Know Your Environment. Protect Your Health.

Diquat

City of Caldwell

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

 

26

Samples

0

Samples exceeding legal limit (MCL)

0

Samples exceeding
health guidelines

Testing results - average by year

 
YearAverage resultSamples takenDetectionsRange of results
2018N/A00N/A
2019ND90ND
2020N/A00N/A
2021ND50ND
2022ND120ND
2023N/A00N/A

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
2019-08-06S1938597ND
2019-08-06S1938599ND
2019-08-06S1938601ND
2019-08-06S1938594ND
2019-08-06S1938591ND
2019-08-06S1938593ND
2019-08-19S1941181ND
2019-08-19S1941172ND
2019-08-19S1941179ND
2021-06-30S2132702ND
2021-10-28S2158342ND
2021-10-28S2158341ND
2021-10-28S2158343ND
2021-11-15S2162154ND
2022-06-29S2231081ND
2022-07-06S2231994ND
2022-07-06S2231993ND
2022-07-06S2232001ND
2022-07-13S2233509ND
2022-10-12S2251056ND
2022-10-12S2251055ND
2022-10-12S2251041ND
2022-10-12S2251030ND
2022-10-19S2252265ND
2022-10-19S2252264ND
2022-10-19S2252266ND