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EWG's Tap Water Database — 2019 UPDATE

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Uranium

Los Angeles County WW District 4 & 34-Lancaster

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.

 

49

Samples

0

Samples exceeding legal limit (MCL)

14

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20120.16 pCi/L203ND - 1.23 pCi/L
20133.71 pCi/L43ND - 6.71 pCi/L
20140.58 pCi/L133ND - 4.28 pCi/L
20150.88 pCi/L72ND - 4.99 pCi/L
20162.84 pCi/L53ND - 6.66 pCi/L
2017N/A00N/A

pCi/L = picocuries per liter

State and national drinking water standards and health guidelines

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
2012-01-245442-002-0842ND
2012-01-245442-053-0903ND
2012-01-245442-054-0937ND
2012-04-125442-053-1030ND
2012-04-125442-054-1015ND
2012-04-305442-055-1130ND
2012-06-135442-069-1030ND
2012-06-215442-011-10420.92 pCi/L
2012-07-265442-016-09301.23 pCi/L
2012-07-315442-053-1043ND
2012-08-085442-055-1157ND
2012-08-085442-053-0857ND
2012-08-085442-054-0903ND
2012-09-055442-040-0928ND
2012-09-115442-048-10510.98 pCi/L
2012-09-115442-054-1019ND
2012-09-115442-053-0940ND
2012-11-085442-055-1159ND
2012-12-185442-053-1040ND
2012-12-185442-054-1105ND
2013-05-145442-023-08403.23 pCi/L
2013-07-295442-037-0951ND
2013-10-215442-026-10206.71 pCi/L
2013-12-165442-026-09554.90 pCi/L
2014-02-195442-069-1022ND
2014-02-195442-070-1004ND
2014-02-205442-067-1100ND
2014-02-255442-041-08504.28 pCi/L
2014-02-255442-035-0924ND
2014-05-135442-011-1035ND
2014-05-145442-036-09241.48 pCi/L
2014-05-285442-063-0834ND
2014-05-285442-071-1000ND
2014-06-245442-071-0936ND
2014-06-255442-063-0917ND
2014-08-255442-028-0925ND
2014-11-175442-062-09051.84 pCi/L
2015-02-045442-016-11331.15 pCi/L
2015-03-045442-053-0910ND
2015-03-045442-054-0915ND
2015-03-125442-055-1000ND
2015-05-055442-040-0943ND
2015-05-055442-048-0910ND
2015-07-075442-045-09384.99 pCi/L
2016-03-285442-067-0856ND
2016-06-285442-037-1132ND
2016-10-175442-093-10551.77 pCi/L
2016-12-285442-041-09306.66 pCi/L
2016-12-285442-026-09205.79 pCi/L