Here is an example. Assuming that all of the radium in the drinking water is radium-226, then a 10-year-old child drinking 2 L of water per day at 5.0 pCi/L would receive a dose of 10.9 millirem (mRem) per year. The same child drinking 2 L of water at 6.0 pCi/L a day, would receive a dose of 13 mRem/year.

(This example is a conservative scenario where all radium is assumed to be radium-226. In reality, the water contains a mixture of radium-226 and radium-228, and radium-228 gives a lower dose than radium-226 for that 10-year-old child.)

Comparing that with other sources of radium exposure:

• Minnesotans receive between 200-400 mRem annually from natural sources.
• A chest X-ray gives a dose of 10 mRem. 
• A dental panoramic X-ray gives a dose of approximately 2.5 mRem.
• A 3-hour flight gives a dose of roughly 1 mRem.
• People living in Denver receive an annual dose of 80 mRem due to the cosmic radiation at high altitude. In comparison, people living at sea level receive an annual dose of 30 mRem from cosmic radiation.

The difference in drinking 2 liters of water per day at the 5.0 pCi/L concentration versus at 6.0 pCi/L is just over 2 mRem for the whole year. This is similar to the dose a person would receive from taking one round-trip flight (3 hours each way). 

In the long-term, some cities may need to upgrade their aging treatment plant as older equipment cannot efficiently remove radium.

The longest duration for a community public water supply to be out of compliance is typically 3- 5 years to fund, design and build a water treatment plant. During this time, the public is provided updates and public education every three months. Historically, communities have not provided bottled water to residents during these times, because, again, the health risk is not acute and the water is safe to drink.

It’s important for city residents to be kept informed of developments as these projects move forward and problems are addressed. City officials can provide the most current information on their website. Under the Safe Drinking Water Act, the city is also required to notify the public every three months about the exceedance, until they are back below the MCL for four quarters.

Natural and human-made radiation surround you every day. About half of the radiation you come in contact with each year is from natural sources, like the sun, soil, and rocks. The other half comes from human-made sources, like medical tests (x-rays) and treatments and building and road construction materials.

Each source of radiation gives you a different dose of radiation. For example, a radiation medical treatment has an extremely high dose of radiation compared to the very low dose of radiation you get from drinking water with radionuclides.

Your lifestyle can also affect how much radiation you come in contact with. Flying in airplanes, living at high altitude, living near a coal mine, and some jobs (like underground mining) put you in contact with higher doses of radiation. Learn more about radiation at Doses in Our Daily Lives.