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EWG's Tap Water Database — 2019 UPDATE

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Diquat

Frostproof, City of

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

 

12

Samples

0

Samples exceeding legal limit (MCL)

2

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2012N/A00N/A
2013N/A00N/A
2014ND60ND
2015N/A00N/A
2016N/A00N/A
20172.53 ppb62ND - 7.60 ppb

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 Result
2014-08-03ND
2014-08-03ND
2014-08-03ND
2014-11-09ND
2014-11-09ND
2014-11-09ND
2017-09-26ND
2017-09-26ND
2017-09-26ND
2017-12-277.60 ppb
2017-12-277.60 ppb
2017-12-27ND