Know Your Environment. Protect Your Health.

Arsenic

Lake Margaret Water System

Arsenic is a potent carcinogen and common contaminant in drinking water. Arsenic causes thousands of cases of cancer each year in the U.S. Click here to read more about arsenic.

 

45

Samples

6

Samples exceeding legal limit (MCL)

31

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018ND70ND
20192.84 ppb95ND - 18.0 ppb
2020N/A00N/A
20217.11 ppb11110.400 ppb - 16.0 ppb
20221.49 ppb98ND - 3.20 ppb
20236.76 ppb97ND - 19.2 ppb

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

EWG Health Guideline: 0.004 ppb

The EWG Health Guideline of 0.004 ppb for arsenic 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. This health guideline protects against cancer.

EPA Maximum Contaminant
Level (MCL): 10 ppb

The legal limit for arsenic, established in 2001, was based on costs for arsenic removal, as calculated at the time that the standard was set. This limit does not fully protect against the risk of cancer due to arsenic exposure.

ppb = parts per billion

All test results

Date Lab ID Result
2018-02-07ND
2018-02-07ND
2018-05-02ND
2018-09-11ND
2018-09-11ND
2018-11-07ND
2018-11-07ND
2019-02-06ND
2019-02-06ND
2019-05-012.50 ppb
2019-05-012.50 ppb
2019-07-1918.0 ppb
2019-09-041.30 ppb
2019-09-041.30 ppb
2019-11-05ND
2019-11-05ND
2021-02-0240711410.400 ppb
2021-02-0240711410.400 ppb
2021-06-02412204716.0 ppb
2021-08-0441512149.30 ppb
2021-08-0441512149.30 ppb
2021-09-0241805898.80 ppb
2021-09-0241805898.80 ppb
2021-10-07418674912.0 ppb
2021-10-07418674912.0 ppb
2021-11-0242021130.600 ppb
2021-11-0242021130.600 ppb
2022-02-0642462570.1000 ppb
2022-02-0642462570.1000 ppb
2022-05-0442822220.600 ppb
2022-05-0442822220.600 ppb
2022-09-0643598532.80 ppb
2022-09-0643598532.80 ppb
2022-10-0343605553.20 ppb
2022-10-034360556ND
2022-10-0343605553.20 ppb
2023-02-0644140660.200 ppb
2023-06-0744763189.40 ppb
2023-06-0744763189.40 ppb
2023-09-07452242019.2 ppb
2023-09-07452242019.2 ppb
2023-10-2645541551.70 ppb
2023-10-2645541551.70 ppb
2023-12-124569159ND
2023-12-124569159ND