Know Your Environment. Protect Your Health.

Radium, combined (-226 and -228)

Town of Clayton Water System

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.

 

96

Samples

0

Samples exceeding legal limit (MCL)

38

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
20180.35 pCi/L237ND - 1.96 pCi/L
20190.40 pCi/L169ND - 0.85 pCi/L
20200.37 pCi/L156ND - 1.43 pCi/L
20210.40 pCi/L126ND - 1.17 pCi/L
20220.23 pCi/L153ND - 1.76 pCi/L
20230.42 pCi/L157ND - 1.94 pCi/L

pCi/L = picocuries per liter

State, National, and Health Guidelines for Drinking Water

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
2018-04-050.76 pCi/L
2018-04-052020625-REPLACEMENT WELL #10.71 pCi/L
2018-04-05202069-WELL #3: RAW WATER0.81 pCi/L
2018-05-0835391166002ND
2018-05-082020414-MAIN STATION WTF (01G)ND
2018-05-08202048-RAW WATER: WELL #2ND
2018-05-082020527-BRIDGE ST. WTP (2G-5G,1.16 pCi/L
2018-05-082020529-FIRE DEPT HEADQUARTERS0.80 pCi/L
2018-05-08353911660011.96 pCi/L
2018-05-08353911660011.96 pCi/L
2018-05-0835391166002ND
2018-08-0135408219001ND
2018-08-012020218-ALL STAR DAIRYND
2018-08-0135408219001ND
2018-08-0135408219001ND
2018-08-0135408219001ND
2018-08-012020519-2 WHITEHEAD RD.ND
2018-08-01202054-WELL #5 PUMPHOUSEND
2018-08-01202055-POINT OF ENTRY POST TREND
2018-11-2035432700002ND
2018-11-2035432700002ND
2018-11-20202054-WELL 2 SOURCE WATER TAPND
2018-11-20202041-RAW WATER: WELL #1ND
2019-02-132020527-38 FELTON ST. (BROOKSBND
2019-02-132020427-WELL #2ND
2019-02-1335449378001ND
2019-02-1335449378001ND
2019-05-17202048-RAW: WELL 4ND
2019-05-17354708820020.54 pCi/L
2019-05-172020225-WELL #50.54 pCi/L
2019-05-17354708820020.54 pCi/L
2019-08-15354911390010.85 pCi/L
2019-08-15202026-LINCOLN NORTHND
2019-08-152020512-PUMP STA. WOODSIDE RD.0.85 pCi/L
2019-08-15354911390010.85 pCi/L
2019-11-132020428-SOUTH ST. GP WELL0.74 pCi/L
2019-11-13202017-BALDWIN POND WTP - FININD
2019-11-13355123950010.74 pCi/L
2019-11-13355123950010.74 pCi/L
2020-02-12202167-MCKEON TREATMENT PLANTND
2020-02-12202147-POINT OF ENTRY POST TRE0.84 pCi/L
2020-02-12355308170010.84 pCi/L
2020-04-142021524-WELL #4 AND #5ND
2020-04-142021420-POINT OF ENTRYND
2020-04-14355441640011.43 pCi/L
2020-04-1435544167001ND
2020-04-14202154-46 EDWARD DRIVE - 1ST W1.43 pCi/L
2020-04-142021615-WELL #6ND
2020-07-01202167-MCKEON TREATMENT PLANTND
2020-07-0135560318002ND
2020-07-01202167-TREATED: SALMON BROOKND
2020-11-05355902180010.51 pCi/L
2020-11-052021413-FINISHED: HARBOR TRACE0.51 pCi/L
2020-11-052021616-CHERYL ANN DRIVEND
2021-03-11356199910010.94 pCi/L
2021-03-1120211026-TRINITY WELLFIELD WTPND
2021-03-112021112-RESIDENCE - 139 FENNO0.94 pCi/L
2021-05-1335635179001ND
2021-05-1320211019-WELL #2ND
2021-05-132021106-HAPPY HOLLOW REPL. WELND
2021-08-0320211011-RESERVOIRS POINT OF E1.17 pCi/L
2021-08-0320211117-WELL #3 & WELL #4ND
2021-08-03356551100011.17 pCi/L
2021-11-15356782360010.28 pCi/L
2021-11-1520211116-TRAINING FIELD WELL (ND
2021-11-152021127-TREATED: WELL #1 - CHU0.28 pCi/L
2022-02-092022824-ELM BANK PS-FINISHED (ND
2022-02-0935696752001ND
2022-02-09202288-RAW WATER #6.4 HOME FARND
2022-06-0135722180002ND
2022-06-012022719-POINT OF ENTRY POST TRND
2022-06-012022926-WELLS #3,#4 (01G,02G)ND
2022-08-15202296-POINT OF ENTRY POST TREND
2022-08-15202296-WELL 17A WATER TREATMENND
2022-08-1535741185002ND
2022-09-15357475180011.76 pCi/L
2022-09-152022713-RAW WATER #6.3 HOME FA1.15 pCi/L
2022-09-15202283-TREATED: WACHUSETT ST.0.61 pCi/L
2022-11-0935760462001ND
2022-11-092022913-RAW WATER: WELL #1 JERND
2022-11-092022914-PATTON TRAIN A 50% VESND
2023-02-22202343-WELLS #1,#2 (01G,02G)ND
2023-02-22202359-WELL #3 PUMPHOUSE (AFTE0.45 pCi/L
2023-02-22357830960010.45 pCi/L
2023-03-132023510-1099 HINGHAM STREET0.77 pCi/L
2023-03-132023615-WELL #2 SOURCE TAPND
2023-03-13357867830010.77 pCi/L
2023-04-1335792647001ND
2023-04-13202353-MAIN ST. GP WELL #1ND
2023-04-13202365-GP WELL # 4ND
2023-07-2735817957001ND
2023-07-272023412-SPRINGVALE WELL #3A-RAND
2023-07-27202359-WELL #5 PUMPHOUSEND
2023-10-24358374750031.94 pCi/L
2023-10-24202353-POINT OF ENTRY0.63 pCi/L
2023-10-24202367-HAPPY HOLLOW PFAS LAG V1.31 pCi/L