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EWG's Tap Water Database — 2021 UPDATE

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Diquat

Houma Water Treatment Service Area

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

 

18

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2014ND20ND
2015ND40ND
2016ND40ND
2017ND40ND
2018N/A00N/A
2019ND40ND

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
2014-02-24AD89295ND
2014-02-24AD89295ND
2015-06-0835192498003ND
2015-06-0835192498003ND
2015-10-1235212325001ND
2015-10-1235212325001ND
2016-03-1535234393004ND
2016-03-1535234393004ND
2016-11-1435277515004ND
2016-11-1435277515004ND
2017-02-1435295627002ND
2017-02-1435295627002ND
2017-11-0135345509001ND
2017-11-0135345509001ND
2019-02-1835449356001ND
2019-02-1835449356001ND
2019-08-2835494058001ND
2019-08-2835494058001ND