Diquat
City of Hollister
Diquat is a herbicide used on potato crops and aquatic weeds.
16
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 | 6 | 0 | ND |
| 2015 | N/A | 0 | 0 | N/A |
| 2016 | ND | 5 | 0 | ND |
| 2017 | ND | 5 | 0 | ND |
| 2018 | N/A | 0 | 0 | N/A |
| 2019 | N/A | 0 | 0 | N/A |
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 |
|---|---|---|
| 2014-03-25 | 1610-001-1635 | ND |
| 2014-03-25 | 1610-002-1700 | ND |
| 2014-03-25 | 1610-005-1540 | ND |
| 2014-03-25 | 1610-006-1425 | ND |
| 2014-03-25 | 1610-007-1445 | ND |
| 2014-03-25 | 1610-009-1555 | ND |
| 2016-12-14 | 1610-001-0952 | ND |
| 2016-12-14 | 1610-002-1013 | ND |
| 2016-12-14 | 1610-005-0848 | ND |
| 2016-12-14 | 1610-006-1105 | ND |
| 2016-12-14 | 1610-007-1144 | ND |
| 2017-12-07 | 9590-001-1120 | ND |
| 2017-12-07 | 9590-002-1132 | ND |
| 2017-12-07 | 9590-005-1048 | ND |
| 2017-12-07 | 9590-006-0950 | ND |
| 2017-12-07 | 9590-007-1014 | ND |