Know Your Environment. Protect Your Health.

Radium, combined (-226 and -228)

Walnut Grove Utilities

Radium is a radioactive element that causes bone cancer and other cancers. It can occur naturally in groundwater, and oil and gas extraction activities such as hydraulic fracturing can elevate concentrations. Read More.

Radium releases radioactive particles that harm health in many ways, causing tumors in bone, lungs and other organs; leukemia; and skin and blood damage. Water utilities typically report radium amounts in picocuries per liter (pCi/L), which is a measure of radioactivity in water. The two most common forms of radium are radium-226 and radium-228. They may be reported separately or together.

Federal law allows up to 5 picocuries per liter of combined radium-226 and radium-228 in tap water. Research by the U.S. Geological Survey shows that in some regions of the country, such as the mid-continental region and North Atlantic coastal region, more than 20 percent of sampled wells have radium in levels exceeding the federal drinking water limit. And the legal limit does not equate safety: The EPA estimates that one in every 10,000 people drinking water containing radium at this level would develop cancer over a lifetime.

California set a public health goal much lower than the federal limit – 0.05 picocuries per liter of radium-226 and 0.019 picocuries per liter of radium-228, concentrations that are lower than the detection limit for most water tests.

Click here to read more on radiological contaminants.

 

44

Samples

0

Samples exceeding legal limit (MCL)

28

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.82 pCi/L110.82 pCi/L
20190.49 pCi/L98ND - 1.11 pCi/L
20200.37 pCi/L660.01 pCi/L - 0.75 pCi/L
20210.50 pCi/L119ND - 1.16 pCi/L
20220.60 pCi/L72ND - 4.00 pCi/L
20230.28 pCi/L103ND - 1.10 pCi/L

pCi/L = picocuries per liter

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 0.05 pCi/L

EWG applied the health guideline of 0.05 pCi/L, defined by the California Office of Environmental Health Hazard Assessment as a public health goal for radium-226, to radium-226 and radium-228 combined. This health guideline protects against cancer.

EPA Maximum Contaminant
Level (MCL): 5 pCi/L

The legal limit for combined radium-226 and radium-228, established in 1976, was based on costs for radium removal, as calculated at the time that the standard was set. This limit does not fully protect against the risk of cancer due to radium exposure.

pCi/L = picocuries per liter

All test results

Date Lab ID Result
2018-10-16302688530010.82 pCi/L
2019-02-26118134R0.48 pCi/L
2019-03-05119879P0.30 pCi/L
2019-03-12107941P0.63 pCi/L
2019-04-02102294P0.15 pCi/L
2019-04-09810-95964-10.85 pCi/L
2019-07-16116869P0.47 pCi/L
2019-08-13103149P1.11 pCi/L
2019-12-03Q24134710090.44 pCi/L
2019-12-04Q2352916009ND
2020-03-12M4F0908-010.30 pCi/L
2020-03-18113301P0.34 pCi/L
2020-06-1135833672001SE10.40 pCi/L
2020-08-3135897237005SE20.01 pCi/L
2020-09-0235897237005SE20.75 pCi/L
2020-11-1735897237001SE20.45 pCi/L
2021-03-1835858660001SE10.32 pCi/L
2021-04-22108997PND
2021-05-1324042044-010.20 pCi/L
2021-08-12117934P0.49 pCi/L
2021-08-16117934P0.87 pCi/L
2021-09-07117933P0.25 pCi/L
2021-12-21105200P0.18 pCi/L
2021-12-21108014P1.08 pCi/L
2021-12-21810-11087-4ND
2021-12-21810-11089-40.99 pCi/L
2021-12-21810-11091-41.16 pCi/L
2022-03-08810-93822-14.00 pCi/L
2022-03-09M4C0682-01ND
2022-03-14M3L0307-01ND
2022-05-16116904P0.17 pCi/L
2022-07-11810-53429-1ND
2022-10-26M4B0407-01ND
2022-11-15108996PND
2023-02-07109907P1.10 pCi/L
2023-02-08104174PND
2023-02-09104174PND
2023-04-04120026P0.64 pCi/L
2023-04-05113362P1.03 pCi/L
2023-04-06113362PND
2023-07-31116534PND
2023-08-02113359PND
2023-11-2071641701ND
2023-11-2071641801ND