Diquat
Monticello Water Department
Diquat is a herbicide used on potato crops and aquatic weeds.
24
Samples
0
Samples exceeding legal limit (MCL)
0
Samples exceeding
health guidelines
Testing results - average by year
| Year | Average result | Samples taken | Detections | Range of results |
|---|---|---|---|---|
| 2013 | N/A | 0 | 0 | N/A |
| 2014 | ND | 8 | 0 | ND |
| 2015 | ND | 1 | 0 | ND |
| 2016 | ND | 3 | 0 | ND |
| 2017 | ND | 8 | 0 | ND |
| 2018 | N/A | 0 | 0 | N/A |
| 2019 | ND | 4 | 0 | ND |
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 |
|---|---|---|
| 2014-07-14 | 14198008708 | ND |
| 2014-07-14 | 14198008608 | ND |
| 2014-09-30 | 14275001508 | ND |
| 2014-09-30 | 14275001608 | ND |
| 2014-11-03 | 14310001908 | ND |
| 2014-11-03 | 14310002208 | ND |
| 2014-11-03 | 14310002108 | ND |
| 2014-11-03 | 14310002008 | ND |
| 2015-08-03 | 15218000308 | ND |
| 2016-01-20 | 16025000208 | ND |
| 2016-05-03 | 16126016408 | ND |
| 2016-05-03 | 16126016308 | ND |
| 2017-07-31 | 17215005406 | ND |
| 2017-07-31 | 17215005506 | ND |
| 2017-07-31 | 17215005206 | ND |
| 2017-07-31 | 17215005306 | ND |
| 2017-11-06 | 17312000508 | ND |
| 2017-11-06 | 17312000308 | ND |
| 2017-11-06 | 17312000408 | ND |
| 2017-11-06 | 17312000608 | ND |
| 2019-02-25 | 4210148 | ND |
| 2019-03-04 | 4217027 | ND |
| 2019-04-30 | 4281319 | ND |
| 2019-04-30 | 4280290 | ND |