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EWG's Tap Water Database — 2021 UPDATE

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Diquat

Shannon

Diquat is a herbicide used on potato crops and aquatic weeds.

 

8

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND50ND
2015ND10ND
2016N/A00N/A
2017ND20ND
2018N/A00N/A
2019N/A00N/A

ppb = parts per billion

State and national drinking water standards and health guidelines

EWG Health Guideline 6 ppb

The EWG Health Guideline of 6 ppb for diquat 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 cataracts.

EPA Maximum Contaminant
Level (MCL) 20 ppb

The legal limit for diquat, established in 1992, was based on a toxicity study in laboratory animals conducted in the 1980s.

ppb = parts per billion

All test results

Date Lab ID Result
2014-01-14SA40214-01_01ND
2014-01-28SA40652-01_01ND
2014-06-11SF40601-01_01ND
2014-08-12SH40838-01_01ND
2014-11-19SK40651-01_01ND
2015-01-27SA50696-01_01ND
2017-02-2117B0470-01_01ND
2017-03-0117C0022-01_01ND