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Radioactivity & Water

There’s been a lot of talk recently about radioactivity in water due to nearby power plants and, in particular, coal ash.

The question we want to discuss today:

Does the community need to worry about radioactivity in Charlotte Water’s drinking water?

The answer is no. Charlotte Water routinely monitors for radioactive materials and the test results do not detect any radioactive materials above testing detection limits or public health goals set forth by the EPA. 

Sources of Radioactivity

Radioactivity can be naturally occurring from rocks or minerals, or artificial. Recent articles in the news are citing radioactivity found in coal ash monitoring wells adjacent to coal powered power plants. According to a fact sheet written by the US Geological Society (USGS), “Some trace elements in coal are naturally radioactive. These radioactive elements include uranium (U), thorium (Th), and their numerous decay products, including radium (Ra) and radon (Rn). The vast majority of coal and the majority of fly ash are not significantly enriched in radioactive elements, or in associated radioactivity, compared to common soils or rocks.” It is possible that groundwater or surface water can become contaminated with radioactive elements from coal ash. However, the USGS study also stated “Limited measurements of dissolved uranium and radium in water leachates of fly ash and in natural water from some ash disposal sites indicate that dissolved concentrations of these radioactive elements are below levels of human health concern.”

Charlotte Water Monitoring

Even though dissolved concentrations of these radioactive elements in coal ash are very low, Charlotte Water monitors for signs of any kind of contaminants in our raw water sources (Lake Norman and Mountain Island Lake), throughout the treatment process, and in the finished drinking water. Charlotte Water monitors for dozens of contaminants including indicators of radioactivity such as alpha and beta particles. All drinking water quality monitoring data can be found on the Charlotte Water website. More than 220,000 laboratory tests are run every year to continuously ensure our community’s drinking water is safe for our community.

Charlotte Water tests the treated drinking water for Radium 226 and Radium 228 annually. The EPA requires utilities to test for these radioactive materials every 9 years. The last test was performed in July 2017 and Charlotte Water will test again in April 2018.

Drinking Water Treatment – flow chart:

Diagram titled with white caps font top left, Water Treatment, depicts how water from nature is treated an moved via a 7 step journey for drinking in the home. On this diagram all water pipes are blue, bodies of water are light blue, all buildings and structures are grey and everything in between is light grassy green. All descriptive fonts are white and listed in a blue field on lower half of page. From the left is a blue area representing a lake with a pipeline connecting the natural body of water to stop 1 - Pump Station, We have pumps and filter stations located at Mountain Island Lake and Lake Norman. Water from Mountain Island goes to Franklin Water Treatment Plant and Vest Water Treatment Plant. Water diverted from Lake Norman flows to The Lee S. Duke Water Treatment Plant. From there the water moves to stop 2 - Raw Water Reservoir, Sediment falls out of suspension in the reservoir; a group of large covered round tanks is stop 3 - Coagulation, During coagulation, liquid aluminum sulfite or alum is added to untreated raw water. When mixed with the water this causes the tiny particles of dirt in the water to stick together or coagulate. At this same location, the water has an additional stop, stop 3a - Flocculation, Paddles in large tanks stir the alum and water mixture, causing them to stick together and form large, heavier particles called floc. Next is stop 4 - Sedimentation, the water and the floc particles move into sedimentation basins where the heavy floc particles settle to the bottom. The water then moves through pipes to a series of filtration tanks during Stop 5, Filtration - from the sedimentation basin, the water flows through a filter designed to move any remaining particles left in the water. The filters are made of layers of sand and carbon. From there the water moves on to the last leg of it journey before it reaches the home: Stops 6 and 7: Corrosion Control, additives and Fluoride are added and Disinfection and Fluoride - Fluoride is added to protect teeth. Clorine is added to kill any germs or contaminants and to keep water disinfected while it is pumped through 4200 miles of pipes to reach customers. In the bottom left corner of the page is the Charlotte Water logo in white font.

Charlotte Water uses a multi-stage treatment process at all three drinking water treatment plants. We can remove physical contaminants as well as dissolved contaminants.

In Summary

  1. Coal ash contains extremely low levels of radioactive materials.
  2. According to public reports, power plant monitoring indicates radioactive materials have only been observed in groundwater monitoring wells adjacent to the coal ash basins.
  3. Lake monitoring and drinking water monitoring results do not detect any radioactive materials above detection limits or public health goals set forth by the EPA.
  4. Charlotte Water treatment plants can remove particulate and dissolved contaminants.
  5. More than 220,000 monitoring tests are conducted each year to ensure our community continuously receives safe, clean drinking water.
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