Know Your Environment. Protect Your Health.

Uranium

Castle Mountain Creeks Owners Association

Uranium is a known human carcinogen. The federal legal limit for uranium is set at 30 micrograms per liter (corresponding to parts per billion), but utilities can also report uranium in picocuries per liter (pCi/L), which is a measure of radioactivity in water. EWG translated all uranium results to pCi/L using a conversion factor developed by the EPA. With this conversion approach, the limit of 30 ppb corresponds to 20 pCi/L. Drinking water with this much uranium would cause more than 4.6 cancer cases in a population of 100,000. California set a public health goal for uranium of 0.43 pCi/L. Read More.

Multiple forms of uranium can be detected in water, including uranium-234, uranium-235 and uranium-238. Uranium-234 is the most toxic form of uranium for human health.

 

12

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018N/A00N/A
2019N/A00N/A
2020ND40ND
2021ND40ND
2022ND40ND
2023N/A00N/A

pCi/L = picocuries per liter

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 0.43 pCi/L

The EWG Health Guideline of 0.43 pCi/L for uranium was defined by the California Office of Environmental Health Hazard Assessment as a public health goal, the level of a drinking water contaminant that does not pose a significant health risk. Three most common uranium isotopes are U-234, U-235 and U-238. All isotopes of uranium are radioactive, and the total radioactivity depends on the ratio of isotopes. This health guideline protects against cancer.

EPA Maximum Contaminant
Level (MCL): 20 pCi/L

pCi/L = picocuries per liter

All test results

Date Lab ID Result
2020-03-03R2009366ND
2020-05-13R2021731ND
2020-08-24R2041261ND
2020-12-08R2061672ND
2021-01-08R2101074ND
2021-04-22R2118982ND
2021-07-28R2138304ND
2021-10-26R2157582ND
2022-03-14R2211963ND
2022-04-06R2216003ND
2022-09-15R2246108ND
2022-12-22R2262581ND