Uranium

City of Tucson

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.

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121

Samples

Samples exceeding legal limit (MCL)

109

Samples exceeding
health guidelines

Testing results - average by year

Year	Average result	Samples taken	Detections	Range of results
2013	N/A	0	0	N/A
2014	N/A	0	0	N/A
2015	N/A	0	0	N/A
2016	2.04 pCi/L	96	89	ND - 15.20 pCi/L
2017	0.70 pCi/L	4	3	ND - 1.07 pCi/L
2018	N/A	0	0	N/A
2019	1.53 pCi/L	21	17	ND - 5.03 pCi/L

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
2016-01-11	RSE53723	1.88 pCi/L
2016-01-11	RSE53724	1.07 pCi/L
2016-01-11	RSE53725	1.21 pCi/L
2016-01-12	RSE53717	ND
2016-01-12	RSE53718	1.01 pCi/L
2016-01-12	RSE53719	0.67 pCi/L
2016-01-12	RSE53720	2.41 pCi/L
2016-01-13	RSE53727	1.74 pCi/L
2016-01-13	RSE53728	2.75 pCi/L
2016-01-13	RSE53729	1.07 pCi/L
2016-01-13	RSE53730	1.07 pCi/L
2016-01-14	RSE53732	9.18 pCi/L
2016-01-19	RSE53743	1.54 pCi/L
2016-01-19	RSE53744	1.14 pCi/L
2016-01-19	RSE53745	0.67 pCi/L
2016-01-19	RSE53746	1.01 pCi/L
2016-01-19	RSE53747	1.07 pCi/L
2016-01-20	RSE53748	0.80 pCi/L
2016-01-20	RSE53749	0.60 pCi/L
2016-01-20	RSE53750	ND
2016-01-20	RSE53751	4.42 pCi/L
2016-01-21	RSE53803	1.01 pCi/L
2016-01-21	RSE53804	1.68 pCi/L
2016-01-21	RSE53805	0.87 pCi/L
2016-01-21	RSE53806	1.27 pCi/L
2016-01-21	RSE53807	1.54 pCi/L
2016-01-25	RSE53824	0.94 pCi/L
2016-01-25	RSE53825	0.67 pCi/L
2016-01-25	RSE53826	0.87 pCi/L
2016-01-25	RSE53827	1.21 pCi/L
2016-01-25	RSE53828	1.01 pCi/L
2016-01-26	RSE53845	ND
2016-01-26	RSE53846	1.27 pCi/L
2016-01-26	RSE53847	ND
2016-01-27	RSE53852	1.94 pCi/L
2016-01-27	RSE53853	1.01 pCi/L
2016-01-27	RSE53854	1.27 pCi/L
2016-01-27	RSE53855	1.21 pCi/L
2016-01-28	RSE53848	1.74 pCi/L
2016-01-28	RSE53849	2.81 pCi/L
2016-01-28	RSE53850	4.29 pCi/L
2016-02-01	RSE53913	1.81 pCi/L
2016-02-01	RSE53914	4.36 pCi/L
2016-02-01	RSE53915	2.61 pCi/L
2016-02-02	RSE53916	1.54 pCi/L
2016-02-02	RSE53917	1.54 pCi/L
2016-02-02	RSE53918	2.48 pCi/L
2016-02-02	RSE53919	2.14 pCi/L
2016-02-03	RSE53960	0.60 pCi/L
2016-02-04	RSE53961	2.81 pCi/L
2016-02-04	RSE53962	2.35 pCi/L
2016-02-04	RSE53963	2.01 pCi/L
2016-02-08	RSE54005	1.01 pCi/L
2016-02-08	RSE54006	1.27 pCi/L
2016-02-08	RSE54007	3.82 pCi/L
2016-02-09	RSE54039	0.87 pCi/L
2016-02-09	RSE54040	1.27 pCi/L
2016-02-10	RSE54041	0.60 pCi/L
2016-02-10	RSE54042	0.60 pCi/L
2016-02-10	RSE54043	0.67 pCi/L
2016-02-11	RSE54044	2.08 pCi/L
2016-02-11	RSE54071	0.60 pCi/L
2016-02-11	RSE54072	1.01 pCi/L
2016-02-11	RSE54074	0.60 pCi/L
2016-02-11	RSE54075	0.80 pCi/L
2016-02-16	RSE54083	0.74 pCi/L
2016-02-16	RSE54084	1.21 pCi/L
2016-02-17	RSE54085	0.54 pCi/L
2016-02-17	RSE54086	0.54 pCi/L
2016-02-18	RSE54144	0.54 pCi/L
2016-02-19	RSE54140	0.67 pCi/L
2016-02-19	RSE54141	ND
2016-02-23	RSE54153	1.47 pCi/L
2016-02-23	RSE54154	1.21 pCi/L
2016-02-23	RSE54155	1.61 pCi/L
2016-02-24	RSE54182	0.87 pCi/L
2016-02-25	RSE54184	1.01 pCi/L
2016-02-29	RSE54197	2.61 pCi/L
2016-02-29	RSE54198	1.68 pCi/L
2016-03-02	RSE54220	1.00 pCi/L
2016-03-07	RSE54257	0.60 pCi/L
2016-04-27	RSE55071	8.31 pCi/L
2016-04-27	RSE55072	1.01 pCi/L
2016-04-28	RSE55069	ND
2016-05-05	RSE55070	0.74 pCi/L
2016-05-31	RSE55257	6.50 pCi/L
2016-05-31	RSE55258	9.90 pCi/L
2016-06-14	RSE55341	ND
2016-06-16	RSE55363	3.00 pCi/L
2016-07-20	RSE55651	13.10 pCi/L
2016-07-20	RSE55652	9.50 pCi/L
2016-07-26	RSE55734	0.80 pCi/L
2016-08-25	RSE56050	7.50 pCi/L
2016-08-30	RSE56051	1.14 pCi/L
2016-10-04	RSE56340	1.20 pCi/L
2016-10-12	RSE56447	15.20 pCi/L
2017-08-28	RSE59034	0.67 pCi/L
2017-08-28	RSE59035	1.07 pCi/L
2017-08-28	RSE9035	1.07 pCi/L
2017-08-29	RSE59036	ND
2019-03-19	RSE61951	3.22 pCi/L
2019-04-01	L190499-06-06251	2.35 pCi/L
2019-04-15	L190597-01-06251	0.74 pCi/L
2019-04-25	L190648-01-06251	1.88 pCi/L
2019-04-30	L190670-01-06251	ND
2019-05-01	L190678-02-06251	1.21 pCi/L
2019-05-01	L190678-03-06251	0.87 pCi/L
2019-05-06	L190704-03-06251	0.80 pCi/L
2019-05-07	L190712-03-07081	1.07 pCi/L
2019-05-14	L190748-01-07081	3.42 pCi/L
2019-05-15	L190761-01-07081	2.35 pCi/L
2019-05-15	L190761-03-07081	1.21 pCi/L
2019-06-03	L190837-02-07081	ND
2019-06-03	L190837-03-07081	1.07 pCi/L
2019-06-04	L190851-04-07090	1.01 pCi/L
2019-06-27	L190983-01-08131	ND
2019-08-20	L191266-02-10031	1.14 pCi/L
2019-09-10	L191409-01-10031	5.03 pCi/L
2019-09-11	L191425-01-10041	0.60 pCi/L
2019-11-08	L191758-01-01030	4.09 pCi/L
2019-11-20	L191829-01-01030	ND