Know Your Environment. Protect Your Health.

Diquat

Guilford Water Authority

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

 

20

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018ND30ND
2019ND10ND
2020ND60ND
2021N/A00N/A
2022N/A00N/A
2023ND100ND

ppb = parts per billion

State, National, and Health Guidelines for Drinking Water

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
2018-05-298055384-01ND
2018-09-048091925-01ND
2018-12-118122846-01ND
2019-03-059032320-01ND
2020-06-0922559579.00ND
2020-06-0922559549.00ND
2020-06-0922559519.00ND
2020-09-0923136521.00ND
2020-09-0923136547.00ND
2020-09-0923136577.00ND
2023-05-1729053245.00ND
2023-05-1729053261.00ND
2023-05-1729053277.00ND
2023-05-2429053446.00ND
2023-05-2429053413.00ND
2023-07-1829651137.00ND
2023-07-1829651228.00ND
2023-07-1829651149.00ND
2023-08-0129651202.00ND
2023-08-2929651294.00ND