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EWG's Tap Water Database — 2019 UPDATE

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Radium, combined (-226 & -228)

City of Phoenix

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.

 

39

Samples

0

Samples exceeding legal limit (MCL)

4

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.10 pCi/L41ND - 0.40 pCi/L
20130.08 pCi/L101ND - 0.80 pCi/L
20140.13 pCi/L242ND - 2.40 pCi/L
2015ND10ND
2016N/A00N/A
2017N/A00N/A

pCi/L = picocuries per liter

State and national drinking water standards and health guidelines

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
2012-03-15RSE43752ND
2012-07-25RSE44575ND
2012-10-01RSE450210.40 pCi/L
2012-11-07RSE45276ND
2013-01-02RSE45543ND
2013-02-05RSE45695ND
2013-02-05RSE45694ND
2013-04-02RSE46186ND
2013-04-16RSE46248ND
2013-04-16RSE46267ND
2013-07-17RSE46897ND
2013-07-23RSE46963ND
2013-10-21RSE47656ND
2013-10-24RSE477220.80 pCi/L
2014-01-06RSE48199ND
2014-01-06RSE48198ND
2014-01-06RSE48176ND
2014-01-07RSE48193ND
2014-01-07RSE48192ND
2014-01-08RSE48221ND
2014-01-08RSE48220ND
2014-01-14RSE48244ND
2014-01-14RSE48243ND
2014-01-15RSE48259ND
2014-01-15RSE48245ND
2014-01-16RSE48264ND
2014-01-16RSE48260ND
2014-01-21RSE48286ND
2014-01-21RSE48287ND
2014-01-22RSE48364ND
2014-01-23RSE483632.40 pCi/L
2014-01-23RSE48362ND
2014-02-18RSE48512ND
2014-02-18RSE48511ND
2014-02-19RSE48544ND
2014-02-26RSE48610ND
2014-04-07RSE489690.70 pCi/L
2014-11-07RSE50543ND
2015-02-03RSE51137ND