SOUTH DAKOTA Department of
Environment & Natural Resources

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Drinking Water Program

Radiological Contaminants

Radiological contaminants are radioactive particles that occur naturally in areas of uranium and radium deposits and in waste from man-made nuclear reactive processes.  Radiological contaminants, even in very small concentrations, pose a cancer risk.   The implementation of the Radionuclide Rule will result in the reduced exposure to uranium for 620,000 persons, resulting in protection from toxic kidney effects of uranium and a reduced risk of cancer.

 

Does the radiological contaminant regulation apply to my water system?

If your system is a community public water system your system must test for these contaminants.  Radiological contaminants have been regulated since 1976 with Maximum Contaminant Levels currently set for five types. 

Frequency of Sampling

 Samples must be taken at each entry point to the distribution system after treatment.

Initial monitoring

Four consecutive quarters of monitoring for:

 Gross Alpha, Combined Radium-226/228, and Uranium.

No monitoring required for most community water systems for:

 Beta Particle and Photon Radioactivity

Vulnerable community water systems must sample quarterly for Gross beta and annually for Tritium and Strontium-90.

Reduced Monitoring

Gross Alpha, Combined Radium-226/228, and Uranium

Beta Particle and Photon Radioactivity

Increased Monitoring

Gross Alpha, Combined Radium-226/228, and Uranium

Beta Particle and Photon Radioactivity

 If your tests indicate levels of radiological contaminants higher than the Maximum Contaminant Level, your water must:

The State may require your system to continue quarterly sampling until the Maximum Contaminant Level is met.

Radiological Contaminants

 

Contaminant

MCL*

Potential Health Effects

Sources In Drinking Water

Gross Alpha Particles

15 picocuries per Liter (pCi/L)

Increased risk of cancer

Erosion of natural deposits of certain minerals that are radioactive and may emit a form of radiation known as alpha radiation

beta particles and photon emitters*

4 millirems per year

Increased risk of cancer

Decay of natural and man-made deposits of certain minerals that are radioactive and may emit forms of radiation known as photons and beta radiation

Radium 226 and Radium 228 (combined)

5 pCi/L

Increased risk of cancer

Erosion of natural deposits

*Maximum Contaminant Levels

These are the current Maximum Contaminant Levels for radiological contaminants.  The units of measure are peculiar to radioactivity and represent very small quantities.  A total of 168 individual beta particle and photon emitters may be used to calculated compliance with the Maximum Contaminant Level

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