Know Your Environment. Protect Your Health.

Uranium

CTWC - Shoreline Region-Guilford System

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.

 

22

Samples

0

Samples exceeding legal limit (MCL)

1

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018ND90ND
20190.14 pCi/L51ND - 0.70 pCi/L
2020N/A00N/A
2021N/A00N/A
2022ND80ND
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
2018-09-12U 200506116ND
2018-09-12U 200506324ND
2018-09-12U 200506117ND
2018-09-13U 200505275ND
2018-09-13U 200505276ND
2018-09-13U 200505266ND
2018-09-27U 200507057ND
2018-09-27U 200507059ND
2018-09-27U 200507058ND
2019-01-30U 200520055ND
2019-07-10U 200539998ND
2019-07-16U 200541091ND
2019-09-17U 2005492370.70 pCi/L
2019-09-18U 200549471ND
2022-08-15CM05637ND
2022-08-15CM05635ND
2022-08-15CM05636ND
2022-08-16CM06936ND
2022-08-16CM06935ND
2022-08-16CM06934ND
2022-08-16CM06910ND
2022-08-29CM17830ND