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EWG's Tap Water Database — 2021 UPDATE

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Diquat

Douglas, City Of

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

 

10

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014N/A00N/A
2015N/A00N/A
2016ND60ND
2017N/A00N/A
2018ND40ND
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
2016-08-11C16080512-001GND
2016-08-11C16080512-002GND
2016-08-11C16080512-003GND
2016-08-30C16081118-001END
2016-08-30C16081118-002END
2016-08-30C16081118-003END
2018-06-27C18060982-002DND
2018-06-27C18060982-001DND
2018-08-21C18080796-001GND
2018-08-21C18080796-002GND