S. residents from other natural sources of about 360 millirem.

Your city is required to monitor the drinking water and report results to residents. If the MCL is exceeded, then the city is required to treat the water to remove sufficient radium to meet the MCL.

I suggest that you first find out if the concentration of radium-226 and radium-228 combined exceeds the MCL of 5 picocuries per liter. If the MCL is exceeded, you could ask your city officials what they plan to do about it and when the water is expected to be brought into compliance.

I would not personally be concerned about drinking water somewhat or even considerably above the MCL for a limited period of time, while the problem is being brought under control. Obviously you could use bottled water for drinking if you are very concerned.

For more information, you may visit an official EPA Web site with information on radionuclides in drinking water.

Thomas F. Gesell, PhD