Diquat
City of Petaluma
Diquat is a herbicide used on potato crops and aquatic weeds.
15
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 | 1 | 0 | ND |
| 2015 | ND | 3 | 0 | ND |
| 2016 | ND | 4 | 0 | ND |
| 2017 | N/A | 0 | 0 | N/A |
| 2018 | ND | 4 | 0 | ND |
| 2019 | ND | 3 | 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 |
|---|---|---|
| 2014-09-16 | 5867-012-1330 | ND |
| 2015-03-19 | 1610-057-1400 | ND |
| 2015-06-18 | 1610-031-1300 | ND |
| 2015-09-28 | 1610-032-1100 | ND |
| 2016-03-09 | 1610-026-1045 | ND |
| 2016-03-09 | 1610-027-1105 | ND |
| 2016-06-22 | 1610-028-1100 | ND |
| 2016-12-07 | 1610-055-1220 | ND |
| 2018-03-14 | 1644-012-0900 | ND |
| 2018-06-06 | 1610-031-1020 | ND |
| 2018-06-06 | 1610-057-1130 | ND |
| 2018-09-13 | 1610-032-1130 | ND |
| 2019-03-13 | 1610-026-1008 | ND |
| 2019-03-13 | 1610-027-0910 | ND |
| 2019-03-13 | 1610-055-1108 | ND |