Diquat
Roberts Creek Water District
Diquat is a herbicide used on potato crops and aquatic weeds.
6
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 |
|---|---|---|---|---|
| 2014 | ND | 1 | 0 | ND |
| 2015 | N/A | 0 | 0 | N/A |
| 2016 | ND | 3 | 0 | ND |
| 2017 | N/A | 0 | 0 | N/A |
| 2018 | N/A | 0 | 0 | N/A |
| 2019 | ND | 2 | 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 |
|---|---|---|
| 2014-01-29 | 401290301-S | ND |
| 2016-02-16 | 602160501 | ND |
| 2016-05-23 | 605231601-S | ND |
| 2016-09-20 | 609201501-S | ND |
| 2019-09-24 | 909240601-S | ND |
| 2019-12-17 | 912172201-S | ND |