Diquat
City of Daly City
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 | N/A | 0 | 0 | N/A |
| 2015 | ND | 2 | 0 | ND |
| 2016 | ND | 9 | 0 | ND |
| 2017 | N/A | 0 | 0 | N/A |
| 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 |
|---|---|---|
| 2015-08-04 | 1610-010-1120 | ND |
| 2015-12-09 | 5867-013-1045 | ND |
| 2016-01-20 | 1610-004-1040 | ND |
| 2016-02-03 | 1610-010-1045 | ND |
| 2016-02-03 | 1610-011-0950 | ND |
| 2016-02-03 | 1610-013-0815 | ND |
| 2016-02-03 | 1610-018-1130 | ND |
| 2016-05-04 | 1610-010-0830 | ND |
| 2016-05-04 | 1610-011-0805 | ND |
| 2016-05-04 | 1610-013-0640 | ND |
| 2016-05-04 | 1610-018-0845 | ND |
| 2019-01-09 | 1610-010-0920 | ND |
| 2019-01-09 | 1610-018-0640 | ND |
| 2019-02-14 | 1610-010-0830 | ND |
| 2019-02-14 | 1610-018-0800 | ND |