Does Reverse Osmosis Remove Radium?

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Radium is a radioactive element commonly found in varying amounts in soil and rocks within the earth’s crust. It can also be found in groundwater.

Radium in water threatens human health, especially when the water is used for cooking and drinking. High levels of radium increase the risk of liver, bone and breast cancer.

So, does reverse osmosis remove radium from drinking water? Yes. Reverse osmosis is the most effective water treatment method for eliminating radium from water.

The process can remove 87 to 98% radium from your drinking water.

How Does Radium Get Into Your Drinking Water?

As aforementioned, radium occurs naturally in the soil and underground rocks. The element then dissolves in water under low pH conditions.

High levels of radium can also occur in deep wells where water is slow-moving and stays in contact with rocks for a long time.

Radium may also be released into rivers and lakes from industrial and medical waste, mining activities and accidentally from nuclear reactors.

How Does Reverse Osmosis Remove Radium From Water?

During reverse osmosis, pressure forces water molecules through a semi-permeable membrane with very tiny pores (0.0001 microns).

These tiny pores block larger molecules, atoms and radioactive particles like radium from getting across. The particles are later washed down the drain with wastewater.

Is reverse osmosis the only option for removing radium from water?

You can also remove radium from water through ion exchange, chemical precipitation and through adsorption onto precipitated MnO2.

Ion exchange

Unlike reverse osmosis, this method does not eliminate minerals like calcium and magnesium from the water.

And like with most impurities removed through ion exchange, radium is adsorbed by a resin bed and swapped with a safer compound. It is then removed from the media through regeneration to prevent buildup.

However, although this method reduces the level of radium in your water, there is a risk of radium bypassing.

Chemical precipitation

You can remove radium from water through co-precipitation with barium. Here, barium chloride is added to the contaminated water, a process that leads to the co-precipitation of barium and radium ions as sulphates.

The method can eliminate up to 95% radium from your drinking water. However, it is unsuitable for home water treatment because of the chemical management and complicated equipment required.

Adsorption with MnO2

It is also possible to remove radium from drinking water through adsorption onto precipitated MnO2. This process is followed by filtration with diatomaceous earth (DE) to eliminate radium and the MnO2.

And although the method can remove up to 97% radium from your water, it is not suitable for residential drinking water treatment.

It can, however, be used on a larger scale to eliminate radium from drinking water supplies.


Q: What are the effects of radium on human health?

High doses of radium can result in anemia, cataracts, broken teeth and reduced bone growth. Additionally, exposure to radium for a long time increases the risk of lung and bone cancer.

Q: What level of radium is safe in your drinking water?

Any radium exposure carries some degree of risk. However, according to the U.S Environmental Protection Agency, the regulated standard for radium in public water supplies is 5 pCi/L (picoCuries per liter).
Any level above that is dangerous to human health.

Q: How can you tell if there is radium in your drinking water?

Radium, like most contaminants, is undetectable through vision, taste or smell. Only a professional water test from a certified laboratory can confirm its presence in your water.

Q: Does reverse osmosis remove radon from water?

Reverse osmosis does not remove radon and other gaseous contaminants.

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Dr. Peter Gleick

Dr. Peter Gleick is an experienced water filtration engineer and technical writer for He is an expert in water purification and filtration, focusing on helping people get clean, safe, and healthy water for domestic use. He has more than 10 years of writing experience and has numerously contributed to leading publications in this field.

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